A lithium ion battery state of health monitoring method and device based on ultrasonic damping

Abstract

This invention relates to the field of battery state monitoring technology, and particularly to a method and apparatus for monitoring the health status of lithium-ion batteries based on ultrasonic damping. The method includes: acquiring the internal structural parameters and mechanical property parameters of the lithium-ion battery to be monitored; obtaining the energy gap transmittance of ultrasonic waves inside the lithium-ion battery based on the internal structural parameters and mechanical property parameters; emitting an ultrasonic incident signal of a preset frequency to a first side of the lithium-ion battery and acquiring the ultrasonic transmission signal on a second side of the lithium-ion battery to obtain the incident signal amplitude and the transmission signal amplitude; obtaining the damping attenuation coefficient of the ultrasonic signal inside the lithium-ion battery based on the energy gap transmittance, the incident signal amplitude, and the transmission signal amplitude; and obtaining the health status parameters of the lithium-ion battery based on the damping attenuation coefficient and a pre-constructed battery health status parameter fitting model. The above technical solution can eliminate interference from external factors and improve the accuracy and stability of the monitoring results.

Description

Technical Field

[0001] This invention relates to the field of battery status monitoring technology, and in particular to a method and apparatus for monitoring the health status of lithium-ion batteries based on ultrasonic damping. Background Technology

[0002] Lithium-ion batteries are widely used in new energy vehicles, energy storage systems and other fields. Their health status directly affects their safety and lifespan. Therefore, it is crucial to monitor them quickly, accurately and stably.

[0003] In existing technologies, the direct probe detection method using transient pulse signals is mainly used to monitor the health status of lithium-ion batteries. However, this method typically only performs a simple analysis of the propagation time and signal amplitude changes of ultrasound inside the battery. The detection results are easily affected by surface dissipation, energy gap dissipation, and external environmental factors and operational procedures. As a result, the obtained health status parameters lack a direct correlation with the internal electrochemical changes of the battery, leading to low detection accuracy and poor stability, making it difficult to meet the needs of large-scale in-situ detection in industrial scenarios.

[0004] Therefore, those skilled in the art urgently need to develop a new technical solution to address the above problems. Summary of the Invention

[0005] This invention provides a method and device for monitoring the health status of lithium-ion batteries based on ultrasonic damping, which can eliminate interference from external factors and improve the accuracy and stability of monitoring results.

[0006] In a first aspect, embodiments of the present invention provide a method for monitoring the health status of a lithium-ion battery based on ultrasonic damping, comprising: The internal structural parameters and mechanical property parameters of the lithium-ion battery to be monitored are obtained. The internal structural parameters include the number of separator layers and the thickness of a single separator layer. The mechanical property parameters include Lamé first parameters and Lamé second parameters. Based on the internal structural parameters and mechanical property parameters, the energy gap transmittance of ultrasonic waves inside the lithium-ion battery is obtained. An ultrasonic incident signal of a preset frequency is emitted toward the first side of the lithium-ion battery, and an ultrasonic transmission signal is collected at the second side of the lithium-ion battery to obtain the incident signal amplitude and the transmission signal amplitude. Based on the energy gap transmittance, incident signal amplitude, and transmitted signal amplitude, the damping attenuation coefficient of the ultrasonic signal inside the lithium-ion battery is obtained. Based on the damping attenuation coefficient and the pre-built battery health state parameter fitting model, the health state parameters of the lithium-ion battery are obtained.

[0007] Secondly, embodiments of the present invention provide a lithium-ion battery health status monitoring device based on ultrasonic damping, comprising: The battery parameter acquisition module acquires the internal structural parameters and mechanical property parameters of the lithium-ion battery to be monitored. The internal structural parameters include the number of separator layers and the thickness of a single separator layer. The mechanical property parameters include Lamé first parameters and Lamé second parameters. The transmittance acquisition module is connected to the battery parameter acquisition module and obtains the energy gap transmittance of ultrasonic waves inside the lithium-ion battery based on the internal structural parameters and mechanical property parameters. An ultrasonic detection module, connected to the transmittance acquisition module, emits an ultrasonic incident signal of a preset frequency toward the first side of the lithium-ion battery and acquires an ultrasonic transmission signal at the second side of the lithium-ion battery to obtain the incident signal amplitude and the transmission signal amplitude. The attenuation coefficient acquisition module is connected to the ultrasonic detection module. Based on the energy gap transmittance, the incident signal amplitude, and the transmitted signal amplitude, it obtains the damping attenuation coefficient of the ultrasonic signal inside the lithium-ion battery. The health status monitoring module is connected to the attenuation coefficient acquisition module. Based on the damping attenuation coefficient and a pre-built battery health status parameter fitting model, the health status parameters of the lithium-ion battery are obtained.

[0008] Thirdly, the present invention provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, it implements the method described in the first aspect of the present invention.

[0009] Fourthly, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, causes the computer to perform the method described in the first aspect of the present invention.

[0010] This invention provides a method and device for monitoring the health status of lithium-ion batteries based on ultrasonic damping. By acquiring the internal structural and mechanical property parameters of the lithium-ion battery, the energy gap transmittance of ultrasonic waves inside the battery is modeled and calculated. Based on this energy gap transmittance, combined with the incident and transmitted signal amplitudes of the ultrasonic waves within the lithium-ion battery, the damping attenuation coefficient of the ultrasonic signal inside the battery is obtained. The acquisition of the energy gap transmittance and damping attenuation coefficient is only related to the internal structural properties of the lithium-ion battery, eliminating interference factors such as surface dissipation, energy gap dissipation, and external environment and operational procedures. This allows the health status quantitative fitting model constructed based on the damping attenuation coefficient to establish an essential correlation with the internal properties of the battery, improving the stability and accuracy of the detection results. Compared with traditional transient pulse detection methods, this method has higher detection accuracy and repeatability, meeting the needs of large-scale, long-term in-situ monitoring in industrial scenarios such as new energy vehicles and energy storage systems. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a flowchart of a lithium-ion battery health status monitoring method based on ultrasonic damping, provided by an embodiment of the present invention. Figure 2 This is a structural diagram of a lithium-ion battery health status monitoring device based on ultrasonic damping, provided in an embodiment of the present invention. Figure 3 This is a schematic diagram of an ultrasonic testing system according to one embodiment; Figure 4 This is a schematic diagram of a microscopic analytical model according to one embodiment; Figure 5 This is a schematic diagram illustrating the dissipation mechanism during ultrasonic wave propagation according to an embodiment; Figure 6 This is a schematic diagram illustrating a method for monitoring the health status of a lithium-ion battery according to an embodiment. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0014] Please refer to Figure 1 This invention provides a method for monitoring the health status of lithium-ion batteries based on ultrasonic damping, the method comprising: Step 100: Obtain the internal structural parameters and mechanical property parameters of the lithium-ion battery to be monitored: Internal structural parameters include the number of diaphragm layers and the thickness of a single diaphragm layer; mechanical property parameters include Lamé first parameter and Lamé second parameter. Step 102: Based on the internal structural parameters and mechanical property parameters, obtain the energy gap transmittance of ultrasound inside the lithium-ion battery; Step 104: Emit an ultrasonic incident signal of a preset frequency to the first side of the lithium-ion battery, and collect the ultrasonic transmission signal on the second side of the lithium-ion battery to obtain the incident signal amplitude and the transmission signal amplitude. Step 106: Based on the energy gap transmittance, incident signal amplitude, and transmitted signal amplitude, obtain the damping attenuation coefficient of the ultrasonic signal inside the lithium-ion battery; Step 108: Based on the damping attenuation coefficient and the pre-built battery health state parameter fitting model, obtain the health state parameters of the lithium-ion battery.

[0015] In this embodiment, the internal structural parameters and mechanical property parameters of the lithium-ion battery under monitoring are obtained through image scanning and mechanical testing, respectively. The internal structural parameters include the positive and negative electrodes, the number of separator layers, and the thickness of each layer. The mechanical property parameters include the first parameter of the battery layer. Lamé's second parameter (Shear modulus), ultrasonic propagation speed , wave number Core mechanical properties and other key indicators. A microscopic analytical model of ultrasonic wave propagation within the lithium-ion battery's internal structure is established based on internal structural and mechanical property parameters. The energy gap transmittance, which is only relevant to changes within the battery, is extracted from the model and used in subsequent battery health assessments, addressing the issues of susceptibility to external interference, low consistency, and low accuracy in detection results. An ultrasonic wave of a preset frequency is emitted to the first side of the lithium-ion battery, and the transmitted signal is received at the second side, yielding the amplitudes of the incident and transmitted signals. A simple contact probe is used to perform the detection operation during ultrasonic signal transmission, replacing expensive ultrasonic imaging systems and addressing the problems of high cost and limited application scenarios for some detection equipment. Based on the energy gap transmittance, incident signal amplitude, and transmitted signal amplitude, the damping attenuation coefficient of the ultrasonic signal within the lithium-ion battery is obtained. The ultrasonic signal is a steady-state harmonic, used for in-situ ultrasonic testing of the lithium-ion battery. The core parameter of damping transmittance, the attenuation coefficient, is extracted through signal dimensionlessness, energy dissipation decomposition, and exponential fitting. A quantitative fitting model for battery health state is constructed based on the damping attenuation coefficient. Using measured data from multiple sets of batteries in different health states, the variation of the damping attenuation coefficient with battery cycle count and state of charge (SOC) is analyzed, establishing a quantitative relationship between the damping attenuation coefficient and the battery health state (SOH). Based on this quantitative relationship, accurate detection and evaluation of lithium-ion battery health state can be achieved, solving the technical problem of existing detection methods lacking a quantitative correlation between detection parameters and battery health state.

[0016] like Figure 6 As shown, this invention integrates microscopic analysis of the battery's internal structure with ultrasonic damping detection technology, innovating in terms of detection principle, signal type, and characteristic parameters. It avoids various shortcomings of existing ultrasonic detection methods, achieving accurate and stable detection of battery health status. It achieves technical effects such as stable and strong detection results, high accuracy, low detection cost, and simple operation. It can perform in-situ, rapid health status monitoring of lithium-ion batteries, adapting to the large-scale application needs of industrial scenarios, while providing reliable quantitative basis for battery safety early warning and lifespan prediction. It helps improve battery utilization efficiency and has broad promotional value and application prospects in lithium-ion battery application fields such as new energy vehicles and energy storage systems.

[0017] In one embodiment of the present invention, obtaining the internal structural parameters and mechanical property parameters of the lithium-ion battery to be monitored includes: Image scanning of lithium-ion batteries yields the number of separator layers and the thickness of a single separator layer; Mechanical tests were conducted on the lithium-ion battery to obtain the Lamé first parameter and the Lamé second parameter.

[0018] In this embodiment, nanoscale CT image scanning (resolution) is used. The internal structural parameters of lithium-ion batteries were determined using mechanical testing methods such as X-ray CT and electronic universal testing machines, providing fundamental data for subsequent ultrasonic propagation modeling. Based on the measured internal structural parameters, a microscopic analytical model of ultrasonic propagation considering the layered structure inside the battery was established using elastic wave propagation theory, realizing the essential physical correlation between ultrasonic signals and internal electrochemical changes in the battery. Specifically, nanoscale X-ray CT equipment was used to scan the internal structure of the lithium-ion battery, accurately determining the number of layers and the thickness of each layer of the positive and negative electrodes and separator. Mechanical testing was performed on the positive and negative electrode sheets and separator cells using an electronic universal testing machine to obtain the first Lamé parameter of the battery layers. Lamé's second parameter (Shear modulus), ultrasonic propagation speed , wave number By analyzing mechanical properties and other indicators, a complete set of battery structural parameters was obtained, providing comprehensive and accurate basic data for the establishment of a microscopic analytical model, thus ensuring the accuracy of the model and the scientific nature of the testing from the source.

[0019] In one embodiment of the present invention, the energy gap transmittance of ultrasound inside a lithium-ion battery is obtained based on internal structural parameters and mechanical property parameters, including: A mesoscopic analytical model is established based on internal structural parameters and mechanical property parameters. The mesoscopic analytical model is used to describe the transmission process of ultrasonic waves inside a lithium-ion battery. The first forward propagation complex coefficient of ultrasonic waves on the first side and the second forward propagation complex coefficient on the second side of the lithium-ion battery are obtained based on the microscopic analytical model. Based on the first and second forward propagation complex coefficients of the lithium-ion battery, the energy gap transmittance is obtained using the following formula:

[0020] in, For energy gap transmittance, The first forward propagation complex coefficient, This is the second forward propagation complex coefficient.

[0021] In this embodiment, the mesoscopic analytical model of ultrasonic wave propagation is constructed based on the layered structural characteristics of the battery's positive and negative electrodes and separator, as well as the mechanical properties of the battery layers, combined with the elastic wave propagation equation, interlayer displacement, and stress boundary conditions. The construction process of the mesoscopic analytical model is as follows: Figure 4As shown, during the model construction process, simple harmonic ultrasound in the frequency range of 0.5MHz-3.5MHz was also input into the model to simulate the correlation between ultrasound propagation and the internal structure and electrochemical properties of the battery. A microscopic model of ultrasound propagation considering the internal structure of the battery was established, realizing an essential correlation between the ultrasound signal and the electrochemical changes inside the battery. This model can accurately simulate the propagation law of ultrasound inside the battery, clarify the reasons for changes in the detection results, and provide a reliable theoretical calculation basis for the analysis of ultrasound transmission characteristics. This model can calculate the ultrasonic energy gap transmittance by constructing a global matrix. ,in, This represents the complex coefficient of ultrasonic wave propagation in the incident layer (layer 1) of the lithium-ion battery, i.e., the first complex coefficient of forward propagation. Let be the complex coefficient of the forward propagation of ultrasound in the cell's emitting layer (Nth layer), i.e., the second complex coefficient of forward propagation. These represent the magnitudes of the first and second forward propagation complex coefficients, respectively. Using this model to obtain the forward propagation complex coefficients on the first and second sides of the battery, we can quantitatively characterize the phase change and amplitude attenuation characteristics of ultrasound in the medium. This allows for accurate simulation of the propagation law of ultrasound within the battery, clearly reflecting the intrinsic relationship between ultrasonic damping (sound dissipation in the porous medium inside the battery) and changes in the battery's internal structure and electrochemical properties (lithium insertion / deintercalation at the positive and negative electrodes), thus helping to understand the reasons for changes in the detection results. The energy gap transmittance is calculated based on the forward propagation complex coefficients on both sides, allowing for the theoretical separation and quantification of the energy gap dissipation effects brought about by the battery's internal structure and materials (the dissipation mechanism during ultrasonic propagation is analyzed as follows). Figure 5 As shown in the figure, this method effectively eliminates interference from non-electrochemical factors such as surface coupling and external environment, making the calculation results more stable and physically meaningful. This approach eliminates the need to rely on empirical values ​​or simplified assumptions, improving the objectivity and accuracy of parameter calculations. It provides reliable intermediate parameters for the subsequent extraction of damping attenuation coefficients and accurate assessment of battery health, significantly enhancing the stability and accuracy of the overall monitoring method.

[0022] In one embodiment of the present invention, the damping attenuation coefficient of the ultrasonic signal inside the lithium-ion battery is calculated by the following formula:

[0023] in, The damping attenuation coefficient is... , The amplitude of the incident signal. The amplitude of the transmitted signal. For energy gap transmittance, The magnitude coefficients are the fitted values ​​of the exponential curve. ω is the incident wave angular frequency.

[0024] In this embodiment, the damping attenuation coefficient can be calculated using the ultrasonic damping transmittance, which is obtained by performing dimensionless processing on the detection signal. The ultrasonic damping transmittance is... It can be decomposed into , The amplitude of the incident signal. The amplitude of the transmitted signal. This represents the energy gap transmittance. Then, according to the formula... The damping attenuation coefficient was calculated. (This parameter is a core characteristic parameter reflecting the internal electrochemical changes of the battery.)

[0025] By combining the incident signal amplitude, transmitted signal amplitude, and energy gap transmittance to calculate the damping attenuation coefficient, the core characteristic parameters reflecting only the internal electrochemical properties of the battery can be accurately extracted from the measured ultrasonic signal. This calculation method uses amplitude ratio and energy gap transmittance for normalization, effectively eliminating interference factors such as surface dissipation, probe contact state, external environment, and operational procedures. This ensures that the damping attenuation coefficient is only related to health-related characteristics such as battery material aging and interface changes. Introducing the exponential fitting amplitude coefficient and incident wave angular frequency into the calculation further compensates for systematic errors in signal transmission, improving the accuracy and robustness of parameter extraction. The calculation process is logically rigorous and physically meaningful. The resulting damping attenuation coefficient exhibits high stability and strong anti-interference capability, providing reliable input for subsequent SOH quantification fitting models. This fundamentally improves the accuracy and repeatability of battery health status detection, meeting the needs of stable, accurate, and in-situ monitoring in industrial scenarios.

[0026] In one embodiment of the present invention, the health state parameters of the lithium-ion battery are obtained based on the damping attenuation coefficient and a pre-built battery health state parameter fitting model, including: The battery health state parameter fitting model is expressed by the following formula:

[0027] The intercept of the linear fit. The slope of the linear fit. Battery health status parameters; The damping attenuation coefficient is input into the battery health state parameter fitting model to obtain the output health state parameters.

[0028] In this embodiment, the quantitative relationship between the damping transmittance parameter and the battery health status is established by performing full-band ultrasonic testing on lithium-ion batteries in different health states. Data is collected at ≥60 equally spaced frequency points within a preset frequency range. First, the core parameter of damping transmittance (damping attenuation coefficient) is constructed. ) and battery health status parameters linear fitting model (in, The intercept of the linear fit. The slope of the linear fit, and the coefficient of determination R0. 2 ≥0.988, R 2 As an index characterizing the goodness of fit (the closer to 1, the higher the fitting accuracy), analysis... The variation pattern of battery cycle count, constructing Battery health status A quantitative fitting model has been developed, which transforms ultrasonic detection parameters into quantitative indicators of battery health status with a fitting error ≤5%, upgrading from qualitative judgment to quantitative assessment. By substituting the damping attenuation coefficient of the lithium-ion battery to be monitored into this model, accurate detection and assessment of the battery health status can be achieved. Simultaneously, quantitative basis can be provided for battery safety warnings and lifespan prediction based on parameter change trends. This linear fitting model has a simple structure and high computational efficiency, quickly outputting stable and reliable health status results, facilitating engineering implementation and real-time online monitoring. The model uses the damping attenuation coefficient as the core input, fully utilizing its characteristic of being related only to the internal electrochemical properties of the battery. This establishes a stable correspondence between health status parameters and essential states such as battery aging, material degradation, and interface changes, effectively avoiding detection bias caused by external interference. This approach establishes a clear quantitative mapping relationship between detection features and health status, solving the problem of traditional methods' difficulty in achieving quantitative assessment. It significantly improves the accuracy, consistency, and repeatability of monitoring results, meeting the practical needs of high-precision, stable, and in-situ monitoring of battery health status in industrial scenarios such as new energy vehicles and energy storage systems.

[0029] In one embodiment of the present invention, the method further includes: A battery state-of-charge (POC) parameter fitting model is constructed, which is expressed by the following formula:

[0030] The intercept of the linear fit. The slope of the linear fit. These are the battery state of charge parameters; The damping attenuation coefficient is input into the battery state-of-charge parameter fitting model to obtain the output state-of-charge parameters.

[0031] In this embodiment, similarly, the quantitative relationship between the damping transmittance parameter and the battery state of charge parameter can also be established by performing full-band ultrasonic testing on lithium-ion batteries in different health states, selecting ≥60 equally spaced frequency points within a preset frequency range to collect data, and first constructing the core parameter of damping transmittance (damping attenuation coefficient). ) and battery state of charge parameters linear fitting model (where is the linear fit intercept, is the linear fit slope, and is the coefficient of determination R) 2 ≥0.988, R 2 As an index characterizing the goodness of fit (the closer to 1, the higher the fitting accuracy), analysis... The variation pattern of battery cycle count, constructing With battery state of charge parameters A quantitative fitting model is implemented, which transforms ultrasonic detection parameters into quantitative indicators of battery state of charge parameters, with a fitting error ≤5%, thus upgrading from qualitative judgment to quantitative evaluation. By substituting the damping attenuation coefficient of the lithium-ion battery to be monitored into this model, accurate detection and evaluation of the lithium-ion battery's state of charge can be achieved.

[0032] By constructing a battery state-of-charge (SOC) parameter fitting model and using the damping attenuation coefficient as a unified input feature to calculate the SOC parameters, joint monitoring of battery state of health (SOH) and state of charge (SOC) can be achieved simultaneously within the same detection process and feature extraction framework. This significantly improves detection efficiency and integration while reducing system complexity. The linear fitting model is computationally simple, responds quickly, and is suitable for online real-time monitoring scenarios, stably outputting high-precision SOC results. Using the damping attenuation coefficient as a unified input fully leverages its advantages of anti-interference and reflecting only internal electrochemical changes in the battery, ensuring that the SOC parameters are unaffected by external environment and operating conditions, thus improving the stability and consistency of monitoring results. This solution achieves multi-state parameter evaluation driven by a single feature, expanding the functional dimensions of battery state monitoring while ensuring detection accuracy and reliability. It can meet the practical needs of industrial scenarios such as new energy vehicles and energy storage systems for multi-state, high-precision, in-situ, and large-scale battery monitoring.

[0033] In one embodiment of the present invention, the ultrasonic wave of the preset frequency is a simple harmonic wave of 0.5MHz-3.5MHz.

[0034] In this embodiment, unlike the transient pulse signals used in existing technologies, a steady-state harmonic wave is used in the ultrasonic testing process, with a frequency range set at 0.5MHz-3.5MHz. This frequency band of steady-state harmonic waves exhibits strong stability when propagating inside the battery. Furthermore, a dedicated transducer probe is used (a 1MHz center frequency probe is used when the harmonic wave frequency range is 0.5MHz-1.75MHz, and a 2.25MHz center frequency probe is used when the harmonic wave frequency range is 1.75MHz-3.5MHz), employing a penetration measurement method. This effectively eliminates interference from external conditions such as environmental noise, probe pressure, and coupling agent type on the ultrasonic testing signal. This significantly improves the repeatability of the test results, and the testing process, combined with a battery cycle testing system, allows for simultaneous in-situ charging and discharging of the battery and ultrasonic testing. Additionally, a simple contact transducer probe combination is used to transmit and receive the steady-state harmonic wave. This can be combined with an arbitrary waveform generator and a digital phosphor oscilloscope to form an ultrasonic testing system (such as...). Figure 3 As shown, the system includes a waveform generator, a transmitting probe, a receiving probe, an oscilloscope, and a battery cycle testing system. It eliminates the need for expensive ultrasonic imaging equipment, reducing equipment costs to only 30% of traditional electrochemical detection methods. This significantly lowers equipment costs while enabling non-disassembly in-situ battery testing. It solves the problems of high cost and limited application scenarios of some existing testing equipment. The probe is easy to operate, signal processing and parameter fitting can be automated through software, the data processing flow is concise, and a single in-situ test takes less than 10 seconds, making it suitable for large-scale industrial applications.

[0035] Furthermore, this invention uses steady-state simple harmonic waves to replace transient pulse signals and extracts the damping attenuation coefficient that is only related to changes inside the battery. It eliminates the interference of external conditions on the detection results from two dimensions: signal type and characteristic parameters. The detection results have better repeatability and solve the technical problems of poor consistency and susceptibility to external factors in existing detection results. The ultrasonic detection accuracy can reach 99% and the repeatability error is less than 5%.

[0036] According to another embodiment, the present invention provides a lithium-ion battery health status monitoring device based on ultrasonic damping. Figure 2 A schematic block diagram of a lithium-ion battery health status monitoring device based on ultrasonic damping is shown. It is understood that this device can be implemented using any device, equipment, platform, or cluster of devices with computing and processing capabilities. Figure 2 As shown, the device includes: a battery parameter acquisition module 200, a transmittance acquisition module 202, an ultrasonic detection module 204, an attenuation coefficient acquisition module 206, and a health status monitoring module 208. The main functions of each component are as follows: The battery parameter acquisition module 200 acquires the internal structural parameters and mechanical property parameters of the lithium-ion battery to be monitored. The internal structural parameters include the number of separator layers and the thickness of a single separator layer. The mechanical property parameters include Lamé first parameters and Lamé second parameters. The transmittance acquisition module 202 is connected to the battery parameter acquisition module, and obtains the energy gap transmittance of ultrasonic waves inside the lithium-ion battery based on the internal structural parameters and mechanical property parameters. The ultrasonic detection module 204 is connected to the transmittance acquisition module. It emits an ultrasonic incident signal of a preset frequency to the first side of the lithium-ion battery and collects the ultrasonic transmission signal on the second side of the lithium-ion battery to obtain the incident signal amplitude and the transmission signal amplitude. The attenuation coefficient acquisition module 206 is connected to the ultrasonic detection module. Based on the energy gap transmittance, the incident signal amplitude, and the transmitted signal amplitude, it obtains the damping attenuation coefficient of the ultrasonic signal inside the lithium-ion battery. The health status monitoring module 208 is connected to the attenuation coefficient acquisition module. Based on the damping attenuation coefficient and the pre-built battery health status parameter fitting model, the health status parameters of the lithium-ion battery are obtained.

[0037] In this embodiment of the specification, the battery parameter acquisition module 200 can be used to perform step 100 in the above method embodiment, the transmittance acquisition module 202 can be used to perform step 102 in the above method embodiment, the ultrasonic detection module 204 can be used to perform step 104 in the above method embodiment, the attenuation coefficient acquisition module 206 can be used to perform step 106 in the above method embodiment, and the health status monitoring module 206 can be used to perform step 108 in the above method embodiment.

[0038] In one embodiment of this specification, obtaining the internal structural parameters and mechanical property parameters of the lithium-ion battery to be monitored includes: The lithium-ion battery was image scanned to obtain the number of separator layers and the thickness of a single separator layer; Mechanical tests were performed on the lithium-ion battery to obtain the Lamé first parameter and the Lamé second parameter.

[0039] In one embodiment of this specification, obtaining the energy gap transmittance of ultrasound within the lithium-ion battery based on the internal structural parameters and mechanical property parameters includes: A mesoscopic analytical model is established based on the internal structural parameters and mechanical property parameters. The mesoscopic analytical model is used to describe the transmission process of ultrasonic waves inside the lithium-ion battery. Based on the aforementioned microscopic analytical model, the first forward propagation complex coefficient of ultrasonic waves on the first side and the second forward propagation complex coefficient on the second side of the lithium-ion battery are obtained. Based on the first and second forward propagation complex coefficients of the lithium-ion battery, the energy gap transmittance is obtained using the following formula:

[0040] in, For energy gap transmittance, The first forward propagation complex coefficient, This is the second forward propagation complex coefficient.

[0041] In one embodiment of this specification, the damping attenuation coefficient of the ultrasonic signal inside the lithium-ion battery is calculated using the following formula:

[0042] in, The damping attenuation coefficient is... , The amplitude of the incident signal. The amplitude of the transmitted signal. For energy gap transmittance, The magnitude coefficients are the fitted values ​​of the exponential curve. ω is the incident wave angular frequency.

[0043] In one embodiment of this specification, obtaining the health state parameters of the lithium-ion battery based on the damping attenuation coefficient and a pre-built battery health state parameter fitting model includes: The battery health state parameter fitting model is expressed by the following formula:

[0044] The intercept of the linear fit. The slope of the linear fit. Battery health status parameters; The damping attenuation coefficient is input into the battery health state parameter fitting model to obtain the output health state parameters.

[0045] In one embodiment of this specification, the method further includes: A battery state-of-charge (POC) parameter fitting model is constructed, which is expressed by the following formula:

[0046] The intercept of the linear fit. The slope of the linear fit. These are the battery state of charge parameters; The damping attenuation coefficient is input into the battery state-of-charge parameter fitting model to obtain the output state-of-charge parameters.

[0047] In one embodiment of this specification, the preset frequency ultrasonic wave is a simple harmonic wave of 0.5MHz-3.5MHz.

[0048] According to another embodiment, an electronic device is also provided, including a memory and a processor, wherein executable code is stored in the memory, and when the processor executes the executable code, it implements a combination... Figure 1 The method.

[0049] In summary, the ultrasonic damping-based lithium-ion battery health status monitoring method and device provided by the present invention can bring the following beneficial effects: By integrating microscopic analysis of the battery's internal structure with ultrasonic damping detection technology, innovations are made in detection principles, signal types, and characteristic parameters, avoiding various shortcomings of existing ultrasonic detection methods and achieving accurate and stable detection of battery health status. Internal structural parameters of the battery are determined through CT scans and mechanical testing, providing precise basic data for the establishment of a microscopic model of ultrasonic wave propagation, ensuring the accuracy of the model and the scientific rigor of the detection from the outset. The microscopic model of ultrasonic wave propagation considering the battery's internal structure establishes an essential correlation between ultrasonic signals and electrochemical changes within the battery, accurately simulating the propagation law of ultrasound within the battery and clarifying the causes of changes in detection results. Steady-state simple harmonic waves of 0.5MHz-3.5MHz are used to replace traditional transient pulse signals for ultrasonic detection. The strong propagation stability of steady-state simple harmonic waves effectively eliminates interference from external conditions on the detection results, improving the repeatability of the results. The damping attenuation coefficient of ultrasound within the battery is extracted as a core detection indicator. This parameter is only related to changes in the electrochemical properties within the battery and is unrelated to external factors, ensuring the accuracy and specificity of the detection at the parameter level. A quantitative relationship between the damping attenuation coefficient and the battery health state was established, and a fitting model between the two was constructed, realizing an upgrade from qualitative judgment to quantitative assessment of battery health state, significantly improving detection accuracy. Ultrasonic testing is performed using a simple contact probe combination, eliminating the need for expensive imaging equipment, greatly reducing equipment costs. It also enables in-situ, rapid battery detection, and the operation process and data processing are simple and easy to learn, adaptable to large-scale application needs in industrial scenarios.

[0050] The various embodiments in this invention are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the device embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0051] Those skilled in the art will recognize that, in one or more of the examples above, the functions described in this invention can be implemented using hardware, software, firmware, or any combination thereof. When implemented in software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or code on a computer-readable medium.

[0052] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made on the basis of the technical solution of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for lithium-ion battery state-of-health monitoring based on ultrasonic damping, characterized by, include: The internal structural parameters and mechanical property parameters of the lithium-ion battery to be monitored are obtained. The internal structural parameters include the number of separator layers and the thickness of a single separator layer. The mechanical property parameters include Lamé first parameters and Lamé second parameters. Based on the internal structural parameters and mechanical property parameters, the energy gap transmittance of ultrasonic waves inside the lithium-ion battery is obtained; An ultrasonic incident signal of a preset frequency is emitted toward the first side of the lithium-ion battery, and an ultrasonic transmission signal is collected at the second side of the lithium-ion battery to obtain the incident signal amplitude and the transmission signal amplitude. Based on the energy gap transmittance, incident signal amplitude, and transmitted signal amplitude, the damping attenuation coefficient of the ultrasonic signal inside the lithium-ion battery is obtained. Based on the damping attenuation coefficient and the pre-built battery health state parameter fitting model, the health state parameters of the lithium-ion battery are obtained.

2. The method of claim 1, wherein, The acquisition of the internal structural parameters and mechanical property parameters of the lithium-ion battery to be monitored includes: The lithium-ion battery was image scanned to obtain the number of separator layers and the thickness of a single separator layer; Mechanical tests were performed on the lithium-ion battery to obtain the Lamé first parameter and the Lamé second parameter.

3. The method of claim 1, wherein, The method for obtaining the energy gap transmittance of ultrasound inside the lithium-ion battery based on the internal structural parameters and mechanical property parameters includes: A mesoscopic analytical model is established based on the internal structural parameters and mechanical property parameters. The mesoscopic analytical model is used to describe the transmission process of ultrasonic waves inside the lithium-ion battery. Based on the aforementioned microscopic analytical model, the first forward propagation complex coefficient of ultrasonic waves on the first side and the second forward propagation complex coefficient on the second side of the lithium-ion battery are obtained. Based on the first and second forward propagation complex coefficients of the lithium-ion battery, the energy gap transmittance is obtained using the following formula: wherein is the energy gap transmission, is the first forward propagation complex coefficient, is the second forward propagation complex coefficient.

4. The method according to claim 3, characterized in that, The damping attenuation coefficient of the ultrasonic signal inside the lithium-ion battery is calculated using the following formula: in, The damping attenuation coefficient is... , The amplitude of the incident signal. The amplitude of the transmitted signal. For energy gap transmittance, The magnitude coefficients are the fitted values ​​of the exponential curve. ω is the incident wave angular frequency.

5. The method according to claim 4, characterized in that, The health state parameters of the lithium-ion battery are obtained by fitting the damping attenuation coefficient and the pre-built battery health state parameter fitting model, including: The battery health state parameter fitting model is expressed by the following formula: The intercept of the linear fit. The slope of the linear fit. Battery health status parameters; The damping attenuation coefficient is input into the battery health state parameter fitting model to obtain the output health state parameters.

6. The method according to claim 5, characterized in that, The method further includes: A battery state-of-charge (POC) parameter fitting model is constructed, which is expressed by the following formula: The intercept of the linear fit. The slope of the linear fit. These are the battery state of charge parameters; The damping attenuation coefficient is input into the battery state-of-charge parameter fitting model to obtain the output state-of-charge parameters.

7. The method according to claim 1, characterized in that, The preset frequency ultrasonic wave is a simple harmonic wave of 0.5MHz-3.5MHz.

8. A lithium-ion battery health status monitoring device based on ultrasonic damping, characterized in that, include: The battery parameter acquisition module acquires the internal structural parameters and mechanical property parameters of the lithium-ion battery to be monitored. The internal structural parameters include the number of separator layers and the thickness of a single separator layer. The mechanical property parameters include Lamé first parameters and Lamé second parameters. The transmittance acquisition module is connected to the battery parameter acquisition module and obtains the energy gap transmittance of ultrasonic waves inside the lithium-ion battery based on the internal structural parameters and mechanical property parameters. An ultrasonic detection module, connected to the transmittance acquisition module, emits an ultrasonic incident signal of a preset frequency toward the first side of the lithium-ion battery and acquires an ultrasonic transmission signal at the second side of the lithium-ion battery to obtain the incident signal amplitude and the transmission signal amplitude. The attenuation coefficient acquisition module is connected to the ultrasonic detection module. Based on the energy gap transmittance, the incident signal amplitude, and the transmitted signal amplitude, it obtains the damping attenuation coefficient of the ultrasonic signal inside the lithium-ion battery. The health status monitoring module is connected to the attenuation coefficient acquisition module. Based on the damping attenuation coefficient and a pre-built battery health status parameter fitting model, the health status parameters of the lithium-ion battery are obtained.

9. An electronic device, characterized in that, It includes a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the method as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, It stores a computer program that, when executed in a computer, causes the computer to perform the method described in any one of claims 1-7.

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