Battery performance determination method and device and nonvolatile storage medium

Abstract

The invention discloses a battery performance determination method and device and a nonvolatile storage medium. The method comprises the steps that a plurality of voltages of a target battery are obtained, and the voltages are obtained through measurement of a plurality of ending durations at the end of discharging; based on a preset charging and discharging condition, calculating a charging and discharging current corresponding to the target battery; detecting the AC internal resistance of the target battery under the preset frequency; based on the AC internal resistance, determining ohmic internal resistance of the target battery; according to the charging and discharging current, the plurality of voltages and the ohmic internal resistance, calculating polarization components of the target battery, the polarization components including an ohmic polarization component, a diffusion polarization component and an electrochemical polarization component; and determining the performance of the target battery based on the polarization component. The technical problem that the accuracy of performance detection based on polarization components is low due to the fact that polarization changes cannot be accurately quantified in the battery circulation process at present and the increase conditions of ohm internal resistance and polarization internal resistance cannot be effectively distinguished and monitored is solved.

Description

Technical Field

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

[0002] Lithium-ion batteries are the mainstream energy source for modern electronic products and electric vehicles, and their performance and lifespan directly affect the reliability and economy of these devices. During battery cycling, changes in internal resistance are a key factor in assessing the state of health (SOH) and predicting the remaining useful life (RUL). Internal resistance consists of ohmic resistance, electrochemical resistance, and diffusion resistance. Ohmic resistance is primarily determined by the conductivity of the battery materials, while electrochemical and diffusion resistances are closely related to the electrochemical reactions within the battery and the diffusion efficiency of lithium ions. During battery aging, the increase in polarization resistance is particularly significant, directly reflecting irreversible damage within the battery, such as SEI film thickening and lithium dendrite growth, which leads to capacity decay and deterioration of power characteristics.

[0003] However, current methods for monitoring and analyzing the internal resistance of lithium-ion batteries have the following shortcomings:

[0004] 1. Limitations of the DC resistance method (DCR): By measuring instantaneous voltage changes through a high-current pulse, this method cannot distinguish between ohmic internal resistance and polarization internal resistance, resulting in an inaccurate assessment of the battery's aging status. Furthermore, applying a high current may accelerate battery aging and cause additional damage to battery health.

[0005] 2. Limitations of the model fitting method: Estimating internal resistance based on an equivalent circuit model relies heavily on prior knowledge and assumptions for parameter identification. During battery cycling and aging, this model exhibits poor adaptability and cannot accurately reflect the dynamic characteristics of internal resistance changes. In particular, its predictive ability significantly decreases when the battery's health deteriorates rapidly.

[0006] 3. Lack of real-time non-destructive testing methods: Current technologies lack a testing method capable of monitoring polarization changes in real time during battery cycling without causing additional damage to the battery. Real-time monitoring is crucial for timely identification of battery capacity degradation causes, assessment of battery safety risks, and lifespan management.

[0007] In summary, there are significant shortcomings in the real-time, non-destructive quantification of changes in the internal resistance of lithium-ion batteries, especially polarization resistance.

[0008] There is currently no effective solution to the above problems. Summary of the Invention

[0009] This invention provides a method, apparatus, and non-volatile storage medium for determining battery performance, at least addressing the current technical problem that it is impossible to accurately quantify polarization changes during battery cycling, and that it is impossible to effectively distinguish and monitor the growth of ohmic internal resistance and polarization internal resistance, resulting in low accuracy of performance testing based on polarization components.

[0010] According to one aspect of the present invention, a method for determining the performance of a battery is provided, comprising: acquiring multiple voltages of a target battery, wherein the multiple voltages are respectively measured after the target battery has been discharged under preset charge-discharge conditions for multiple durations; calculating the charge-discharge current corresponding to the target battery based on the preset charge-discharge conditions; detecting the AC internal resistance of the target battery at a preset frequency; determining the ohmic internal resistance of the target battery based on the AC internal resistance; calculating the polarization components of the target battery according to the charge-discharge current, the multiple voltages, and the ohmic internal resistance, wherein the polarization components include: an ohmic polarization component, a diffusion polarization component, and an electrochemical polarization component; and determining the performance of the target battery based on the polarization components.

[0011] Optionally, the multiple voltages are a first voltage measured at the end of discharge, a second voltage measured after a first preset time after the end of discharge, and a third voltage measured after a second preset time after the end of discharge, wherein the multiple end times include the first preset time and the second preset time, and the second preset time is longer than the first preset time.

[0012] Optionally, the ohmic polarization component of the target battery is calculated, including: calculating the product of the charge / discharge current and the ohmic internal resistance to determine the ohmic polarization component of the target battery.

[0013] Optionally, the electrochemical polarization component of the target battery is calculated, including: determining the ohmic polarization component based on the product of the charge / discharge current and the ohmic internal resistance; and determining the electrochemical polarization component based on the first voltage, the second voltage, and the ohmic polarization component.

[0014] Optionally, calculating the diffusion polarization component of the target cell includes: calculating the difference between the third voltage and the second voltage; and determining the diffusion polarization component based on the difference.

[0015] Optionally, the performance of the target battery is determined based on the polarization components, including: obtaining the polarization components of the target battery after multiple charge-discharge cycles; calculating the first growth rate of the ohmic polarization component, the second growth rate of the diffusion polarization component, and the third growth rate of the electrochemical polarization component based on the polarization vectors corresponding to each of the multiple charge-discharge cycles; and determining the performance of the target battery based on the first growth rate, the second growth rate, and the third growth rate.

[0016] According to another aspect of the present invention, a battery performance determination apparatus is also provided, comprising: an acquisition module for acquiring multiple voltages of a target battery, wherein the multiple voltages are respectively measured after the target battery has been discharged under preset charge-discharge conditions for multiple durations; a first calculation module for calculating the charge-discharge current corresponding to the target battery based on the preset charge-discharge conditions; a detection module for detecting the AC internal resistance of the target battery at a preset frequency; a first determination module for determining the ohmic internal resistance of the target battery based on the AC internal resistance; a second calculation module for calculating the polarization components of the target battery according to the charge-discharge current, the multiple voltages, and the ohmic internal resistance, wherein the polarization components include: ohmic polarization components, diffusion polarization components, and electrochemical polarization components; and a second determination module for determining the performance of the target battery based on the polarization components.

[0017] According to another aspect of the present invention, a non-volatile storage medium is also provided, the non-volatile storage medium including a stored program, wherein, when the program is running, the device where the non-volatile storage medium is located executes any of the above-described battery performance determination methods.

[0018] According to another aspect of the present invention, a computer device is also provided, the computer device including a processor, the processor being configured to run a program, wherein the program executes any of the battery performance determination methods described above.

[0019] According to another aspect of the present invention, a computer program product is also provided, including a computer program that, when executed by a processor, implements any of the above-described battery performance determination methods.

[0020] In this embodiment of the invention, a battery performance determination method is employed. This method involves acquiring multiple voltages of the target battery, each voltage measured after a predetermined discharge duration under pre-defined charge / discharge conditions. Based on these pre-defined conditions, the corresponding charge / discharge current of the target battery is calculated. The AC internal resistance of the target battery at a predetermined frequency is detected. Based on the AC internal resistance, the ohmic internal resistance of the target battery is determined. The polarization components of the target battery are calculated based on the charge / discharge current, multiple voltages, and ohmic internal resistance. These polarization components include ohmic polarization, diffusion polarization, and electrochemical polarization. Based on these polarization components, the performance of the target battery is determined. This method achieves the goal of accurately acquiring different polarization components, thereby improving the accuracy of battery performance testing. It also solves the current technical problem that it is impossible to accurately quantify polarization changes during battery cycling, and it is impossible to effectively distinguish and monitor the growth of ohmic and polarization internal resistance, resulting in low accuracy in performance testing based on polarization components. Attached Figure Description

[0021] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0022] Figure 1 A hardware block diagram of a computer terminal for implementing a method for determining battery performance is shown.

[0023] Figure 2 This is a flowchart illustrating a battery performance determination method according to an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram illustrating the change in polarization with the number of cycles during normal battery cycling, provided by an optional embodiment of the present invention.

[0025] Figure 4 This is a schematic diagram illustrating the change in polarization with the number of cycles during the cycling process of a diving battery according to an optional embodiment of the present invention;

[0026] Figure 5 This is a structural block diagram of a battery performance determination device provided according to an embodiment of the present invention. Detailed Implementation

[0027] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0028] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0029] According to an embodiment of the present invention, a method embodiment for determining battery performance is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0030] The method embodiment provided in Embodiment 1 of this application can be executed on a mobile terminal, computer terminal, or similar computing device. Figure 1 A hardware block diagram of a computer terminal for implementing a method for determining battery performance is shown. Figure 1 As shown, the computer terminal 10 may include one or more processors (shown as 102a, 102b, ..., 102n in the figure) (the processor may include, but is not limited to, a microprocessor MCU or a programmable logic device FPGA, etc.) and a memory 104 for storing data. In addition, it may also include: a display, an input / output interface (I / O interface), a universal serial bus (USB) port (which may be included as one of the ports of a BUS bus), a network interface, a power supply, and / or a camera. Those skilled in the art will understand that... Figure 1 The structure shown is for illustrative purposes only and does not limit the structure of the aforementioned electronic device. For example, computer terminal 10 may also include... Figure 1 The more or fewer components shown, or having the same Figure 1 The different configurations shown.

[0031] It should be noted that the aforementioned one or more processors and / or other data processing circuits are generally referred to herein as "data processing circuits". These data processing circuits may be embodied, in whole or in part, in software, hardware, firmware, or any other combination thereof. Furthermore, the data processing circuits may be a single, independent processing module, or may be integrated, in whole or in part, into any other element within the computer terminal 10. As involved in the embodiments of this application, the data processing circuits serve as a processor control mechanism (e.g., selection of a variable resistor termination path connected to an interface).

[0032] The memory 104 can be used to store software programs and modules of application software, such as the program instructions / data storage device corresponding to the battery performance determination method in this embodiment of the invention. The processor executes various functional applications and data processing by running the software programs and modules stored in the memory 104, thereby implementing the battery performance determination method of the aforementioned application. The memory 104 may include high-speed random access memory, and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory 104 may further include memory remotely located relative to the processor, and these remote memories can be connected to the computer terminal 10 via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0033] The display can be, for example, a touchscreen liquid crystal display (LCD) that allows the user to interact with the user interface of the computer terminal 10.

[0034] Figure 2 This is a flowchart illustrating a battery performance determination method according to an embodiment of the present invention, as shown below. Figure 2 As shown, the method includes the following steps:

[0035] Step S202: Obtain multiple voltages of the target battery, wherein the multiple voltages are obtained by measuring multiple end times after the target battery finishes discharging under preset charge and discharge conditions.

[0036] In this step, it is ensured that the test equipment is correctly connected to the target battery and that all test parameters (such as charge / discharge rate, voltage range, etc.) have been set. The battery is charged to full capacity to ensure it is in the same state at the start of each test. A complete charge / discharge cycle is performed according to the pre-set charge / discharge conditions (e.g., 1C charge / discharge rate) until the battery discharges to the predetermined termination voltage. Immediately after discharge (i.e., t=0), the first voltage value of the battery is measured, representing the voltage at the end of discharge. Subsequently, voltage measurements are taken at multiple preset time points after the end of discharge. These time points may include, but are not limited to, 0.01 seconds, 1 minute, 10 minutes, 1 hour, 24 hours, etc. These voltage values ​​reflect the voltage recovery of the battery at different time periods after discharge and can be used to evaluate the battery's relaxation characteristics, i.e., its ability to recover to a steady state after discharge.

[0037] Step S204: Calculate the charging and discharging current corresponding to the target battery based on preset charging and discharging conditions.

[0038] In this step, the charge / discharge conditions typically include the charge / discharge rate, charge / discharge cutoff voltage, and charge / discharge time. The rated capacity of the target battery can be obtained, usually in Ah (ampere-hours) or mAh (milliampere-hours). For example, the rated capacity of the battery is 3000mAh. The charge / discharge rate is represented by "C," where 1C means the charge / discharge current equals the battery's rated capacity, thus allowing the determination of the charge / discharge current. For example, for a 3000mAh battery, the 1C charge / discharge current is 3A (amperes).

[0039] Step S206: Detect the AC internal resistance of the target battery at a preset frequency.

[0040] In this step, the AC internal resistance test is typically performed in the battery's static or slightly dormant state to ensure that the measured internal resistance primarily reflects the battery's ohmic internal resistance, avoiding electrochemical polarization interference during dynamic charging and discharging. This ensures the battery is in a safe testing environment, such as a temperature-controlled laboratory. The battery is charged to near full capacity or discharged to a specific SOC (State of Charge) point to ensure a stable operating state during testing. An electrochemical workstation or battery testing equipment with AC impedance testing capabilities is used to connect the battery. Set the test frequency: The preset frequency is typically 1000Hz, a commonly used frequency for evaluating battery ohmic internal resistance because the effects of electrochemical polarization and diffusion polarization are relatively small at this frequency. Set the AC voltage amplitude: This amplitude is usually small to avoid excessive stress on the battery or altering its state. Common amplitude selections are between 5mV and 20mV. Set the test time: Ensure the test time is long enough to collect stable data without unnecessarily straining the battery. The test time is generally set to several minutes.

[0041] Start the test equipment and apply an AC signal of a preset frequency to the battery. The test equipment will automatically measure the battery's voltage response and calculate the battery's AC internal resistance using a formula. The calculation of AC internal resistance is based on an extension of Ohm's law, namely Z = V / I, where Z is the impedance, V is the voltage, and I is the current. In this test, Z mainly consists of the resistive component, i.e., ACR. Record the AC internal resistance value to ensure the accuracy and repeatability of the data.

[0042] Step S208: Determine the ohmic internal resistance of the target battery based on the AC internal resistance.

[0043] In this step, the ohmic internal resistance is mainly composed of the battery's electrode materials, electrolyte, separator, and internal contact resistance, and does not change significantly with the battery's state of charge (SOC) or temperature. In AC internal resistance testing, the battery's impedance characteristics can be analyzed by applying a small-amplitude AC signal (typically a sine wave between 5mV and 20mV) across the battery terminals and measuring the voltage response at multiple frequencies. However, the battery's total AC internal resistance (ACR) consists of the ohmic internal resistance and the electrochemical impedance at high frequencies (diffusion resistance is usually ignored because it is insignificant at high frequencies). An electrochemical workstation or a battery tester with AC impedance testing capabilities can be used to perform AC impedance spectroscopy testing at multiple frequencies (e.g., from 10Hz to 100kHz). The impedance values ​​at different frequencies are recorded, and the battery's Nyquist or Bode plot is plotted. In the Nyquist plot, the ohmic internal resistance typically appears as a straight line in the high-frequency region (i.e., close to 100kHz), and the intercept of this line on the real axis is the battery's ohmic internal resistance. Alternatively, in a Bode plot, observe the resistance value as a function of frequency. In the high-frequency region, when the impedance value stabilizes, its value is close to the battery's ohmic internal resistance. Electrochemical polarization resistance is more pronounced in the low-frequency region (such as around 10Hz), forming a semicircle or arc, distinguishing it from the straight line of the ohmic internal resistance in the high-frequency region. The impedance value in the high-frequency region of the Nyquist or Bode plot can be selected as the measured value of the ohmic internal resistance.

[0044] Step S210: Calculate the polarization components of the target battery based on the charge / discharge current, multiple voltages, and ohmic internal resistance. The polarization components include: ohmic polarization components, diffusion polarization components, and electrochemical polarization components.

[0045] In this step, the ohmic polarization component can be calculated using Ohm's law, i.e., voltage drop equals current multiplied by resistance. At the end of battery discharge, if the battery immediately stops discharging, the voltage will change immediately due to the cessation of current; part of this change is due to the voltage drop caused by the ohmic internal resistance. Electrochemical polarization is caused by electrochemical reactions during charge transfer, and it typically does not recover immediately after the charging / discharging process stops. Diffusion polarization is caused by a mismatch in the diffusion rates of lithium ions in the electrode material, and it requires a longer recovery time.

[0046] Therefore, the ohmic polarization component is the instantaneous voltage drop caused by the ohmic internal resistance and can be directly calculated from the current and the ohmic internal resistance. The electrochemical polarization component is the voltage drop caused by the charge transfer reaction, and it does not disappear immediately after the charging and discharging process stops. The diffusion polarization component reflects the diffusion limitation of lithium ions in the electrode and typically recovers gradually over a timescale of minutes to hours.

[0047] These calculations allow us to decompose the total voltage drop of a battery during charging and discharging into different polarization components, thus providing a deeper understanding of the battery's electrochemical performance and aging mechanisms. This is crucial for optimizing battery management systems, improving battery performance and lifespan, and predicting battery health.

[0048] Step S212: Determine the performance of the target battery based on the polarization components.

[0049] In this step, the performance of the target battery is determined based on polarization components (ohmic polarization, diffusion polarization, and electrochemical polarization). Lower ohmic polarization implies lower internal resistance, which is typically associated with higher energy density and capacity. High internal resistance reduces battery efficiency during charge and discharge, decreasing usable capacity. Electrochemical polarization is closely related to the utilization rate of active materials, electrolyte decomposition, and SEI film formation. Higher electrochemical polarization may lead to reduced effective capacity and lower energy density. Diffusion polarization reflects the diffusion rate of lithium ions in the electrode material. High diffusion polarization may result in longer charging times and limited discharge rates, affecting the effective utilization of energy density and capacity.

[0050] Detailed analysis of the ohmic, diffusion, and electrochemical polarization components of a battery provides insights into its health and allows for prediction of performance degradation trends. This information is crucial for optimizing battery design, improving battery management systems, enhancing overall battery performance, and extending its lifespan. In practical applications, continuous monitoring and analysis of these polarization components can guide battery maintenance and optimized operating strategies, thereby achieving optimal battery performance in real-world usage scenarios.

[0051] The above steps, by acquiring multiple voltage values ​​at different end times of the target battery's discharge, combined with the charge / discharge current and the AC internal resistance detected at a preset frequency, achieve real-time monitoring and precise quantification of polarization resistance changes during battery cycling. Specifically, the ohmic internal resistance of the target battery is first determined, and then, based on the charge / discharge current, multiple voltage values, and ohmic internal resistance, the ohmic polarization component, diffusion polarization component, and electrochemical polarization component of the battery are accurately calculated. This technical approach effectively overcomes the current difficulty in distinguishing the various components of battery internal resistance, enabling non-destructive and high-precision assessment of the degree of aging and potential safety risks caused by polarization. By analyzing the trend of polarization component changes with the number of cycles, early signals of battery performance degradation can be identified in a timely manner, providing real-time data support for the battery management system, optimizing battery usage strategies, and extending its service life. It is particularly beneficial for dynamically adjusting the battery's operating state during cycling, avoiding the risk of battery degradation due to excessively rapid polarization, and significantly improving the effectiveness and safety of battery health management.

[0052] As an optional embodiment, the multiple voltages are a first voltage measured at the end of discharge, a second voltage measured after a first preset time after the end of discharge, and a third voltage measured after a second preset time after the end of discharge. The multiple end times include the first preset time and the second preset time, and the second preset time is longer than the first preset time.

[0053] Optionally, in battery charge-discharge testing, by measuring the voltage at different time points, the battery's polarization characteristics and their impact on performance can be analyzed in depth. The multiple voltages mentioned here, namely the first voltage (U1), the second voltage (U2), and the third voltage (U3), are measured immediately after discharge, at a first preset time after discharge (e.g., 0.01 seconds), and at a second preset time after discharge (e.g., 1 hour, much longer than the first preset time), respectively. The selection and analysis of these voltage values ​​are crucial for understanding the battery's ohmic polarization, electrochemical polarization, and diffusion polarization.

[0054] First voltage (U1):

[0055] Measurement timing: The first voltage U1, measured immediately after the discharge process is completely finished, mainly reflects the instantaneous state at the end of the discharge process.

[0056] Second voltage (U2):

[0057] Measurement timing: The second voltage U2 is measured after a first preset time (e.g., 0.01 seconds) following the end of the discharge. This time point is usually short enough that the electrochemical polarization and diffusion polarization have not yet recovered significantly.

[0058] Third voltage (U3):

[0059] Measurement timing: The third voltage U3 is measured after the discharge ends and a second preset time (e.g., 1 hour) has elapsed. This time is long enough that the electrochemical polarization has basically recovered, but the diffusion polarization may not have been completely eliminated.

[0060] As an optional embodiment, calculating the ohmic polarization component of the target battery includes: calculating the product of the charge / discharge current and the ohmic internal resistance to determine the ohmic polarization component of the target battery.

[0061] Optionally, when calculating ohmic polarization, the ohmic polarization component is obtained by using the product IR of the charge / discharge current I and the ohmic internal resistance R. Calculating the ohmic polarization component allows for the evaluation of battery efficiency and performance under high-current charge / discharge conditions, which is crucial for optimizing the battery management system (BMS), monitoring battery health, and improving battery performance. An increase in the ohmic polarization component is typically associated with battery aging, performance degradation, and reduced power output capability. Therefore, monitoring the trend of ohmic polarization component changes is an important part of battery maintenance and life prediction.

[0062] As an optional embodiment, calculating the electrochemical polarization component of the target battery includes: determining the ohmic polarization component based on the product of the charge / discharge current and the ohmic internal resistance; and determining the electrochemical polarization component based on a first voltage, a second voltage, and the ohmic polarization component.

[0063] Optionally, the ohmic polarization component IR can be calculated first based on the charge / discharge current I and the ohmic internal resistance R, and then the electrochemical polarization component can be calculated using the formula U2-U1-IR. This technical solution can effectively separate the internal resistance changes caused by the electrochemical process, and by monitoring the evolution of the electrochemical polarization component in real time, the health status of the battery during cycling can be accurately assessed.

[0064] As an optional embodiment, calculating the diffusion polarization component of the target cell includes: calculating the difference between a third voltage and a second voltage; and determining the diffusion polarization component based on the difference.

[0065] Optionally, the difference between the third voltage U3 and the second voltage U2 is determined. This difference represents the voltage change caused by the imbalance in the lithium-ion diffusion process between the end of battery discharge and the complete relaxation state. Based on this difference, the diffusion polarization component can be directly quantified without additional testing or complex model calculations, simplifying the data processing flow and improving efficiency. This quantification method can not only monitor the changes in diffusion polarization during battery cycling in real time, but also compare it with electrochemical polarization and ohmic polarization, helping to analyze different types of polarization phenomena inside the battery and their impact on battery life. By continuously tracking this indicator and combining it with the calculation of the polarization growth rate, the trend of battery performance degradation can be predicted in advance, providing strong data support for the battery management system (BMS) to optimize charging strategies and monitor battery health status, effectively extending battery life and enhancing system safety and reliability.

[0066] As an optional embodiment, determining the performance of a target battery based on polarization components includes: obtaining the polarization components of the target battery after multiple charge-discharge cycles; calculating a first growth rate of the ohmic polarization component, a second growth rate of the diffusion polarization component, and a third growth rate of the electrochemical polarization component based on the polarization vectors corresponding to each of the multiple charge-discharge cycles; and determining the performance of the target battery based on the first growth rate, the second growth rate, and the third growth rate.

[0067] Optionally, a series of standard charge-discharge cycles can be performed on the target battery, recording the charge-discharge current, first voltage, second voltage, and third voltage for each cycle. After each cycle, the corresponding ohmic polarization component, electrochemical polarization component, and diffusion polarization component are calculated using the method described above. The trend of the ohmic polarization component changing with the number of cycles can be tracked, and the data can be fitted using linear regression or other statistical methods to calculate the growth rate, i.e., the amount by which the ohmic polarization component increases with each additional cycle. Similarly, the data on the change of the diffusion polarization component with the number of cycles is recorded, and the amount by which the diffusion polarization component increases with each additional cycle is calculated; the changes in the electrochemical polarization component are recorded, and the amount by which the electrochemical polarization component increases with each additional cycle is calculated. The first growth rate, second growth rate, and third growth rate can be combined for analysis to comprehensively understand the degradation of battery performance with increasing cycle count. Thresholds for the growth rate of each polarization component are set according to application requirements and battery type. Once the growth rate exceeds the set threshold, it may indicate abnormal aging or damage to the battery, requiring further diagnosis or replacement.

[0068] By utilizing collected data on polarization component growth rates, predictive models of battery performance degradation can be established. This helps in planning battery maintenance cycles in advance and optimizing the charge-discharge strategies of the battery management system (BMS) to slow down performance degradation and extend battery life. Based on the differences in polarization component growth rates, parameters such as charge-discharge current, depth of cycle (DOD), and charging cutoff voltage can be adjusted to reduce specific types of polarization components, thereby improving the overall performance of the battery.

[0069] By sampling the battery voltage under specific charge-discharge cycle conditions—specifically, selecting the voltage U1 at the end of discharge, the voltage U2 0.01 seconds after discharge, and the voltage U3 1 hour after discharge—the polarization components are effectively obtained. Subsequently, using the battery's AC impedance test results after each cycle, the ohmic internal resistance R of the battery is accurately calculated, thus distinguishing different types of polarization—ohmic polarization, diffusion polarization, and electrochemical polarization. This method eliminates the need for additional high-current loads or complex model fitting, simplifying the data processing flow and enabling the battery management system (BMS) to monitor the battery's health status in real time. Specifically, after the 100th cycle, the precise value of electrochemical polarization can be obtained by calculating U2-U1-IR, while U3-U2 reflects the degree of influence of diffusion polarization. A curve showing the change in polarization voltage with the number of cycles can be plotted, allowing for a visual observation of the polarization growth rate. Figure 3 This is a schematic diagram illustrating the change in polarization with the number of cycles during normal battery cycling, provided by an optional embodiment of the present invention. Figure 4 This is a schematic diagram illustrating the change in polarization with the number of cycles during the cycling process of a diving battery according to an optional embodiment of the present invention. Figure 3 and Figure 4As can be seen, the diffusion polarization growth rate during normal battery cycling is 35%, while in batteries with increased risk of rapid degradation, this value jumps to 62%. This quantitative analysis helps to predict battery performance degradation trends in advance, providing a scientific basis for battery maintenance and replacement decisions. In summary, this embodiment not only provides a real-time, non-destructive polarization monitoring method, but also establishes a quantitative correlation between polarization components and battery performance, greatly improving the accuracy and efficiency of battery health management.

[0070] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, because according to the present invention, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0071] Through the above description of the embodiments, those skilled in the art can clearly understand that the battery performance determination method according to the above embodiments can be implemented by means of software plus necessary general-purpose hardware platform. Of course, it can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0072] According to an embodiment of the present invention, a battery performance determination apparatus for implementing the above-described battery performance determination method is also provided. Figure 5 This is a structural block diagram of a battery performance determination device provided according to an embodiment of the present invention, such as... Figure 5 As shown, the battery performance determination device includes: an acquisition module 502, a first calculation module 504, a detection module 506, a first determination module 508, a second calculation module 510, and a second determination module 512. The battery performance determination device will be described below.

[0073] The acquisition module 502 is used to acquire multiple voltages of the target battery, wherein the multiple voltages are obtained by measuring multiple end times after the target battery finishes discharging under preset charge and discharge conditions.

[0074] The first calculation module 504, connected to the acquisition module 502, is used to calculate the charging and discharging current corresponding to the target battery based on preset charging and discharging conditions.

[0075] The detection module 506 is connected to the first calculation module 504 and is used to detect the AC internal resistance of the target battery at a preset frequency.

[0076] The first determining module 508, connected to the detection module 506, is used to determine the ohmic internal resistance of the target battery based on the AC internal resistance.

[0077] The second calculation module 510, connected to the first determination module 508, is used to calculate the polarization components of the target battery based on the charge / discharge current, multiple voltages, and ohmic internal resistance. The polarization components include ohmic polarization components, diffusion polarization components, and electrochemical polarization components.

[0078] The second determining module 512, connected to the second calculation module 510, is used to determine the performance of the target battery based on the polarization component.

[0079] It should be noted that the aforementioned acquisition module 502, first calculation module 504, detection module 506, first determination module 508, second calculation module 510, and second determination module 512 correspond to steps S202 to S212 in the embodiments. Multiple modules implement the same instances and application scenarios as their corresponding steps, but are not limited to the content disclosed in the above embodiments. It should also be noted that the aforementioned modules, as part of the device, can run on the computer terminal 10 provided in the embodiments.

[0080] Embodiments of the present invention may provide a computer device. Optionally, in this embodiment, the computer device may be located in at least one of a plurality of network devices in a computer network. The computer device includes a memory and a processor.

[0081] The memory can be used to store software programs and modules, such as the program instructions / modules corresponding to the battery performance determination method and apparatus in this embodiment of the invention. The processor executes various functional applications and data processing by running the software programs and modules stored in the memory, thereby realizing the aforementioned battery performance determination method. The memory may include high-speed random access memory, and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory may further include memory remotely located relative to the processor, and these remote memories can be connected to a computer terminal via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0082] The processor can access information and application programs stored in the memory via a transmission device to perform the following steps: acquiring multiple voltages of the target battery, wherein the multiple voltages are measured after the target battery has been discharged under preset charge and discharge conditions for multiple durations; calculating the charge and discharge current corresponding to the target battery based on the preset charge and discharge conditions; detecting the AC internal resistance of the target battery at a preset frequency; determining the ohmic internal resistance of the target battery based on the AC internal resistance; calculating the polarization components of the target battery based on the charge and discharge current, multiple voltages, and ohmic internal resistance, wherein the polarization components include: ohmic polarization components, diffusion polarization components, and electrochemical polarization components; and determining the performance of the target battery based on the polarization components.

[0083] Optionally, the processor may also execute program code for the following steps: multiple voltages are a first voltage measured at the end of discharge, a second voltage measured after a first preset duration after the end of discharge, and a third voltage measured after a second preset duration after the end of discharge, wherein the multiple end durations include the first preset duration and the second preset duration, and the second preset duration is longer than the first preset duration.

[0084] Optionally, the processor may also execute program code that performs the following steps: calculating the ohmic polarization component of the target battery, including: calculating the product of the charging / discharging current and the ohmic internal resistance to determine the ohmic polarization component of the target battery.

[0085] Optionally, the processor may also execute program code for the following steps: calculating the electrochemical polarization component of the target battery, including: determining the ohmic polarization component based on the product of the charge / discharge current and the ohmic internal resistance; and determining the electrochemical polarization component based on the first voltage, the second voltage, and the ohmic polarization component.

[0086] Optionally, the processor may also execute program code that performs the following steps: calculating the diffusion polarization component of the target cell, including: calculating the difference between the third voltage and the second voltage; and determining the diffusion polarization component based on the difference.

[0087] Optionally, the processor may also execute program code for the following steps: determining the performance of the target battery based on the polarization components, including: obtaining the polarization components of the target battery after multiple charge-discharge cycles; calculating the first growth rate of the ohmic polarization component, the second growth rate of the diffusion polarization component, and the third growth rate of the electrochemical polarization component based on the polarization vectors corresponding to each of the multiple charge-discharge cycles; and determining the performance of the target battery based on the first growth rate, the second growth rate, and the third growth rate.

[0088] This invention provides a method for determining battery performance. The method involves acquiring multiple voltages of a target battery, each voltage measured after a predetermined discharge duration under pre-defined charge / discharge conditions. Based on these pre-defined conditions, the method calculates the corresponding charge / discharge current. It then detects the AC internal resistance of the target battery at a predetermined frequency. Based on the AC internal resistance, it determines the ohmic internal resistance of the target battery. Finally, it calculates the polarization components of the target battery, including ohmic polarization, diffusion polarization, and electrochemical polarization, based on the charge / discharge current, multiple voltages, and ohmic internal resistance. The method determines the performance of the target battery based on these polarization components, achieving the goal of accurately acquiring different polarization components. This improves the accuracy of battery performance testing and solves the current technical problem of low accuracy in performance testing based on polarization components, which is currently unable to accurately quantify polarization changes during battery cycling and effectively distinguish and monitor the growth of ohmic and polarization resistance.

[0089] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by a program instructing the hardware related to the terminal device. The program can be stored in a non-volatile storage medium, which may include: flash drive, read-only memory (ROM), random access memory (RAM), disk or optical disk, etc.

[0090] Embodiments of the present invention also provide a non-volatile storage medium. Optionally, in this embodiment, the aforementioned non-volatile storage medium can be used to store the program code executed by the battery performance determination method provided in the above embodiments.

[0091] Optionally, in this embodiment, the non-volatile storage medium may be located in any computer terminal in a group of computer terminals in a computer network, or in any mobile terminal in a group of mobile terminals.

[0092] Optionally, in this embodiment, the non-volatile storage medium is configured to store program code for performing the following steps: acquiring multiple voltages of the target battery, wherein the multiple voltages are respectively measured after multiple end times following the discharge of the target battery under preset charge-discharge conditions; calculating the charge-discharge current corresponding to the target battery based on the preset charge-discharge conditions; detecting the AC internal resistance of the target battery at a preset frequency; determining the ohmic internal resistance of the target battery based on the AC internal resistance; calculating the polarization components of the target battery according to the charge-discharge current, multiple voltages, and ohmic internal resistance, wherein the polarization components include: ohmic polarization components, diffusion polarization components, and electrochemical polarization components; and determining the performance of the target battery based on the polarization components.

[0093] Optionally, in this embodiment, the non-volatile storage medium is configured to store program code for performing the following steps: multiple voltages are a first voltage measured at the end of discharge, a second voltage measured after a first preset duration after the end of discharge, and a third voltage measured after a second preset duration after the end of discharge, wherein the multiple end durations include the first preset duration and the second preset duration, and the second preset duration is longer than the first preset duration.

[0094] Optionally, in this embodiment, the non-volatile storage medium is configured to store program code for performing the following steps: calculating the ohmic polarization component of the target battery, including: calculating the product of the charge / discharge current and the ohmic internal resistance to determine the ohmic polarization component of the target battery.

[0095] Optionally, in this embodiment, the non-volatile storage medium is configured to store program code for performing the following steps: calculating the electrochemical polarization component of the target battery, including: determining the ohmic polarization component based on the product of the charge / discharge current and the ohmic internal resistance; and determining the electrochemical polarization component based on the first voltage, the second voltage, and the ohmic polarization component.

[0096] Optionally, in this embodiment, the non-volatile storage medium is configured to store program code for performing the following steps: calculating the diffusion polarization component of the target battery, including: calculating the difference between a third voltage and a second voltage; and determining the diffusion polarization component based on the difference.

[0097] Optionally, in this embodiment, the non-volatile storage medium is configured to store program code for performing the following steps: determining the performance of a target battery based on polarization components, including: obtaining the polarization components of the target battery after multiple charge-discharge cycles; calculating a first growth rate of the ohmic polarization component, a second growth rate of the diffusion polarization component, and a third growth rate of the electrochemical polarization component based on the polarization vectors corresponding to each of the multiple charge-discharge cycles; and determining the performance of the target battery based on the first growth rate, the second growth rate, and the third growth rate.

[0098] Embodiments of the present invention also provide a computer program product, including a computer program. Optionally, in this embodiment, when the computer program is executed by a processor, it can: acquire multiple voltages of a target battery, wherein the multiple voltages are respectively measured after multiple end times following the discharge of the target battery under preset charge-discharge conditions; calculate the charge-discharge current corresponding to the target battery based on the preset charge-discharge conditions; detect the AC internal resistance of the target battery at a preset frequency; determine the ohmic internal resistance of the target battery based on the AC internal resistance; calculate the polarization components of the target battery according to the charge-discharge current, multiple voltages, and ohmic internal resistance, wherein the polarization components include: ohmic polarization components, diffusion polarization components, and electrochemical polarization components; and determine the performance of the target battery based on the polarization components.

[0099] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0100] In the above embodiments of the present invention, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0101] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0102] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0103] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0104] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a non-volatile storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0105] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for determining the performance of a battery, characterized in that, include: Multiple voltages of the target battery are obtained, wherein the multiple voltages are measured after multiple end times respectively when the target battery finishes discharging under preset charge and discharge conditions; Based on the preset charge and discharge conditions, calculate the charge and discharge current corresponding to the target battery; The AC internal resistance of the target battery is detected at a preset frequency; Based on the AC internal resistance, the ohmic internal resistance of the target battery is determined; The polarization components of the target battery are calculated based on the charge / discharge current, the plurality of voltages, and the ohmic internal resistance, wherein the polarization components include: ohmic polarization components, diffusion polarization components, and electrochemical polarization components. The performance of the target battery is determined based on the polarization components.

2. The method according to claim 1, characterized in that, The plurality of voltages are a first voltage measured at the end of discharge, a second voltage measured after a first preset duration after the end of discharge, and a third voltage measured after a second preset duration after the end of discharge. The plurality of end durations include the first preset duration and the second preset duration, wherein the second preset duration is longer than the first preset duration.

3. The method according to claim 1, characterized in that, The calculation of the ohmic polarization component of the target battery includes: The ohmic polarization component of the target battery is determined by calculating the product of the charge / discharge current and the ohmic internal resistance.

4. The method according to claim 2, characterized in that, The calculation of the electrochemical polarization components of the target battery includes: The ohmic polarization component is determined based on the product of the charging / discharging current and the ohmic internal resistance. The electrochemical polarization component is determined based on the first voltage, the second voltage, and the ohmic polarization component.

5. The method according to claim 2, characterized in that, The calculation of the diffusion polarization component of the target battery includes: Calculate the difference between the third voltage and the second voltage; The diffusion polarization component is determined based on the difference.

6. The method according to any one of claims 1 to 5, characterized in that, Determining the performance of the target battery based on the polarization component includes: Obtain the polarization components of the target battery after multiple charge-discharge cycles. Based on the polarization vectors corresponding to each of the multiple charge-discharge cycles, the first growth rate of the ohmic polarization component, the second growth rate of the diffusion polarization component, and the third growth rate of the electrochemical polarization component are calculated. The performance of the target battery is determined based on the first growth rate, the second growth rate, and the third growth rate.

7. A battery performance determination device, characterized in that, include: The acquisition module is used to acquire multiple voltages of the target battery, wherein the multiple voltages are respectively measured after multiple end times when the target battery finishes discharging under preset charge and discharge conditions; The first calculation module is used to calculate the charging and discharging current corresponding to the target battery based on the preset charging and discharging conditions. The detection module is used to detect the AC internal resistance of the target battery at a preset frequency; The first determining module is used to determine the ohmic internal resistance of the target battery based on the AC internal resistance. The second calculation module is used to calculate the polarization components of the target battery based on the charging and discharging current, the plurality of voltages and the ohmic internal resistance, wherein the polarization components include: ohmic polarization components, diffusion polarization components and electrochemical polarization components. The second determining module is used to determine the performance of the target battery based on the polarization component.

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

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

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

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