Infiltration evaluation method, electronic device, and storage medium

Abstract

The application discloses an infiltrability evaluation method, an electronic device and a storage medium, and belongs to the technical field of batteries. The infiltrability evaluation method comprises the following steps: collecting impedance values and temperature values of a target battery to be evaluated at multiple time points after electrolyte injection is completed; determining a target attenuation model for representing impedance change of the target battery with time based on a pre-constructed correlation relationship model among temperature, time and impedance, and the impedance values and the temperature values at the multiple time points; and identifying a time corresponding to when the impedance value of the target battery tends to be stable based on the target attenuation model, so as to obtain an infiltration end time of the target battery, and the timeliness and accuracy of battery infiltrability evaluation are improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a wettability evaluation method, electronic device, and storage medium. Background Technology

[0002] Batteries are widely used in energy storage, new energy vehicles, and other fields. After electrolyte filling, the electrolyte needs to fully wet the porous structure of the electrodes to ensure the effective transport of active ions in the electrolyte, reduce the battery's internal resistance, and ensure its electrochemical and safety performance. Insufficient wetting can lead to wasted pores, increased internal resistance, and even abnormal heating during charging and discharging.

[0003] However, as a sealed structure, the degree of wetting within the pores of a battery is difficult to assess directly from the outside. Currently, destructive post-evaluation methods are commonly used, which involve disassembling the battery after it has been left to stand or undergone a certain number of cycles, and then visually or microscopically observing the electrode interfaces to infer the wetting effect. This method is both time-consuming and destructive, and the judgment relies on human experience, lacks a unified quantitative standard, and is difficult to evaluate quickly and accurately during the production process. Summary of the Invention

[0004] A method, electronic device, and storage medium for evaluating wettability are provided to improve the timeliness and accuracy of battery wettability evaluation.

[0005] Firstly, a method for evaluating infiltration is provided, the method comprising: The impedance and temperature values ​​of the target battery to be evaluated were collected at multiple time points after the electrolyte injection was completed. Based on a pre-built model of the relationship between temperature, time and impedance, and the impedance and temperature values ​​at multiple time points, a target decay model for characterizing the impedance of the target battery over time is determined. Based on the target attenuation model, the time corresponding to when the impedance value of the target battery tends to stabilize is identified, so as to obtain the immersion endpoint time of the target battery.

[0006] In some of these design approaches, the correlation model is determined based on a preset attenuation function and a temperature correction function. The preset attenuation function is used to characterize the attenuation change of impedance over time, and the temperature correction function is used to characterize the effect of temperature on impedance.

[0007] In some design approaches, the preset attenuation function includes specified parameters to be solved. The target attenuation model, determined based on a pre-built model of the relationship between temperature, time, and impedance, and the impedance and temperature values ​​at multiple time points, characterizes the impedance of the target battery over time. This includes: Based on a pre-built model of the relationship between temperature, time and impedance, and the impedance and temperature values ​​at multiple time points, the specified parameters in the preset attenuation function are determined to obtain the target attenuation model.

[0008] In some of these design approaches, the preset attenuation function includes a first attenuation function and a second attenuation function, wherein the first attenuation function characterizes the relationship between impedance and time during the process of the electrolyte being absorbed by the first structural layer of the target battery, and the second attenuation function characterizes the relationship between impedance and time during the process of the electrolyte diffusing from the first structural layer to the second structural layer inside the target battery.

[0009] In some design approaches, identifying the time when the impedance value of the target battery tends to stabilize based on the target attenuation model, in order to obtain the immersion endpoint time of the target battery, includes: Determine the derivative value of the target decay model at each time point; The first time point at which the absolute value of the derivative is less than a first preset threshold is determined as the immersion end time.

[0010] In some design approaches, after identifying the time corresponding to the stabilization of the target battery's impedance value based on the target attenuation model to obtain the immersion endpoint time of the target battery, the method further includes: The internal wetting state of several reference batteries after disassembly is obtained, and the critical time point for whether the reference battery is qualified or unqualified is determined based on the wetting state of each reference battery. The reference batteries are of the same type and produced in the same environment as the target battery. The accuracy of determining the immersion endpoint time is based on the critical time point.

[0011] In some design approaches, after identifying the time corresponding to the stabilization of the target battery's impedance value based on the target attenuation model to obtain the immersion endpoint time of the target battery, the method further includes: For a new battery to be evaluated that is the same type and production environment as the target battery, impedance data and temperature data of the new battery to be evaluated are collected at at least one time point after the electrolyte injection is completed. If the deviation between the impedance data and temperature data and the predicted value of the target attenuation model is less than a second preset threshold, the immersion endpoint time is taken as the immersion completion time of the new battery to be evaluated.

[0012] In some of these design approaches, the acquisition of impedance and temperature values ​​of the target battery under evaluation at multiple time points after electrolyte injection is completed includes: The impedance and temperature values ​​of the target battery being evaluated are collected at multiple time points after the electrolyte injection is completed using an interval sampling method. In the initial stage after the electrolyte injection is completed, a first sampling interval is used for sampling. After a first preset number of samplings or after a first preset time, the sampling is switched to a second sampling interval. The first sampling interval is shorter than the second sampling interval.

[0013] In some design approaches, after identifying the time corresponding to the stabilization of the target battery's impedance value based on the target attenuation model to obtain the immersion endpoint time of the target battery, the method further includes: If the immersion endpoint time exceeds a preset time range, it is determined that the immersion process of the target battery is abnormal.

[0014] In a second aspect, an electronic device is also provided, including a processor and a memory, wherein the memory stores a computer program that, when executed by the processor, causes the processor to perform any of the methods designed above.

[0015] Thirdly, a computer-readable storage medium is also provided, including a computer program that, when run on an electronic device, causes the electronic device to perform any of the methods described above.

[0016] Beneficial effects: By collecting impedance and temperature values ​​of the target battery at multiple time points after liquid injection, and combining them with a pre-established correlation model, the interference of temperature fluctuations on impedance measurement can be eliminated, thereby accurately fitting the impedance decay law over time. Based on this decay law, the corresponding time when the impedance tends to stabilize can be identified, that is, the time point when the battery reaches the immersion endpoint. Moreover, the battery does not need to be disassembled, avoiding lag and subjectivity of human judgment, realizing the quantitative evaluation of the immersion degree, and facilitating the rapid and accurate determination of whether the battery has completed immersion. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of an implementation scenario of the wettability evaluation method provided in the exemplary embodiments of this disclosure; Figure 2 This is a schematic flowchart of the wettability evaluation method provided by an exemplary embodiment of this disclosure; Figure 3 This is a schematic diagram of the relationship curve between the acquired impedance value and time provided in an exemplary embodiment of this disclosure; Figure 4 This is a schematic diagram of the relationship curve between the collected temperature value and time provided in an exemplary embodiment of this disclosure; Figure 5 This is a schematic diagram of the relationship between impedance value and time for the target attenuation model provided in the exemplary embodiments of this disclosure; Figure 6 This is a schematic diagram of the structure of the wettability evaluation device provided in an exemplary embodiment of this disclosure; Figure 7 This is a schematic diagram of the structure of an electronic device provided by an exemplary embodiment of this disclosure. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0021] "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.

[0022] The use of "applies to" or "configured to" in this application implies open and inclusive language, which does not exclude the applicability to or configuration to devices performing additional tasks or steps. Additionally, the use of "based on" implies openness and inclusivity, because processes, steps, calculations, or other actions "based on" one or more of the stated conditions or values ​​may in practice be based on additional conditions or values ​​beyond those stated.

[0023] In this application, the term "exemplary" is used to mean "used as an example, illustration, or description." Any embodiment described as "exemplary" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use this application. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that this application can be made without using these specific details. In other instances, well-known structures and processes are not described in detail to avoid obscuring the description of this application with unnecessary detail. Therefore, this application is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0024] This application provides a wettability evaluation method, a wettability evaluation device, an electronic device, a computer-readable storage medium, and a computer program product. The wettability evaluation device can be integrated into an electronic device, which can be a server, a terminal, or related equipment in an energy storage system.

[0025] The server can be a standalone physical server, a server cluster or distributed system composed of multiple physical servers, or a cloud server providing basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, content delivery network (CDN) acceleration services, and big data and artificial intelligence platforms. The terminal can include, but is not limited to, mobile phones, computers, smart voice interaction devices, smart home appliances, vehicle terminals, and aircraft. The terminal and server can be directly or indirectly connected via wired or wireless communication, which is not limited herein.

[0026] Please see Figure 1 Taking the integration of an infiltration evaluation device into electronic equipment as an example, Figure 1This is a schematic diagram of an implementation scenario of the wettability evaluation method provided in an exemplary embodiment of this disclosure. The electronic device can be a server or a terminal. The electronic device can collect the impedance and temperature values ​​of the target battery to be evaluated at multiple time points after the electrolyte injection is completed. Based on a pre-constructed correlation model between temperature, time and impedance, and the impedance and temperature values ​​at multiple time points, a target decay model for characterizing the impedance change of the target battery over time is determined. Based on the target decay model, the time corresponding to when the impedance value of the target battery tends to stabilize is identified, so as to obtain the wettability endpoint time of the target battery.

[0027] It should be noted that, Figure 1 The schematic diagram illustrating the implementation environment of the infiltration evaluation method is merely an example. The implementation environment of the infiltration evaluation method described in this application is intended to more clearly illustrate the technical solutions of this application and does not constitute a limitation on the technical solutions provided in this application. Those skilled in the art will recognize that, with the evolution of data processing and the emergence of new business scenarios, the technical solutions provided in this application are equally applicable to similar technical problems.

[0028] The solutions provided in this application are specifically illustrated through the following embodiments. It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of the embodiments.

[0029] like Figure 2 The diagram shown is a flowchart illustrating an exemplary embodiment of the wettability evaluation method provided in this disclosure. The method includes steps S21-S23: S21. Collect the impedance and temperature values ​​of the target battery to be evaluated at multiple time points after the electrolyte injection is completed.

[0030] Specifically, the target battery to be evaluated can be of various types of electrochemical energy storage batteries. For example, the target battery can be a lithium-ion battery (including lithium-ion power batteries with different structures and packaging forms such as stacked, wound, pouch, and cylindrical), a sodium-ion battery, or other batteries that require electrolyte immersion to function normally. The wettability evaluation process begins after a quantitative amount of electrolyte is injected into the target battery.

[0031] For a period of time after the electrolyte injection is completed, data is collected at preset time points. Two sets of data need to be recorded at each collection time: the first set is the impedance value between the positive and negative electrodes of the battery (e.g., AC impedance value), which can be measured by connecting an impedance testing device (e.g., AC impedance testing device); the second set is the temperature value of the battery surface, which can be obtained by attaching a temperature recorder (e.g., thermocouple or thermistor) to the battery surface.

[0032] Data needs to be collected at multiple time points, specifically impedance values ​​and corresponding temperature values ​​at at least two different times. The more time points collected and the more reasonably distributed they are, the more accurately the subsequent model will reflect the changing patterns of the entire wetting process. This collected raw data forms the basis for subsequent modeling, providing direct physical quantity information for assessing the wetting progress of the electrolyte in the electrode pores.

[0033] By simultaneously recording impedance and temperature, the necessary input parameters are prepared to distinguish the effects of time and temperature on impedance, thereby avoiding evaluation distortion caused by ignoring temperature fluctuations in the actual production environment.

[0034] After collecting impedance and temperature values ​​at multiple time points, the impedance value versus time curve and the temperature value versus time curve can be plotted with time as the x-axis and impedance and temperature values ​​as the y-axis, respectively. Figure 3 and Figure 4 As shown.

[0035] Figure 3 This is a schematic diagram illustrating the relationship between the acquired impedance value and time, provided in an exemplary embodiment of this disclosure. The horizontal axis represents time (in hours), and the vertical axis represents the impedance value (in ohms). Figure 3 As can be seen, in the initial stage after electrolyte injection, the impedance value is high and decreases rapidly. Over time, the impedance value shows a gradual decreasing trend. This indicates that the electrolyte is gradually permeating the pores inside the electrode, and ion transport channels are gradually established, thus continuously reducing the AC impedance of the battery.

[0036] However, Figure 3 The curve in the figure is not a smooth, monotonous decline, but rather exhibits a certain degree of fluctuation. This fluctuation is not entirely caused by the immersion process itself, but may be affected by other factors such as changes in ambient temperature. Directly judging the immersion endpoint based on this curve is prone to error and makes it difficult to obtain a stable and reliable plateau time point.

[0037] Figure 4 This is a schematic diagram illustrating the relationship between collected temperature values ​​and time, provided in an exemplary embodiment of this disclosure. The horizontal axis represents time (in hours), and the vertical axis represents temperature values ​​(in degrees Celsius). Figure 4 It can be observed that in actual production environments, the temperature of the battery surface is not constant, but fluctuates periodically over time.

[0038] These temperature fluctuations affect the viscosity of the electrolyte, the ion migration rate, and the measured AC impedance of the battery. Specifically, as the temperature increases, the electrolyte viscosity decreases, the ionic conductivity increases, and the measured impedance value decreases accordingly; conversely, as the temperature decreases, the impedance value increases.

[0039] contrast Figure 3 and Figure 4 It can be observed that, Figure 3 The fluctuation pattern of the impedance curve and Figure 4 The fluctuation patterns of the temperature curves show a certain correlation, which confirms that temperature is one of the important factors affecting impedance measurements.

[0040] Therefore, if the influence of temperature fluctuations is ignored and wettability is evaluated solely based on the curve of the original impedance value changing over time, it will be difficult to obtain accurate evaluation results. Therefore, it is necessary to eliminate the interference caused by temperature fluctuations in subsequent data processing and restore the impedance attenuation law dominated by the wetting process itself.

[0041] S22. Based on a pre-built correlation model between temperature, time and impedance, and the impedance and temperature values ​​at multiple time points, determine a target attenuation model to characterize the impedance of the target battery as a function of time.

[0042] because Figure 3 The original impedance curve shown exhibits irregular fluctuations, while Figure 4 The temperature curves shown exhibit obvious periodic changes, and the fluctuation patterns of the two parameters are somewhat correlated, indicating that temperature fluctuations interfere with the impedance measurements. Directly determining the wetting endpoint based on the original impedance curve is unlikely to yield accurate results. Therefore, this embodiment introduces a pre-constructed correlation model between temperature, time, and impedance.

[0043] Specifically, this correlation model can be a pre-defined mathematical expression that reflects the theoretical relationship between temperature, time, and impedance. Multiple time points, along with the corresponding impedance and temperature values ​​for each time point, are collected and substituted into this pre-constructed correlation model. Then, a mathematical fitting algorithm (such as the least squares method) is used to solve for the unknown parameters in the model. Once all parameters are determined, the model is transformed into a model that describes the impedance change of the target battery over time, i.e., the target attenuation model.

[0044] The target attenuation model is derived by taking into account the effect of temperature, and can more realistically reflect the impedance change trend dominated by the wetting process itself.

[0045] In some embodiments, the correlation model is determined based on a preset attenuation function and a temperature correction function, wherein the preset attenuation function is used to characterize the attenuation change of impedance over time, and the temperature correction function is used to characterize the effect of temperature on impedance.

[0046] In this embodiment, the pre-constructed correlation model can be determined based on a preset attenuation function and a temperature correction function. The preset attenuation function characterizes the attenuation of impedance over time under ideal isothermal conditions. Specifically, as the electrolyte gradually wets the electrode pores and ion transport channels are established, the AC impedance of the battery gradually decreases exponentially or approximately exponentially from an initial high value. The preset attenuation function is a mathematical expression used to describe this physical process.

[0047] The temperature correction function is used to characterize the effect of actual temperature deviating from the reference temperature on the impedance value. Since the viscosity and ionic conductivity of the electrolyte are closely related to temperature, changes in temperature will cause corresponding changes in the impedance measurement value, and the temperature correction function can correct for this effect.

[0048] By combining the preset attenuation function with the temperature correction function, a correlation model incorporating both time and temperature variables can be obtained. This correlation model not only reflects the impedance attenuation characteristics of the immersion process itself but also eliminates interference from ambient temperature fluctuations. Consequently, the target attenuation model obtained through subsequent fitting more accurately reproduces the impedance change pattern dominated by immersion, improving the accuracy of immersion endpoint determination.

[0049] In some embodiments, the preset decay function includes a first decay function and a second decay function, wherein the first decay function characterizes the relationship between impedance and time during the process of the electrolyte being absorbed by the first structural layer of the target battery, and the second decay function characterizes the relationship between impedance and time during the process of the electrolyte diffusing from the first structural layer to the second structural layer inside the target battery.

[0050] Specifically, the first decay function characterizes the relationship between impedance and time during the absorption of electrolyte by the first structural layer (e.g., electrode structure) of the target battery. In the initial stage of electrolyte filling, the electrolyte first contacts and is absorbed by the outermost electrode structure (e.g., separator or electrode surface layer). This process is relatively fast, and the corresponding impedance decreases rapidly. The first decay function is a mathematical expression describing the impedance change during this rapid absorption phase.

[0051] The second decay function characterizes the relationship between impedance and time during the diffusion of the electrolyte from the first structural layer to the second structural layer inside the target battery (e.g., pores deep within the electrode). After the electrolyte has completed absorption in the first structural layer, it needs to diffuse into the pores deep within the electrode (e.g., inside the electrode sheet). This process is relatively slow, and the corresponding impedance decrease is also relatively gradual. The second decay function describes the impedance change pattern during this slow diffusion phase.

[0052] By decomposing the preset attenuation function into a first attenuation function and a second attenuation function, the multi-stage physical characteristics of the electrolyte wetting process can be characterized more precisely, making the correlation model closer to the actual wetting mechanism. This improves the accuracy of the impedance attenuation curve obtained by subsequent fitting and provides a more reliable basis for judging the wetting endpoint.

[0053] In some embodiments, the preset attenuation function includes specified parameters to be solved. The determination of the target attenuation model characterizing the impedance change of the target battery over time, based on a pre-built model of the relationship between temperature, time, and impedance, and the impedance and temperature values ​​at multiple time points, includes: Based on a pre-built model of the relationship between temperature, time and impedance, and the impedance and temperature values ​​at multiple time points, the specified parameters in the preset attenuation function are determined to obtain the target attenuation model.

[0054] In this embodiment, the aforementioned preset attenuation function includes specified parameters to be solved, which determine the attenuation pattern of the impedance over time. To accurately determine these specified parameters, a pre-constructed correlation model is needed. This model includes not only the preset attenuation function but also a temperature correction function. The temperature correction function quantifies the impact of ambient temperature deviating from the reference temperature on the impedance measurement value.

[0055] The relationship model can be represented by the following formula: R_measure(t,T)=[A1 e^( t / τ1)+A2 e^( t / τ2)+R ∞ ] exp(α (T Tref)) Where R_measure(t,T) represents the impedance value measured under time t and temperature T, and in the formula [A1 e^( t / τ1)+A2 e^( t / τ2)+R ∞ [ ] is the preset attenuation function, using a double exponential attenuation form: A1 and A2 are attenuation amplitude parameters, corresponding to the contribution of the rapid wetting process and the slow wetting process to the impedance change, respectively; τ1 and τ2 are time constant parameters, representing the time scale of the rapid wetting process and the slow wetting process, respectively; R ∞ This represents the steady-state impedance value as time approaches infinity, indicating the impedance level after complete immersion.

[0056] In the formula exp(α) (T Tref is the temperature correction function, where α is the temperature correction coefficient, reflecting the degree of influence of temperature change on impedance; Tref is the preset reference temperature (e.g., 23.27℃). When the actual temperature T equals Tref, the correction factor is 1, that is, no correction is made; when T deviates from Tref, the correction factor adjusts the impedance value exponentially.

[0057] During the fitting process, the impedance values ​​and corresponding temperature values ​​collected in step S21 at multiple time points are substituted into the correlation model. Specifically, for each acquisition time t_i, the measured impedance is R_i, and the measured temperature is T_i. These are substituted into the above formula, and the specified parameters to be solved (including A1, A2, τ1, τ2, R_i, and T_i) are adjusted. ∞ The parameters α and β are used to minimize the overall error between the calculated R_measure(t_i, T_i) and the measured impedance R_i (e.g., by using the least squares method). Once the fitting is complete and all specified parameters are determined, the resulting preset attenuation function with the specific values ​​of these specified parameters is the target attenuation model.

[0058] The target attenuation model can be expressed as: R_corrected(t) = A1 e^( t / τ1)+A2 e^( t / τ2)+R ∞ Here, R_corrected(t) represents the change in impedance value over time at the reference temperature Tref (i.e., after eliminating the influence of temperature fluctuations). It is obtained by uniformly correcting the measured impedance values ​​at each actual temperature to the equivalent impedance value at the reference temperature using a temperature correction function during the fitting process, and then performing attenuation fitting on the corrected data. In other words, the target attenuation model reflects the impedance attenuation curve determined only by the immersion process itself, and no longer includes temperature variables.

[0059] It should be noted that the temperature correction function is no longer explicitly included in the final target attenuation model. This is because the effect of the temperature correction function has already been absorbed during the parameter solving process. The fitting algorithm has already eliminated the interference of temperature fluctuations on impedance based on measured temperature data, thus restoring the intrinsic relationship between impedance and time determined solely by the wetting process itself. Therefore, the target attenuation model characterizes the change of impedance over time after temperature correction, without needing to include the temperature variable again. This approach allows subsequent analysis to directly use the target attenuation model to determine the time when the impedance tends to stabilize, without considering temperature fluctuations, thereby obtaining an accurate wetting endpoint.

[0060] S23. Based on the target attenuation model, identify the time corresponding to when the impedance value of the target battery tends to stabilize, so as to obtain the immersion endpoint time of the target battery.

[0061] Specifically, after obtaining the target attenuation model, it is analyzed to determine the time corresponding to the impedance value stabilizing. From a physical perspective, as the electrolyte gradually wets the pores inside the electrode, the battery's impedance value gradually decreases from an initial high value and eventually tends towards a stable value. When the impedance value no longer changes over time, the wetting process can be considered to have reached a stable state.

[0062] Therefore, by observing the impedance change curve described by the target attenuation model over time, we can find the point in time where the impedance value flattens out and stops decreasing. This point in time corresponds to the point where the impedance value stabilizes and can be determined as the immersion endpoint time of the target battery.

[0063] This approach transforms the traditional method of judging wettability based on manual experience or destructive disassembly into a data-driven and mathematically model-based analytical process. The resulting wettability endpoint time is a clear and quantifiable value, providing an objective basis for setting static process parameters in battery production. The entire evaluation process does not require battery disassembly, is real-time and non-destructive, and overcomes the interference of temperature fluctuations on impedance values ​​in actual production environments, thus improving the accuracy and practicality of wettability evaluation.

[0064] In some embodiments, identifying the time when the impedance value of the target battery tends to stabilize based on the target attenuation model, in order to obtain the immersion endpoint time of the target battery, includes: Determine the derivative value of the target decay model at each time point; The first time point at which the absolute value of the derivative is less than a first preset threshold is determined as the immersion end time.

[0065] Specifically, the derivative value of the target attenuation model at each time point is first determined. Mathematically, the derivative reflects the rate of change of the function at that point. For the target attenuation model, its derivative represents how quickly the impedance value changes with time. In the initial stage of immersion, the impedance value decreases rapidly, the derivative is negative and has a large absolute value; as the immersion process gradually completes, the impedance value tends to stabilize, and the derivative approaches zero.

[0066] Then, the first time point at which the absolute value of the derivative becomes less than a first preset threshold is determined as the immersion endpoint time of the target battery. The first preset threshold is a pre-set positive number close to zero, and its specific value can be set according to the type of target battery, accuracy requirements, and actual production experience. When the absolute value of the derivative is less than this first preset threshold, it indicates that the change in impedance value has become very slow, and the immersion process can be considered essentially complete. Thereafter, extending the resting time has little effect on improving battery performance.

[0067] In this way, the infiltration endpoint time can be objectively identified from the target decay model without the need for manual judgment, thus improving the standardization and repeatability of the evaluation results. Furthermore, the infiltration evaluation method provided in this embodiment is non-destructive and real-time.

[0068] like Figure 5 The figure shown is a schematic diagram of the relationship between impedance value and time for the target attenuation model provided in the exemplary embodiment of this disclosure, where the horizontal axis represents time (in hours) and the vertical axis represents impedance value (in ohms).

[0069] Figure 5 The document includes illustrations of four types of data or curves. "Acquired impedance values" represent the raw impedance data points directly measured at multiple time points in step S21. These points show some fluctuation and do not exhibit a smooth decline. "Model-fitted impedance values ​​(time, temperature)" represent the impedance values ​​calculated by substituting the time and temperature values ​​at each acquisition moment into the correlation model (i.e., the complete formula including temperature correction). These points are relatively close to the original acquisition points, indicating that the model fits the measured data well. "Temperature-corrected impedance values ​​(normalized to average temperature)" represent the equivalent impedance values ​​after uniformly correcting the measured impedance values ​​at each acquisition moment to a reference temperature Tref (e.g., 23.27℃) using a temperature correction function. The corrected points show significantly reduced fluctuations and a more orderly distribution along the curve. "The curve corresponding to the target attenuation model" is a continuous curve plotted based on the fitted parameters, showing the change of the preset attenuation function (i.e., R_corrected(t) without the temperature term) over time. This curve is smooth and shows a gradual decline from an initial high value to a stable state.

[0070] from Figure 5 As can be seen, after temperature correction, the fluctuations in the impedance data are eliminated, and the target attenuation model curve can fit the corrected data points well, reflecting the impedance attenuation law determined solely by the immersion process itself. As time progresses, the curve gradually stabilizes, and the moment the curve begins to enter the stable region is the immersion endpoint time. Figure 5 and Figure 3 As can be seen from the comparison, after introducing the temperature correction mechanism in this embodiment, the target decay model obtained eliminates the interference caused by ambient temperature fluctuations, making the determination of the immersion endpoint time more accurate and reliable.

[0071] In some embodiments, after identifying the time corresponding to the stabilization of the impedance value of the target battery based on the target attenuation model to obtain the immersion endpoint time of the target battery, the method further includes: The internal wetting state of several reference batteries after disassembly is obtained, and the critical time point for whether the reference battery is qualified or unqualified is determined based on the wetting state of each reference battery. The reference batteries are of the same type and produced in the same environment as the target battery. The accuracy of determining the immersion endpoint time is based on the critical time point.

[0072] Specifically, several reference batteries can be obtained. These reference batteries are of the same type as the target battery and are manufactured under the same production environment. These reference batteries are disassembled at different time points after electrolyte injection to observe their internal wetting state. Based on the disassembly results, the critical time point between successful wetting (i.e., the electrolyte has fully wetted the electrode pores) and unsuccessful wetting (i.e., unwetted areas still exist within the pores) is determined. For example, if a reference battery shows successful wetting after 30 hours of disassembly but unsuccessful wetting after 28 hours, the critical time point can be determined to be approximately 29 hours.

[0073] Then, the critical time point is compared with the immersion endpoint time obtained in the above steps. If the two are basically consistent or the deviation is within an acceptable range, it indicates that the immersion endpoint time determined by this embodiment has high accuracy and can be relied upon. Conversely, if the deviation is large, the parameters in the correlation model can be adjusted, and the fitting and calculation can be repeated until it matches the critical time point.

[0074] By calibrating and validating the model calculation results using actual disassembly results, the reliability of the wettability evaluation results can be improved, ensuring that the determined wettability endpoint time truly corresponds to the actual completion time of the wettability process. Furthermore, once calibration is complete, the wettability evaluation method provided in this embodiment can be directly used for non-destructive evaluation of other batteries of the same type and produced in the same environment, without the need for further disassembly.

[0075] In some embodiments, after identifying the time corresponding to the stabilization of the impedance value of the target battery based on the target attenuation model to obtain the immersion endpoint time of the target battery, the method further includes: For a new battery to be evaluated that is the same type and production environment as the target battery, impedance data and temperature data of the new battery to be evaluated are collected at at least one time point after the electrolyte injection is completed. If the deviation between the impedance data and temperature data and the predicted value of the target attenuation model is less than a second preset threshold, the immersion endpoint time is taken as the immersion completion time of the new battery to be evaluated.

[0076] Specifically, for a new battery to be evaluated that is the same type as the target battery and manufactured in the same production environment, impedance and temperature data are collected at at least one time point after electrolyte injection. Here, "at least one time point" means that data can be collected at only one or a few time points, without the need to collect data at multiple time points for complete fitting as with the target battery.

[0077] Then, the collected impedance and temperature data are substituted into the target attenuation model (i.e., the temperature-corrected impedance attenuation curve previously fitted to the target battery) to calculate the predicted value (predicted impedance value) of the target attenuation model at that time point. The deviation between the measured impedance value and the predicted value is compared. If the deviation is less than a pre-set second threshold, it indicates that the immersion process of the new battery to be evaluated is basically consistent with that of the target battery, and the immersion endpoint time of the previously determined target battery can be directly used as the immersion completion time of the new battery to be evaluated.

[0078] In this way, the target degradation model and the determination of the immersion endpoint time are completed based on one or a small number of batteries. For a large number of batteries of the same type and in the same production environment, only data from a very small number of time points are needed to quickly determine whether the immersion has proceeded as expected, and the determined immersion endpoint time can be directly used as the process parameter. This reduces the workload and time cost of online inspection, improves production efficiency, and still maintains the accuracy of the evaluation.

[0079] In some embodiments, the acquisition of impedance and temperature values ​​of the target battery to be evaluated at multiple time points after electrolyte injection is completed includes: The impedance and temperature values ​​of the target battery being evaluated are collected at multiple time points after the electrolyte injection is completed using an interval sampling method. In the initial stage after the electrolyte injection is completed, a first sampling interval is used for sampling. After a first preset number of samplings or after a first preset time, the sampling is switched to a second sampling interval. The first sampling interval is shorter than the second sampling interval.

[0080] Specifically, in the initial stage after electrolyte injection, the wetting process between the electrolyte and electrode materials changes drastically, and the battery impedance decreases rapidly over time. To accurately capture the changes in this stage and ensure the accuracy of subsequent model fitting, a shorter initial sampling interval can be used. For example, the initial sampling interval can be set to 2 minutes, 5 minutes, or 10 minutes.

[0081] After a first preset number of samplings (e.g., 10 consecutive samplings), or after a first preset time has elapsed since the injection was completed, the trend of the immersion process gradually slows down, but there are still relatively obvious changes. At this point, in order to reduce data redundancy while maintaining tracking of the trend, sampling can be switched to a second sampling interval, which is longer than the first sampling interval. For example, the second sampling interval can be set to 15 minutes, 20 minutes, or 30 minutes.

[0082] Building upon this, a third or even more sampling stages can be set. For example, after continuously sampling a certain number of times (e.g., 10 times) using the second sampling interval or after a certain period of time, the sampling can be switched to a third sampling interval, which is longer than the second sampling interval. An application example could be: after the injection is completed, the first 10 samplings use a 5-minute sampling interval, the next 10 use a 15-minute sampling interval, and all subsequent sampling points use a 30-minute sampling interval.

[0083] By using this multi-stage, gradually sparse interval sampling method, a sufficient number of data points can be obtained in the early stage when the infiltration change is most critical, so as to accurately capture the rapid decay law of impedance; at the same time, the sampling frequency can be appropriately reduced in the later stage when the change is slow, so as to avoid collecting a large amount of duplicate or invalid data.

[0084] This phased adjustment of the sampling interval ensures the accuracy of the established target decay model while controlling the amount of data and the duration of the entire acquisition process, thus improving the practicality and economy of battery wettability evaluation. It is particularly suitable for production line environments requiring batch evaluation. It should be noted that the number of sampling phases and the specific sampling interval and duration of each phase can be set according to the type of target battery, electrolyte characteristics, and actual production environment requirements; this application does not impose any limitations on this.

[0085] In some embodiments, after identifying the time corresponding to the stabilization of the impedance value of the target battery based on the target attenuation model to obtain the immersion endpoint time of the target battery, the method further includes: If the immersion endpoint time exceeds a preset time range, it is determined that the immersion process of the target battery is abnormal.

[0086] Specifically, a preset time range corresponding to the completion time of the normal immersion process can be set in advance. This preset time range can be determined based on historical production data, the immersion time of similar batteries, or process requirements. For example, for a certain model of battery, the normal immersion endpoint time is usually between 30 and 40 hours.

[0087] After calculating the immersion endpoint time of the target battery, it is compared with a preset time range. If the immersion endpoint time exceeds the preset time range (e.g., greater than the upper limit of 40 hours), it can be determined that the immersion process of the target battery is abnormal. Possible causes of abnormality include, but are not limited to: insufficient electrolyte volume, abnormal electrolyte properties, excessive compaction of electrode pore structure, and blockage inside the battery.

[0088] In this way, a preset time range can be used as a diagnostic indicator to detect abnormalities in the production process in a timely manner, preventing batteries with wetting defects from flowing into subsequent processes, thereby improving product yield and production safety.

[0089] like Figure 6 The diagram shown is a schematic representation of the structure of a wettability evaluation device 60 provided in an exemplary embodiment of this disclosure. The wettability evaluation device 60 includes: The acquisition module 61 is used to acquire the impedance and temperature values ​​of the target battery to be evaluated at multiple time points after the electrolyte injection is completed. The determination module 62 is used to determine a target decay model that characterizes the impedance of the target battery as a function of time, based on a pre-built correlation model between temperature, time and impedance, and the impedance and temperature values ​​at multiple time points. The identification module 63 is used to identify the time when the impedance value of the target battery tends to stabilize based on the target attenuation model, so as to obtain the immersion end time of the target battery.

[0090] In some embodiments, the correlation model is determined based on a preset attenuation function and a temperature correction function, wherein the preset attenuation function is used to characterize the attenuation change of impedance over time, and the temperature correction function is used to characterize the effect of temperature on impedance.

[0091] In some embodiments, the preset attenuation function includes specified parameters to be solved, and the determining module 62 is specifically used for: Based on a pre-built model of the relationship between temperature, time and impedance, and the impedance and temperature values ​​at multiple time points, the specified parameters in the preset attenuation function are determined to obtain the target attenuation model.

[0092] In some embodiments, the preset decay function includes a first decay function and a second decay function, wherein the first decay function characterizes the relationship between impedance and time during the process of the electrolyte being absorbed by the first structural layer of the target battery, and the second decay function characterizes the relationship between impedance and time during the process of the electrolyte diffusing from the first structural layer to the second structural layer inside the target battery.

[0093] In some embodiments, the identification module 63 is specifically used for: Determine the derivative value of the target decay model at each time point; The first time point at which the absolute value of the derivative is less than a first preset threshold is determined as the immersion end time.

[0094] In some embodiments, the wettability evaluation device 60 further includes a verification module (not shown), the verification module being used for: The internal wetting state of several reference batteries after disassembly is obtained, and the critical time point for whether the reference battery is qualified or unqualified is determined based on the wetting state of each reference battery. The reference batteries are of the same type and produced in the same environment as the target battery. The accuracy of determining the immersion endpoint time is based on the critical time point.

[0095] In some embodiments, the identification module 63 is further configured to: For a new battery to be evaluated that is the same type and production environment as the target battery, impedance data and temperature data of the new battery to be evaluated are collected at at least one time point after the electrolyte injection is completed. If the deviation between the impedance data and temperature data and the predicted value of the target attenuation model is less than a second preset threshold, the immersion endpoint time is taken as the immersion completion time of the new battery to be evaluated.

[0096] In some embodiments, the acquisition module 61 is specifically used for: The impedance and temperature values ​​of the target battery being evaluated are collected at multiple time points after the electrolyte injection is completed using an interval sampling method. In the initial stage after the electrolyte injection is completed, a first sampling interval is used for sampling. After a first preset number of samplings or after a first preset time, the sampling is switched to a second sampling interval. The first sampling interval is shorter than the second sampling interval.

[0097] In some embodiments, the wettability evaluation device 60 further includes a detection module (not shown), the detection module being used for: If the immersion endpoint time exceeds a preset time range, it is determined that the immersion process of the target battery is abnormal.

[0098] The wettability evaluation device 60 provided in this embodiment collects the impedance and temperature values ​​of the target battery at multiple time points after liquid injection, and combines them with a pre-established correlation model to eliminate the interference of temperature fluctuations on impedance measurement. This allows for accurate fitting of the impedance decay law over time. Based on this decay law, the corresponding time when the impedance tends to stabilize can be identified, i.e., the time point when the battery reaches the wettability endpoint. Moreover, it does not require disassembling the battery, avoiding lag and subjectivity of human judgment, and realizing a quantitative evaluation of the wettability degree. This facilitates quick and accurate determination of whether the battery has completed wettability.

[0099] like Figure 7 The diagram shown is a schematic representation of an electronic device provided in an exemplary embodiment of this disclosure. The electronic device includes a processor, a memory, an input / output interface, a communication interface, a display unit, and an input device. The processor, memory, and input / output interface are connected via a system bus, and the communication interface, display unit, and input device are also connected to the system bus via the input / output interface. The processor provides computing and control capabilities. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The input / output interface is used for exchanging information between the processor and external devices. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, mobile cellular networks, NFC (Near Field Communication), or other technologies. When the computer program is executed by the processor, it implements an immersion evaluation method. The display unit of the electronic device is used to form a visually visible image. It can be a display screen, a projection device, or a virtual reality imaging device. The display screen can be an LCD screen or an e-ink screen. The input device of the electronic device can be a touch layer covering the display screen, or buttons, trackballs, or touchpads set on the casing of the electronic device, or external keyboards, touchpads, or mice, etc.

[0100] Those skilled in the art will understand that Figure 7 The structure shown is only a block diagram of a part of the structure related to the present application and does not constitute a limitation on the electronic device to which the present application is applied. The specific electronic device may include more or fewer components than shown in the figure, or combine certain components, or have different component arrangements.

[0101] Based on the same inventive concept, embodiments of this application also provide a computer-readable storage medium, which may include: read-only memory (ROM), random access memory (RAM), disk or optical disk, etc.

[0102] Since the computer program stored in the computer-readable storage medium can execute any of the infiltration evaluation methods provided in the embodiments of this application, the beneficial effects that any of the infiltration evaluation methods provided in the embodiments of this application can achieve can be realized, as detailed in the preceding embodiments, and will not be repeated here.

[0103] Based on the same inventive concept, embodiments of this application also provide a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of an electronic device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the electronic device to perform the methods provided in the various optional implementations of the above embodiments.

[0104] It should be noted that, in the data processing stage, the technical solution of this application has strictly limited the scope of data collection to the minimum necessary to achieve the technical objectives, preventing the acquisition of irrelevant information. For any user information to be collected, the data subject will be clearly informed and their consent obtained. Furthermore, technologies such as encrypted storage and access control are employed to strengthen data security and ensure the security and compliance of the entire data processing process. The technical model and decision-making mechanism are based on objective technical parameters and do not introduce unnecessary parameters such as gender or age that may lead to discrimination, resolutely eliminating algorithmic discrimination and upholding public order and good morals. In addition, the specification fully describes the technical implementation methods, application scenarios, and compliance protection details. The claims are consistent with the content of the specification, key compliance designs are clear and verifiable, and the overall technical design is guided by the protection of public interests and adherence to social ethics, without any circumstances that harm public interests or violate public order and good morals.

[0105] Any reference to memory, database, or other media used in the embodiments provided in this application may include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory may include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM may be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0106] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0107] In the above embodiments of the wettability evaluation device, computer-readable storage medium, electronic device, and computer program product, the descriptions of each embodiment have different focuses. Parts not described in detail in a particular embodiment can be referred to in the relevant descriptions of other embodiments. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes and beneficial effects of the wettability evaluation device, computer-readable storage medium, computer program product, electronic device, and their corresponding units described above can be referred to the description of the wettability evaluation method in the above embodiments, and will not be repeated here.

[0108] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0109] The above provides a detailed description of the wettability evaluation method, wettability evaluation device, electronic device, computer-readable storage medium, and computer program product provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for evaluating wettability, characterized in that, The method includes: The impedance and temperature values ​​of the target battery to be evaluated were collected at multiple time points after the electrolyte injection was completed. Based on a pre-built model of the relationship between temperature, time and impedance, and the impedance and temperature values ​​at multiple time points, a target decay model for characterizing the impedance of the target battery over time is determined. Based on the target attenuation model, the time corresponding to when the impedance value of the target battery tends to stabilize is identified, so as to obtain the immersion endpoint time of the target battery.

2. The method according to claim 1, characterized in that, The correlation model is determined based on a preset attenuation function and a temperature correction function. The preset attenuation function is used to characterize the attenuation change of impedance over time, and the temperature correction function is used to characterize the effect of temperature on impedance.

3. The method according to claim 2, characterized in that, The preset attenuation function includes specified parameters to be solved. The target attenuation model, determined based on a pre-built correlation model between temperature, time, and impedance, and the impedance and temperature values ​​at multiple time points, characterizes the impedance of the target battery as a function of time. This includes: Based on a pre-built model of the relationship between temperature, time and impedance, and the impedance and temperature values ​​at multiple time points, the specified parameters in the preset attenuation function are determined to obtain the target attenuation model.

4. The method according to claim 2, characterized in that, The preset decay function includes a first decay function and a second decay function, wherein the first decay function characterizes the relationship between impedance and time during the process of the electrolyte being absorbed by the first structural layer of the target battery, and the second decay function characterizes the relationship between impedance and time during the process of the electrolyte diffusing from the first structural layer to the second structural layer inside the target battery.

5. The method according to claim 1, characterized in that, The step of identifying the time when the impedance value of the target battery tends to stabilize based on the target attenuation model, in order to obtain the immersion endpoint time of the target battery, includes: Determine the derivative value of the target decay model at each time point; The first time point at which the absolute value of the derivative is less than a first preset threshold is determined as the immersion end time.

6. The method according to claim 1, characterized in that, After identifying the time corresponding to the point where the impedance value of the target battery tends to stabilize based on the target attenuation model, and thus obtaining the immersion endpoint time of the target battery, the method further includes: The internal wetting state of several reference batteries after disassembly is obtained, and the critical time point for whether the reference battery is qualified or unqualified is determined based on the wetting state of each reference battery. The reference batteries are of the same type and produced in the same environment as the target battery. The accuracy of determining the immersion endpoint time is based on the critical time point.

7. The method according to any one of claims 1-6, characterized in that, After identifying the time corresponding to the point where the impedance value of the target battery tends to stabilize based on the target attenuation model, and thus obtaining the immersion endpoint time of the target battery, the method further includes: For a new battery to be evaluated that is the same type and production environment as the target battery, impedance data and temperature data of the new battery to be evaluated are collected at at least one time point after the electrolyte injection is completed. If the deviation between the impedance data and temperature data and the predicted value of the target attenuation model is less than a second preset threshold, the immersion endpoint time is taken as the immersion completion time of the new battery to be evaluated.

8. The method according to any one of claims 1-6, characterized in that, The impedance and temperature values ​​of the target battery to be evaluated are collected at multiple time points after the electrolyte injection is completed, including: The impedance and temperature values ​​of the target battery being evaluated are collected at multiple time points after the electrolyte injection is completed using an interval sampling method. In the initial stage after the electrolyte injection is completed, a first sampling interval is used for sampling. After a first preset number of samplings or after a first preset time, the sampling is switched to a second sampling interval. The first sampling interval is shorter than the second sampling interval.

9. The method according to any one of claims 1-6, characterized in that, After identifying the time corresponding to the point where the impedance value of the target battery tends to stabilize based on the target attenuation model, and thus obtaining the immersion endpoint time of the target battery, the method further includes: If the immersion endpoint time exceeds a preset time range, it is determined that the immersion process of the target battery is abnormal.

10. An electronic device, characterized in that, It includes a processor and a memory, wherein the memory stores a computer program that, when executed by the processor, causes the processor to perform the steps of the immersion evaluation method according to any one of claims 1-9.

11. A storage medium, characterized in that, Includes a computer program, which, when run on an electronic device, causes the electronic device to perform the steps of the immersion evaluation method according to any one of claims 1-9.

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