A non-destructive lithium plating detection method and system for a lithium battery

Abstract

The present invention provides a method and system for non-destructive lithium plating detection of a lithium battery, relating to the technical field of lithium batteries. The method includes: performing constant current and constant voltage charging on the lithium battery, and collecting the electrical parameters of the lithium battery during the charging process; calculating a first lithium plating current generated due to the lithium plating phenomenon during the constant current stage; calculating a second lithium plating current generated due to the lithium plating phenomenon during the constant voltage stage; combining the ambient temperature, substituting the first lithium plating current and the second lithium plating current into the BV kinetic equation based on the Marcus-Hush kinetic model to obtain an effective lithium plating current density considering the ambient temperature; calculating the charging duration deviation value between the SOC full duration and the standard SOC full duration of the lithium battery; and calculating the lithium plating mass based on Faraday's theorem according to the effective lithium plating current density and the charging duration deviation value. The automatic detection of lithium plating of the lithium battery is completed online, with high accuracy, avoiding the risk of disassembly detection, improving the detection efficiency, and reducing the detection cost.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and particularly to a method and system for non-destructive lithium plating detection of lithium batteries. Background Art

[0002] A lithium battery is a rechargeable battery that uses lithium metal or lithium ions as electrode materials. Due to its high energy density, long service life, and light weight, it is widely used in portable electronic devices, electric vehicles, and energy storage devices. Non-destructive lithium plating detection is a detection method that does not damage the battery structure. By analyzing the electrochemical parameters of the battery during charge and discharge, the lithium plating phenomenon is detected, avoiding damage to the battery caused by detection.

[0003] Non-destructive lithium plating detection of lithium batteries can monitor the lithium plating phenomenon inside the battery in real time without damaging the battery structure, prevent the decline of battery performance, capacity loss, and potential safety risks. Through this detection method, the service life of the battery can be extended, its reliability in electric vehicles and energy storage systems can be enhanced, and the safe operation of the equipment can be ensured.

[0004] However, during the lithium plating detection of existing lithium batteries, it is necessary to manually disassemble the lithium battery for contact detection. During the detection process, the structure of the lithium battery will be changed. The detection process is complex and extremely likely to damage the normal structure of the lithium battery, resulting in high detection risks, increased lithium plating detection costs, low practicability, and inability to achieve online real-time detection. Summary of the Invention

[0005] In order to solve the technical problems existing in the prior art that during the lithium plating detection of lithium batteries, it is necessary to manually disassemble the lithium battery for contact detection, the structure of the lithium battery will be changed during the detection process, the detection process is complex and extremely likely to damage the normal structure of the lithium battery, resulting in high detection risks, increased lithium plating detection costs, low practicability, and inability to achieve online real-time detection, the present invention provides a method and system for non-destructive lithium plating detection of lithium batteries.

[0006] The technical solutions provided by the embodiments of the present invention are as follows:

[0007] First Aspect

[0008] A method for non-destructive lithium plating detection of a lithium battery provided by an embodiment of the present invention includes:

[0009] S1: Charge the lithium battery with constant current and constant voltage, and collect the electrical parameters of the lithium battery during the charging process. Among them, the electrical parameters of the lithium battery include the charging voltage in the constant current stage during the constant current charging stage, the charging voltage in the constant voltage stage and the current decay rate in the constant voltage stage, the SOC full charge duration, and the ambient temperature;

[0010] S2: Calculate the first lithium plating current generated due to lithium plating phenomenon during the constant current stage based on the charging voltage in the constant current stage;

[0011] S3: Calculate the second lithium plating current generated due to lithium plating phenomenon during the constant voltage stage based on the charging voltage in the constant voltage stage and the current decay rate in the constant voltage stage;

[0012] S4: Combine the ambient temperature, substitute the first lithium plating current and the second lithium plating current into the BV kinetic equation based on the Marcus-Hush kinetic model to obtain the effective lithium plating current density considering the ambient temperature;

[0013] S5: Calculate the charging duration deviation value between the SOC full duration and the standard SOC full duration of the lithium battery;

[0014] S6: Calculate the lithium plating mass based on Faraday's law according to the effective lithium plating current density and the charging duration deviation value;

[0015] S7: Output the lithium plating mass.

[0016] Second aspect

[0017] A non-destructive lithium plating detection system for a lithium battery provided by an embodiment of the present invention includes:

[0018] A processor;

[0019] A memory, on which computer-readable instructions are stored. When the computer-readable instructions are executed by the processor, the non-destructive lithium plating detection method for the lithium battery as described in the first aspect is implemented.

[0020] Third aspect

[0021] A computer-readable storage medium provided by an embodiment of the present invention, on which a computer program is stored. When the program is executed by the processor, the non-destructive lithium plating detection method for the lithium battery as described in the first aspect is implemented.

[0022] The beneficial effects brought by the technical solutions provided by the embodiments of the present invention at least include:

[0023] In the present invention, based on the online charging electrical parameters of lithium batteries, which are easy to collect, in the general constant current and constant voltage charging method, combined with the charging voltage in the constant current stage of the constant current charging stage, the charging voltage in the constant voltage stage and the current decay rate in the constant voltage charging stage, the SOC full charge duration, and the ambient temperature, considering the influence of the actual ambient temperature on charging, the lithium plating current generated due to the lithium plating phenomenon in the constant current stage and the second lithium plating current generated due to the lithium plating phenomenon in the constant voltage stage are calculated based on the collected parameters. Then, the obtained lithium plating current is substituted into the BV kinetic equation based on the Marcus-Hush kinetic model, fully considering the kinetic mechanism of charge transfer during the lithium plating process and the influence of ambient temperature on the lithium plating reaction rate, which can more accurately simulate and quantify the lithium plating phenomenon, making the calculation of the lithium plating current density more accurate, thereby improving the accuracy and reliability of the final lithium plating quality detection. After that, the effective lithium plating current density considering the kinetic characteristics of the electrochemical reaction and the temperature influence is obtained. Then, based on Faraday's law, the lithium plating mass is calculated according to the effective lithium plating current density and the charging duration deviation value. Considering the current change and charging duration difference during the battery charging process, it can more accurately reflect the cumulative effect of the lithium plating phenomenon, thereby improving the calculation accuracy of the lithium plating mass and avoiding errors caused by a single parameter. The data of the whole process can be obtained online, and the acquisition method is simple. The real-time detection of the lithium plating mass can be automatically completed without damaging the original structure of the lithium battery, greatly improving the detection efficiency, reducing the detection cost and detection risk. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0025] Figure 1 It is a schematic flowchart of a non-destructive lithium plating detection method for a lithium battery provided by an embodiment of the present invention;

[0026] Figure 2 It is a schematic structural diagram of a non-destructive lithium plating detection system for a lithium battery provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The following will describe the technical solutions in the present invention with reference to the drawings.

[0028] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to represent examples, illustrations or explanations. Any embodiment or design solution described as an "example" in the present invention should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Rather, the use of the word "example" is intended to present concepts in a specific manner. In addition, in the embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one of the two.

[0029] To make the technical problems to be solved, technical solutions and advantages of the present invention clearer, the following will be described in detail with reference to the accompanying drawings and specific embodiments.

[0030] Refer to the attached Figure 1 figures, which show a schematic flow chart of a method for non-destructive lithium plating detection of a lithium battery provided by an embodiment of the present invention.

[0031] The embodiments of the present invention provide a method for non-destructive lithium plating detection of a lithium battery. This method can be implemented by a non-destructive lithium plating detection device for a lithium battery, and this non-destructive lithium plating detection device for a lithium battery can be a terminal or a server. The processing flow of the method for non-destructive lithium plating detection of a lithium battery can include the following steps:

[0032] S1: Charge the lithium battery with constant current and constant voltage, and collect the electrical parameters of the lithium battery during the charging process.

[0033] Among them, the electrical parameters of the lithium battery include the charging voltage in the constant current charging stage, the charging voltage in the constant voltage charging stage, the current decay rate in the constant voltage charging stage, the full SOC duration, and the ambient temperature.

[0034] Among them, constant current and constant voltage charging is a commonly used charging method. The charging process is divided into two stages: first is the constant current stage, where the current remains unchanged and the voltage gradually increases. When the voltage reaches the set value, it enters the constant voltage stage, where the voltage remains unchanged and the current gradually decreases. The charging voltage in the constant current stage is the voltage that gradually rises as the battery is charged during the constant current charging process, and this voltage is the charging voltage in the constant current stage. The charging voltage in the constant voltage stage refers to the voltage remaining at the set value unchanged until the current gradually decays to a very small value. In the constant voltage stage, as the charging progresses, the current gradually decreases, and the rate of current decay is the current decay rate in the constant voltage stage. The full SOC duration refers to the time when the battery is fully charged, that is, the time required from the start of charging to the battery being fully charged.

[0035] It should be noted that by obtaining parameters such as the constant current voltage, constant voltage, current decay rate, and full SOC duration, the electrochemical reaction characteristics and current change trends in different charging stages can be accurately reflected. These data can precisely capture the occurrence time, degree, and dynamic changes of the lithium plating process, which helps to identify the lithium plating phenomenon in different charging stages and improve the comprehensiveness and accuracy of lithium plating detection.

[0036] In a possible implementation, S2 specifically includes:

[0037] S201: Calculate the charging overpotential during the constant current stage based on the charging voltage during the constant current stage:

[0038] η 恒流 = V 实际 - V 平衡

[0039] Where η 恒流 represents the charging overpotential during the constant current stage, V 实际 represents the charging voltage during the constant current stage, and V 平衡 represents the equilibrium voltage of the lithium battery in the non-lithium deposition state.

[0040] S202: Based on the charging voltage during the constant current stage, calculate the first lithium deposition current using the Tafel equation:

[0041]

[0042] Where I 1 represents the first lithium deposition current, e represents the natural constant, k 0 represents the exchange current density when the overpotential is 0, b represents the Tafel slope related to the lithium battery electrode material, g represents the gas constant, T represents the absolute temperature inside the lithium battery, C represents the pre-exponential factor of the lithium battery, and E a represents the activation energy of the lithium battery reaction.

[0043] Where I 0 specifically represents the exchange current density that reflects the reaction rate of the lithium battery in the non-lithium deposition state. The pre-exponential factor of the lithium battery specifically represents the frequency at which the reaction occurs successfully without any energy barriers (such as activation energy). The activation energy of the lithium battery reaction specifically represents the minimum energy required for the lithium battery reaction, usually in joules per mole (J / mol). It represents the energy barrier that the reactants need to overcome to transform into products.

[0044] It should be noted that the Tafel equation describes the relationship between the current and the overpotential in the electrode reaction. By calculating the first lithium deposition current using the Tafel equation, the relationship between the overpotential and the current change during the lithium deposition process can be accurately quantified. Considering factors such as the lithium battery material characteristics (such as the Tafel slope) and temperature, it ensures that the calculation of the lithium deposition current is more in line with the actual kinetic process of the electrochemical reaction. This method can improve the detection accuracy of the lithium deposition phenomenon, especially in the constant current stage, it can effectively identify the early influence of lithium deposition on the charging current.

[0045] S2: Calculate the first lithium deposition current generated due to the lithium deposition phenomenon during the constant current stage based on the charging voltage during the constant current stage.

[0046] Among them, the first lithium plating current is the additional current caused by the lithium plating phenomenon during the constant current charging stage. When lithium ions are deposited as lithium metal on the negative electrode surface, it will cause a change in current, and this part of the current is called the first lithium plating current. By calculating the first lithium plating current during the constant current stage, the current change during the lithium plating process can be accurately quantified, providing basic data for the subsequent calculation of the lithium plating quality. This method can capture the initial signs of lithium plating in the early stage of charging, thereby more precisely evaluating the lithium plating quality and improving the accuracy of the final detection result.

[0047] S3: Calculate the second lithium plating current generated due to the lithium plating phenomenon during the constant voltage stage according to the charging voltage during the constant voltage stage and the current decay rate during the constant voltage stage.

[0048] Among them, the second lithium plating current is the additional current caused by the lithium plating phenomenon during the constant voltage stage. At this time, the battery voltage remains constant, but the current gradually decays as the battery charging approaches saturation, and the current change caused by the lithium plating phenomenon is the second lithium plating current. By calculating the second lithium plating current during the constant voltage stage, the current change of lithium plating at the end of the charging of the battery can be captured, especially identifying the lithium plating phenomenon during the current decay process. In this way, the lithium plating information throughout the charging cycle can be obtained more comprehensively, ensuring that the calculation of the lithium plating quality is more accurate and complete, and improving the comprehensive evaluation of the battery health status.

[0049] In a possible implementation manner, S3 specifically includes:

[0050] S301: Calculate the charging overpotential during the constant voltage stage according to the charging voltage during the constant voltage stage:

[0051] η 恒压 = V' 实际 - V 平衡

[0052] Among them, η 恒压 represents the charging overpotential during the constant voltage stage, V' 实际 represents the charging voltage during the constant voltage stage, and V 平衡 represents the equilibrium voltage of the lithium battery in the state without lithium plating.

[0053] S302: Calculate the actual current after decay according to the current decay rate during the constant voltage stage:

[0054] I 衰减 = I 初始 × (1 - θ)

[0055] Among them, I 衰减 represents the actual current, I 初始 represents the initial current during the constant voltage stage, and θ represents the current decay rate during the constant voltage stage.

[0056] S303: Combine the charging overpotential and the actual current during the constant voltage stage, and use the Tafel equation to calculate the second lithium plating current:

[0057]

[0058] Among them, I 2 represents the second lithium plating current.

[0059] It should be noted that by combining the charging overpotential and the actual current during the constant voltage stage and using the Tafel equation to calculate the second lithium plating current, the dynamic change of current decay when the voltage is constant can be effectively considered, and the continuous impact of the lithium plating phenomenon on the current can be accurately reflected. It not only considers the current decay characteristics but also quantifies the relationship between the overpotential and the current, improving the detection accuracy of the lithium plating phenomenon in the later stage of charging. Especially when the battery is close to full charge, it can more effectively evaluate the long-term impact of lithium plating on battery health.

[0060] S4: Combine the ambient temperature, substitute the first lithium plating current and the second lithium plating current into the BV kinetic equation based on the Marcus-Hush kinetic model, and obtain the effective lithium plating current density considering the ambient temperature.

[0061] Among them, the Marcus-Hush kinetic model is a classical theoretical model for describing electron transfer reactions, mainly used to explain the process of electron transfer from one molecule or ion to another in electrochemical reactions. The BV kinetic equation of the Marcus-Hush kinetic model is a model for describing the rate of electron transfer reactions, especially suitable for electrochemical reactions. It combines factors such as electrode potential, overpotential, and reaction activation energy to explain the process of electron transfer from one reactant to another. The BV (Butler-Volmer) equation is a commonly used equation in electrochemistry to describe the relationship between current and potential. The Marcus-Hush model further introduces the concept of free energy of electron transfer reactions on the basis of the BV equation, considering the kinetic characteristics between molecules.

[0062] It should be noted that the current density calculated by substituting the first and second lithium plating currents into the BV kinetic equation and combining influencing factors such as ambient temperature can more realistically reflect the intensity of the lithium plating phenomenon under actual working conditions. First of all, in this process, considering the complexity of ambient temperature, reaction kinetics, and electrochemical processes, a more realistic lithium plating current density is obtained. This can not only improve the accuracy of the calculation but also better reflect the dynamic changes of the lithium plating process under different conditions, helping to improve the accuracy of lithium plating quality assessment. In addition, the calculated effective lithium plating current density can more comprehensively reflect the influence of different charging stages and ambient temperature on the lithium plating process, ensure more accurate lithium plating detection, reduce errors, and thus improve the effectiveness and reliability of battery health status monitoring.

[0063] In a possible implementation, the calculation method of the effective lithium stripping current density is specifically as follows:

[0064]

[0065] where α represents the charge transfer coefficient, represents the effective lithium stripping current density, and J eff represents an intermediate variable, and T env represents the ambient temperature, represents the activation free energy required for electron transfer in the lithium battery calculated based on the Marcus-Hush kinetic model, and F represents the Faraday constant.

[0066] It should be noted that by calculating the effective lithium stripping current density based on the Marcus-Hush kinetic model, the kinetic factors in the charge transfer process, such as the charge transfer coefficient, activation free energy, and temperature, can be comprehensively considered. This model accurately describes the electron transfer behavior during the lithium stripping process, especially introducing the influence of temperature and kinetic barriers, making the current density calculation more in line with the actual electrochemical environment. Compared with the simple current-potential relationship model, such a calculation method can more comprehensively reflect the occurrence of lithium stripping under different conditions, improving the recognition accuracy of the lithium stripping phenomenon and the evaluation effect of the battery health state.

[0067] In a possible implementation, the calculation method of the activation free energy is specifically as follows:

[0068]

[0069] where λ represents the reorganization energy required for solvent polarization of the lithium battery, and η in represents the overpotential during the charging process. During the constant current charging process, η in = η 恒流 , and during the constant voltage charging process, η in = η 恒压 .

[0070] The activation free energy is the minimum energy barrier that needs to be overcome for the conversion from reactants to products in a chemical reaction. In an electrochemical reaction, it represents the energy required for the reactants during the electron transfer process to be able to cross the energy potential barrier and carry out the reaction. The activation free energy is an important factor determining the reaction rate. The higher the energy, the slower the reaction, and vice versa. For the lithium stripping phenomenon in a lithium battery, the activation free energy is used to describe the energy barrier that needs to be overcome when lithium ions precipitate on the electrode surface. By calculating the activation free energy, the difficulty and reaction rate of lithium stripping can be predicted, helping to better understand the behavior of the battery under different charging conditions.

[0071] By combining the activation free energy calculation formula with the reorganization energy of lithium battery solvent polarization and the overpotential during the charging process, it is possible to more accurately reflect the energy barrier that needs to be overcome during the electron transfer process. Such a method takes into account the actual kinetic characteristics of the electrode reaction and combines the different characteristics of the charging stage, making the calculation of the activation free energy more accurate. Especially when describing the energy requirements of complex electrochemical reactions, it can better predict the lithium plating behavior and its occurrence probability.

[0072] S5: Calculate the charging duration deviation value between the full SOC charging duration and the standard full SOC charging duration of the lithium battery.

[0073] It should be noted that by calculating the charging duration deviation value between the full SOC charging duration and the standard full SOC charging duration, the abnormal charging time change caused by lithium plating during the charging process of the battery can be quantified. This deviation value can be used as an indirect indicator of the lithium plating state of the battery, helping to identify the decrease in charging efficiency and the deterioration of the battery health state caused by lithium plating, thereby providing an effective reference value to detect the lithium plating phenomenon and improving the accuracy and comprehensiveness of the overall lithium plating detection.

[0074] In a possible implementation manner, the charging duration deviation value is specifically:

[0075] Δt = t actual -t standard

[0076] where Δt represents the charging duration deviation value, t actual represents the full SOC charging duration, and t standard represents the standard full SOC charging duration.

[0077] It should be noted that by calculating the charging duration deviation value between the full SOC charging duration and the standard full charging duration, the abnormal conditions during the charging process can be quantified. This calculation method can directly reflect the problem of decreased charging efficiency caused by lithium plating or battery aging, providing a simple and effective indicator to evaluate the battery health status, thereby helping to detect the deterioration or potential failure of the battery performance in a timely manner.

[0078] S6: Calculate the lithium plating mass based on Faraday's law according to the effective lithium plating current density and the charging duration deviation value.

[0079] Among them, Faraday's law, or Faraday's law of electrolysis, describes the relationship between current and the substances generated in an electrochemical reaction. It describes the principle that during electrolysis, after a certain period of time, the amount of substances generated on the electrodes is proportional to the electric charge. By combining the effective lithium plating current density and the charging duration deviation value, and using Faraday's law to calculate the lithium plating mass, the lithium plating phenomenon can be quantified into specific mass values. This method can not only directly reflect the impact of lithium plating on the battery capacity, but also correlate the complex electrochemical process with the actual mass change, thus providing more accurate results for lithium plating detection and helping to evaluate the health status and lifespan of the battery.

[0080] In a possible implementation, the calculation method of the lithium plating mass is specifically as follows:

[0081]

[0082] Among them, m Li represents the lithium plating mass, A represents the effective area of the lithium battery electrode, M Li represents the molar mass of lithium element, n = 1 represents the number of electron transfers, and Δt represents the charging duration deviation value.

[0083] It should be noted that by combining the effective lithium plating current density, the charging duration deviation value, the effective area of the electrode, and the molar mass of lithium element for lithium plating mass calculation, the impact of the lithium plating phenomenon under different charging conditions can be more comprehensively reflected. This method precisely considers multiple factors such as current, time, and electrode surface area, can quantify the actual impact of lithium plating on the battery capacity and performance, thereby improving the accuracy of lithium plating mass calculation and providing a scientific basis for battery performance evaluation.

[0084] S7: Output the lithium plating mass.

[0085] In a possible implementation, after S7, it further includes:

[0086] In the case where the lithium plating mass is greater than the preset lithium plating mass, issue a warning.

[0087] It should be noted that by issuing a warning when the lithium plating mass exceeds the preset value, it can timely remind the user that the battery has shown an obvious lithium plating phenomenon, which helps to take preventive measures in advance to avoid the rapid decline of battery performance or the occurrence of safety hazards. This mechanism ensures that the battery operates within a safe range during work, extends the battery lifespan, and improves the overall system reliability.

[0088] During actual use, by collecting key electrical parameters in the charging stage of a lithium battery, including the voltage, current decay rate, and SOC full charge duration in the constant current stage and the constant voltage stage, the currents generated by lithium plating in the constant current and constant voltage stages are calculated respectively. Then, these currents are substituted into the BV kinetic equation of the Marcus-Hush kinetic model, and the effective lithium plating current density is calculated in combination with the ambient temperature. The deviation value between the SOC full charge duration and the standard duration is calculated, and based on Faraday's law, combined with the effective lithium plating current density and the charging duration deviation value, the lithium plating mass is finally calculated. This process combines the electrochemical characteristics of different charging stages with environmental factors, can comprehensively and accurately quantify the lithium plating phenomenon, and improves the accuracy of lithium plating detection and the reliability of battery health status assessment.

[0089] The beneficial effects brought by the technical solution provided in the embodiment of the present invention at least include:

[0090] In the present invention, through the electrical parameters of the online charging of a lithium battery that is easy to collect in the common constant current and constant voltage charging method, combined with the charging voltage in the constant current stage of the constant current charging stage, the charging voltage in the constant voltage stage of the constant voltage charging stage, the current decay rate in the constant voltage stage, the SOC full charge duration, and the ambient temperature, considering the influence of the actual ambient temperature on charging, and then based on the collected parameters, the lithium plating current generated by the lithium plating phenomenon in the constant current stage and the second lithium plating current generated by the lithium plating phenomenon in the constant voltage stage are calculated. Then, the obtained lithium plating currents are substituted into the BV kinetic equation based on the Marcus-Hush kinetic model, fully considering the kinetic mechanism of charge transfer during lithium plating and the influence of ambient temperature on the lithium plating reaction rate, can more accurately simulate and quantify the lithium plating phenomenon, make the calculation of the lithium plating current density more accurate, and then improve the accuracy and reliability of the detection of the final lithium plating mass. After that, the effective lithium plating current density considering the kinetic characteristics of the electrochemical reaction and the influence of temperature is obtained, and then according to the effective lithium plating current density and the charging duration deviation value, the lithium plating mass is calculated based on Faraday's law. Considering the current change and charging duration difference during the battery charging process, it can more accurately reflect the cumulative effect of the lithium plating phenomenon, thereby improving the calculation accuracy of the lithium plating mass and avoiding errors caused by a single parameter. The data of the whole process can be obtained online, and the acquisition method is simple. The real-time detection of the lithium plating mass can be automatically completed without damaging the original structure of the lithium battery, greatly improving the detection efficiency, reducing the detection cost and detection risk.

[0091] Refer to the attached Figure 2 illustrates the structural schematic diagram of a non-destructive lithium plating detection system for a lithium battery provided by the present invention.

[0092] The present invention also provides a non-destructive lithium plating detection system 20 for a lithium battery, which is applied to the above-mentioned non-destructive lithium plating detection method for a lithium battery, and includes:

[0093] Processor 201.

[0094] A memory 202 stores computer-readable instructions thereon. When the computer-readable instructions are executed by the processor 201, a non-destructive lithium plating detection method for a lithium battery as in the method embodiment is implemented.

[0095] The non-destructive lithium plating detection system 20 for a lithium battery provided by the present invention can execute the above-mentioned non-destructive lithium plating detection method for a lithium battery and achieve the same or similar technical effects. To avoid repetition, the present invention will not elaborate further.

[0096] The beneficial effects brought by the technical solution provided by the embodiments of the present invention at least include:

[0097] In the present invention, based on the online charging electrical parameters of a lithium battery in a common constant current and constant voltage charging method that are easy to collect, combined with the charging voltage in the constant current stage of the constant current charging stage, the charging voltage in the constant voltage stage and the current decay rate in the constant voltage charging stage, the SOC full charge duration, and the ambient temperature, considering the influence of the actual ambient temperature on charging, then the lithium plating current generated due to the lithium plating phenomenon in the constant current stage and the second lithium plating current generated due to the lithium plating phenomenon in the constant voltage stage are calculated based on the collected parameters. Then, the obtained lithium plating current is substituted into the BV kinetic equation based on the Marcus-Hush kinetic model, fully considering the kinetic mechanism of charge transfer during the lithium plating process and the influence of ambient temperature on the lithium plating reaction rate, which can more accurately simulate and quantify the lithium plating phenomenon, making the calculation of the lithium plating current density more accurate, thereby improving the accuracy and reliability of the final lithium plating quality detection. After that, an effective lithium plating current density considering the kinetic characteristics of the electrochemical reaction and the influence of temperature is obtained. Then, based on Faraday's law, the lithium plating mass is calculated according to the effective lithium plating current density and the charging duration deviation value. Considering the current change and charging duration difference during the battery charging process, it can more accurately reflect the cumulative effect of the lithium plating phenomenon, thereby improving the calculation accuracy of the lithium plating mass and avoiding errors caused by a single parameter. The data of the whole process can be obtained online, and the acquisition method is simple. The real-time detection of the lithium plating mass can be automatically completed without damaging the original structure of the lithium battery, greatly improving the detection efficiency, reducing the detection cost and detection risk.

[0098] It should be understood that the processor in the embodiments of the present invention may be a central processing unit (CPU), and the processor may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0099] It should also be understood that the memory in the embodiments of the present invention may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example but not limitation, many forms of random access memory (RAM) are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM), and direct rambus RAM (DR RAM).

[0100] The above embodiments can be implemented in whole or in part by software, hardware (such as circuits), firmware, or any other combination. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, the processes or functions described in the embodiments of the present invention are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by wired (such as infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that can be accessed by a computer, or a data storage device such as a server or data center that contains one or more collections of available media. The available media can be magnetic media (such as floppy disks, hard disks, magnetic tapes), optical media (such as DVDs), or semiconductor media. The semiconductor media can be a solid-state drive.

[0101] It should be understood that the term "and / or" in this document is merely a description of the association relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. Here, A and B can be singular or plural. In addition, the character " / " in this document generally represents an "or" relationship between the associated objects before and after, but it may also represent an "and / or" relationship, which can be specifically understood by referring to the context.

[0102] In the present invention, "at least one" means one or more, and "a plurality" means two or more. "At least one of the following" or its similar expressions refer to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c can represent: a, b, c, a - b, a - c, b - c, or a - b - c, where a, b, and c can be single or multiple.

[0103] It should be understood that in various embodiments of the present invention, the magnitudes of the sequence numbers of the above stages do not mean the order of execution. The order of execution of each stage should be determined by its function and internal logic, and should not constitute any limitation to the implementation stages of the embodiments of the present invention.

[0104] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0105] Those skilled in the art can clearly understand that for the convenience and conciseness of description, the specific working stages of the devices, apparatuses, and units described above can refer to the corresponding stages in the foregoing method embodiments, and will not be elaborated herein.

[0106] In several embodiments provided by the present invention, it should be understood that the disclosed devices, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection between each other can be through some interfaces. The indirect coupling or communication connection of the devices or units can be in an electrical, mechanical, or other form.

[0107] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0108] In addition, the functional units in each embodiment of the present invention can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit.

[0109] When the above-mentioned functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable 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 a part of this 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 for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memories (ROM), random access memories (RAM), magnetic disks, or optical discs.

[0110] An embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, it implements the non-destructive lithium stripping detection method for lithium batteries as described in the method embodiment.

[0111] The computer-readable storage medium provided by the present invention can implement the steps and effects of the non-destructive lithium stripping detection method for lithium batteries in the above method embodiment. To avoid repetition, the present invention will not elaborate further.

[0112] The beneficial effects brought by the technical solution provided by the embodiment of the present invention at least include:

[0113] In the present invention, by using the electrical parameters of online charging of lithium batteries that are easily collected in a common constant current and constant voltage charging method, combining the charging voltage in the constant current stage of the constant current charging stage, the charging voltage in the constant voltage stage of the constant voltage charging stage, the current decay rate in the constant voltage stage, the SOC full charge duration, and the ambient temperature, considering the influence of the actual ambient temperature on charging, and then calculating the lithium plating current generated due to lithium plating phenomenon in the constant current stage and the second lithium plating current generated due to lithium plating phenomenon in the constant voltage stage based on the collected parameters. Then, substituting the obtained lithium plating current into the BV kinetic equation based on the Marcus-Hush kinetic model, fully considering the kinetic mechanism of charge transfer during the lithium plating process and the influence of ambient temperature on the lithium plating reaction rate, the lithium plating phenomenon can be more accurately simulated and quantified, making the calculation of the lithium plating current density more accurate. Furthermore, the accuracy and reliability of the final lithium plating quality detection are improved. After that, an effective lithium plating current density considering the kinetic characteristics of the electrochemical reaction and the influence of temperature is obtained. Then, based on Faraday's law, the lithium plating mass is calculated according to the effective lithium plating current density and the charging duration deviation value. Considering the current change and charging duration difference during the battery charging process, the cumulative effect of the lithium plating phenomenon can be more accurately reflected, thereby improving the calculation accuracy of the lithium plating mass and avoiding errors caused by a single parameter. The data of the whole process can be obtained online, and the acquisition method is simple. The real-time detection of the lithium plating mass can be automatically completed without damaging the original structure of the lithium battery, greatly improving the detection efficiency, reducing the detection cost and detection risk.

[0114] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

[0115] The following points need to be explained:

[0116] (1) The drawings of the embodiments of the present invention only relate to the structures involved in the embodiments of the present invention, and other structures can refer to the usual designs.

[0117] (2) For clarity, in the drawings used to describe the embodiments of the present invention, the thickness of the layer or region is enlarged or reduced, that is, these drawings are not drawn according to the actual ratio. It can be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "under" another element, the element can be "directly" on or under another element or there can be an intermediate element.

[0118] (3) Without conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other to obtain new embodiments.

[0119] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. The protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A non-destructive lithium deposition detection method for lithium batteries, characterized in that: include: S1: Perform constant current and constant voltage charging on the lithium battery, and collect the electrical parameters of the lithium battery during the charging process, wherein the electrical parameters of the lithium battery include the constant current stage charging voltage in the constant current charging stage, the constant voltage stage charging voltage in the constant voltage charging stage, the constant voltage stage current decay rate, the SOC full charge time, and the ambient temperature; S2: Calculating a first lithium deposition current generated by lithium deposition in the constant current stage according to the charging voltage in the constant current stage; S3: calculating a second lithium deposition current generated by the lithium deposition phenomenon in the constant voltage stage according to the charging voltage in the constant voltage stage and the current attenuation rate in the constant voltage stage; S4: In combination with the ambient temperature, substituting the first lithium deposition current and the second lithium deposition current into a BV kinetic equation based on a Marcus-Hush kinetic model to obtain an effective lithium deposition current density considering the ambient temperature; S5: Calculating a charging time deviation between the SOC full charge time and a standard SOC full charge time of the lithium battery; S6: Calculating the lithium deposition mass based on the effective lithium deposition current density and the charging time deviation value based on Faraday's theorem; S7: Outputting the lithium deposition mass; Wherein, the S2 specifically includes: S201: Calculate the constant current stage charging overpotential according to the constant current stage charging voltage: η 恒流 =V 实际 -V 平衡 Among them, η 恒流 Indicates the charging overpotential during the constant current stage, V 实际 Indicates the charging voltage in the constant current stage, V 平衡 Indicates the equilibrium voltage of the lithium battery without lithium deposition; S202: Based on the charging voltage in the constant current stage, the first lithium deposition current is calculated using the Tafel equation: Where I1 represents the first lithium deposition current, e represents the natural constant, k0 represents the exchange current density when the overpotential is 0, b represents the Tafel slope related to the lithium battery electrode material, g represents the gas constant, T represents the absolute temperature inside the lithium battery, C represents the lithium battery pre-factor, E a Represents the activation energy of lithium battery reaction; Wherein, the S3 specifically includes: S301: Calculate the constant voltage stage charging overpotential according to the constant voltage stage charging voltage: η 恒压 =V' 实际 -V 平衡 Among them, η 恒压 Indicates the charging overpotential in the constant voltage stage, V' 实际 Indicates the charging voltage in the constant voltage stage, V 平衡 Indicates the equilibrium voltage of the lithium battery without lithium deposition; S302: Calculate the actual current after attenuation according to the current attenuation rate in the constant voltage stage: I 衰减 =I 初始 ×(1-θ) Among them, I 衰减 Indicates the actual current, I 初始 represents the initial current in the constant voltage stage, and θ represents the current decay rate in the constant voltage stage; S303: Calculate the second lithium deposition current by using the Tafel equation based on the charging overpotential in the constant voltage stage and the actual current: Wherein, I2 represents the second lithium deposition current.

2. The non-destructive lithium deposition detection method of a lithium battery according to claim 1, characterized in that: The calculation method of the effective lithium precipitation current density is specifically as follows: Where α represents the charge transfer coefficient, represents the effective lithium deposition current density, J eff represents the intermediate variable, T env Indicates the ambient temperature, It represents the activation free energy required for electron transfer in lithium batteries calculated based on the Marcus-Hush kinetic model, and F represents the Faraday constant.

3. The non-destructive lithium deposition detection method of a lithium battery according to claim 2, characterized in that: The activation free energy is calculated as follows: Among them, λ represents the reorganization energy required for the polarization of lithium battery solvent, η in Indicates the overpotential during charging, η during constant current charging in =η 恒流 , during constant voltage charging, η in =η 恒压 .

4. The non-destructive lithium deposition detection method of a lithium battery according to claim 1, characterized in that: The charging time deviation value is specifically: Δt=t actual -t standard Among them, Δt represents the charging time deviation value, t actual Indicates the SOC full time, t standard Indicates the standard SOC full charge time.

5. The non-destructive lithium deposition detection method of a lithium battery according to claim 2, characterized in that: The calculation method of the lithium precipitation mass is specifically as follows: Among them, m Li represents the mass of lithium precipitated, A represents the effective area of ​​lithium battery electrode, M Li represents the molar mass of lithium element, n=1 represents the number of electron transfers, and Δt represents the deviation value of charging time.

6. The non-destructive lithium deposition detection method of a lithium battery according to claim 5, characterized in that: After S7, the method further includes: When the lithium deposition mass is greater than the preset lithium deposition mass, an early warning is issued.

7. A non-destructive lithium deposition detection system for lithium batteries, characterized in that: include: processor; A memory having computer-readable instructions stored thereon, wherein when the computer-readable instructions are executed by the processor, the non-destructive lithium deposition detection method for a lithium battery as claimed in any one of claims 1 to 6 is implemented.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, a non-destructive lithium deposition detection method for a lithium battery as described in any one of claims 1 to 6 is implemented.

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