Lithium precipitation detection method and device of lithium ion battery, computer equipment, readable storage medium and program product

Abstract

The invention relates to a lithium separation detection method, device and equipment of a lithium ion battery, a storage medium and a program product, and relates to the technical field of battery detection. The method can improve the precision of lithium precipitation detection. The method comprises the following steps: constructing a lithium precipitation electrochemical model according to electrochemical parameters of the lithium ion battery, constructing a lithium precipitation thermal model according to thermal parameters of the lithium ion battery, and constructing a lithium precipitation strain model according to geometric parameters of the lithium ion battery; coupling the lithium precipitation electrochemical model with the lithium precipitation thermal model, and coupling the lithium precipitation electrochemical model with the lithium precipitation strain model to obtain an electrochemical-thermal-stress coupling model; obtaining a target characteristic parameter value of the lithium ion battery when a lithium precipitation phenomenon occurs, and setting a lithium precipitation threshold condition according to the target characteristic parameter value; and acquiring the current characteristic parameter value of the lithium ion battery by using an electrochemical-thermal-stress coupling model, and detecting whether the lithium ion battery has a lithium precipitation phenomenon or not according to the current characteristic parameter value and a lithium precipitation threshold condition.

Description

Technical Field

[0001] The present application relates to the technical field of battery detection, and in particular to a method, device, computer equipment, computer-readable storage medium and computer program product for detecting lithium plating of a lithium-ion battery. Background Art

[0002] With the development of energy storage technology, electrochemical energy storage technology has emerged. Lithium battery energy storage is the core of electrochemical energy storage. Lithium-ion batteries have the technical advantages of high power, high energy density, long cycle life, no memory effect and no pollution. Lithium-ion batteries show good electrochemical performance under normal working conditions, but lithium deposition is prone to occur under extreme conditions such as overcharging, low-temperature charging and fast charging.

[0003] In traditional technology, lithium deposition detection of lithium-ion batteries is mainly carried out through in-situ detection methods, such as based on the shape of the battery internal resistance distribution curve during intermittent charging, and determining the degree of lithium deposition of the battery according to the data relationship model between the degree of lithium deposition and the internal resistance value. However, the above scheme needs to be carried out under specific intermittent charging conditions, and cannot detect lithium deposition behavior in real time. The applicability is limited. It only relies on the shape of the internal resistance distribution curve, and it is difficult to accurately quantify the degree and location of lithium deposition. In addition, the change of internal resistance is not the only factor affecting lithium deposition. Other factors (such as temperature changes, etc.) can also cause changes in internal resistance, which is easy to cause misjudgment, resulting in the problem of low accuracy of lithium deposition detection in traditional technology. Summary of the invention

[0004] Based on this, it is necessary to provide a lithium plating detection method, device, computer equipment, computer readable storage medium and computer program product for lithium ion batteries in response to the above technical problems.

[0005] In a first aspect, the present application provides a method for detecting lithium deposition in a lithium-ion battery, comprising:

[0006] Determine a lithium-ion battery to be tested, and obtain battery parameters of the lithium-ion battery; the battery parameters include electrochemical parameters, thermal parameters, and geometric parameters;

[0007] According to the electrochemical parameters, a lithium deposition electrochemical model of the lithium ion battery is constructed, according to the thermal parameters, a lithium deposition thermal model of the lithium ion battery is constructed, and according to the geometric parameters, a lithium deposition strain model of the lithium ion battery is constructed;

[0008] The lithium deposition electrochemical model is coupled with the lithium deposition thermal model, and the lithium deposition electrochemical model is coupled with the lithium deposition strain model to obtain an electrochemical-thermal-stress coupling model of the lithium ion battery;

[0009] Simulating the lithium deposition phenomenon of the lithium-ion battery by using a lithium deposition simulation system to obtain a target characteristic parameter value of the lithium-ion battery when the lithium deposition phenomenon occurs, and setting a lithium deposition threshold condition according to the target characteristic parameter value;

[0010] The electrochemical-thermal-stress coupling model is used to obtain the current characteristic parameter value of the lithium-ion battery, and whether the lithium deposition phenomenon occurs in the lithium-ion battery is detected according to the current characteristic parameter value and the lithium deposition threshold condition.

[0011] In one embodiment, coupling the lithium deposition electrochemical model with the lithium deposition thermal model, and coupling the lithium deposition electrochemical model with the lithium deposition strain model, includes:

[0012] The heat generation rate of the lithium ion battery is calculated by the lithium deposition electrochemical model, and a heat generation rate plane is obtained according to the heat generation rate. The heat generation rate plane is used as the heat source term of the lithium deposition thermal model to calculate the temperature of the internal temperature field in the lithium ion battery; a temperature distribution plane is obtained according to the temperature, and the temperature distribution plane is used as the temperature term of the lithium deposition electrochemical model; the lithium ion concentration of the lithium deposition side reaction in the lithium ion battery is calculated by the lithium deposition electrochemical model, and a lithium ion concentration distribution plane is obtained according to the lithium ion concentration, and the lithium ion concentration distribution plane is used as the input term of the lithium deposition strain model.

[0013] In one embodiment, before using the electrochemical-thermal-stress coupling model to obtain the current characteristic parameter value of the lithium-ion battery, the method further includes: obtaining temperature data and strain data of the lithium-ion battery collected by a fiber grating device;

[0014] The method of using the electrochemical-thermal-stress coupling model to obtain the current characteristic parameter value of the lithium-ion battery includes: inputting the temperature data and the strain data into the electrochemical-thermal-stress coupling model for numerical calculation and data fitting to obtain the current characteristic parameter value output by the electrochemical-thermal-stress coupling model.

[0015] In one embodiment, the detecting whether the lithium deposition phenomenon occurs in the lithium-ion battery according to the current characteristic parameter value and the lithium deposition threshold condition includes:

[0016] Determine whether the current characteristic parameter value meets the lithium deposition threshold condition; if the current characteristic parameter value meets the lithium deposition threshold condition, confirm that the lithium deposition phenomenon has occurred in the lithium-ion battery and trigger a warning signal; if the current characteristic parameter value does not meet the lithium deposition threshold condition, confirm that the lithium deposition phenomenon has not occurred in the lithium-ion battery.

[0017] In one embodiment, constructing the lithium electrochemical model of the lithium ion battery according to the electrochemical parameters includes:

[0018] When the lithium ion battery meets preset assumptions, lithium deposition kinetic parameters are added to the negative electrode of the lithium ion battery according to the electrochemical parameters; and according to the lithium deposition kinetic parameters, a charge conservation sub-model, a mass conservation sub-model and an electrode kinetic sub-model of the lithium ion battery are constructed as the lithium deposition electrochemical model.

[0019] In one embodiment, constructing a thermal model of lithium deposition of the lithium-ion battery according to the thermal parameters includes:

[0020] According to the thermal parameters, the heat source term in the lithium-ion battery is determined; the heat source term includes polarization heat, ohmic heat and reaction heat; according to the sum of the heat generated by the heat source term, the total heat generated by the lithium-ion battery is obtained; the total amount of flow heat exchange between the surface of the lithium-ion battery and the air is obtained, and according to the total heat and the total amount of flow heat exchange, the lithium precipitation thermal model is constructed.

[0021] In a second aspect, the present application also provides a lithium ion battery lithium deposition detection device, comprising:

[0022] A parameter acquisition module, used to determine the lithium-ion battery to be tested and acquire battery parameters of the lithium-ion battery; the battery parameters include electrochemical parameters, thermal parameters and geometric parameters;

[0023] A model building module, used to build a lithium deposition electrochemical model of the lithium ion battery according to the electrochemical parameters, to build a lithium deposition thermal model of the lithium ion battery according to the thermal parameters, and to build a lithium deposition strain model of the lithium ion battery according to the geometric parameters;

[0024] A model coupling module, used to couple the lithium deposition electrochemical model with the lithium deposition thermal model, and to couple the lithium deposition electrochemical model with the lithium deposition strain model, so as to obtain an electrochemical-thermal-stress coupling model of the lithium ion battery;

[0025] A lithium deposition simulation module, used to simulate the lithium deposition phenomenon of the lithium-ion battery using a lithium deposition simulation system to obtain a target characteristic parameter value of the lithium-ion battery when the lithium deposition phenomenon occurs, and to set a lithium deposition threshold condition according to the target characteristic parameter value;

[0026] The lithium deposition detection module is used to obtain the current characteristic parameter value of the lithium ion battery by using the electrochemical-thermal-stress coupling model, and detect whether the lithium deposition phenomenon occurs in the lithium ion battery according to the current characteristic parameter value and the lithium deposition threshold condition.

[0027] In a third aspect, the present application further provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the following steps are implemented:

[0028] Determine a lithium ion battery to be detected, and obtain battery parameters of the lithium ion battery; the battery parameters include electrochemical parameters, thermal parameters and geometric parameters; construct a lithium deposition electrochemical model of the lithium ion battery according to the electrochemical parameters, construct a lithium deposition thermal model of the lithium ion battery according to the thermal parameters, and construct a lithium deposition strain model of the lithium ion battery according to the geometric parameters; couple the lithium deposition electrochemical model with the lithium deposition thermal model, and couple the lithium deposition electrochemical model with the lithium deposition strain model to obtain an electrochemical-thermal-stress coupling model of the lithium ion battery; simulate the lithium deposition phenomenon of the lithium ion battery using a lithium deposition simulation system to obtain a target characteristic parameter value of the lithium ion battery when the lithium deposition phenomenon occurs, and set a lithium deposition threshold condition according to the target characteristic parameter value; use the electrochemical-thermal-stress coupling model to obtain a current characteristic parameter value of the lithium ion battery, and detect whether the lithium deposition phenomenon occurs in the lithium ion battery according to the current characteristic parameter value and the lithium deposition threshold condition.

[0029] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the following steps are implemented:

[0030] Determine a lithium ion battery to be detected, and obtain battery parameters of the lithium ion battery; the battery parameters include electrochemical parameters, thermal parameters and geometric parameters; construct a lithium deposition electrochemical model of the lithium ion battery according to the electrochemical parameters, construct a lithium deposition thermal model of the lithium ion battery according to the thermal parameters, and construct a lithium deposition strain model of the lithium ion battery according to the geometric parameters; couple the lithium deposition electrochemical model with the lithium deposition thermal model, and couple the lithium deposition electrochemical model with the lithium deposition strain model to obtain an electrochemical-thermal-stress coupling model of the lithium ion battery; simulate the lithium deposition phenomenon of the lithium ion battery using a lithium deposition simulation system to obtain a target characteristic parameter value of the lithium ion battery when the lithium deposition phenomenon occurs, and set a lithium deposition threshold condition according to the target characteristic parameter value; use the electrochemical-thermal-stress coupling model to obtain a current characteristic parameter value of the lithium ion battery, and detect whether the lithium deposition phenomenon occurs in the lithium ion battery according to the current characteristic parameter value and the lithium deposition threshold condition.

[0031] In a fifth aspect, the present application further provides a computer program product, including a computer program, which implements the following steps when executed by a processor:

[0032] Determine a lithium ion battery to be detected, and obtain battery parameters of the lithium ion battery; the battery parameters include electrochemical parameters, thermal parameters and geometric parameters; construct a lithium deposition electrochemical model of the lithium ion battery according to the electrochemical parameters, construct a lithium deposition thermal model of the lithium ion battery according to the thermal parameters, and construct a lithium deposition strain model of the lithium ion battery according to the geometric parameters; couple the lithium deposition electrochemical model with the lithium deposition thermal model, and couple the lithium deposition electrochemical model with the lithium deposition strain model to obtain an electrochemical-thermal-stress coupling model of the lithium ion battery; simulate the lithium deposition phenomenon of the lithium ion battery using a lithium deposition simulation system to obtain a target characteristic parameter value of the lithium ion battery when the lithium deposition phenomenon occurs, and set a lithium deposition threshold condition according to the target characteristic parameter value; use the electrochemical-thermal-stress coupling model to obtain a current characteristic parameter value of the lithium ion battery, and detect whether the lithium deposition phenomenon occurs in the lithium ion battery according to the current characteristic parameter value and the lithium deposition threshold condition.

[0033] The above-mentioned lithium deposition detection method, device, computer equipment, computer-readable storage medium and computer program product of lithium ion battery respectively construct a lithium deposition electrochemical model, a lithium deposition thermal model and a lithium deposition strain model of the lithium ion battery according to the electrochemical parameters, thermal parameters and geometric parameters of the lithium ion battery, couple the lithium deposition electrochemical model with the lithium deposition thermal model, and couple the lithium deposition electrochemical model with the lithium deposition strain model to construct an electrochemical-thermal-stress coupling model of the lithium ion battery, thereby unifying the electrochemical behavior, thermal effect and strain effect of the lithium ion battery in the same mathematical model, and accurately quantifying the degree of lithium deposition through the coupled detection of multiple characteristic parameters such as comprehensive electrochemistry, heat and stress, and being able to accurately locate the area where lithium deposition occurs, avoiding misjudgment and missed judgment, thereby improving the accuracy of lithium deposition detection. In addition, this solution can monitor the lithium plating condition in real time during the operation of lithium-ion batteries (including charging, discharging or static conditions), without relying on intermittent testing or specific experimental conditions. It can adapt to different types of lithium-ion battery systems (including different electrolytes, positive and negative electrode materials, etc.), and is not significantly disturbed by the external environment (such as temperature, vibration, etc.). It can accurately detect lithium plating behavior under extreme conditions such as high-rate charging, low-temperature charging, and overcharging conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 An application environment diagram of a lithium deposition detection method for a lithium-ion battery in one embodiment;

[0036] Figure 2 The figure is a schematic flow chart of a lithium deposition detection method for a lithium ion battery in one embodiment;

[0037] Figure 3 A schematic diagram of a flow chart of a model coupling step in an embodiment;

[0038] Figure 4 It is a schematic diagram of a flow chart of a lithium deposition detection method for a lithium ion battery in a specific embodiment;

[0039] Figure 5 It is a structural block diagram of a lithium deposition detection device for a lithium ion battery in one embodiment;

[0040] Figure 6 FIG. 4 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0042] The lithium deposition detection method of the lithium ion battery provided in the embodiment of the present application can be applied to Figure 1 In the application environment shown, the terminal communicates with the server through the network. The data storage system can store the data that the server needs to process. The data storage system can be integrated on the server or placed on the cloud or other network servers.

[0043] Specifically, the lithium plating detection method for a lithium-ion battery provided in an embodiment of the present application can be executed by a terminal.

[0044] Exemplarily, the terminal determines a lithium-ion battery to be detected and obtains battery parameters of the lithium-ion battery; the battery parameters include electrochemical parameters, thermal parameters and geometric parameters; the terminal constructs a lithium deposition electrochemical model of the lithium-ion battery according to the electrochemical parameters, constructs a lithium deposition thermal model of the lithium-ion battery according to the thermal parameters, and constructs a lithium deposition strain model of the lithium-ion battery according to the geometric parameters; the terminal couples the lithium deposition electrochemical model with the lithium deposition thermal model, and couples the lithium deposition electrochemical model with the lithium deposition strain model to obtain an electrochemical-thermal-stress coupling model of the lithium-ion battery; the terminal simulates the lithium deposition phenomenon of the lithium-ion battery using a lithium deposition simulation system to obtain a target characteristic parameter value of the lithium-ion battery when lithium deposition occurs, and sets a lithium deposition threshold condition according to the target characteristic parameter value; the terminal obtains the current characteristic parameter value of the lithium-ion battery using the electrochemical-thermal-stress coupling model, and detects whether lithium deposition occurs in the lithium-ion battery according to the current characteristic parameter value and the lithium deposition threshold condition.

[0045] In such Figure 1 In the application environment shown, the terminal can be, but is not limited to, various personal computers, laptops, smart phones, and tablet computers. The server can be implemented as an independent server or a server cluster consisting of multiple servers.

[0046] In one embodiment, Figure 2 As shown, a lithium ion battery lithium plating detection method is provided, and the method is applied to Figure 1 The terminal in is used as an example to illustrate, including the following steps:

[0047] Step S201, determining a lithium-ion battery to be tested, and obtaining battery parameters of the lithium-ion battery; the battery parameters include electrochemical parameters, thermal parameters, and geometric parameters.

[0048] Among them, electrochemical parameters include battery electrode materials, electrolyte concentration, volume fraction, diffusion coefficient, conductivity, radius of porous electrode particles and lithium ion concentration; thermal parameters include battery specific heat capacity, thermal conductivity and density; geometric parameters include battery width, thickness, height, and the width, thickness, height and tab position of each layer in the basic electrochemical unit.

[0049] Specifically, the terminal responds to a lithium plating detection instruction of a lithium-ion battery, determines a lithium-ion battery to be detected according to the instruction, and obtains battery parameters of the lithium-ion battery.

[0050] Step S202, constructing a lithium deposition electrochemical model of a lithium ion battery according to electrochemical parameters, constructing a lithium deposition thermal model of a lithium ion battery according to thermal parameters, and constructing a lithium deposition strain model of a lithium ion battery according to geometric parameters.

[0051] Among them, the lithium deposition electrochemical model includes a charge conservation sub-model, a mass conservation sub-model and an electrode kinetics sub-model.

[0052] Specifically, first, when the lithium-ion battery meets preset assumptions, the terminal adds lithium plating kinetic parameters to the negative electrode of the lithium-ion battery according to the electrochemical parameters, and constructs a charge conservation sub-model, a mass conservation sub-model and an electrode kinetic sub-model of the lithium-ion battery according to the lithium plating kinetic parameters as a lithium plating electrochemical model; then, the terminal determines the heat source terms in the lithium-ion battery according to the thermal parameters, obtains the total heat generated by the lithium-ion battery according to the sum of the heat generated by the heat source terms, and constructs a lithium plating thermal model according to the total heat and the total flow heat exchange; finally, the terminal constructs a lithium plating strain model of the lithium-ion battery according to the geometric parameters.

[0053] To further explain, constructing the lithium plating strain model of lithium-ion batteries specifically includes the following steps:

[0054] When lithium ions diffuse into the negative electrode spherical particles and some lithium ions are precipitated on the surface of the negative electrode particles, the particles expand and deform. The "Solid Mechanics" module of simulation software such as COMSOL can be used to build a lithium precipitation strain model to simulate the volume expansion caused by lithium precipitation and its effect on the stress distribution of the battery shell. The expression is as follows:

[0055]

[0056] In the above formula, and are radial strain and hoop strain, respectively; and are radial stress and hoop stress respectively; , is the initial lithium ion concentration; is the elastic modulus; is Poisson’s ratio; is the partial molar volume.

[0057] The geometric equation is:

[0058]

[0059] In the above formula, u is the radial displacement.

[0060] Assuming that there is no physical force acting on the negative electrode spherical particles, the mechanical equilibrium equation is:

[0061]

[0062] In order to quickly determine the dangerous area of ​​negative electrode particle damage during lithium ion charging and discharging, the following VonMises stress is introduced:

[0063]

[0064] Step S203, coupling the lithium deposition electrochemical model with the lithium deposition thermal model, and coupling the lithium deposition electrochemical model with the lithium deposition strain model, to obtain an electrochemical-thermal-stress coupling model of the lithium ion battery.

[0065] Specifically, the terminal uses the lithium deposition electrochemical model to calculate the heat generation rate of the lithium-ion battery, obtains the heat generation rate plane according to the heat generation rate, uses the heat generation rate plane as the heat source term of the lithium deposition thermal model, and calculates the temperature of the internal temperature field in the lithium-ion battery; then, according to the temperature, obtains the temperature distribution plane, and uses the temperature distribution plane as the temperature term of the lithium deposition electrochemical model; then, the lithium deposition electrochemical model is used to calculate the lithium ion concentration of the lithium deposition side reaction in the lithium-ion battery, obtains the lithium ion concentration distribution plane according to the lithium ion concentration, uses the lithium ion concentration distribution plane as the input term of the lithium deposition strain model, and obtains the electrochemical-thermal-stress coupling model of the lithium-ion battery.

[0066] Step S204, using a lithium deposition simulation system to simulate the lithium deposition phenomenon of a lithium-ion battery to obtain a target characteristic parameter value of the lithium-ion battery when the lithium deposition phenomenon occurs, and setting a lithium deposition threshold condition according to the target characteristic parameter value.

[0067] Among them, the target characteristic parameter value can be the negative electrode potential, lithium deposition current density, lithium deposition amount, thermal effect, and stress and strain data of the lithium-ion battery when lithium deposition occurs.

[0068] Specifically, the terminal constructs a lithium deposition simulation system, and uses the lithium deposition simulation system to simulate the lithium deposition behavior of lithium-ion batteries under different working conditions (high-rate charging, low-temperature charging or overcharging), records the corresponding data, and obtains the target characteristic parameter value of the lithium-ion battery when lithium deposition occurs, and sets the corresponding lithium deposition threshold condition according to the target characteristic parameter value.

[0069] To further explain, building a lithium precipitation simulation system specifically includes the following steps:

[0070] The lithium plating behavior of lithium-ion batteries under different working conditions (high rate charging, low temperature charging or overcharging) is simulated and the corresponding data is recorded.

[0071] Monitoring of negative electrode potential, including:

[0072] Output the distribution of the negative electrode potential in the model , analyze the negative electrode potential distribution through post-processing to check whether If a negative area appears, record the location and range of the area.

[0073] Calculation of lithium deposition current density, including:

[0074] Calculation of the current density of the lithium deposition side reaction And the exchange current density of the lithium deposition reaction , record the changes of lithium plating current density with time and position.

[0075] Record the area with higher lithium deposition current density (such as the electrode edge or the location where the current density is concentrated). Calculation of lithium deposition amount includes:

[0076] Define the calculation formula of lithium deposition amount, take the time integral of lithium deposition current density as variable, the equation is expressed as:

[0077]

[0078] In the above formula, is the amount of metallic lithium generated by lithium deposition, A is the surface area of ​​the electrode, n is the number of electrons in the lithium deposition reaction, and F is the Faraday constant.

[0079] Output lithium deposition distribution map, showing the amount of lithium deposition at each location on the electrode surface; output lithium deposition accumulation curve, showing the growth trend of lithium deposition over time; thermal effect analysis, including: output temperature distribution map, showing the temperature rise in the area where lithium deposition occurs. Analyze local hot spots caused by the heat of lithium deposition reaction; stress and strain data, including: strain distribution of battery shell, shell strain abnormality (such as local expansion) can be used as indirect evidence of lithium deposition. Local mechanical stress distribution, local stress concentration area is a high-risk location for lithium deposition, which can be used for detection and positioning.

[0080] Based on the above analysis of the lithium deposition reaction, the data of the negative electrode potential, lithium deposition current density, lithium deposition amount, thermal effect, stress and strain of the battery when lithium deposition occurs are obtained as the basis for early warning of lithium deposition and detection of the location of lithium deposition, including: increased overpotential, local temperature abnormality, shell strain or mechanical stress concentration, high current density on the negative electrode surface, and local temperature rise. Set the corresponding threshold, and trigger the warning signal when it exceeds the threshold.

[0081] Step S205, using the electrochemical-thermal-stress coupling model, obtaining the current characteristic parameter value of the lithium-ion battery, and detecting whether lithium deposition occurs in the lithium-ion battery according to the current characteristic parameter value and the lithium deposition threshold condition.

[0082] Among them, the current characteristic parameter value can be the current negative electrode potential, lithium deposition current density, lithium deposition amount, thermal effect, and stress and strain data of the lithium-ion battery.

[0083] Specifically, the terminal inputs the temperature data and strain data of the lithium-ion battery into the electrochemical-thermal-stress coupling model for numerical calculation and data fitting, obtains the current characteristic parameter value output by the electrochemical-thermal-stress coupling model, and then determines whether the current characteristic parameter value meets the lithium deposition threshold condition; if the current characteristic parameter value meets the lithium deposition threshold condition, it is confirmed that lithium deposition has occurred in the lithium-ion battery and a warning signal is triggered; if the current characteristic parameter value does not meet the lithium deposition threshold condition, it is confirmed that lithium deposition has not occurred in the lithium-ion battery.

[0084] In the above-mentioned lithium deposition detection method of lithium ion battery, according to the electrochemical parameters, thermal parameters and geometric parameters of the lithium ion battery, the lithium deposition electrochemical model, lithium deposition thermal model and lithium deposition strain model of the lithium ion battery are respectively constructed, the lithium deposition electrochemical model is coupled with the lithium deposition thermal model, and the lithium deposition electrochemical model is coupled with the lithium deposition strain model to construct an electrochemical-thermal-stress coupling model of the lithium ion battery, thereby unifying the electrochemical behavior, thermal effect and strain effect of the lithium ion battery in the same mathematical model, and through the coupled detection of multiple characteristic parameters such as comprehensive electrochemical, thermal and stress, the degree of lithium deposition can be accurately quantified, and the area where lithium deposition occurs can be accurately located to avoid misjudgment and missed judgment, thereby improving the accuracy of lithium deposition detection. In addition, this solution can monitor the lithium plating condition in real time during the operation of lithium-ion batteries (including charging, discharging or static conditions), without relying on intermittent testing or specific experimental conditions. It can adapt to different types of lithium-ion battery systems (including different electrolytes, positive and negative electrode materials, etc.), and is not significantly disturbed by the external environment (such as temperature, vibration and other factors). It can accurately detect lithium plating behavior under extreme conditions such as high-rate charging, low-temperature charging and overcharging conditions.

[0085] In one embodiment, if Figure 3 As shown, in the above step S203, the lithium deposition electrochemical model is coupled with the lithium deposition thermal model, and the lithium deposition electrochemical model is coupled with the lithium deposition strain model, which specifically includes the following steps:

[0086] Step S301, calculate the heat generation rate of the lithium ion battery by the lithium deposition electrochemical model, obtain the heat generation rate plane according to the heat generation rate, use the heat generation rate plane as the heat source term of the lithium deposition thermal model, and calculate the temperature of the internal temperature field in the lithium ion battery.

[0087] Step S302, obtaining a temperature distribution plane according to the temperature, and using the temperature distribution plane as a temperature term of the lithium deposition electrochemical model.

[0088] Step S303, calculating the lithium ion concentration of the lithium deposition side reaction in the lithium ion battery by the lithium deposition electrochemical model, obtaining the lithium ion concentration distribution plane according to the lithium ion concentration, and using the lithium ion concentration distribution plane as an input item of the lithium deposition strain model.

[0089] Specifically, the terminal integrates the heat generation rate calculated by the lithium deposition electrochemical model along the thickness direction of the battery, and takes the average value to obtain a two-dimensional heat generation rate plane, and inputs the two-dimensional heat generation rate plane into the lithium deposition thermal model as the heat source term of the lithium deposition thermal model, thereby completing the coupling of the heat generation rate from the lithium deposition electrochemical model to the lithium deposition thermal model; then, the terminal integrates the temperature calculated by the lithium deposition thermal model along the thickness direction of the battery, and takes the average value to obtain a two-dimensional temperature distribution plane, and inputs the two-dimensional temperature distribution plane into the lithium deposition electrochemical model as the heat source term of the lithium deposition thermal model. The temperature term of the lithium deposition electrochemical model is used to complete the coupling of the heat generation rate from the lithium deposition electrochemical model to the lithium deposition thermal model. Finally, the terminal integrates the lithium ion concentration of the lithium deposition side reaction in the lithium deposition electrochemical model and calculates the average value to obtain a two-dimensional lithium ion concentration distribution plane. The two-dimensional lithium ion concentration distribution plane is input into the lithium deposition strain model as the input item of the lithium deposition strain model. In this way, the coupling of the lithium ion concentration from the lithium deposition electrochemical model to the lithium deposition strain model is completed, thereby accurately constructing the electrochemical-thermal-stress coupling model of the lithium-ion battery.

[0090] In one embodiment, before obtaining the current characteristic parameter value of the lithium-ion battery using the electrochemical-thermal-stress coupling model, the following steps are also included:

[0091] Acquire temperature data and strain data of lithium-ion batteries collected by fiber grating equipment;

[0092] In the above step S205, the current characteristic parameter value of the lithium-ion battery is obtained by using the electrochemical-thermal-stress coupling model, which specifically includes the following steps:

[0093] The temperature data and strain data are input into the electrochemical-thermal-stress coupling model for numerical calculation and data fitting to obtain the current characteristic parameter values ​​output by the electrochemical-thermal-stress coupling model.

[0094] Specifically, the terminal uses fiber grating equipment to collect temperature data and strain data of lithium-ion batteries, arranges optical fibers on the surface of lithium-ion batteries, and focuses on the hot spots of the batteries, such as the center of the battery surface (heat concentration area) and the corner area of ​​the battery; the collected temperature data and strain data are input into the electrochemical-thermal-stress coupling model, and the current characteristic parameters related to lithium deposition are extracted through numerical calculation and data fitting, including negative electrode potential, lithium deposition current density, lithium deposition amount, and lithium deposition location.

[0095] In one embodiment, in the above step S205, detecting whether lithium deposition occurs in the lithium-ion battery according to the current characteristic parameter value and the lithium deposition threshold condition specifically includes the following steps:

[0096] Determine whether the current characteristic parameter value meets the lithium deposition threshold condition; if the current characteristic parameter value meets the lithium deposition threshold condition, it is confirmed that lithium deposition has occurred in the lithium-ion battery and a warning signal is triggered; if the current characteristic parameter value does not meet the lithium deposition threshold condition, it is confirmed that lithium deposition has not occurred in the lithium-ion battery.

[0097] Specifically, the terminal detects whether lithium deposition has occurred in the lithium-ion battery by determining whether the current characteristic parameter value meets the lithium deposition threshold condition; if the current characteristic parameter value meets the lithium deposition threshold condition, it is confirmed that lithium deposition has occurred in the lithium-ion battery, and a warning signal is triggered, while the user is advised to take corresponding measures, such as stopping charging or replacing the battery; if the current characteristic parameter value does not meet the lithium deposition threshold condition, it is confirmed that lithium deposition has not occurred in the lithium-ion battery.

[0098] In one embodiment, in the above step S202, a lithium electrochemical model of lithium ion battery is constructed according to electrochemical parameters, which specifically includes the following steps:

[0099] When the lithium-ion battery meets the preset assumptions, the lithium plating kinetic parameters are added to the negative electrode of the lithium-ion battery according to the electrochemical parameters; based on the lithium plating kinetic parameters, the charge conservation sub-model, mass conservation sub-model and electrode kinetic sub-model of the lithium-ion battery are constructed as the lithium plating electrochemical model.

[0100] Specifically, the terminal can make the following assumptions about the lithium-ion battery, including: assuming that the active particles in the positive and negative electrodes are spherical particles with uniform distribution and uniform size; assuming that the charging and discharging process of the lithium-ion battery occurs only in the solid and liquid phases, and no gas is generated; assuming that the volume of the lithium-ion battery does not change during operation, and the electrode porosity does not change.

[0101] You can use the "Lithium Ion Battery" interface in simulation software such as COMSOL to add lithium deposition kinetic parameters, including lithium deposition reaction rate constant and lithium deposition current density calculation formula, to the negative electrode of the lithium ion battery based on the length of the positive current collector, positive electrode, separator, negative electrode and negative current collector in the two-dimensional plane, as well as the concentration, volume fraction, diffusion coefficient, conductivity, porous electrode particle radius and lithium ion concentration of the battery electrode material and electrolyte. Build a lithium ion battery electrochemical model based on the pseudo two-dimensional model (P2D model) that considers lithium deposition and double-layer effects, including charge conservation sub-model, mass conservation sub-model and electrode kinetic sub-model.

[0102] The steps to build the charge conservation submodel are as follows: The double-layer capacitor exists at the interface between the positive and negative active material particles and the electrolyte. Since the distance between the double layers is extremely small, a small potential difference can cause a large field strength, which will inevitably affect the Li +The transfer rate is affected, so that the pulse current can pass smoothly. Considering the double layer effect, the solid phase charge conservation equation is:

[0103]

[0104] In the above formula, is the solid phase potential, is the solid phase current density, is the solid phase conductivity, is the solid volume fraction, and γ refers to the Brugger coefficient.

[0105] According to the concentrated solution theorem, the battery liquid phase charge conservation satisfies the following equation:

[0106]

[0107] In the above formula, is the liquid phase lithium ion conductivity, is the liquid phase potential, is the gas constant, Faraday constant, is the absolute temperature, is the ion activity correlation, is the ion transfer coefficient, is the lithium ion liquid phase concentration, is the liquid phase current density.

[0108] The steps to build the mass conservation sub-model are as follows: According to Fick's second law, the diffusion equation of lithium ions in the solid phase is:

[0109]

[0110] In the above formula, is the solid phase concentration of lithium ions, is the solid phase diffusion coefficient of lithium ions, is the coordinate of the active material particle in the radial direction, is the radius of the active material particle, is the reaction current density on the particle surface.

[0111] According to Fick's second law, the diffusion equation of lithium ions in the liquid phase is:

[0112]

[0113] In the above formula, is the effective lithium ion liquid phase diffusion coefficient, is the liquid phase diffusion coefficient.

[0114] The steps to build the electrode kinetics sub-model are as follows: Since lithium ion charging at low temperature may cause lithium precipitation side reaction, the total current of the electrochemical reaction on the surface of the active material particles is divided into two parts: the normal lithium ion deintercalation current and the precipitation current. Both parts of the current are represented by their own Butler-Volmer equations, which are as follows:

[0115]

[0116] In the above formula, is the current density of the normal lithium insertion and extraction reaction, is the current density of the lithium deposition side reaction, and are the corresponding exchange current densities, and are the corresponding anode charge transfer coefficients, and are the corresponding cathode charge transfer coefficients, and are the corresponding overpotentials respectively.

[0117] The exchange current density during lithium ion insertion and extraction is expressed as:

[0118]

[0119] In the above formula, is the normal lithium insertion and extraction reaction rate constant, is the maximum lithium concentration on the active electrode surface, is the electrolyte lithium ion concentration, is the reference concentration of electrolyte on the surface of active particles.

[0120] The exchange current density of the lithium precipitation reaction is expressed as:

[0121]

[0122] In the above formula, is the lithium deposition reaction rate constant.

[0123] The overpotential of normal lithium insertion and extraction reaction is:

[0124]

[0125] In the above formula, It is the open circuit voltage of the positive and negative electrode active materials and is a function of the battery state of charge (SOC) and temperature.

[0126] The overpotential of the lithium deposition side reaction is as follows:

[0127]

[0128] In the above formula, The equilibrium potential of the lithium precipitation reaction is generally taken as the potential of lithium metal 0V. is the total resistance of the particle surface.

[0129] In one embodiment, in the above step S202, a thermal model of lithium deposition of a lithium-ion battery is constructed according to thermal parameters, which specifically includes the following steps:

[0130] According to the thermal parameters, the heat source terms in the lithium-ion battery are determined; the heat source terms include polarization heat, ohmic heat and reaction heat; the total heat generated by the lithium-ion battery is obtained based on the sum of the heat generated by the heat source terms; the total amount of flow heat exchange between the surface of the lithium-ion battery and the air is obtained, and the lithium precipitation thermal model is constructed based on the total heat and the total amount of flow heat exchange.

[0131] Specifically, the terminal can establish a thermal model of the lithium-ion battery based on the three-dimensional geometric parameters of the battery to be modeled, the specific heat capacity of each part of the battery, the thermal conductivity coefficient and the density parameters through the "solid heat transfer" interface in simulation software such as COMSOL.

[0132] The battery energy balance equation is expressed as follows:

[0133]

[0134] In the above formula, is the battery density, is the specific heat capacity of the battery, is the thermal conductivity, is the total heat generation rate.

[0135] The energy balance in lithium-ion batteries consists of three heat sources, two of which are irreversible heat sources: polarization heat and Ohm heat , a reversible heat source is the reaction heat , the total heat generated by the battery is the sum of the heat generated by the three heat sources.

[0136]

[0137]

[0138]

[0139] In the above formula, is the specific surface area of ​​the porous electrode, is the temperature derivative of the equilibrium potential.

[0140] When the battery undergoes lithium deposition reaction, the heat release formula is expressed as:

[0141]

[0142] In the above formula, is the thermal power of the lithium precipitation reaction.

[0143] The temperature of the battery during operation is not only related to the heat generated, but also affected by the external environment. For the battery usage scenario in this application, only the heat convection between the battery surface and the air is considered, and the Newton formula is used to express it as follows:

[0144]

[0145] In the above formula, Q is the total amount of convective heat transfer, h is the convective heat transfer coefficient of the battery surface, S is the convective heat transfer area, is the ambient temperature.

[0146] In one embodiment, Figure 4 As shown, a lithium plating detection method for a lithium ion battery in a specific embodiment is provided, which specifically includes the following steps:

[0147] Step S401, determining a lithium-ion battery to be tested, and obtaining battery parameters of the lithium-ion battery; the battery parameters include electrochemical parameters, thermal parameters, and geometric parameters.

[0148] Step S402, when the lithium-ion battery meets the preset assumptions, according to the electrochemical parameters, adding lithium plating kinetic parameters to the negative electrode of the lithium-ion battery; according to the lithium plating kinetic parameters, constructing the charge conservation sub-model, mass conservation sub-model and electrode kinetic sub-model of the lithium-ion battery as the lithium plating electrochemical model.

[0149] Step S403, determining the heat source term in the lithium-ion battery according to the thermal parameters; the heat source term includes polarization heat, ohmic heat and reaction heat; obtaining the total heat generated by the lithium-ion battery according to the sum of the heat generated by the heat source term; obtaining the total amount of flow heat exchange between the surface of the lithium-ion battery and the air, and constructing a lithium precipitation thermal model according to the total heat and the total amount of flow heat exchange.

[0150] Step S404: constructing a lithium deposition strain model of a lithium-ion battery according to the geometric parameters.

[0151] Step S405, calculate the heat generation rate of the lithium ion battery by the lithium deposition electrochemical model, obtain the heat generation rate plane according to the heat generation rate, use the heat generation rate plane as the heat source term of the lithium deposition thermal model, and calculate the temperature of the internal temperature field in the lithium ion battery; obtain the temperature distribution plane according to the temperature, and use the temperature distribution plane as the temperature term of the lithium deposition electrochemical model.

[0152] Step S406, calculating the lithium ion concentration of the lithium deposition side reaction in the lithium ion battery by the lithium deposition electrochemical model, obtaining the lithium ion concentration distribution plane according to the lithium ion concentration, and using the lithium ion concentration distribution plane as an input item of the lithium deposition strain model to obtain the electrochemical-thermal-stress coupling model of the lithium ion battery.

[0153] Step S407, obtaining the temperature data and strain data of the lithium-ion battery collected by the fiber Bragg grating device, inputting the temperature data and strain data into the electrochemical-thermal-stress coupling model for numerical calculation and data fitting, and obtaining the current characteristic parameter value output by the electrochemical-thermal-stress coupling model.

[0154] Step S408, determining whether the current characteristic parameter value meets the lithium deposition threshold condition; if the current characteristic parameter value meets the lithium deposition threshold condition, it is confirmed that lithium deposition has occurred in the lithium-ion battery and a warning signal is triggered; if the current characteristic parameter value does not meet the lithium deposition threshold condition, it is confirmed that lithium deposition has not occurred in the lithium-ion battery.

[0155] The beneficial effects brought by the above embodiments are as follows:

[0156] 1) By constructing a multi-physics field coupling model (electrochemical-thermal-stress coupling model), the electrochemical behavior, thermal effect and strain effect of the battery are unified in a mathematical model, thereby improving the accuracy of lithium plating prediction.

[0157] 2) The multi-physics field coupling model can deduce the internal lithium deposition behavior (such as lithium deposition rate, amount and location) that cannot be directly measured through external measurable parameters (temperature, strain) without destroying the battery structure.

[0158] 3) This solution can monitor lithium plating behavior in real time during battery operation and realize dynamic early warning.

[0159] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps is not strictly limited in order, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0160] Based on the same inventive concept, the embodiment of the present application also provides a lithium ion battery lithium deposition detection device for implementing the above-mentioned lithium ion battery lithium deposition detection method. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above-mentioned method, so the specific limitations in the embodiments of one or more lithium ion battery lithium deposition detection devices provided below can refer to the limitations of the lithium ion battery lithium deposition detection method above, and will not be repeated here.

[0161] In an exemplary embodiment, Figure 5 As shown, a lithium deposition detection device for a lithium ion battery is provided, comprising:

[0162] The parameter acquisition module 501 is used to determine the lithium-ion battery to be tested and acquire the battery parameters of the lithium-ion battery; the battery parameters include electrochemical parameters, thermal parameters and geometric parameters;

[0163] A model building module 502 is used to build a lithium electrochemical model of lithium ion battery according to electrochemical parameters, build a lithium thermal model of lithium ion battery according to thermal parameters, and build a lithium strain model of lithium ion battery according to geometric parameters;

[0164] A model coupling module 503 is used to couple the lithium deposition electrochemical model with the lithium deposition thermal model, and to couple the lithium deposition electrochemical model with the lithium deposition strain model to obtain an electrochemical-thermal-stress coupling model of the lithium ion battery;

[0165] The lithium deposition simulation module 504 is used to simulate the lithium deposition phenomenon of the lithium-ion battery using the lithium deposition simulation system to obtain the target characteristic parameter value of the lithium-ion battery when the lithium deposition phenomenon occurs, and set the lithium deposition threshold condition according to the target characteristic parameter value;

[0166] The lithium deposition detection module 505 is used to obtain the current characteristic parameter value of the lithium-ion battery by using the electrochemical-thermal-stress coupling model, and detect whether lithium deposition occurs in the lithium-ion battery according to the current characteristic parameter value and the lithium deposition threshold condition.

[0167] In one embodiment, the model coupling module 503 is also used to calculate the heat generation rate of the lithium-ion battery from the lithium electrochemical model, obtain the heat generation rate plane according to the heat generation rate, use the heat generation rate plane as the heat source term of the lithium thermal model, and calculate the temperature of the internal temperature field in the lithium-ion battery; obtain the temperature distribution plane according to the temperature, and use the temperature distribution plane as the temperature term of the lithium electrochemical model; calculate the lithium ion concentration of the lithium deposition side reaction in the lithium-ion battery from the lithium electrochemical model, obtain the lithium ion concentration distribution plane according to the lithium ion concentration, and use the lithium ion concentration distribution plane as the input term of the lithium deposition strain model.

[0168] In one embodiment, the lithium deposition detection device for a lithium-ion battery also includes a data acquisition device for acquiring temperature data and strain data of the lithium-ion battery acquired by a fiber grating device; the lithium deposition detection module 505 is also used to input the temperature data and strain data into an electrochemical-thermal-stress coupling model for numerical calculation and data fitting to obtain the current characteristic parameter value output by the electrochemical-thermal-stress coupling model.

[0169] In one embodiment, the lithium deposition detection module 505 is also used to determine whether the current characteristic parameter value meets the lithium deposition threshold condition; if the current characteristic parameter value meets the lithium deposition threshold condition, it is confirmed that lithium deposition has occurred in the lithium-ion battery and a warning signal is triggered; if the current characteristic parameter value does not meet the lithium deposition threshold condition, it is confirmed that lithium deposition has not occurred in the lithium-ion battery.

[0170] In one embodiment, the model building module 502 is also used to add lithium plating kinetic parameters to the negative electrode of the lithium ion battery according to the electrochemical parameters when the lithium ion battery meets preset assumptions; and to construct a charge conservation sub-model, a mass conservation sub-model and an electrode kinetic sub-model of the lithium ion battery as a lithium plating electrochemical model according to the lithium plating kinetic parameters.

[0171] In one embodiment, the model building module 502 is also used to determine the heat source terms in the lithium-ion battery based on thermal parameters; the heat source terms include polarization heat, ohmic heat and reaction heat; the total heat generated by the lithium-ion battery is obtained based on the sum of the heat generated by the heat source terms; the total amount of flow heat exchange between the surface of the lithium-ion battery and the air is obtained, and a lithium precipitation thermal model is constructed based on the total heat and the total amount of flow heat exchange.

[0172] Each module in the above-mentioned lithium ion battery lithium deposition detection device can be implemented in whole or in part by software, hardware and a combination thereof. Each of the above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to each of the above modules.

[0173] In an exemplary embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as shown in FIG. Figure 6As shown. The computer device includes a processor, a memory, an input / output interface, a communication interface, a display unit and an input device. Among them, the processor, the memory and the input / output interface are connected through a system bus, and the communication interface, the display unit and the input device are connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and the external device. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be realized through WIFI, a mobile cellular network, near field communication (Near Field Communication, NFC) or other technologies. When the computer program is executed by the processor, a lithium plating detection method for a lithium-ion battery is implemented. The display unit of the computer device is used to form a visually visible picture, which can be a display screen, a projection device or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covering the display screen, or a button, trackball or touchpad set on the computer device shell, or an external keyboard, touchpad or mouse.

[0174] Those skilled in the art will understand that Figure 6 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0175] In one embodiment, a computer device is further provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above method embodiments when executing the computer program.

[0176] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0177] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0178] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0179] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can 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 can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., but are not limited to this.

[0180] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, 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 application.

[0181] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A lithium ion battery lithium deposition detection method, characterized in that: The method comprises: Determine a lithium-ion battery to be tested, and obtain battery parameters of the lithium-ion battery; the battery parameters include electrochemical parameters, thermal parameters, and geometric parameters; According to the electrochemical parameters, a lithium deposition electrochemical model of the lithium ion battery is constructed, according to the thermal parameters, a lithium deposition thermal model of the lithium ion battery is constructed, and according to the geometric parameters, a lithium deposition strain model of the lithium ion battery is constructed; The lithium deposition electrochemical model is coupled with the lithium deposition thermal model, and the lithium deposition electrochemical model is coupled with the lithium deposition strain model to obtain an electrochemical-thermal-stress coupling model of the lithium ion battery; Simulating the lithium deposition phenomenon of the lithium-ion battery by using a lithium deposition simulation system to obtain a target characteristic parameter value of the lithium-ion battery when the lithium deposition phenomenon occurs, and setting a lithium deposition threshold condition according to the target characteristic parameter value; The electrochemical-thermal-stress coupling model is used to obtain the current characteristic parameter value of the lithium-ion battery, and whether the lithium deposition phenomenon occurs in the lithium-ion battery is detected according to the current characteristic parameter value and the lithium deposition threshold condition.

2. The method according to claim 1, characterized in that The coupling of the lithium deposition electrochemical model with the lithium deposition thermal model, and coupling of the lithium deposition electrochemical model with the lithium deposition strain model, includes: Calculating the heat generation rate of the lithium ion battery by the lithium electrochemical model, obtaining a heat generation rate plane according to the heat generation rate, using the heat generation rate plane as a heat source term of the lithium thermal model, and calculating the temperature of the internal temperature field in the lithium ion battery; According to the temperature, a temperature distribution plane is obtained, and the temperature distribution plane is used as a temperature term of the lithium deposition electrochemical model; The lithium ion concentration of the lithium ion side reaction in the lithium ion battery is calculated by the lithium ion electrochemical model, and a lithium ion concentration distribution plane is obtained according to the lithium ion concentration, and the lithium ion concentration distribution plane is used as an input item of the lithium ion strain model.

3. The method according to claim 1, characterized in that: Before obtaining the current characteristic parameter value of the lithium-ion battery by using the electrochemical-thermal-stress coupling model, the method further includes: Acquiring temperature data and strain data of the lithium-ion battery collected by a fiber grating device; The obtaining of the current characteristic parameter value of the lithium-ion battery by using the electrochemical-thermal-stress coupling model includes: The temperature data and the strain data are input into the electrochemical-thermal-stress coupling model for numerical calculation and data fitting to obtain the current characteristic parameter value output by the electrochemical-thermal-stress coupling model.

4. The method according to claim 3, characterized in that The detecting whether the lithium deposition phenomenon occurs in the lithium-ion battery according to the current characteristic parameter value and the lithium deposition threshold condition includes: Determining whether the current characteristic parameter value meets the lithium precipitation threshold condition; If the current characteristic parameter value meets the lithium deposition threshold condition, it is confirmed that the lithium deposition phenomenon has occurred in the lithium-ion battery, and a warning signal is triggered; If the current characteristic parameter value does not meet the lithium deposition threshold condition, it is confirmed that the lithium deposition phenomenon does not occur in the lithium-ion battery.

5. The method according to claim 1, characterized in that: The step of constructing a lithium electrochemical model of the lithium ion battery according to the electrochemical parameters comprises: When the lithium ion battery meets the preset assumption conditions, adding lithium deposition kinetic parameters to the negative electrode of the lithium ion battery according to the electrochemical parameters; According to the lithium deposition kinetic parameters, a charge conservation sub-model, a mass conservation sub-model and an electrode kinetic sub-model of the lithium ion battery are constructed as the lithium deposition electrochemical model.

6. The method according to any one of claims 1 to 5, characterized in that: The step of constructing a thermal model of lithium deposition of the lithium-ion battery according to the thermal parameters comprises: Determining a heat source term in the lithium-ion battery according to the thermal parameters; the heat source term includes polarization heat, ohmic heat and reaction heat; Obtaining the total heat generated by the lithium-ion battery according to the sum of the heat generated by the heat source items; The total amount of heat exchange between the surface of the lithium-ion battery and the air is obtained, and the lithium deposition thermal model is constructed according to the total heat and the total amount of heat exchange.

7. A lithium ion battery lithium deposition detection device, characterized in that: The device comprises: A parameter acquisition module, used to determine the lithium-ion battery to be tested and acquire battery parameters of the lithium-ion battery; the battery parameters include electrochemical parameters, thermal parameters and geometric parameters; A model building module, used to build a lithium deposition electrochemical model of the lithium ion battery according to the electrochemical parameters, to build a lithium deposition thermal model of the lithium ion battery according to the thermal parameters, and to build a lithium deposition strain model of the lithium ion battery according to the geometric parameters; A model coupling module, used to couple the lithium deposition electrochemical model with the lithium deposition thermal model, and to couple the lithium deposition electrochemical model with the lithium deposition strain model, so as to obtain an electrochemical-thermal-stress coupling model of the lithium ion battery; A lithium deposition simulation module, used to simulate the lithium deposition phenomenon of the lithium-ion battery using a lithium deposition simulation system to obtain a target characteristic parameter value of the lithium-ion battery when the lithium deposition phenomenon occurs, and to set a lithium deposition threshold condition according to the target characteristic parameter value; The lithium deposition detection module is used to obtain the current characteristic parameter value of the lithium ion battery by using the electrochemical-thermal-stress coupling model, and detect whether the lithium deposition phenomenon occurs in the lithium ion battery according to the current characteristic parameter value and the lithium deposition threshold condition.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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