Lithium battery thermal runaway model construction method and device, equipment and storage medium

Abstract

The invention relates to the technical field of power batteries, and discloses a lithium battery thermal runaway model construction method, device and equipment and a storage medium, and the method comprises the steps: constructing a thermal runaway reaction kinetic model and a battery equivalent circuit model of a lithium battery; the thermal runaway reaction kinetic model comprises a battery temperature and heat production power equation, a battery temperature and external environment heat exchange equation, a component heat production power and concentration equation in thermal chemical reaction and an electric energy heat production equation; the battery equivalent circuit model is a model constructed by taking an equivalent internal resistance model as a basis and combining a voltage drop caused by an internal short-circuit current, a thermodynamic voltage drop caused by battery entropy change under a high-temperature condition and a voltage drop caused by battery active material loss. By applying the technical scheme, the change trend of the internal characteristics of the battery and the change trend of the battery temperature along with time in the thermal runaway process can be comprehensively and accurately reflected, the thermal runaway phenomenon of the battery can be deeply understood and predicted, and a basis is provided for researching and designing a safer and more reliable power battery.

Description

Technical Field

[0001] The present application relates to the technical field of power batteries, and particularly to a method, device, equipment and storage medium for constructing a lithium battery thermal runaway model. Background Art

[0002] At present, the remarkable characteristics of lithium-ion batteries (hereinafter referred to as lithium batteries) are their huge energy density, which brings a wider cruising range for electric vehicles; the long-lasting operating life of lithium batteries, which can still maintain high energy storage performance during multiple charge and discharge processes; the faster charging speed of lithium batteries, which can be fully charged in a shorter time; and the lighter weight of lithium batteries, which can reduce the weight of the whole vehicle. These advantages make lithium batteries one of the most ideal power batteries for new energy vehicles.

[0003] However, when the battery or battery pack is collided or squeezed in a traffic accident, it may cause an internal short circuit, the battery generates a large amount of heat, and then leads to battery thermal runaway or explosion. Therefore, it is particularly important to deeply analyze the reasons for triggering lithium battery thermal runaway, reveal the mechanism of lithium-ion battery thermal runaway, and explore its further evolution process. In the prior art, an auxiliary physical model is often established through simulation software to predict the battery thermal runaway behavior. These simulation models require a large amount of computing resources, a relatively long computing time, and cannot well explain the internal electrochemical and kinetic mechanisms of battery thermal runaway. Summary of the Invention

[0004] In view of the above problems, the present application provides a method, device, equipment and storage medium for constructing a lithium battery thermal runaway model, which is used to solve the problem that the internal electrochemical and kinetic mechanisms of battery thermal runaway cannot be well explained in the prior art.

[0005] According to one aspect of the embodiments of the present application, a method for constructing a lithium battery thermal runaway model is provided, and the method includes:

[0006] Construct a thermal runaway reaction kinetic model and a battery equivalent circuit model of the lithium battery; wherein, the thermal runaway reaction kinetic model includes: a first equation characterizing the battery temperature and heat generation power, a second equation characterizing the heat exchange between the battery temperature and the external environment, a third equation characterizing the heat generation power and concentration of each component in the thermal chemical reaction, and a fourth equation characterizing the heat generation of electric energy; the battery equivalent circuit model is a model constructed based on the equivalent internal resistance model and combined with the voltage drop caused by the internal short-circuit current, the thermodynamic voltage drop caused by the entropy change of the battery under high temperature conditions, and the voltage drop caused by the loss of battery active substances;

[0007] Couple the thermal runaway reaction kinetic model with the battery equivalent circuit model to obtain a lithium battery coupled thermal runaway model.

[0008] In an alternative embodiment, the method further includes:

[0009] Obtaining the battery physical property parameters of the test lithium battery and inputting them into the lithium battery coupled thermal runaway model to obtain the thermal runaway test results of the test lithium battery;

[0010] When the difference between the thermal runaway experimental results of the test lithium battery and the thermal runaway test results meets a preset condition, using the lithium battery coupled thermal runaway model to perform thermal runaway prediction on the lithium battery to be tested.

[0011] In an alternative embodiment, the battery physical property parameters include: battery geometric parameters, battery kinetic parameters, and battery electrochemical parameters;

[0012] The battery geometric parameters include at least one of: battery length, battery width, battery height, battery tab length, battery tab width, battery tab thickness, and tab position;

[0013] The battery kinetic parameters include at least one of: battery mass, battery specific heat capacity, battery thermal conductivity, battery convective heat transfer coefficient, battery chemical reaction enthalpy of formation, battery pre-exponential factor, battery reaction activation energy, and battery normalized concentration;

[0014] The battery electrochemical parameters include at least one of: battery open circuit voltage, battery charge and discharge current, battery internal resistance, battery equivalent internal short circuit resistance, and battery positive electrode stoichiometry.

[0015] In an alternative embodiment, the lithium battery to be tested is at least one of: nickel cobalt manganese battery, lithium iron phosphate battery, lithium cobalt oxide battery, lithium nickel oxide battery, lithium manganese oxide battery, and lithium manganese phosphate battery.

[0016] In an alternative embodiment, the method further includes:

[0017] Collecting the thermal runaway experimental results of the test lithium battery by using an external thermocouple; wherein, the thermal runaway experimental results are: the battery surface temperature value of the test lithium battery.

[0018] In an alternative embodiment, the second equation is used to: obtain the heat exchange amount between the lithium battery and the environment through the convective radiation heat transfer equation;

[0019] The third equation is used to: respectively calculate the heat release amounts of the thermal reactions and decomposition reactions of each component of the lithium battery by using the Arrhenius formula;

[0020] The fourth equation is used to: convert the electrical energy generated during the internal short circuit of the lithium battery into heat energy through the principle of energy conservation.

[0021] In an alternative approach, the coupling correlation method in the lithium battery coupled thermal runaway model is as follows: Calculate the temperature change of the lithium battery using the thermal runaway reaction kinetics model, and send the temperature change of the lithium battery to the battery equivalent circuit model; The battery equivalent circuit model calculates the equivalent internal short-circuit resistance, internal resistance, electrode stoichiometry, battery terminal voltage, and total internal short-circuit electrical energy based on the temperature change of the lithium battery and sends them to the thermal runaway reaction kinetics model to calculate the heat generation of the SEI film decomposition reaction, the heat generation of the film and electrolyte reaction, the heat generation of the electrolyte solution decomposition, the heat generation of the lithium iron phosphate cathode material decomposition, and the heat generation of electrical energy.

[0022] According to another aspect of the embodiments of the present application, there is provided a device for constructing a lithium battery thermal runaway model, including:

[0023] A construction module, configured to construct a thermal runaway reaction kinetics model and a battery equivalent circuit model of a lithium battery; wherein, the thermal runaway reaction kinetics model includes: a first equation characterizing the relationship between battery temperature and heat generation power, a second equation characterizing the heat exchange between the battery temperature and the external environment, a third equation characterizing the relationship between the heat generation power of each component in the thermal chemical reaction and the concentration, and a fourth equation characterizing the heat generation of electrical energy; The battery equivalent circuit model is a model constructed based on an equivalent internal resistance model and combined with the voltage drop caused by the internal short-circuit current, the thermodynamic voltage drop caused by the entropy change of the battery under high temperature conditions, and the voltage drop caused by the loss of battery active materials.

[0024] A coupling module, configured to couple the thermal runaway reaction kinetics model with the battery equivalent circuit model to obtain a lithium battery coupled thermal runaway model.

[0025] According to another aspect of the embodiments of the present application, there is provided a device for constructing a lithium battery thermal runaway model, including: a processor, a memory, a communication interface, and a communication bus. The processor, the memory, and the communication interface complete communication with each other through the communication bus;

[0026] The memory is used to store at least one executable instruction, and the executable instruction causes the processor to execute the operations of the lithium battery thermal runaway model construction method of the present invention.

[0027] According to yet another aspect of the embodiments of the present invention, there is provided a computer-readable storage medium, in which at least one executable instruction is stored, and the executable instruction causes the lithium battery thermal runaway model construction device / equipment to execute the operations of the lithium battery thermal runaway model construction method of the present invention.

[0028] In the embodiments of the present application, a thermal runaway reaction kinetic model and a battery equivalent circuit model of a lithium battery are constructed. Among them, the thermal runaway reaction kinetic model includes: a first equation characterizing the battery temperature and the heat generation power, a second equation characterizing the heat exchange between the battery temperature and the external environment, a third equation characterizing the heat generation power and concentration of each component in the thermal chemical reaction, and a fourth equation characterizing the heat generation of electric energy. The battery equivalent circuit model is constructed based on the equivalent internal resistance model and combines the voltage drop caused by the internal short-circuit current, the thermodynamic voltage drop caused by the entropy change of the battery under high temperature conditions, and the voltage drop caused by the loss of battery active substances. Coupling the thermal runaway reaction kinetic model with the battery equivalent circuit model to obtain a lithium battery coupled thermal runaway model, which can comprehensively and accurately reflect the changing trend of the internal characteristics of the battery during the thermal runaway process, more precisely describe the trend of the battery temperature changing with time, help to deeply understand and predict the battery thermal runaway phenomenon, and provide a basis for researching and designing safer and more reliable power batteries.

[0029] The above description is only an overview of the technical solutions of the embodiments of the present application. In order to be able to understand the technical means of the embodiments of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the embodiments of the present application more obvious and understandable, the following specifically gives the specific implementation manners of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings are only used to illustrate the embodiments and are not considered as a limitation to the present application. And throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0031] Figure 1 It shows a schematic flow chart of the first embodiment of the method for constructing a lithium battery thermal runaway model provided by the present application;

[0032] Figure 2 It shows a schematic structural diagram of the battery equivalent circuit model;

[0033] Figure 3 It shows a schematic diagram of the change of the battery internal resistance and the equivalent short-circuit internal resistance of the battery with temperature;

[0034] Figure 4 It shows a schematic diagram of the relationship between the electrode voltage and the positive and negative stoichiometric ratios;

[0035] Figure 5 It shows a schematic diagram of the coupling correlation in the lithium battery coupled thermal runaway model;

[0036] Figure 6 It shows a schematic flow chart of the second embodiment of the method for constructing a lithium battery thermal runaway model provided by the present application;

[0037] Figure 7A schematic diagram showing the parameter value range of a tested lithium battery;

[0038] Figure 8 A schematic diagram showing the comparison between the results of a thermal runaway experiment and the results of a thermal runaway test;

[0039] Figure 9 A schematic diagram showing the battery physical property parameters of a lithium battery to be tested;

[0040] Figure 10 A schematic diagram showing the structure of an embodiment of a device for constructing a lithium battery thermal runaway model provided by the present application;

[0041] Figure 11 A schematic diagram showing the structure of an embodiment of a device for constructing a lithium battery thermal runaway model provided by the present application. Detailed Description of the Invention

[0042] Here, exemplary embodiments will be described in detail, and the examples are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0043] The block diagrams shown in the drawings are only functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software form, or implemented in one or more hardware modules or integrated circuits, or implemented in different networks and / or processor devices and / or microcontroller devices.

[0044] The flowcharts shown in the drawings are only exemplary descriptions and do not necessarily include all the contents and operations / steps, nor do they necessarily need to be executed in the described order. For example, some operations / steps can be decomposed, while some operations / steps can be combined or partially combined. Therefore, the actual execution order may change according to the actual situation.

[0045] In the present application, "a plurality of" means two or more. "And / or" describes the association relationship of associated objects and indicates 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. The character " / " generally represents an "or" relationship between the associated objects before and after.

[0046] When a battery or battery pack is collided or squeezed in a traffic accident, it may cause an internal short circuit, generating a large amount of heat in the battery, which may further lead to battery thermal runaway or explosion. Therefore, it becomes particularly important to deeply analyze the reasons for triggering lithium battery thermal runaway, reveal the mechanism of lithium-ion battery thermal runaway, and explore its further evolution process. In the existing technology, an auxiliary physical model is often established through simulation software to predict battery thermal runaway behavior. These simulation models require a large amount of computing resources, a relatively long computing time, and cannot well explain the internal electrochemical and kinetic mechanisms of battery thermal runaway. Based on this:

[0047] Figure 1 FIG. 4 shows a flowchart of a first embodiment of a method for constructing a lithium battery thermal runaway model provided by the present application. This method is executed by a lithium battery thermal runaway model construction device. Please refer to Figure 1 shown, this method includes the following steps:

[0048] Step S110: Construct a thermal runaway reaction kinetic model and a battery equivalent circuit model of the lithium battery.

[0049] Among them, the thermal runaway reaction kinetic model includes: a first equation characterizing the battery temperature and heat generation power, a second equation characterizing the heat exchange between the battery temperature and the external environment, a third equation characterizing the heat generation power and concentration of each component in the thermal chemical reaction, and a fourth equation characterizing the heat generation of electric energy; the battery equivalent circuit model is constructed based on the equivalent internal resistance model, combined with the voltage drop caused by the internal short-circuit current, the thermodynamic voltage drop caused by the entropy change of the battery under high temperature conditions, and the voltage drop caused by the loss of battery active substances.

[0050] Among them, in this embodiment, MATLAB is used to establish a thermal runaway reaction kinetic model and a battery equivalent circuit model. For the thermal runaway reaction kinetic model, specifically:

[0051] 1) The first equation is:

[0052]

[0053] Among them, represents the temperature rise rate of the lithium battery, M b represents the mass of the lithium battery (M b is defaulted to 4.14 kg); C p represents the specific heat capacity of the lithium battery (C p is defaulted to 1100 J / (kg·K)), and the specific heat capacity of the lithium battery can be obtained through adiabatic accelerated calorimeter (ARC) experiments; Q(t) represents the net heat generation power inside the lithium battery, Q chem (t) represents the heat generation power of chemical reactions per unit time, Q e (t) represents the heat generation of thermal runaway electric energy per unit time, Qdiss (t) represents the heat dissipation power of the lithium battery to the environment per unit time; Q sei (t) represents the heat generation power of the SEI film decomposition reaction per unit time; Q an (t) represents the heat generation power when lithium at the negative electrode reacts with the electrolyte after the SEI film decomposes per unit time; t ele (t) represents the heat release power of the decomposition reaction of the electrolyte solution per unit time; Q ca (t) represents the heat generation power when the lithium iron phosphate cathode material decomposes at high temperature per unit time.

[0054] The construction principle of the first equation specifically includes:

[0055] ① The formula for the change in battery temperature over time is:

[0056]

[0057] ② In the formula in ①, represents the battery temperature rise rate, which satisfies the energy conservation formula:

[0058] ③ In the formula in ②, M b represents the mass of the lithium battery (M b is defaulted to 4.14 kg); C p represents the specific heat capacity of the lithium battery (C p is defaulted to 1100 J / (kg·K)), and the specific heat capacity of the lithium battery can be obtained through experiments using an adiabatic calorimeter (ARC); Q(t) represents the net heat generation power inside the lithium battery, which is calculated by the following formula:

[0059] Q(t) = Q chem (t) + Q e (t) + Q diss (t);

[0060] ④ In the formula in ③, Q chem (t) represents the heat generation power of the chemical reaction per unit time, Q e (t) represents the heat generation of thermal runaway electrical energy per unit time, Q diss (t) represents the heat dissipation power of the lithium battery to the environment per unit time; the heat generation power of the chemical reaction is set according to the reaction conditions of each component during thermal runaway and can be calculated by the following formula: Q chem (t) = Q sei (t) + Q an (t) + Q ele (t) + Q ca (t); Q sei(t) represents the heat generation power of the SEI film decomposition reaction per unit time; Q an (t) represents the heat generation power when lithium at the negative electrode reacts with the electrolyte after the SEI film decomposes per unit time; Q ele (t) represents the heat release power of the decomposition reaction of the electrolyte solution per unit time; Q ca (t) represents the heat generation power when the lithium iron phosphate cathode material decomposes at high temperature per unit time.

[0061] 2) The second equation is used to obtain the heat exchange amount between the lithium battery and the environment through the convective radiation heat transfer equation; the second equation is:

[0062]

[0063] Among them, Q conv (t) represents the convective heat exchange amount of the lithium battery per unit time, Q rad (t) represents the thermal radiation amount of the lithium battery per unit time, A ba represents the heat exchange area between the surface of the lithium battery and the air, h conv represents the convective heat transfer coefficient (default value is 10), ε represents the emissivity (default value is 0.8), T h (t) represents the experimental environment temperature per unit time, σ is the Stefan-Boltzmann constant, and the value is 5.67×10 -8 .

[0064] 3) The third equation is used to calculate the heat release amounts of the thermal reactions and decomposition reactions of each component of the lithium battery respectively by using the Arrhenius formula. The third formula includes: the SEI film decomposition heat generation equation, the negative electrode and electrolyte reaction heat generation equation, the positive electrode and electrolyte reaction heat generation equation, and the electrolyte decomposition reaction equation. Specifically:

[0065] ① The SEI film decomposition heat generation equation is:

[0066]

[0067] Among them, the heat release amount of the SEI film decomposition reaction is obtained from the first formula of the above formula, and the relationship between the reactant concentration and the decomposition rate is obtained from the last two formulas of the above formula. ΔH sei represents the chemical reaction formation enthalpy of the SEI film, m sei represents the mass of the SEI film, R sei (t) represents the SEI film decomposition reaction rate per unit time, c sei (t) represents the normalized concentration of SEI per unit time, A sei represents the pre-exponential factor of the SEI film, E a,sei represents the reaction activation energy of the SEI film.

[0068] ② The heat generation equation for the reaction between the negative electrode and the electrolyte is as follows:

[0069]

[0070] Among them, the heat release amount generated by the reaction between the intercalated lithium in the negative electrode and the decomposition of the electrolyte is obtained from the first formula of the above formula. In addition to being related to the concentration c an of the intercalated lithium in the negative electrode, the reaction rate between the negative electrode and the electrolyte decomposition is also related to the thickness δ sei of the SEI film due to the regeneration reaction of the SEI film, and is specifically obtained from the last three formulas of the above formula. ΔH an represents the enthalpy of formation of the chemical reaction of the negative electrode, m an represents the mass of the negative electrode; R an (t) represents the decomposition reaction rate of the negative electrode per unit time; c an (t) represents the normalized concentration of the negative electrode per unit time; A an represents the pre-exponential factor of the negative electrode, E a,an represents the activation energy of the negative electrode reaction, δ sei,ref represents the reference value (δ sei,ref is defaulted to 0.033).

[0071] ③ The heat generation equation for the reaction between the positive electrode and the electrolyte is as follows:

[0072]

[0073] Among them, the heat release amount generated by the reaction between the positive electrode and the electrolyte is obtained from the first formula of the above formula. The relationship between the reaction rate and the conversion rate c ca of the positive electrode can be determined by the last two formulas of the above formula. ΔH ca represents the enthalpy of formation of the chemical reaction of the positive electrode, m ca represents the mass of the positive electrode; R ca (t) represents the decomposition reaction rate of the positive electrode per unit time; c ca (t) represents the normalized concentration of the positive electrode per unit time; A ca represents the pre-exponential factor of the positive electrode, E a,ca represents the activation energy of the positive electrode reaction.

[0074] ④ The electrolyte decomposition reaction equation is as follows:

[0075]

[0076] Among them, the heat release amount of the self-decomposition of the electrolyte is obtained from the first formula of the above formula. The relationship between the reaction rate and the normalized concentration c ele of the electrolyte is determined by the last two formulas of the above formula. ΔH ele represents the enthalpy of formation of the chemical reaction of the electrolyte, m ele represents the mass of the electrolyte, R ele(t) represents the rate of electrolyte decomposition reaction per unit time, c ele (t) represents the normalized concentration of the electrolyte per unit time, A ele represents the pre-exponential factor of the electrolyte, E a,ele represents the activation energy of the electrolyte reaction.

[0077] 4) The fourth equation is used to convert the electrical energy generated during internal short circuit of the lithium battery into heat energy through the principle of energy conservation. The fourth equation is:

[0078]

[0079] Among them, the heat generation of electrical energy can be calculated using Ohm's law when the circuit is working normally. However, in the case of a violent thermal runaway reaction, using the internal short-circuit current and resistance to calculate the heat generation of electrical energy will result in a large error. Therefore, the energy conservation formula is used for calculation. ΔH e represents the total electrical energy of the battery when internal short circuit occurs; Δt represents the average time of electrical energy release. In the fourth equation, Δt is taken as 10 s, T TR is the temperature when the diaphragm collapses, and the default value is 220 °C.

[0080] The battery equivalent circuit model (as Figure 2 shown) consists of an equivalent circuit equation and a battery voltage drop equation. Specifically:

[0081] 1) The equivalent circuit equation is:

[0082]

[0083] Among them, T0 represents the initial temperature of the lithium battery. T0 will decrease according to the loss of active substances inside the lithium battery and will also generate a voltage drop due to the loss of electrolyte caused by the rupture of the lithium battery shell.

[0084] 2) The voltage drop caused by the internal short-circuit current. The internal short-circuit current needs to satisfy the following formula:

[0085]

[0086] Among them, R cell represents the internal resistance of the lithium battery, R short represents the equivalent internal short-circuit resistance. Both the internal resistance of the battery and the equivalent internal short-circuit resistance are affected by temperature. To ensure the accuracy of this voltage drop link and ensure that the voltage simulation during the thermal runaway of the power battery conforms to the actual situation, the changes of the battery internal resistance and the equivalent internal short-circuit battery with temperature are calibrated and analyzed, as Figure 3 shown.

[0087] 3) Thermodynamic voltage drop caused by the entropy change of the battery under high-temperature conditions. In a high-temperature environment, the chemical reactions inside the battery usually occur more rapidly, leading to an increase in the entropy inside the battery. These chemical reactions can cause adverse processes such as corrosion of the electrode materials, decomposition of the electrolyte, and inactivation of the active materials, which have a negative impact on the electrochemical performance of the battery. In this embodiment, the voltage change of the battery at room temperature can be estimated through empirical values. Therefore, during the modeling process, regardless of the temperature range, it will be assumed to be a fixed value of 0.2 mV / K at room temperature. Such a simplified assumption is helpful for the establishment and analysis of the model.

[0088] 4) Voltage drop caused by the loss of battery active materials. During the thermal runaway evolution process, as the temperature rises, it may cause the melting, detachment from the electrodes, or destruction of the positive and negative active materials. The loss of these active materials will lead to a decrease in the battery capacity and the occurrence of electrochemical reactions. Due to the loss of the positive and negative active materials, the voltage of the battery will decrease. The specific formula is:

[0089] U oc =V ca (Y(t)) - V an (X(t))

[0090] where Y(t) and X(t) represent the stoichiometric ratios of the battery electrodes, that is, the state of charge of the electrodes; in the fully charged state of the battery, Y → 0, X → 1. As the battery discharges or there is a loss of battery active materials, the stoichiometric ratio will change. The relationship between the positive and negative electrode voltages and the stoichiometric ratio can be obtained through half-cell test experiments. The relationship between the electrode voltages and the stoichiometric ratio used in this embodiment is as Figure 4 shown. The half-cell test experiment is to charge and discharge the battery with a small current, and then take the average value of the obtained charge-discharge curves. The relationship between the stoichiometric ratios of the positive and negative electrodes and the temperature can be fitted from the results identified by the experiment.

[0091] 5) The expression of the battery equivalent circuit model is:

[0092]

[0093] where V ca (Y(T)) and V an (X(T)) represent the relationship between the electrode voltage and the battery temperature. I m,short ·R cell represents the voltage drop caused by the internal short-circuit current of the lithium battery, and dU / dT·(T - T0) represents the voltage drop generated by the high-temperature entropy change of the lithium battery.

[0094] Step S120: Couple the thermal runaway reaction kinetic model with the battery equivalent circuit model to obtain a lithium battery coupled thermal runaway model.

[0095] Among them, as Figure 5 shown, the coupling correlation method in the lithium battery coupling thermal runaway model is as follows: The temperature change of the lithium battery is calculated by using the thermal runaway reaction kinetics model, and the temperature change of the lithium battery is sent to the battery equivalent circuit model; The battery equivalent circuit model calculates the equivalent internal short-circuit resistance R short , internal resistance R cell , electrode stoichiometry (Y(t) and X(t)), battery terminal voltage V, and total internal short-circuit electrical energy ΔH e and sends them to the thermal runaway reaction kinetics model to calculate the heat generation Q sei (t) of the SEI film decomposition reaction, heat generation Q an (t) of the film and electrolyte reaction, heat generation Q ele (t) of the electrolyte solution decomposition, heat generation Q ca (t) of the lithium iron phosphate cathode material decomposition, and heat generation Q e (t) of electrical energy. The inputs of the thermal runaway reaction kinetics model are: the total electrical energy of the internal short circuit of the battery equivalent circuit model, the ambient temperature, the heat generation of each component in the chemical reaction, and the heat exchange of the battery. The output is: the change value of the temperature of the battery under test over time. The inputs of the battery equivalent circuit model are: the change in the battery temperature obtained from the thermal runaway reaction kinetics model, the charge and discharge current, and the stoichiometry of the active material. The output of the thermal runaway reaction kinetics model is: the change values of the total internal short-circuit electrical energy, voltage, and current over time. The temperature obtained from the thermal runaway reaction kinetics model is transmitted to the battery equivalent circuit model in real time to affect some electrochemical parameters in the electrochemical model through the temperature and Arrhenius relationship.

[0096] The technical solution of this embodiment can comprehensively and accurately reflect the change trend of the internal characteristics of the battery during thermal runaway, more accurately describe the trend of the battery temperature changing over time, help to deeply understand and predict the battery thermal runaway phenomenon, and provide a basis for researching and designing safer and more reliable power batteries.

[0097] Figure 6 shows the flowchart of the second embodiment of the method for constructing a lithium battery thermal runaway model provided by this application, and this method is executed by a lithium battery thermal runaway model construction device. Please refer to Figure 6 shown, this method includes the following steps:

[0098] Step S210: Construct a thermal runaway reaction kinetics model and a battery equivalent circuit model of the lithium battery.

[0099] Among them, the thermal runaway reaction kinetic model includes: a first equation characterizing the battery temperature and heat generation power, a second equation characterizing the heat exchange between the battery temperature and the external environment, a third equation characterizing the heat generation power and concentration of each component in the thermal chemical reaction, and a fourth equation characterizing the heat generation of electric energy; the battery equivalent circuit model is a model constructed based on the equivalent internal resistance model and combined with the voltage drop caused by the internal short-circuit current, the thermodynamic voltage drop caused by the entropy change of the battery under high-temperature conditions, and the voltage drop caused by the loss of battery active materials.

[0100] Step S220: Couple the thermal runaway reaction kinetic model with the battery equivalent circuit model to obtain a lithium battery coupled thermal runaway model.

[0101] Step S230: Obtain the battery physical property parameters of the test lithium battery and input them into the lithium battery coupled thermal runaway model to obtain the thermal runaway test results of the test lithium battery.

[0102] Among them, the lithium battery to be tested is at least one of a nickel-cobalt-manganese battery, a lithium iron phosphate battery, a lithium cobalt oxide battery, a lithium nickel oxide battery, a lithium manganese oxide battery, and a lithium manganese phosphate battery. The battery physical property parameters include: battery geometric parameters, battery kinetic parameters, and battery electrochemical parameters. The battery geometric parameters include at least one of battery length, battery width, battery height, battery tab length, battery tab width, battery tab thickness, and tab position. The battery kinetic parameters include at least one of battery mass, battery specific heat capacity, battery thermal conductivity, battery convective heat transfer coefficient, battery chemical reaction enthalpy of formation, battery pre-exponential factor, battery reaction activation energy, and battery normalized concentration. The battery electrochemical parameters include at least one of battery open-circuit voltage, battery charge and discharge current, battery internal resistance, battery equivalent internal short-circuit resistance, and battery positive electrode stoichiometry.

[0103] Step S240: When the difference between the thermal runaway experimental results and the thermal runaway test results of the test lithium battery meets the preset conditions, use the lithium battery coupled thermal runaway model to predict the thermal runaway of the lithium battery to be tested.

[0104] Among them, the thermal runaway experimental results of the test lithium battery are collected by using an external thermocouple. The thermal runaway experimental results are the battery surface temperature values of the test lithium battery. The number of test lithium batteries can be multiple. Multiple test lithium batteries are abnormally heated to trigger a thermal runaway experiment, and the external thermocouple is used to collect the battery surface temperature. The preset conditions can be set according to the actual situation and are not limited here. Figure 7 Shows the parameter value ranges of the test lithium battery. Figure 8 Shows a comparison chart between the thermal runaway experimental results and the thermal runaway test results. Figure 8The results of the thermal runaway experiment are very close to the results of the thermal runaway test, which fully demonstrates the accuracy of the lithium battery coupled thermal runaway model. The lithium battery to be tested is the lithium battery that needs to be detected in this embodiment. The lithium battery to be tested is defaulted to be a lithium iron phosphate battery, and the specific battery physical property parameters are as Figure 9 shown. There are no strict restrictions on the electrochemical test and thermal test methods in this embodiment. The kinetic parameters and electrochemical parameters can also be obtained through methods such as theoretical calculation and literature records.

[0105] The technical solution of this embodiment further verifies the accuracy of the lithium battery coupled thermal runaway model through the thermal runaway experiment of the lithium battery. Thus, the lithium battery coupled thermal runaway model can comprehensively and accurately reflect the changing trend of the internal characteristics of the battery during thermal runaway, more precisely describe the trend of the battery temperature changing with time, help to deeply understand and predict the phenomenon of battery thermal runaway, and provide a basis for researching and designing safer and more reliable power batteries.

[0106] Figure 10 shows a schematic structural diagram of an embodiment of the lithium battery thermal runaway model construction device provided by the present application. Please refer to Figure 10 shown. The device 300 includes: a construction module 310 and a coupling module 320.

[0107] The construction module 310 is used to construct a thermal runaway reaction kinetic model and a battery equivalent circuit model of the lithium battery; wherein, the thermal runaway reaction kinetic model includes: a first equation characterizing the battery temperature and the heat generation power, a second equation characterizing the heat exchange between the battery temperature and the external environment, a third equation characterizing the heat generation power and concentration of each component in the thermal chemical reaction, and a fourth equation characterizing the heat generation of electric energy; the battery equivalent circuit model is a model constructed based on the equivalent internal resistance model and combined with the voltage drop caused by the internal short-circuit current, the thermodynamic voltage drop caused by the entropy change of the battery under high temperature conditions, and the voltage drop caused by the loss of battery active substances;

[0108] The coupling module 320 is used to couple the thermal runaway reaction kinetic model with the battery equivalent circuit model to obtain a lithium battery coupled thermal runaway model.

[0109] In an optional manner, the device 200 further includes: a test module; the test module is used for:

[0110] Obtain the battery physical property parameters of the test lithium battery and input them into the lithium battery coupled thermal runaway model to obtain the thermal runaway test results of the test lithium battery;

[0111] When the difference between the thermal runaway experiment results of the test lithium battery and the thermal runaway test results meets a preset condition, use the lithium battery coupled thermal runaway model to predict the thermal runaway of the lithium battery to be tested.

[0112] In an alternative embodiment, the battery physical property parameters include: battery geometric parameters, battery kinetic parameters, and battery electrochemical parameters;

[0113] The battery geometric parameters include at least one of: battery length, battery width, battery height, tab length, tab width, tab thickness, and tab position;

[0114] The battery kinetic parameters include at least one of: battery mass, battery specific heat capacity, battery thermal conductivity, battery convective heat transfer coefficient, enthalpy of formation of battery chemical reaction, battery pre-exponential factor, battery reaction activation energy, and battery normalized concentration;

[0115] The battery electrochemical parameters include at least one of: battery open-circuit voltage, battery charge and discharge current, battery internal resistance, battery equivalent internal short-circuit resistance, and battery positive electrode stoichiometry.

[0116] In an alternative embodiment, the lithium-ion battery to be tested is at least one of: nickel-cobalt-manganese battery, lithium iron phosphate battery, lithium cobalt oxide battery, lithium nickel oxide battery, lithium manganese oxide battery, and lithium manganese phosphate battery.

[0117] In an alternative embodiment, the device 300 further includes: an experiment module; the experiment module is configured to:

[0118] Collect the thermal runaway experiment results of the test lithium-ion battery by using an external thermocouple; wherein, the thermal runaway experiment results are: the battery surface temperature value of the test lithium-ion battery.

[0119] In an alternative embodiment, the second equation is used to: obtain the heat exchange amount between the lithium-ion battery and the environment through the convective radiation heat transfer equation;

[0120] The third equation is used to: calculate the heat release amounts of the thermal reactions and decomposition reactions of each component of the lithium-ion battery respectively by using the Arrhenius formula;

[0121] The fourth equation is used to: convert the electrical energy generated during the internal short circuit of the lithium-ion battery into heat energy through the principle of energy conservation.

[0122] In an alternative embodiment, the coupling correlation method in the lithium-ion battery coupled thermal runaway model is: calculating the lithium-ion battery temperature change by using the thermal runaway reaction kinetics model, and sending the lithium-ion battery temperature change to the battery equivalent circuit model; the battery equivalent circuit model calculates the equivalent internal short-circuit resistance, internal resistance, electrode stoichiometry, battery terminal voltage, and total internal short-circuit electrical energy according to the lithium-ion battery temperature change and sends them to the thermal runaway reaction kinetics model to calculate the heat generation amount of the SEI film decomposition reaction, the heat generation amount of the film and electrolyte reaction, the heat generation amount of the electrolyte solution decomposition, the heat generation amount of the lithium iron phosphate cathode material decomposition, and the heat generation of electrical energy.

[0123] The technical solution of this embodiment can comprehensively and accurately reflect the changing trend of the internal characteristics of the battery during thermal runaway, more precisely describe the trend of the battery temperature changing with time, contribute to a deeper understanding and prediction of the battery thermal runaway phenomenon, and provide a basis for the research and design of safer and more reliable power batteries.

[0124] It should be noted that the lithium battery thermal runaway model construction device provided in the above embodiment and the lithium battery thermal runaway model construction method provided in the foregoing embodiment belong to the same concept. The specific manners in which each module and unit perform operations have been described in detail in the method embodiment, and will not be elaborated here.

[0125] Figure 11 The structural schematic diagram of the embodiment of the lithium battery thermal runaway model construction device provided by the present application is shown, which shows the structural schematic diagram of the computer system suitable for implementing the lithium battery thermal runaway model construction device of the embodiment of the present application. The specific implementation of the lithium battery thermal runaway model construction device in the specific embodiment of the present application is not limited.

[0126] Please refer to Figure 11 As shown, the lithium battery thermal runaway model construction device includes: a controller; a memory for storing one or more programs, which when executed by the controller, are used to execute the above-mentioned lithium battery thermal runaway model construction method.

[0127] Please continue to refer to Figure 11 As shown, the computer system 500 of the lithium battery thermal runaway model construction device includes a central processing unit (CPU) 501, which can perform various appropriate actions and processes according to the program stored in the read-only memory (ROM) 502 or the program loaded from the storage section 508 into the random access memory (RAM) 503, such as executing the method in the above embodiment. In the RAM 503, various programs and data required for system operation are also stored. The CPU 501, ROM 502, and RAM 503 are connected to each other through a bus 504. The input / output (I / O) interface 505 is also connected to the bus 504.

[0128] The following components are connected to the I / O interface 505: an input section 506 including a keyboard, a mouse, etc.; an output section 507 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 508 including a hard disk, etc.; and a communication section 509 including a network interface card such as a LAN (Local Area Network) card, a modem, etc. The communication section 509 performs communication processing via a network such as the Internet. A drive 510 is also connected to the I / O interface 505 as required. A removable medium 511 such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc. is installed on the drive 510 as required so that a computer program read from it can be installed into the storage section 508 as required.

[0129] Specifically, according to an embodiment of the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present application includes a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a computer program for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from the network through the communication section 509, and / or installed from the removable medium 511. When the computer program is executed by a central processing unit (CPU) 501, various functions defined in the system of the present application are executed.

[0130] Another aspect of the present application also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the method for constructing a lithium battery thermal runaway model as described above is implemented. The computer-readable storage medium may be included in the lithium battery thermal runaway model construction device described in the above embodiment, or may exist alone without being assembled into the electronic device.

[0131] Another aspect of the present application also provides a computer program product or a computer program, and the computer program product or the computer program includes at least one executable instruction, and when the executable instruction runs on the lithium battery thermal runaway model construction device / equipment, the lithium battery thermal runaway model construction device / equipment is caused to execute the lithium battery thermal runaway model construction method as described above.

[0132] The executable instruction can specifically be used to cause the lithium battery thermal runaway model construction equipment / device to perform the following operations:

[0133] Build a thermal runaway reaction kinetic model and a battery equivalent circuit model for a lithium battery; wherein, the thermal runaway reaction kinetic model includes: a first equation characterizing the battery temperature and heat generation power, a second equation characterizing the heat exchange between the battery temperature and the external environment, a third equation characterizing the heat generation power and concentration of each component in the thermal chemical reaction, and a fourth equation characterizing the heat generation of electrical energy; the battery equivalent circuit model is a model constructed based on an equivalent internal resistance model and combined with the voltage drop caused by the internal short-circuit current, the thermodynamic voltage drop caused by the entropy change of the battery under high temperature conditions, and the voltage drop caused by the loss of battery active materials;

[0134] Couple the thermal runaway reaction kinetic model with the battery equivalent circuit model to obtain a lithium battery coupled thermal runaway model.

[0135] In an alternative embodiment, the method further includes:

[0136] Obtain the battery physical property parameters of a test lithium battery and input them into the lithium battery coupled thermal runaway model to obtain the thermal runaway test results of the test lithium battery;

[0137] When the difference between the thermal runaway experimental results and the thermal runaway test results of the test lithium battery meets a preset condition, use the lithium battery coupled thermal runaway model to predict the thermal runaway of the lithium battery to be tested.

[0138] In an alternative embodiment, the battery physical property parameters include: battery geometric parameters, battery kinetic parameters, and battery electrochemical parameters;

[0139] The battery geometric parameters include at least one of: battery length, battery width, battery height, battery tab length, battery tab width, battery tab thickness, and tab position;

[0140] The battery kinetic parameters include at least one of: battery mass, battery specific heat capacity, battery thermal conductivity, battery convective heat transfer coefficient, battery chemical reaction enthalpy of formation, battery pre-exponential factor, battery reaction activation energy, and battery normalized concentration;

[0141] The battery electrochemical parameters include at least one of: battery open-circuit voltage, battery charge and discharge current, battery internal resistance, battery equivalent internal short-circuit resistance, and battery positive electrode stoichiometry.

[0142] In an alternative embodiment, the lithium battery to be tested is at least one of: nickel cobalt manganese battery, lithium iron phosphate battery, lithium cobalt oxide battery, lithium nickel oxide battery, lithium manganese oxide battery, and lithium manganese phosphate battery.

[0143] In an alternative embodiment, the method further includes:

[0144] Collect the thermal runaway experimental results of the test lithium battery by using an external thermocouple; wherein, the thermal runaway experimental results are the battery surface temperature values of the test lithium battery.

[0145] In an alternative manner, the second equation is used to obtain the heat exchange amount between the lithium battery and the environment through the convective-radiative heat transfer equation.

[0146] The third equation is used to calculate the heat release amounts of the thermal reactions and decomposition reactions of each component of the lithium battery respectively by using the Arrhenius formula.

[0147] The fourth equation is used to convert the electrical energy generated during the internal short circuit of the lithium battery into heat energy through the principle of energy conservation.

[0148] In an alternative manner, the coupling correlation method in the lithium battery coupled thermal runaway model is as follows: calculate the temperature change of the lithium battery by using the thermal runaway reaction kinetics model, and send the temperature change of the lithium battery to the battery equivalent circuit model; the battery equivalent circuit model calculates the equivalent internal short circuit resistance, internal resistance, electrode stoichiometry, battery terminal voltage and total internal short circuit electrical energy according to the temperature change of the lithium battery and sends them to the thermal runaway reaction kinetics model to calculate the heat generation amount of the SEI film decomposition reaction, the heat generation amount of the film and electrolyte reaction, the heat generation amount of the electrolyte solution decomposition, the heat generation amount of the lithium iron phosphate cathode material decomposition and the heat generation of electrical energy.

[0149] The technical solution of this embodiment can comprehensively and accurately reflect the change trend of the internal characteristics of the battery during thermal runaway, more accurately describe the trend of the battery temperature changing with time, help to deeply understand and predict the phenomenon of battery thermal runaway, and provide a basis for researching and designing safer and more reliable power batteries.

[0150] It should be noted that the computer-readable medium shown in the embodiments of the present application can be a computer-readable signal medium, a computer-readable storage medium, or any combination of the two. A computer-readable storage medium can be, for example, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples of the computer-readable storage medium may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present application, the computer-readable storage medium can be any tangible medium that contains or stores a program, and this program can be used by or in combination with an instruction execution system, apparatus, or device. In the present application, a computer-readable signal medium can include a data signal propagated in a baseband or as part of a carrier wave, which carries a computer-readable computer program. Such a propagated data signal can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. A computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium, and this computer-readable medium can send, propagate, or transmit a program for use by or in combination with an instruction execution system, apparatus, or device. The computer program contained on the computer-readable medium can be transmitted using any appropriate medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0151] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to various embodiments of the present application. Among them, each block in the flowchart or block diagram can represent a module, a program segment, or a part of code, and the above module, program segment, or part of code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in an order different from that marked in the accompanying drawings. For example, two consecutive blocks shown may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram or flowchart, as well as the combination of blocks in the block diagram or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or operations, or can be implemented by a combination of dedicated hardware and computer instructions.

[0152] The units involved in the embodiments described in this application can be implemented in software or in hardware, and the described units can also be provided in a processor. Among them, the names of these units do not constitute a limitation on the units themselves in some cases.

[0153] According to one aspect of the embodiments of the present application, a computer system is further provided, including a central processing unit (CPU), which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) or a program loaded from a storage section into a random access memory (RAM), such as performing the methods in the above embodiments. In the RAM, various programs and data required for system operations are also stored. The CPU, ROM, and RAM are connected to each other via a bus. An input / output (I / O) interface is also connected to the bus.

[0154] The following components are connected to the I / O interface: an input section including a keyboard, a mouse, etc.; an output section including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker; a storage section including a hard disk, etc.; and a communication section including a network interface card such as a LAN (Local Area Network) card, a modem, etc. The communication section performs communication processing via a network such as the Internet. A drive is also connected to the I / O interface as needed. A removable medium, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive as needed so that a computer program read from it can be installed into the storage section as needed.

[0155] The above content is only a preferred exemplary embodiment of the present application and is not used to limit the implementation of the present application. Those of ordinary skill in the art can make corresponding adaptations or modifications very conveniently according to the main concept and spirit of the present application. Therefore, the protection scope of the present application should be subject to the protection scope required by the claims.

Claims

1. A method for constructing a lithium battery thermal runaway model, characterized in that: include: Constructing a thermal runaway reaction kinetic model and a battery equivalent circuit model for lithium batteries; wherein the thermal runaway reaction kinetic model includes: a first equation characterizing battery temperature and heat generation power, a second equation characterizing heat exchange between battery temperature and external environment, a third equation characterizing heat generation power and concentration of each component in a thermochemical reaction, and a fourth equation characterizing heat generation by electric energy; the battery equivalent circuit model is based on an equivalent internal resistance model and is constructed by combining the voltage drop caused by internal short-circuit current, the thermodynamic voltage drop caused by battery entropy change under high temperature conditions, and the voltage drop caused by loss of battery active substances; The thermal runaway reaction kinetic model is coupled with the battery equivalent circuit model to obtain a lithium battery coupled thermal runaway model.

2. The method according to claim 1, characterized in that The method further comprises: Obtaining battery physical property parameters of the test lithium battery and inputting them into the lithium battery coupled thermal runaway model to obtain a thermal runaway test result of the test lithium battery; When the difference between the thermal runaway experimental result of the tested lithium battery and the thermal runaway test result meets a preset condition, the lithium battery coupled thermal runaway model is used to predict thermal runaway of the tested lithium battery.

3. The method according to claim 2, characterized in that The battery physical parameters include: battery geometric parameters, battery kinetic parameters and battery electrochemical parameters; The battery geometric parameters include: at least one of battery length, battery width, battery height, battery tab length, battery tab width, battery tab thickness and tab position; The battery kinetic parameters include: at least one of battery mass, battery specific heat capacity, battery thermal conductivity, battery convection heat transfer coefficient, battery chemical reaction generation enthalpy, battery pre-exponential factor, battery reaction activation energy and battery normalized concentration; The battery electrochemical parameters include: at least one of the battery open circuit voltage, the battery charge and discharge current, the battery internal resistance, the battery equivalent internal short circuit resistance and the battery positive electrode stoichiometric ratio.

4. The method according to claim 2, characterized in that: The lithium battery to be tested is at least one of a nickel-cobalt-manganese battery, a lithium iron phosphate battery, a lithium cobalt oxide battery, a lithium nickel oxide battery, a lithium manganese oxide battery and a lithium manganese phosphate battery.

5. The method according to claim 2, characterized in that: The method further comprises: The thermal runaway test result of the test lithium battery is collected by means of an external thermocouple; wherein the thermal runaway test result is: the battery surface temperature value of the test lithium battery.

6. The method for constructing a lithium battery thermal runaway model according to any one of claims 1 to 5, characterized in that: The second equation is used to obtain the heat exchange between the lithium battery and the environment through the convection radiation heat transfer equation; The third equation is used to: use the Arrhenius formula to calculate the heat release of the thermal reaction and decomposition reaction of each component of the lithium battery respectively; The fourth equation is used to convert the electrical energy generated when a short circuit occurs in a lithium battery into heat energy through the principle of conservation of energy.

7. The method for constructing a thermal runaway model of a lithium battery according to claim 6, characterized in that: The coupling association mode in the lithium battery coupled thermal runaway model is as follows: the temperature change of the lithium battery is calculated using the thermal runaway reaction kinetic model, and the temperature change of the lithium battery is sent to the battery equivalent circuit model; the battery equivalent circuit model calculates the equivalent internal short-circuit resistance, internal resistance, electrode stoichiometric ratio, battery terminal voltage and total internal short-circuit electric energy according to the temperature change of the lithium battery and sends them to the thermal runaway reaction kinetic model, and calculates the heat generation of the SEI film decomposition reaction, the heat generation of the film and electrolyte reaction, the heat generation of the electrolyte solution decomposition, the heat generation of the lithium iron phosphate positive electrode material decomposition, and the heat generation of electric energy.

8. A device for constructing a thermal runaway model of a lithium battery, characterized in that: include: A construction module for constructing a thermal runaway reaction kinetic model and a battery equivalent circuit model of a lithium battery; wherein the thermal runaway reaction kinetic model includes: a first equation characterizing the battery temperature and heat generation power, a second equation characterizing the heat exchange between the battery temperature and the external environment, a third equation characterizing the heat generation power and concentration of each component in the thermochemical reaction, and a fourth equation characterizing the heat generation of electric energy; the battery equivalent circuit model is based on an equivalent internal resistance model, and is constructed by combining the voltage drop caused by the internal short-circuit current, the thermodynamic voltage drop caused by the entropy change of the battery under high temperature conditions, and the voltage drop caused by the loss of active substances in the battery; A coupling module is used to couple the thermal runaway reaction kinetics model with the battery equivalent circuit model to obtain a lithium battery coupled thermal runaway model.

9. A lithium battery thermal runaway model building device, characterized in that: include: Controller; A memory for storing one or more programs. When the one or more programs are executed by the controller, the controller implements the method for constructing a thermal runaway model of a lithium battery according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The storage medium stores at least one executable instruction. When the executable instruction is executed on the lithium battery thermal runaway model construction device / equipment, the lithium battery thermal runaway model construction device / equipment performs the operation of the lithium battery thermal runaway model construction method according to any one of claims 1 to 7.

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