Lithium battery thermal runaway quantitative evaluation method

Abstract

The invention provides a lithium battery thermal runaway quantitative evaluation method, which comprises the following steps: determining a thermal runaway test type, and research variables and key parameters corresponding to the thermal runaway test type so as to carry out a thermal runaway test; fitting the research variable and the key parameter to obtain an intercept; carrying out correlation calculation on the research variables and the key parameters to obtain weights; and calculating the thermal runaway strength corresponding to the thermal runaway test type based on the intercept, the weight and the key parameters. By using the method of the invention, quantitative evaluation can be carried out on thermal runaway more accurately.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and in particular to a method for quantitatively evaluating thermal runaway of lithium batteries. Background Art

[0002] As environmental and energy issues become increasingly prominent, the development and utilization of new energy, especially clean energy, has become the main demand of future society and the focus of academic research. In the research of related energy fields, secondary batteries have become the most widely used power energy storage batteries due to their early development and mature research. Lithium-ion batteries use the redox couple of metallic lithium as the energy storage-work couple. They have the advantages of large specific energy, high peak power, and long cycle life. They have been used in various small electronic devices and automotive power batteries. However, under extreme conditions, such as heating, overcharging and stamping, the thermal runaway (TR) process will be triggered in LIBs (lithium-ion batteries). This rapid process of heat and flammable gas generation will bring huge fire and explosion hazards.

[0003] The hazards of thermal runaway in thermal runaway triggered by different battery characteristics and conditions are different. Therefore, quantifying thermal runaway is conducive to the comparison between different thermal runaways, and is of great significance for formulating methods to suppress thermal runaway. At present, the company's evaluation method for thermal runaway of lithium batteries is mainly based on the "pass or fail" of the national standard test verification test, and can only be roughly qualitatively evaluated. In addition, the method of using a single parameter (such as battery temperature) also has limitations and cannot effectively evaluate the thermal runaway behavior of lithium-ion batteries. There are also some studies that propose relatively subjective thermal runaway evaluation methods, and these overly subjective evaluations cannot provide direct guidance for thermal runaway suppression. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0005] To this end, the first object of the present invention is to provide a quantitative evaluation method for thermal runaway of a lithium battery, so as to more accurately perform a quantitative evaluation of the thermal runaway.

[0006] The second objective of the present invention is to provide a lithium battery thermal runaway quantitative assessment system.

[0007] A third objective of the present invention is to provide an electronic device.

[0008] A fourth object of the present invention is to provide a computer-readable storage medium.

[0009] To achieve the above-mentioned purpose, the first aspect of the present invention provides a method for quantitatively evaluating thermal runaway of a lithium battery, comprising:

[0010] Determining a thermal runaway test type, research variables and key parameters corresponding to the thermal runaway test type, so as to conduct a thermal runaway test;

[0011] Fitting the research variables and the key parameters to obtain an intercept;

[0012] performing correlation calculation on the research variables and the key parameters to obtain weights;

[0013] The thermal runaway intensity corresponding to the thermal runaway test type is calculated based on the intercept, the weight and the key parameter.

[0014] In the method of the first aspect of the present invention, the fitting of the research variable and the key parameter to obtain the intercept includes: taking the research variable as the independent variable and the key parameter as the dependent variable, performing linear fitting on the research variable and the key parameter to obtain a fitting relationship, and obtaining the intercept based on the fitting relationship.

[0015] In the method of the first aspect of the present invention, the correlation calculation of the research variable and the key parameter to obtain the weight includes: taking the research variable as the independent variable and the key parameter as the dependent variable, performing correlation calculation on the research variable and the key parameter to obtain the correlation coefficient; and normalizing the correlation coefficient to obtain the weight.

[0016] In the method of the first aspect of the present invention, the correlation calculation is calculated using the Pearson correlation coefficient.

[0017] In the method of the first aspect of the present invention, the key parameters include at least one of the average temperature rise rate from the start of the battery test to thermal runaway, the thermal runaway trigger temperature, the maximum temperature rise rate of the thermal runaway surface, the maximum temperature of the thermal runaway surface, the thermal runaway voltage drop, the battery internal resistance change, the weight change, the stress fluctuation, the stress fluctuation duration, and the gas release amount.

[0018] In the method of the first aspect of the present invention, the research variables include self-characteristic variables, and the self-characteristic variables include at least one of the battery rated capacity, the battery SOC, the battery positive electrode material characteristics, the negative electrode material characteristics, and the number of single cells in the module.

[0019] In the method of the first aspect of the present invention, the research variables include triggering thermal runaway variables, and the triggering thermal runaway variables include the power of the heating plate, the area of ​​the heating plate and the ambient temperature during heating thermal runaway; the charging rate and overcharge time during overcharge thermal runaway; the puncture speed and puncture diameter during puncture thermal runaway; and at least one of the extrusion displacement and extrusion strength during extrusion thermal runaway.

[0020] To achieve the above-mentioned purpose, the second aspect of the present invention proposes a lithium battery thermal runaway quantitative assessment system, comprising:

[0021] A determination module, used to determine a thermal runaway test type, research variables and key parameters corresponding to the thermal runaway test type, so as to perform a thermal runaway test;

[0022] An intercept calculation module, used for fitting the research variables and the key parameters to obtain an intercept;

[0023] A weight calculation module, used for performing correlation calculation on the research variables and the key parameters to obtain weights;

[0024] A quantitative evaluation module is used to calculate the thermal runaway intensity corresponding to the thermal runaway test type based on the intercept, the weight and the key parameter.

[0025] To achieve the above-mentioned purpose, the third aspect of the present invention proposes an electronic device, comprising: a processor, and a memory communicatively connected to the processor; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the method proposed in the first aspect of the present invention.

[0026] To achieve the above-mentioned purpose, the fourth aspect of the present invention proposes a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the method proposed in the first aspect of the present invention.

[0027] The lithium battery thermal runaway quantitative assessment method, system, electronic device and storage medium provided by the present invention perform thermal runaway tests by determining the thermal runaway test type, the research variables and key parameters corresponding to the thermal runaway test type; fitting the research variables and key parameters to obtain an intercept; performing correlation calculations on the research variables and key parameters to obtain weights; and calculating the thermal runaway intensity corresponding to the thermal runaway test type based on the intercept, weights and key parameters. In this case, for different thermal runaway test types, fitting and correlation calculations are performed on the research variables and key parameters under the corresponding thermal runaway test type to obtain intercepts and weights, and then the corresponding thermal runaway intensity is calculated, thereby achieving objective and effective calculations of thermal runaway results and improving the accuracy of quantitative assessments of thermal runaway.

[0028] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0030] Figure 1 A schematic diagram of a flow chart of a method for quantitatively evaluating thermal runaway of a lithium battery provided by an embodiment of the present invention;

[0031] Figure 2 A schematic diagram of a specific process of a method for quantitatively evaluating thermal runaway of a lithium battery provided by an embodiment of the present invention;

[0032] Figure 3 A fitting diagram of the rated capacity of the battery and various key parameters in Example 1 provided in an embodiment of the present invention;

[0033] Figure 4 The fitting diagram of acupuncture diameter and various key parameters in Example 2 provided in the embodiment of the present invention;

[0034] Figure 5 A fitting diagram of the number of single cells and various key parameters in Example 3 provided in an embodiment of the present invention;

[0035] Figure 6 A block diagram of a lithium battery thermal runaway quantitative assessment system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0036] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0037] The following describes a method and system for quantitatively evaluating thermal runaway of a lithium battery according to an embodiment of the present invention with reference to the accompanying drawings.

[0038] The embodiment of the present invention provides a method for quantitatively evaluating thermal runaway of a lithium battery, so as to more accurately perform quantitative evaluation of thermal runaway.

[0039] Figure 1 A schematic diagram of a flow chart of a method for quantitatively evaluating thermal runaway of a lithium battery provided in an embodiment of the present invention.

[0040] like Figure 1 As shown, the lithium battery thermal runaway quantitative evaluation method includes the following steps:

[0041] Step S101, determining a thermal runaway test type, research variables and key parameters corresponding to the thermal runaway test type, so as to perform a thermal runaway test.

[0042] In step S101 , the thermal runaway test types include but are not limited to heating thermal runaway, overshoot thermal runaway, puncture thermal runaway, or extrusion thermal runaway.

[0043] In step S101, the research variables corresponding to different thermal runaway test types include the self-characteristic variable Sc, and the self-characteristic variable Sc includes at least one of the battery rated capacity, the battery SOC (state of charge), the battery positive electrode material characteristics, the negative electrode material characteristics, the number of single cells in the module, etc.

[0044] In step S101, the research variables also include a thermal runaway triggering variable It, which includes at least one of the power of the heating plate, the area of ​​the heating plate and the ambient temperature during heating thermal runaway; the charging rate and overcharging time during overcharge thermal runaway; the puncture speed and puncture diameter during puncture thermal runaway; and the extrusion displacement and extrusion strength during extrusion thermal runaway.

[0045] In step S101, the key parameter corresponding to the thermal runaway test type is also called the thermal runaway key parameter P. The thermal runaway key parameter P includes the average temperature rise rate R from the start of the battery test to the thermal runaway a (Unit: °C / s), thermal runaway trigger temperature T r (Unit: °C), maximum temperature rise rate of thermal runaway surface R max (unit: ℃ / s), maximum temperature of thermal runaway surface (unit: ℃), thermal runaway voltage drop (unit: V), battery internal resistance change △R (unit: mΩ), weight change △G (unit: g), stress fluctuation ΔF, stress fluctuation duration τ, and at least one of the gas release amount n.

[0046] In step S101, after determining the thermal runaway test type, the research variables and key parameters corresponding to the thermal runaway test type, a thermal runaway test is performed to obtain the specific values ​​of the key parameters corresponding to the research variables during the test, as well as the battery surface temperature and voltage changes.

[0047] Step S102, fitting the research variables and key parameters to obtain the intercept.

[0048] In step S102, the research variables and key parameters are fitted to obtain an intercept, including: taking the research variables as independent variables and the key parameters as dependent variables, performing linear fitting on the research variables and the key parameters to obtain a fitting relationship, and obtaining the intercept based on the fitting relationship.

[0049] Step S103, performing correlation calculation on the research variables and key parameters to obtain weights.

[0050] In step S103, correlation calculation is performed on the research variables and key parameters to obtain weights, including: taking the research variables as independent variables and the key parameters as dependent variables, performing correlation calculation on the research variables and key parameters to obtain correlation coefficients; and normalizing the correlation coefficients to obtain weights. The correlation calculation is performed using the Pearson correlation coefficient.

[0051] It should be noted that if there are multiple key parameters, the intercept and weight of each key parameter and the same research variable are calculated to facilitate the subsequent calculation of the thermal runaway intensity corresponding to the research variable.

[0052] Step S104, calculating the thermal runaway intensity corresponding to the thermal runaway test type based on the intercept, weight and key parameters.

[0053] In step S104, considering that the thermal runaway of the battery includes the thermal runaway of the single cell and the thermal runaway of the battery module, the thermal runaway strength of the single cell satisfies:

[0054]

[0055] Where i is the index of the key parameter. If the number of key parameters is M, then i is 1-M. i is the i-th key parameter, α i is the weight corresponding to the i-th key parameter, b i is the intercept corresponding to the i-th key parameter.

[0056] The thermal runaway strength of the battery module meets the following requirements:

[0057]

[0058] Where N is the number of single cells.

[0059] Take the case where linear fitting is used for fitting and Pearson correlation coefficient is used for correlation calculation as an example. Figure 2 The specific flow chart of the method for quantitatively evaluating thermal runaway of a lithium battery provided by an embodiment of the present invention is as follows. Figure 2 As shown in the figure, the specific process of the quantitative evaluation method for thermal runaway of lithium batteries is as follows:

[0060] 1) Determine the thermal runaway test type, which includes but is not limited to heating thermal runaway, overshoot thermal runaway, puncture thermal runaway, or extrusion thermal runaway.

[0061] 2) Determine the research variable. The research variable includes the self-characteristic variable Sc or the trigger thermal runaway variable It. The trigger thermal runaway variable It can be referred to as the trigger variable. The relevant description can refer to step S101, which will not be repeated here.

[0062] 3) Perform thermal runaway test on the battery and detect changes in battery surface temperature and voltage.

[0063] 4) Determine the key parameters for quantifying thermal runaway. For related descriptions, please refer to step S101, which will not be repeated here.

[0064] 5) Linear fitting of key parameters of thermal runaway and self-characteristic variables or trigger variables. For related description, please refer to step S102, which will not be repeated here.

[0065] 6) Obtain the intercept b and Pearson correlation coefficient of the straight line. For related descriptions, please refer to step S102 and step S103, which will not be repeated here.

[0066] 7) The Pearson correlation coefficient is normalized to obtain the weight α of the key parameter of thermal runaway in the evaluation process. For the relevant description, please refer to step S103, which will not be repeated here.

[0067] 8) Calculate the thermal runaway intensity by formula. For the related description, please refer to step S104, which will not be described here.

[0068] In order to better illustrate the method of the present invention, three embodiments are listed below for specific description.

[0069] Example 1 takes a single cell, a thermal runaway test type of heating thermal runaway, and a research variable of battery rated capacity as an example, and calculates the thermal runaway intensity H1 of square-shell lithium iron phosphate batteries with different rated capacities when heated at 500W to reach thermal runaway. Figure 3 The figure is a fitting diagram of the battery rated capacity and various key parameters in Example 1 provided in the embodiment of the present invention. The calculation method of the thermal runaway intensity H1 includes the following steps:

[0070] 11) Determine the thermal runaway test type as single cell heating thermal runaway;

[0071] 12) Determine the research variable as the battery rated capacity Q (in Ah) among the battery self-characteristic variables;

[0072] 13) Perform thermal runaway test on the battery (500W heating) and detect the battery surface temperature and voltage changes;

[0073] 14) Determine the key parameters of thermal runaway (see Table 1): the average temperature rise rate Ra (℃ / s) from the start of the battery test to the thermal runaway, the thermal runaway trigger temperature Tr (℃), the maximum temperature rise rate Rmax (℃ / s) of the thermal runaway surface, the maximum temperature Tmax (℃) of the thermal runaway surface, the internal resistance change △R (mΩ), and the weight change △G (g);

[0074] Table 1 Ra, Tr, Rmax, Tmax, △R, △G values ​​obtained from thermal runaway tests of batteries with different rated capacities

[0075]

[0076]

[0077] 15) Take the battery rated capacity Q as the horizontal coordinate and the key parameters of thermal runaway Ra, Tr, Rmax, Tmax, △R, △G as the vertical coordinates for linear fitting to obtain the linear intercept b and Pearson correlation coefficient (see Figure 3 ), specific data see Table 2;

[0078] Table 2 Intercept and weight table of rated capacity and different key parameters of thermal runaway

[0079]

[0080] 16) The Pearson correlation coefficient |R| is normalized to obtain the weight α of the key thermal runaway parameter in the evaluation process, and the intensity H1 of thermal runaway of batteries with different rated capacities is calculated according to the formula in step S104, see Table 3.

[0081] Table 3 Intensity H1 of battery heating thermal runaway corresponding to different rated capacities

[0082] Rated capacity Q(Ah) Thermal runaway intensity H1 166 3.30 89 2.19 128 2.78 159 3.17 207 4.24 130 2.86

[0083] Example 2 takes a single cell, the thermal runaway test type is needle puncture thermal runaway, and the research variable is the needle puncture diameter D as an example, and calculates the thermal runaway intensity H2 of a square-shell lithium iron phosphate battery with a rated capacity of 207Ah when punctured with steel needles of different diameters to achieve thermal runaway. Figure 4 This is a fitting diagram of the needle puncture diameter and various key parameters in Example 2 provided in the embodiment of the present invention. The thermal runaway strength H2 calculation method includes the following steps:

[0084] 21) Determine the thermal runaway test type as single cell thermal runaway by needle puncture;

[0085] 22) Determine the needle puncture diameter D (mm) in the research variable as the trigger variable of battery thermal runaway;

[0086] 23) Conduct a thermal runaway test on a 207Ah battery by puncturing it with steel needles of different diameters at a speed of 25 mm / s, and detect changes in battery surface temperature and voltage;

[0087] 24) Determine the key parameters of thermal runaway (see Table 4): maximum temperature rise rate Rmax (℃ / s) of thermal runaway surface, maximum temperature Tmax (℃) of thermal runaway surface, and voltage drop △U (V) of thermal runaway;

[0088] Table 4 Rmax, Tmax, △U values ​​obtained from thermal runaway of batteries tested with different needle puncture diameters

[0089]

[0090] 25) Linear fitting was performed with the needle puncture diameter as the horizontal coordinate and the key parameters of thermal runaway Rmax, Tmax, and △U as the vertical coordinates to obtain the linear intercept b and Pearson correlation coefficient ( Figure 4 ), see Table 5 for specific data;

[0091] Table 5 Intercept and weight table of needle puncture diameter and different key parameters of thermal runaway

[0092]

[0093] 26) The Pearson correlation coefficient |R| is normalized to obtain the weight α of the key parameters of thermal runaway in the evaluation process, and the intensity H2 of thermal runaway with different needle puncture diameters is calculated according to the formula in step S104, see Table 6.

[0094] Table 6 The intensity of battery thermal runaway corresponding to different needle puncture diameters H2

[0095] Needle puncture diameter (mm) Thermal runaway strength H2 2 0.886 5 1.402 8 3.966 10 4.215

[0096] Example 3 takes a battery module, a thermal runaway test type of heating thermal runaway, and a research variable of the number of single cells as an example, and calculates the thermal runaway intensity H3 of a module composed of square-shell lithium iron phosphate batteries with a rated capacity of 50Ah and different numbers of single cells when heated at 500W to reach thermal runaway. Figure 5 This is a fitting diagram of the number of single cells and various key parameters in Example 3 provided in an embodiment of the present invention. The calculation method of the thermal runaway intensity H3 includes the following steps:

[0097] 31) Determine the thermal runaway type as battery module heating thermal runaway;

[0098] 32) Determine that the research variable is the number of single cells N in the module among the battery self-characteristic variables;

[0099] 33) Perform a thermal runaway test on modules containing different numbers of single cells at a power of 500W, and detect changes in module surface temperature;

[0100] 34) Determine the key parameters of thermal runaway (see Table 7): thermal runaway trigger temperature Tr (°C) (taking the minimum thermal runaway trigger temperature as an example), the maximum temperature of the module surface Tmax (°C);

[0101] Table 7 Tr and Tmax values ​​obtained from thermal runaway tests of batteries with different numbers of single cells

[0102] Number of single cells N Thermal runaway minimum trigger temperature Tr(℃) Thermal runaway maximum temperature Tmax(℃) 1 133.6 407 2 99 365 3 93 355

[0103] 35) Linear fitting is performed with the number of single cells as the horizontal axis and the key parameters of thermal runaway Tr and Tmax as the vertical axis to obtain the linear intercept b and Pearson correlation coefficient (see Figure 5 ), see Table 8 for specific data;

[0104] Table 8 Intercept and weight table of the number of single cells and different key parameters of thermal runaway

[0105]

[0106] 36) The Pearson correlation coefficient |R| is normalized to obtain the weight α of the key thermal runaway parameter in the evaluation process, and the intensity H3 of thermal runaway of battery heating with different numbers of single cells is calculated according to the formula in step S104, see Table 9.

[0107] Table 9 The intensity of battery thermal runaway corresponding to different numbers of single cells H3

[0108] Number of single cells N Thermal runaway strength H3 1 0.924 2 1.817 3 2.920

[0109] In order to implement the above embodiment, the present invention also proposes a lithium battery thermal runaway quantitative assessment system.

[0110] Figure 6 A block diagram of a lithium battery thermal runaway quantitative assessment system provided by an embodiment of the present invention.

[0111] like Figure 6 As shown, the lithium battery thermal runaway quantitative evaluation system includes a determination module 11, an intercept calculation module 12, a weight calculation module 13 and a quantitative evaluation module 14, wherein:

[0112] A determination module 11 is used to determine the thermal runaway test type, the research variables and key parameters corresponding to the thermal runaway test type, so as to perform the thermal runaway test;

[0113] An intercept calculation module 12, used for fitting the research variables and key parameters to obtain the intercept;

[0114] A weight calculation module 13 is used to calculate the correlation between the research variables and key parameters to obtain weights;

[0115] The quantitative evaluation module 14 is used to calculate the thermal runaway intensity corresponding to the thermal runaway test type based on the intercept, weight and key parameters.

[0116] Furthermore, in a possible implementation of an embodiment of the present invention, in the determination module 11, the key parameters include at least one of the average temperature rise rate from the start of the battery test to thermal runaway, the thermal runaway trigger temperature, the maximum temperature rise rate of the thermal runaway surface, the maximum temperature of the thermal runaway surface, the thermal runaway voltage drop, the battery internal resistance change, the weight change, the stress fluctuation, the stress fluctuation duration, and the gas release amount.

[0117] Furthermore, in a possible implementation of an embodiment of the present invention, in the determination module 11, the research variables include self-characteristic variables, and the self-characteristic variables include at least one of the battery rated capacity, the battery SOC, the battery positive electrode material characteristics, the negative electrode material characteristics, and the number of single cells in the module.

[0118] Furthermore, in a possible implementation of an embodiment of the present invention, in the determination module 11, the research variables include triggering thermal runaway variables, and the triggering thermal runaway variables include the power of the heating plate, the area of ​​the heating plate and the ambient temperature during heating thermal runaway; the charging rate and overcharging time during overcharge thermal runaway; the puncture speed and puncture diameter during puncture thermal runaway; and at least one of the extrusion displacement and extrusion strength during extrusion thermal runaway.

[0119] Furthermore, in a possible implementation of an embodiment of the present invention, the intercept calculation module 12 is specifically used to: take the research variable as the independent variable and the key parameter as the dependent variable, perform linear fitting on the research variable and the key parameter to obtain a fitting relationship, and obtain the intercept based on the fitting relationship.

[0120] Furthermore, in a possible implementation of an embodiment of the present invention, the weight calculation module 13 is specifically used to: take the research variable as the independent variable and the key parameter as the dependent variable, perform correlation calculation on the research variable and the key parameter to obtain the correlation coefficient; and normalize the correlation coefficient to obtain the weight.

[0121] Furthermore, in a possible implementation of the embodiment of the present invention, in the weight calculation module 13, the correlation calculation is performed by Pearson correlation coefficient calculation.

[0122] It should be noted that the aforementioned explanation of the embodiment of the lithium battery thermal runaway quantitative assessment method is also applicable to the lithium battery thermal runaway quantitative assessment system of this embodiment, and will not be repeated here.

[0123] In the embodiment of the present invention, a thermal runaway test is performed by determining the thermal runaway test type, the research variables and key parameters corresponding to the thermal runaway test type; fitting the research variables and key parameters to obtain an intercept; performing correlation calculation on the research variables and key parameters to obtain weights; and calculating the thermal runaway intensity corresponding to the thermal runaway test type based on the intercept, weights and key parameters. In this case, for different thermal runaway test types, fitting and correlation calculation are performed on the research variables and key parameters under the corresponding thermal runaway test type to obtain an intercept and weights, and then the corresponding thermal runaway intensity is calculated, thereby achieving an objective and effective calculation of the thermal runaway results and improving the accuracy of the quantitative evaluation of thermal runaway.

[0124] In view of the shortcomings of the existing thermal runaway assessment methods, the method and system of the present invention will cause apparent phenomena such as explosion-proof valve breaking, battery temperature rising continuously, and voltage dropping during the thermal runaway process of lithium batteries. The present invention tests the change of temperature, temperature rise rate, and voltage over time and defines these parameters as the key parameters P of thermal runaway. The variables related to the battery itself are called independent characteristic variables Sc, and the variables that trigger thermal runaway are called trigger variables It. By linearly fitting the key parameters of thermal runaway and the independent characteristic variables or trigger variables, an evaluation relationship is obtained, and the thermal runaway intensity values ​​under different independent variables or trigger variables are calculated.

[0125] Compared with the existing methods, the present invention has the advantages of being simple, objective, and quantifiable. By obtaining the weights of different key parameters of thermal runaway through linear fitting, the thermal runaway intensity can be objectively and effectively calculated, and the thermal runaway results can be quantitatively evaluated. By comparing thermal runaway under different variables, methods for suppressing thermal runaway can be studied more efficiently.

[0126] In order to implement the above embodiments, the present invention also proposes an electronic device, comprising: a processor, and a memory communicatively connected to the processor; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the method provided by the above embodiments.

[0127] In order to implement the above embodiments, the present invention further proposes a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the methods provided by the above embodiments.

[0128] In order to implement the above embodiments, the present invention further provides a computer program product, including a computer program, which implements the methods provided by the above embodiments when executed by a processor.

[0129] In the description of the aforementioned embodiments, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0130] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0131] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present invention belong.

[0132] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute the instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purpose of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0133] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0134] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0135] In addition, each functional unit in each embodiment of the present invention may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0136] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for quantitatively evaluating thermal runaway of a lithium battery, characterized in that: include: Determining a thermal runaway test type, research variables and key parameters corresponding to the thermal runaway test type, so as to conduct a thermal runaway test; Fitting the research variables and the key parameters to obtain an intercept; performing correlation calculation on the research variables and the key parameters to obtain weights; The thermal runaway intensity corresponding to the thermal runaway test type is calculated based on the intercept, the weight and the key parameter.

2. The method for quantitatively evaluating thermal runaway of a lithium battery according to claim 1, characterized in that: The step of fitting the research variables and the key parameters to obtain an intercept comprises: The research variable is taken as the independent variable and the key parameter is taken as the dependent variable. A linear fit is performed on the research variable and the key parameter to obtain a fitting equation, and the intercept is obtained based on the fitting equation.

3. The method for quantitatively evaluating thermal runaway of a lithium battery according to claim 1, characterized in that: The performing correlation calculation on the research variables and the key parameters to obtain weights includes: The research variable is taken as the independent variable and the key parameter is taken as the dependent variable. The research variable and the key parameter are correlated to obtain the correlation coefficient; the correlation coefficient is normalized to obtain the weight.

4. The method for quantitatively evaluating thermal runaway of a lithium battery according to claim 3, characterized in that: The correlation calculation is performed using the Pearson correlation coefficient.

5. The method for quantitatively evaluating thermal runaway of a lithium battery according to claim 1, characterized in that: The key parameters include at least one of the average temperature rise rate from the start of battery testing to thermal runaway, the thermal runaway trigger temperature, the maximum temperature rise rate of the thermal runaway surface, the maximum temperature of the thermal runaway surface, the thermal runaway voltage drop, the battery internal resistance change, the weight change, the stress fluctuation, the stress fluctuation duration, and the gas release amount.

6. The method for quantitatively evaluating thermal runaway of a lithium battery according to claim 1, characterized in that: The research variables include self-characteristic variables, and the self-characteristic variables include at least one of the battery rated capacity, the battery SOC, the positive electrode material characteristics, the negative electrode material characteristics of the battery, and the number of single cells in the module.

7. The method for quantitatively evaluating thermal runaway of a lithium battery according to claim 1, characterized in that: The research variables include triggering thermal runaway variables, which include the power of the heating plate, the area of ​​the heating plate and the ambient temperature during heating thermal runaway; the charging rate and overcharging time during overcharge thermal runaway; the puncture speed and puncture diameter during puncture thermal runaway; and at least one of the extrusion displacement and extrusion strength during extrusion thermal runaway.

8. A lithium battery thermal runaway quantitative assessment system, characterized in that: include: A determination module, used to determine a thermal runaway test type, research variables and key parameters corresponding to the thermal runaway test type, so as to perform a thermal runaway test; An intercept calculation module, used for fitting the research variables and the key parameters to obtain an intercept; A weight calculation module, used for performing correlation calculation on the research variables and the key parameters to obtain weights; A quantitative evaluation module is used to calculate the thermal runaway intensity corresponding to the thermal runaway test type based on the intercept, the weight and the key parameter.

9. An electronic device, characterized in that: include: A processor, and a memory communicatively connected to the processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory to implement the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, which are used to implement the method according to any one of claims 1 to 7 when executed by a processor.

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