A method and device for testing and analyzing thermal runaway of a power battery

Abstract

The application discloses a power battery thermal runaway test analysis method and device, the method comprises the following steps: obtaining the runaway parameters of a test sample after thermal runaway under different pre-tightening forces, comparing the runaway parameters to determine the optimal value of the pre-tightening force; the pre-tightening force is an external pressure applied to the test sample; the runaway parameters are thermal runaway parameters of the test sample without a heat insulation film; obtaining the diffusion parameters of the test sample when thermal runaway occurs under the optimal pre-tightening force, obtaining the type identifier of the current heat insulation film of the test sample, and establishing an association mapping between the diffusion parameters and the type identifier; the diffusion parameters are thermal runaway parameters of the test sample with a heat insulation film; the association mappings of different types of heat insulation films are obtained in sequence, the diffusion parameters are screened according to a preset screening condition, and the target type identifier corresponding to the diffusion parameters meeting the screening condition is output; the heat insulation film corresponding to the target type identifier is the most suitable heat insulation film for the test sample.

Description

Technical Field

[0001] This application relates to the field of thermal runaway testing and analysis technology, and more specifically, to a method and apparatus for thermal runaway testing and analysis of power batteries. Background Technology

[0002] With the rapid development and maturation of power battery technology, lithium batteries have gradually become the main type of power battery. The number of new energy vehicles on the road is also increasing year by year.

[0003] Conventional safety materials are no longer sufficient to keep pace with the ever-evolving battery technologies. They lack specific measures to protect against thermal runaway, relying primarily on uniform protection that fails to effectively prevent thermal runaway reactions and hinders the reasonable control of safety protection costs. Even worse, the indiscriminate use of protective materials can lead to more severe thermal runaway reactions. Therefore, research into thermal runaway prevention methods for various new energy batteries, the development of corresponding protective measures, and the improvement of existing safety hazards are imperative.

[0004] Therefore, the main objective of this invention is to facilitate the study and analysis of thermal runaway in batteries and to derive corresponding thermal runaway protection materials. Summary of the Invention

[0005] To address the aforementioned issues, this application provides a method and apparatus for testing and analyzing thermal runaway of power batteries. Based on testing and verifying the applicability of protective materials for thermal runaway response of power batteries, it provides targeted and effective protection against thermal runaway of power batteries.

[0006] In a first aspect, embodiments of this application provide a method for testing and analyzing thermal runaway of a power battery, the method comprising: The runaway parameters of the test sample after thermal runaway under different preloads are obtained, and the optimal value of the preload is determined by comparing the runaway parameters. The preload is the external pressure applied to the test sample. The runaway parameters are the thermal runaway parameters of the test sample without a heat insulation film. Obtain the diffusion parameters of the test sample when thermal runaway occurs under optimal preload, obtain the type identifier of the current thermal insulation film of the test sample, and establish an association mapping between the diffusion parameters and the type identifier; the diffusion parameters are the thermal runaway parameters of the test sample when a thermal insulation film is provided. The association mappings of different types of heat insulation films are obtained sequentially. The diffusion parameters are filtered according to preset filtering conditions. The target type identifier corresponding to the diffusion parameters that meet the filtering conditions is output. The heat insulation film corresponding to the target type identifier is the most suitable heat insulation film for the test sample.

[0007] Preferably, "obtaining the runaway parameters of the test sample after thermal runaway under different preloads, and comparing the runaway parameters to determine the optimal value of the preload" specifically includes: Multiple sets of test samples are preset, and each test sample is independently equipped with a heating film. Different pre-tightening forces are applied to each test sample; the different pre-tightening forces are all preset initial values. When a heating command is received, each heating film is activated to perform thermal runaway heating on all the test samples, and the temperature rise rate and pressure drop data of the test samples are monitored in real time. When the test sample experiences thermal runaway based on the preset thermal runaway determination conditions, the duration of thermal runaway of the test sample is calculated. When the duration reaches a preset first duration value, the heating film stops heating the test sample; the test sample completes thermal runaway. The runaway parameters of each test sample under different preloads are obtained, and the optimal value of the preload is determined by comparison; the optimal value is the optimal preload. The runaway parameters include at least the state of the test sample after thermal runaway, the temperature at which thermal runaway is triggered, the diffusion range of thermal runaway, the composition of the gas generated by thermal runaway, and the expansion force value of the test sample.

[0008] Preferably, the step of "obtaining the runaway parameters of each test sample under different preloads and comparing them to determine the optimal value of the preload" specifically includes: Based on the actual application environment of the test sample, a set of initial values ​​for preload force are preset; the ideal parameters of the test sample after thermal runaway are preset; the ideal parameters are the ideal values ​​of the runaway parameters; Thermal runaway experiments were conducted on each of the test samples using the initial values ​​to obtain the runaway parameters of each of the test samples under the initial values. The runaway parameters of each test sample that are less than the ideal parameter are compared and selected, and the corresponding preload value is output. A safety warning range is generated based on all the output preload values ​​and the ideal parameter. After obtaining the security warning range, it is divided into multiple segments: The number of preload segments is determined based on the number of test samples, and the safety warning range is numerically segmented, generating a segment warning value based on each numerical segmentation point; the number of segment warning values ​​is consistent with the number of test samples. Thermal runaway experiments were conducted on each of the test samples using the segmentation warning value to obtain the runaway parameters of each of the test samples under the segmentation warning value. The runaway parameters of each test sample that are closer to the ideal parameters are compared and selected, and the corresponding segmentation warning value is output. A segmentation range is generated based on the segmentation warning value and the ideal parameters. Repeat the above steps multiple times. When the spacing of the segmented range is less than the preset first spacing, take the middle value of the segmented range as the optimal value of the preload.

[0009] Preferably, the thermal runaway determination conditions include at least: the temperature rise rate of the test sample reaches a preset value, and the test sample generates a pressure drop; When both of the above conditions are met simultaneously, the test sample is determined to have experienced thermal runaway.

[0010] Preferably, the step of "obtaining the diffusion parameters of the test sample when it experiences thermal runaway under optimal preload, obtaining the type identifier of the current thermal insulation film of the test sample, and establishing a correlation mapping between the diffusion parameters and the type identifier" specifically includes: Multiple sets of test samples are preset, and a heat insulation film is provided between each test sample; the optimal preload is applied to each test sample; a heating film is provided only for one test sample located in the middle or at the end, and this test sample is defined as the target sample; When a heating command is received, the heating film is activated to perform thermal runaway heating on the target sample, and the temperature rise rate and pressure drop data of the target sample and other test samples are monitored in real time. When the target sample is determined to have thermal runaway according to the preset thermal runaway determination conditions, the diffusion parameters of the target sample are obtained. The diffusion parameters include the thermal runaway parameters of the target sample when a heat insulation film is provided, and the hazard parameters of the other test samples in the same group as the target sample; The causation parameter refers to the parameter of the thermal runaway phenomenon generated by other test samples under the influence of the thermal runaway of the target sample; the detection items of the causation parameter include at least: thermal runaway determination detection, temperature detection, and expansion force detection of the test sample; Obtain the type identifier of the current heat insulation film of the target sample, associate the diffusion parameters with the type identifier, and establish an association mapping.

[0011] Preferably, the step of "sequentially acquiring the association mapping of different types of heat insulation films, filtering the diffusion parameters according to preset filtering conditions, and outputting the target type identifier corresponding to the diffusion parameters that satisfy the filtering conditions" specifically includes: The selection of the heat insulation film type is based on the runaway parameters of the test sample; the selection parameters of the heat insulation film include at least the highest temperature of the test sample during thermal runaway and the composition of the gas generated by thermal runaway. By changing the type of heat insulation film of the target sample, the thermal runaway experiment under the optimal preload was repeated multiple times, and the type identifier of the heat insulation film was associated with the corresponding diffusion parameters. Obtain the associated mappings for the different types of heat insulation films, and generate a mapping set; In the mapping set, diffusion parameters are sequentially filtered according to preset filtering adjustments, and diffusion parameters that meet the filtering conditions are output. Based on the mapping relationship in the mapping set, query the type identifier corresponding to the diffusion parameter, and output the type identifier as the target type identifier.

[0012] Preferably, the screening conditions specifically include: The test sample adjacent to the target sample does not experience thermal runaway, and the temperature of the test sample is below the preset valve opening point; When both of the above conditions are met, the type identifier corresponding to the diffusion parameter is output as the target type identifier.

[0013] Secondly, embodiments of this application provide a power battery thermal runaway test and analysis device, the device comprising: Preload optimization module: Obtains runaway parameters of test samples after thermal runaway under different preloads, and determines the optimal value of preload by comparing the runaway parameters; preload is the external pressure applied to the test sample; runaway parameters are the thermal runaway parameters of the test sample without insulation film; Diffusion runaway module: acquires the diffusion parameters of the test sample when thermal runaway occurs under optimal preload, acquires the current type identifier of the thermal insulation film of the test sample, and establishes a correlation mapping between diffusion parameters and type identifier; the diffusion parameters are the thermal runaway parameters of the test sample when thermal insulation film is installed. Target screening module: sequentially acquires the association mapping of different types of heat insulation films, filters the diffusion parameters according to preset screening conditions, and outputs the target type identifier corresponding to the diffusion parameters that meet the screening conditions. The heat insulation film corresponding to the target type identifier is the most suitable heat insulation film for the test sample.

[0014] Thirdly, embodiments of this application provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method provided as in the first aspect or any possible implementation of the first aspect.

[0015] Fourthly, embodiments of this application provide a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the method provided as in the first aspect or any possible implementation thereof.

[0016] The beneficial effects of this invention are as follows: This invention relates to a method and apparatus for testing and analyzing thermal runaway in power batteries. First, thermal runaway experiments are conducted on battery cells with different preload forces to determine the optimal preload force suitable for the cells. Then, thermal runaway experiments are performed on battery cells with an insulating film applied under the optimal preload force. The insulating film material is screened based on the runaway gas composition of the battery cells. Repeated experiments are conducted with different insulating film types to determine the optimal insulating film to prevent runaway propagation after thermal runaway. This reduces the safety risks after battery thermal runaway, provides targeted protection against the thermal runaway effect of battery cells, and thus ensures the safety of consumers' lives and property, helping to enhance the core competitiveness of products. Attached Figure Description

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

[0018] Figure 1 A flowchart illustrating a power battery thermal runaway test and analysis method provided in this application embodiment; Figure 2 This is a schematic diagram of the structure of a power battery thermal runaway test and analysis device provided in an embodiment of this application; Figure 3 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application; Figure 4 This application provides an experimental apparatus for thermal runaway. Detailed Implementation

[0019] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0020] In the following description, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The following description provides multiple embodiments of this application, which can be substituted or combined with each other. Therefore, this application can also be considered to include all possible combinations of the same and / or different embodiments described. Thus, if one embodiment includes features A, B, and C, and another embodiment includes features B and D, then this application should also be considered to include embodiments containing one or more other possible combinations of A, B, C, and D, even if such embodiments are not explicitly described in the following text.

[0021] The following description provides examples and does not limit the scope, applicability, or examples set forth in the claims. Changes may be made to the function and arrangement of the described elements without departing from the scope of this application. Various processes or components may be appropriately omitted, substituted, or added to the examples. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Furthermore, features described with respect to some examples may be combined into other examples.

[0022] First, let's take lithium-ion batteries as an example to explain thermal runaway: The principle of thermal runaway in lithium-ion batteries is caused by the chemical reaction process inside the battery. The positive and negative electrodes of a lithium-ion battery are separated by an electrolyte. When the battery is charging, lithium ions move from the positive electrode to the negative electrode; when the battery is discharging, lithium ions move from the vicinity to the positive electrode.

[0023] During charging and discharging, lithium ions react chemically with the motor materials, generating heat. If the charging speed is too fast, the charging voltage is too high, or the temperature is too high, the chemical reaction inside the battery will accelerate, generating more heat and potentially causing thermal runaway.

[0024] Similarly, during battery discharge, if the discharge rate is too fast, the discharge current is too large, or the temperature is too high, it will also cause the internal chemical reaction rate of the battery to accelerate, generate more heat, and thus cause thermal runaway of the battery.

[0025] Once a battery experiences thermal runaway, the internal temperature rises sharply, potentially causing the internal materials to melt or burn, releasing large amounts of gas and heat, leading to serious accidents such as explosions or fires. Therefore, the design and manufacture of lithium-ion batteries require strict control over parameters such as charging / discharging speed, voltage, and temperature to prevent thermal runaway.

[0026] Secondly, to facilitate understanding of the technical solution of this application, the following is an explanation of some relevant principles: When the battery is heated, the internal separator will decompose, which will cause an internal short circuit between the positive and negative electrodes of the battery, resulting in thermal runaway. The thermal runaway triggering of this application is based on this principle.

[0027] When a battery experiences thermal runaway, it often leads to a dramatic increase in temperature, which intensifies internal reactions and releases a large amount of gas. Therefore, this application detects the composition of the gas during the experiment. Detecting the composition and content of the generated gas can help in deduce the possible chemical reactions inside the battery, aiding in the screening of suitable protective materials. A heat-insulating film is then made from this protective material.

[0028] Understandably, the thickness of the heat insulation film cannot be changed arbitrarily during battery development, as it involves issues such as battery space utilization and weight reduction. Therefore, this application does not discuss specific size issues.

[0029] To achieve battery safety, specifically preventing the spread of thermal runaway from a single cell, the most suitable heat insulation film must be selected without increasing the thickness. Heat insulation films with different thermal conductivity often have significant cost differences. From a cost perspective, directly selecting the heat insulation film with the lowest thermal conductivity is not conducive to cost control and is not specifically designed for cell protection, so the protective effect may not be optimal.

[0030] When a large amount of gas is generated, the battery expands, and the outer casing deforms. To prevent the battery from over-expanding and exploding, a certain preload force needs to be applied. By analyzing and selecting different preload forces, the optimal preload force can be obtained to ensure the safety of the experiment.

[0031] See Figure 1 , Figure 1 This is a flowchart illustrating a method for testing and analyzing thermal runaway of a power battery according to an embodiment of this application. In this embodiment, the method includes: S101. Obtain the runaway parameters of the test sample after thermal runaway under different preloads, and determine the optimal value of the preload by comparing the runaway parameters.

[0032] In the embodiments of this application, the test sample can be a single battery cell, and multiple battery cells can be assembled together in parallel for thermal runaway detection, which can realize a detection environment where the thermal runaway of a single battery cell causes a diffusion effect on surrounding battery cells. The preload force is the external pressure applied to the test sample, and the runaway parameter is the thermal runaway parameter of the test sample without a heat insulation film.

[0033] The subject of this application can be a thermal runaway detection instrument, which uses an external probe to detect and acquire various data of the battery cell, control heating, and process the detected data.

[0034] In one specific embodiment, please refer to Figure 4 The experimental apparatus of this application may include a thermal runaway reaction chamber, a threaded metal rod, a hexagonal fixing nut, a pressure sensor, a sensor pressure plate, a gas detection sensor, a high-temperature resistant data transmission line, an aerogel insulation layer (multiple layers can be provided), a heating film, a high-temperature resistant thermocouple, the sample to be tested (battery cell), and insulation films between the battery cells (including various optional types), with specific structural configurations as follows: Figure 4 As shown.

[0035] Based on practical considerations, the experiments in this application can be conducted in several groups. Thermocouples can be placed in advance at the center of the back of each battery cell. To detect the temperature of the target battery cell, the temperature rise rate can be calculated. A heating film can be installed on the other side. The steel plates of the pressure sensor and the aerogel insulation film must be strong enough to prevent deformation. The gas detection sensor can be placed inside the thermal runaway reaction chamber.

[0036] Due to the diversity of battery cell structure research and development, the appropriate preload force varies for different battery cell structures. Before adapting materials to the sample to be tested, the optimal preload force should be determined first to simulate the real change effect of the battery cell from the optimal normal state to the thermal runaway state, so as to more rationally select the material of the heat insulation film.

[0037] It is understandable that the structural limitations of this application on the battery cell are almost negligible, and its application scope is wide. In the process of developing the battery cell structure, it can also be used to test and analyze the research and development samples, thereby optimizing and improving the corresponding structure of the battery cell, adapting the best protective materials, and making it have safer and better performance.

[0038] In the embodiments of this application, step S101 specifically includes: Multiple sets of test samples are preset, and each test sample is independently equipped with a heating film. Different pre-tightening forces are applied to each test sample; the different pre-tightening forces are all preset initial values. When a heating command is received, each heating film is activated to perform thermal runaway heating on all the test samples, and the temperature rise rate and pressure drop data of the test samples are monitored in real time. When the test sample experiences thermal runaway based on the preset thermal runaway determination conditions, the duration of thermal runaway of the test sample is calculated. When the duration reaches a preset first duration value, the heating film stops heating the test sample; the test sample completes thermal runaway. The runaway parameters of each test sample under different preloads are obtained, and the optimal value of the preload is determined by comparison; the optimal value is the optimal preload. The runaway parameters include at least the state of the test sample after thermal runaway, the temperature at which thermal runaway is triggered, the diffusion range of thermal runaway, the composition of the gas generated by thermal runaway, and the expansion force value of the test sample.

[0039] The heating command to activate the heating film can be actively triggered and controlled by the operator. During the heating process, the temperature rise rate and pressure drop data of the test sample are simultaneously monitored. In this application, changes in these two parameters are used to determine the triggering of thermal runaway; specifically: The criteria for determining thermal runaway include at least: the temperature rise rate of the test sample reaches a preset value, and the test sample generates a pressure drop; When both of the above conditions are met simultaneously, the test sample is determined to have experienced thermal runaway. For example, the preset value for the temperature rise rate can be 1℃ / min. Furthermore, it can be determined whether the duration of this temperature rise rate meets the standard, so as to avoid the occurrence of a staged temperature rise that is too fast but not long enough to trigger a real thermal runaway phenomenon.

[0040] After thermal runaway is detected, the thermal runaway detection can be repeated to prevent false positives. The duration of thermal runaway is calculated. When the duration of thermal runaway reaches the first duration value, the thermal runaway of the current sample is detected as complete, the test sample completes thermal runaway, and the heating film automatically stops heating.

[0041] For example, the first duration value can be set to 3 seconds. After the thermal runaway is triggered for three seconds, the heating effect of the heating film will stop. The reference value for the duration of the temperature rise rate can also be 3 seconds.

[0042] In this application, multiple sets of test samples can be prepared, and different preload forces can be applied to each sample for experimentation. Each test sample is equipped with an independently controlled heating film. In the experiment to determine the optimal preload force, the initially applied preload force can be a preset initial value. The initial value can be set to a relatively wide range of values ​​according to the actual application environment. For example, six sets of samples can be assembled with preset preload forces of 0 kg, 100 kg, 200 kg, 300 kg, 400 kg, and 500 kg. After the wiring is connected, the heating film can be activated to conduct a thermal runaway experiment, triggering thermal runaway.

[0043] A relatively broad initial value is used for initial comparison to obtain a relatively small safety warning range for preload. The safety warning range is then divided multiple times, and the experiment is repeated based on the segmented values ​​to continuously narrow the safety warning range until the spacing of the safety warning range is reduced to a certain extent. Then, the median value of the safety warning range can be determined as the optimal value, i.e., the optimal preload.

[0044] In one specific embodiment, determining the optimal value through comparison includes: Based on the actual application environment of the test sample, a set of initial values ​​for preload force are preset; the ideal parameters of the test sample after thermal runaway are preset; the ideal parameters are the ideal values ​​of the runaway parameters; Thermal runaway experiments were conducted on each of the test samples using the initial values ​​to obtain the runaway parameters of each of the test samples under the initial values. The runaway parameters of each test sample that are less than the ideal parameter are compared and selected, and the corresponding preload value is output. A safety warning range is generated based on all the output preload values ​​and the ideal parameter. After obtaining the security warning range, it is divided into multiple segments: The number of preload segments is determined based on the number of test samples, and the safety warning range is numerically segmented, generating a segment warning value based on each numerical segmentation point; the number of segment warning values ​​is consistent with the number of test samples. Thermal runaway experiments were conducted on each of the test samples using the segmentation warning value to obtain the runaway parameters of each of the test samples under the segmentation warning value. The runaway parameters of each test sample that are closer to the ideal parameters are compared and selected, and the corresponding segmentation warning value is output. A segmentation range is generated based on the segmentation warning value and the ideal parameters. Repeat the above steps multiple times. When the spacing of the segmented range is less than the preset first spacing, take the middle value of the segmented range as the optimal value of the preload.

[0045] In the embodiments of this application, ideal parameters for thermal runaway of the battery cell can be preset as a comparative reference to screen the range of preload inclination. Specifically, ideal parameters can be set based on the maximum allowable value and range of various detection data in the runaway parameters. For example, the maximum value of expansion force, gas composition and generation amount, diffusion range, etc.

[0046] In one specific implementation, the upper limit of the ideal parameter can be appropriately increased so that the two boundary values ​​of the safety warning range can fluctuate on both sides of the true ideal parameter, making it more reasonable to take the median value as the optimal value.

[0047] In the embodiments of this application, when generating the safety warning range for the first time, the upper limit of the ideal parameter is used as the upper limit of the safety warning range, and the minimum value among all output preload values ​​is used as the lower limit; when generating the segmentation range subsequently, the upper limit of the ideal parameter is used as the upper limit of the safety warning range, and the minimum value of the output segmentation warning value is used as the lower limit.

[0048] Understandably, after multiple segmentations, the spacing between the segmentation ranges gradually decreases. A preset first spacing can be used to determine if the current segmentation range is small enough, and the median value can be used as the optimal value to represent the segmentation range. Understandably, each segmentation can be performed at equal intervals, retaining two boundary values ​​to be included in the number of segmentation warning values.

[0049] S102. Obtain the diffusion parameters of the test sample when thermal runaway occurs under the optimal preload, obtain the type identifier of the current heat insulation film of the test sample, and establish the association mapping between the diffusion parameters and the type identifier.

[0050] After determining the optimal preload, thermal runaway experiments can be conducted on different thermal insulation films using the controlled variable method. However, the materials of thermal insulation films are quite diverse, and the environment and gaseous products generated by the thermal runaway reaction of the battery cell do not have obvious targeted effects. Therefore, this application analyzes the gas composition generated by the thermal runaway reaction during the thermal runaway process, reverse-engineers the possible chemical reactions that may occur during the thermal runaway process, and specifically screens the materials of the thermal insulation film to narrow down the selection range, which is beneficial to reduce experimental costs and the number of experiments.

[0051] Based on this concept, when conducting thermal runaway experiments on different battery cells, the range of materials that can be selected for the thermal insulation film varies to some extent. The selection preference of the thermal insulation film can be adjusted according to the adaptability of the electrolyte, reactive particles, conductive materials, etc. in the battery cell.

[0052] In one possible implementation, step S102 specifically includes: Multiple sets of test samples are preset, and a heat insulation film is provided between each test sample; the optimal preload is applied to each test sample; a heating film is provided only for one test sample located in the middle or at the end, and this test sample is defined as the target sample; When a heating command is received, the heating film is activated to thermally runaway heat the target sample, and the temperature rise rate and pressure drop data of the target sample and other test samples are monitored in real time. When the target sample is determined to have thermal runaway according to the preset thermal runaway determination conditions, the diffusion parameters of the target sample are obtained. The diffusion parameters include the thermal runaway parameters of the target sample when a heat insulation film is provided, and the hazard parameters of the other test samples in the same group as the target sample; The causation parameter refers to the parameter of the thermal runaway phenomenon generated by other test samples under the influence of the thermal runaway of the target sample; the detection items of the causation parameter include at least: thermal runaway determination detection, temperature detection, and expansion force detection of the test sample; Obtain the type identifier of the current heat insulation film of the target sample, associate the diffusion parameters with the type identifier, and establish an association mapping.

[0053] In the embodiments of this application, in the thermal runaway test for screening the heat insulation film, a heat insulation film is set between each test sample, and the preload of each test sample is the optimal value; the heating film is selectively set, preferably on a test sample located in the middle or at the end, so that the sub-tests of the target sample with the heating film in the middle and the target sample with the heating film at the end can be carried out simultaneously, so as to improve the final results and have the verification effect.

[0054] In this embodiment, the diffusion parameter is the thermal runaway parameter of the test sample when a heat insulation film is provided. During the screening test of the heat insulation film, a heating film can be provided to the test sample in the middle position or only to the test sample located in the boundary region. This test sample is the target sample, and the diffusion parameter includes the runaway parameter of the target sample and the accretion parameter of other test samples in the same group.

[0055] The affected parameters are characterized as the slight thermal runaway phenomena or effects on other test samples in the same group as the target sample caused by the thermal runaway of the target sample. The detection items mainly include thermal runaway determination detection, temperature detection, and expansion force detection of the test samples to determine the current effect of the heat insulation film.

[0056] In one specific embodiment, during the screening test of the heat insulation film, the material type of the heat insulation film in each group of test samples is consistent; the material type of the heat insulation film in different groups of test samples may differ, but the size should be consistent. It is understood that if the size of the heat insulation film needs to be adjusted, the size of the heat insulation film in the comparative test should be adjusted simultaneously.

[0057] The material of the heat insulation film can be changed, and multiple comparative experiments can be conducted with the optimal preload to compare the thermal runaway parameters of the battery cell under the protection of various heat insulation films, thereby confirming and selecting the best heat insulation film material.

[0058] S103. Sequentially obtain the association mapping of different types of heat insulation films, filter the diffusion parameters according to preset filtering conditions, and output the target type identifier corresponding to the diffusion parameters that meet the filtering conditions.

[0059] In the embodiments of this application, the composition and quantity of gas during the thermal runaway process can be obtained through the preliminary thermal runaway test of the battery cell. The gas can be analyzed, and the chemical reactions that may occur during thermal runaway can be deduced by combining the materials and structural characteristics of the battery cell. This provides an effective reference standard for the selection of heat insulation film materials and confirms the range of options.

[0060] Within the selectable range, step S102 is performed independently for each type of heat insulation film to establish the correspondence between the type identifier of each heat insulation film and the diffusion parameters during thermal runaway. After screening according to the screening conditions, the diffusion parameters that meet the requirements are selected, and the type identifier is output according to the correspondence to obtain the more preferred heat insulation film material.

[0061] In one possible implementation, step S103 specifically includes: The selection of the heat insulation film type is based on the runaway parameters of the test sample; the selection parameters of the heat insulation film include at least the highest temperature of the test sample during thermal runaway and the composition of the gas generated by thermal runaway. By changing the type of heat insulation film of the target sample, the thermal runaway experiment under the optimal preload was repeated multiple times, and the type identifier of the heat insulation film was associated with the corresponding diffusion parameters. Obtain the associated mappings for the different types of heat insulation films, and generate a mapping set; In the mapping set, diffusion parameters are sequentially filtered according to preset filtering adjustments, and diffusion parameters that meet the filtering conditions are output. Based on the mapping relationship in the mapping set, query the type identifier corresponding to the diffusion parameter, and output the type identifier as the target type identifier.

[0062] It is understandable that the heat insulation film corresponding to the target type identifier is the most suitable heat insulation film for the test sample.

[0063] When screening diffusion parameters, one item can be selected from the runaway parameters of the target sample and the hazard parameters of other samples. For example, whether other samples near the target sample have thermal runaway, or whether the temperature of the target sample is lower than the set value, can be selectively adjusted or added according to the actual situation.

[0064] In the embodiments of this application, the screening conditions specifically include: the test sample adjacent to the target sample does not generate thermal runaway, and the temperature of the test sample is lower than a preset valve opening point; When both of the above conditions are met, the type identifier corresponding to the diffusion parameter is output as the target type identifier.

[0065] Regarding the valve opening point, in the design of power battery cells, an explosion-proof valve is often added to the top cover of the cell. Before thermal runaway occurs, the top cover ruptures, releasing a large amount of gas and carrying away a significant amount of heat, thus preventing thermal runaway. Since the experiment in this application induced thermal runaway through heating, the valve opening critical temperature can be defined as the valve opening point, indicating that the cell is about to experience further thermal runaway effects. This effect must be protected against; otherwise, it will pose a serious safety hazard and interfere with or damage the experiment.

[0066] The following will be combined with the appendix Figure 2 This application provides a detailed description of the power battery thermal runaway testing and analysis device provided in its embodiments. It should be noted that the appendix... Figure 2 The power battery thermal runaway test and analysis device shown is used to perform the test and analysis of this application. Figure 1 The methods shown in the embodiments are for illustrative purposes only, illustrating the parts relevant to the embodiments of this application. For specific technical details not disclosed, please refer to this application. Figure 1 The example shown.

[0067] Please see Figure 2 , Figure 2 This is a schematic diagram of the structure of a power battery thermal runaway testing and analysis device provided in an embodiment of this application. Figure 2 As shown, the device includes: Preload Optimization Module 201: Obtains the runaway parameters of the test sample after thermal runaway under different preloads, and determines the optimal value of the preload by comparing the runaway parameters; the preload is the external pressure applied to the test sample; the runaway parameters are the thermal runaway parameters of the test sample without the insulation film. Diffusion runaway module 202: acquires the diffusion parameters of the test sample when thermal runaway occurs under the optimal preload, acquires the current type identifier of the thermal insulation film of the test sample, and establishes the association mapping between diffusion parameters and type identifier; the diffusion parameters are the thermal runaway parameters of the test sample when thermal insulation film is installed. Target screening module 203: sequentially acquires the association mapping of different types of heat insulation films, filters the diffusion parameters according to preset screening conditions, and outputs the target type identifier corresponding to the diffusion parameters that meet the screening conditions. The heat insulation film corresponding to the target type identifier is the most suitable heat insulation film for the test sample.

[0068] Those skilled in the art will clearly understand that the technical solutions of the embodiments of this application can be implemented by means of software and / or hardware. In this specification, "unit" and "module" refer to software and / or hardware that can independently complete or cooperate with other components to complete a specific function, wherein the hardware may be, for example, a field-programmable gate array (FPGA), an integrated circuit (IC), etc.

[0069] Each processing unit and / or module in the embodiments of this application can be implemented by an analog circuit that implements the functions described in the embodiments of this application, or by software that executes the functions described in the embodiments of this application.

[0070] See Figure 3 It shows a schematic diagram of the structure of an electronic device according to an embodiment of this application, which can be used to implement... Figure 1 The method in the illustrated embodiment. (As shown) Figure 3 As shown, the electronic device 300 may include: at least one central processing unit 301, at least one network interface 304, user interface 303, memory 305, and at least one communication bus 302.

[0071] The communication bus 302 is used to enable communication between these components.

[0072] The user interface 303 may include a display screen and a camera. Optionally, the user interface 303 may also include a standard wired interface and a wireless interface.

[0073] The network interface 304 may optionally include a standard wired interface or a wireless interface (such as a Wi-Fi interface).

[0074] The central processing unit 301 may include one or more processing cores. The central processing unit 301 connects to various parts within the electronic device 300 using various interfaces and lines. It executes various functions of the terminal 300 and processes data by running or executing instructions, programs, code sets, or instruction sets stored in the memory 305, and by calling data stored in the memory 305. Optionally, the central processing unit 301 may be implemented using at least one hardware form of Digital Signal Processing (DSP), Field-Programmable Gate Array (FPGA), or Programmable Logic Array (PLA). The central processing unit 301 may integrate one or more of the following: a central processing unit (CPU), a graphics processing unit (GPU), and a modem. The CPU primarily handles the operating system, user interface, and applications; the GPU is responsible for rendering and drawing the content required for display; and the modem handles wireless communication. It is understood that the modem may also be implemented as a separate chip without being integrated into the central processing unit 301.

[0075] The memory 305 may include random access memory (RAM) or read-only memory. Optionally, the memory 305 may include a non-transitory computer-readable storage medium. The memory 305 may be used to store instructions, programs, code, code sets, or instruction sets. The memory 305 may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for at least one function (such as touch function, sound playback function, image playback function, etc.), instructions for implementing the above-described method embodiments, etc.; the data storage area may store data involved in the above-described method embodiments, etc. Optionally, the memory 305 may also be at least one storage device located remotely from the aforementioned central processing unit 301. Figure 3 As shown, the memory 305, which serves as a computer storage medium, may include an operating system, a network communication module, a user interface module, and program instructions.

[0076] exist Figure 3 In the illustrated electronic device 300, the user interface 303 is mainly used to provide an input interface for the user and to acquire user input data; while the central processing unit 301 can be used to call the power battery thermal runaway test analysis application stored in the memory 305, and specifically perform the following operations: The runaway parameters of the test sample after thermal runaway under different preloads are obtained, and the optimal value of the preload is determined by comparing the runaway parameters. The preload is the external pressure applied to the test sample. The runaway parameters are the thermal runaway parameters of the test sample without the insulation film. Obtain the diffusion parameters of the test sample when thermal runaway occurs under optimal preload, obtain the type identifier of the current thermal insulation film of the test sample, and establish the correlation mapping between diffusion parameters and type identifier; the diffusion parameters are the thermal runaway parameters of the test sample when thermal insulation film is installed. The association mapping of different types of heat insulation films is obtained in sequence. The diffusion parameters are filtered according to the preset screening conditions. The target type identifier corresponding to the diffusion parameters that meet the screening conditions is output. The heat insulation film corresponding to the target type identifier is the most suitable heat insulation film for the test sample.

[0077] This application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method. The computer-readable storage medium may include, but is not limited to, any type of disk, including floppy disks, optical disks, DVDs, CD-ROMs, microdrives, as well as magneto-optical disks, ROMs, RAMs, EPROMs, EEPROMs, DRAMs, VRAMs, flash memory devices, magnetic cards or optical cards, nanosystems (including molecular memory ICs), or any type of medium or device suitable for storing instructions and / or data.

[0078] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0079] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0080] In the several embodiments provided in this application, it should be understood that the disclosed apparatus can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some service interface; the indirect coupling or communication connection between devices or units may be electrical or other forms.

[0081] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0082] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0083] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage device (CMD). Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a memory and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned memory includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0084] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, which may include: a flash drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, etc.

[0085] The foregoing description is merely an exemplary embodiment of this disclosure and should not be construed as limiting the scope of this disclosure. Any equivalent changes and modifications made in accordance with the teachings of this disclosure shall still fall within the scope of this disclosure. Those skilled in the art will readily conceive of embodiments of this disclosure upon considering the specification and practicing the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not described herein. The specification and embodiments are to be considered exemplary only, and the scope and spirit of this disclosure are defined by the claims.

Claims

1. A method for testing and analyzing thermal runaway of a power battery, characterized in that, The method includes: The runaway parameters of the test sample after thermal runaway under different preloads are obtained, and the optimal value of the preload is determined by comparing the runaway parameters. The preload is the external pressure applied to the test sample. The runaway parameters are the thermal runaway parameters of the test sample without a heat insulation film. Obtain the diffusion parameters of the test sample when thermal runaway occurs under optimal preload, obtain the type identifier of the current thermal insulation film of the test sample, and establish an association mapping between the diffusion parameters and the type identifier; the diffusion parameters are the thermal runaway parameters of the test sample when a thermal insulation film is provided. The association mappings of different types of heat insulation films are obtained sequentially. The diffusion parameters are filtered according to preset filtering conditions. The target type identifier corresponding to the diffusion parameters that meet the filtering conditions is output. The heat insulation film corresponding to the target type identifier is the most suitable heat insulation film for the test sample. Specifically, the process of acquiring runaway parameters of test samples after thermal runaway under different preloads, and comparing these runaway parameters to determine the optimal value of the preload, includes: Multiple sets of test samples are preset, and each test sample is independently equipped with a heating film. Different pre-tightening forces are applied to each test sample; the different pre-tightening forces are all preset initial values. When a heating command is received, each heating film is activated to perform thermal runaway heating on all the test samples, and the temperature rise rate and pressure drop data of the test samples are monitored in real time. When the test sample experiences thermal runaway based on the preset thermal runaway determination conditions, the duration of thermal runaway of the test sample is calculated. When the duration reaches a preset first duration value, the heating film stops heating the test sample; the test sample completes thermal runaway. The runaway parameters of each test sample under different preloads are obtained, and the optimal value of the preload is determined by comparison; the optimal value is the optimal preload. The runaway parameters include at least the state of the test sample after thermal runaway, the temperature at which thermal runaway is triggered, the diffusion range of thermal runaway, the composition of the gas generated by thermal runaway, and the expansion force value of the test sample. Specifically, obtaining the runaway parameters of each test sample under different preloads and comparing them to determine the optimal value of the preload includes: Based on the actual application environment of the test sample, a set of initial values ​​for preload force are preset; the ideal parameters of the test sample after thermal runaway are preset; the ideal parameters are the ideal values ​​of the runaway parameters; Thermal runaway experiments were conducted on each of the test samples using the initial values ​​to obtain the runaway parameters of each of the test samples under the initial values. The runaway parameters of each test sample that are less than the ideal parameter are compared and selected, and the corresponding preload value is output. A safety warning range is generated based on all the output preload values ​​and the ideal parameter. After obtaining the security warning range, it is divided into multiple segments: The number of preload segments is determined based on the number of test samples, and the safety warning range is numerically segmented, generating a segment warning value based on each numerical segmentation point; the number of segment warning values ​​is consistent with the number of test samples. Thermal runaway experiments were conducted on each of the test samples using the segmentation warning value to obtain the runaway parameters of each of the test samples under the segmentation warning value. The runaway parameters of each test sample that are closer to the ideal parameters are compared and selected, and the corresponding segmentation warning value is output. A segmentation range is generated based on the segmentation warning value and the ideal parameters. Repeat the above steps multiple times. When the spacing of the segmented range is less than the preset first spacing, take the middle value of the segmented range as the optimal value of the preload.

2. The method according to claim 1, characterized in that, The thermal runaway determination conditions include at least: the temperature rise rate of the test sample reaches a preset value, and the test sample generates a pressure drop; When both of the above conditions are met simultaneously, the test sample is determined to have experienced thermal runaway.

3. The method according to claim 2, characterized in that, The phrase "obtaining the diffusion parameters of the test sample when it experiences thermal runaway under optimal preload, obtaining the type identifier of the current thermal insulation film of the test sample, and establishing a correlation mapping between the diffusion parameters and the type identifier" specifically includes: Multiple sets of test samples are preset, and a heat insulation film is provided between each test sample; the optimal preload is applied to each test sample; a heating film is provided only for one test sample located in the middle or at the end, and this test sample is defined as the target sample; When a heating command is received, the heating film is activated to perform thermal runaway heating on the target sample, and the temperature rise rate and pressure drop data of the target sample and other test samples are monitored in real time. When the target sample is determined to have thermal runaway according to the preset thermal runaway determination conditions, the diffusion parameters of the target sample are obtained. The diffusion parameters include the thermal runaway parameters of the target sample when a heat insulation film is provided, and the hazard parameters of the other test samples in the same group as the target sample; The causation parameter refers to the parameter of the thermal runaway phenomenon generated by other test samples under the influence of the thermal runaway of the target sample; the detection items of the causation parameter include at least: thermal runaway determination detection, temperature detection, and expansion force detection of the test sample; Obtain the type identifier of the current heat insulation film of the target sample, associate the diffusion parameters with the type identifier, and establish an association mapping.

4. The method according to claim 3, characterized in that, The phrase "sequentially acquiring the association mappings of different types of heat insulation films, filtering the diffusion parameters according to preset filtering conditions, and outputting the target type identifier corresponding to the diffusion parameters that satisfy the filtering conditions" specifically includes: The selection of the heat insulation film type is based on the runaway parameters of the test sample; the selection parameters of the heat insulation film include at least the highest temperature of the test sample during thermal runaway and the composition of the gas generated by thermal runaway. By changing the type of heat insulation film of the target sample, the thermal runaway experiment under the optimal preload was repeated multiple times, and the type identifier of the heat insulation film was associated with the corresponding diffusion parameters. Obtain the associated mappings for the different types of heat insulation films, and generate a mapping set; In the mapping set, diffusion parameters are sequentially filtered according to preset filtering adjustments, and diffusion parameters that meet the filtering conditions are output. Based on the mapping relationship in the mapping set, query the type identifier corresponding to the diffusion parameter, and output the type identifier as the target type identifier.

5. The method according to claim 4, characterized in that, The specific filtering criteria include: The test sample adjacent to the target sample does not experience thermal runaway, and the temperature of the test sample is below the preset valve opening point; When both of the above conditions are met, the type identifier corresponding to the diffusion parameter is output as the target type identifier.

6. A power battery thermal runaway testing and analysis device, characterized in that, The apparatus applicable to the power battery thermal runaway test and analysis method as described in claim 1 includes: Preload optimization module: Obtains runaway parameters of test samples after thermal runaway under different preloads, and determines the optimal value of preload by comparing the runaway parameters; preload is the external pressure applied to the test sample; runaway parameters are the thermal runaway parameters of the test sample without insulation film; Diffusion runaway module: acquires the diffusion parameters of the test sample when thermal runaway occurs under optimal preload, acquires the current type identifier of the thermal insulation film of the test sample, and establishes a correlation mapping between diffusion parameters and type identifier; the diffusion parameters are the thermal runaway parameters of the test sample when thermal insulation film is installed. Target screening module: sequentially acquires the association mapping of different types of heat insulation films, filters the diffusion parameters according to preset screening conditions, and outputs the target type identifier corresponding to the diffusion parameters that meet the screening conditions. The heat insulation film corresponding to the target type identifier is the most suitable heat insulation film for the test sample.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method as described in any one of claims 1-5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1-5.

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