High-temperature plateau thermal safety test method and device after fast charging cycle of lithium ion battery

Abstract

The invention discloses a high-temperature plateau thermal safety testing method and device for a lithium ion battery after fast charging circulation, and relates to the technical field of battery test.The method comprises the steps that lithium ion battery samples after fast charging circulation are obtained, and the lithium ion battery samples are grouped; the lithium ion battery sample is subjected to a low-pressure test after high-temperature storage, and end open-circuit voltage and tab temperature data of the lithium ion battery sample in the low-pressure test after high-temperature storage are obtained; performing a short-circuit test on the lithium ion battery sample to obtain tab heating and spark phenomenon data of the lithium ion battery sample in the short-circuit test; according to the end open-circuit voltage, the tab temperature data and the tab heating and spark phenomenon data, judging the thermal safety state of the lithium ion battery sample after the fast charging cycle; and outputting a thermal safety evaluation result of the lithium ion battery sample.

Description

Technical Field

[0001] The present application relates to the technical field of battery testing, and particularly to a method and device for high-temperature and high-altitude thermal safety testing of lithium-ion batteries after fast charge cycling. Background Art

[0002] With the rapid development of the global new energy vehicle industry, as the core component of new energy vehicles, the performance of power batteries directly affects the driving range, charging time, service life and safety of vehicles. In recent years, the production and sales scale of new energy vehicles has increased rapidly, especially in the Chinese market, where the penetration rate of new energy vehicles has been significantly improved.

[0003] Existing testing methods mainly focus on the charging efficiency and cycle life of batteries, lacking a comprehensive evaluation of the thermal safety performance of batteries after fast charge cycling. During the fast charging process, the current borne by the battery is relatively large, which easily leads to an increase in the internal temperature of the battery, thereby triggering the risk of thermal runaway, and the existing technology fails to effectively evaluate this risk. Existing testing methods are usually only carried out in a laboratory environment and fail to fully simulate the complex working conditions that the battery may encounter in actual use, such as extreme environments like high temperature and low air pressure. This results in a large difference between the test results and the battery performance in actual use. Summary of the Invention

[0004] The purpose of the present application is to provide a method and device for high-temperature and high-altitude thermal safety testing of lithium-ion batteries after fast charge cycling.

[0005] To achieve the above purpose, the present application provides the following solutions:

[0006] In the first aspect, the present application provides a method for high-temperature and high-altitude thermal safety testing of lithium-ion batteries after fast charge cycling, including:

[0007] Obtaining lithium-ion battery samples after fast charge cycling and grouping the lithium-ion battery samples;

[0008] Performing a low air pressure test after high-temperature storage on the lithium-ion battery samples, and obtaining the open-circuit voltage at the terminals and the data of the tab temperatures of the lithium-ion battery samples during the low air pressure test after high-temperature storage;

[0009] Performing a short-circuit test on the lithium-ion battery samples, and obtaining the data of the tab heating and spark phenomena of the lithium-ion battery samples during the short-circuit test;

[0010] Judging the thermal safety state of the lithium-ion battery samples after fast charge cycling according to the open-circuit voltage at the terminals, the data of the tab temperatures, the data of the tab heating and the spark phenomena;

[0011] Outputting the thermal safety evaluation results of the lithium-ion battery samples.

[0012] Optionally, the steps of obtaining the lithium-ion battery samples after fast charge cycling and grouping the lithium-ion battery samples include:

[0013] Prepare 8 lithium-ion battery samples after fast charge cycling, divide the lithium-ion battery samples into 4 groups, with 2 lithium-ion battery samples in each group;

[0014] The fast charge cycling is defined as the charge rate ≥ 3C, and the lithium-ion battery samples are subjected to 300 cycles of 3C fast charge and 1C fast discharge full charge and full discharge, or the fast charge cycle is completed according to the number of times specified by the preset standard.

[0015] Optionally, the steps of performing a low-pressure test on the lithium-ion battery samples after high-temperature storage and obtaining the open-circuit voltage and tab temperature data of the lithium-ion battery samples during the low-pressure test after high-temperature storage include:

[0016] Place the lithium-ion battery samples in a low-pressure chamber with a high-temperature function, perform high-temperature normal-pressure storage at 45°C, and synchronously install and arrange sensors to measure the open-circuit voltage of the lithium-ion battery samples and the temperatures of the two tabs;

[0017] After keeping the lithium-ion battery samples stored in the high-temperature environment for 30 days, adjust the temperature in the low-pressure chamber to room temperature of 25°C, and adjust the air pressure level to 61.2 Kpa at an altitude simulating 4000 meters and leave it for 5 hours;

[0018] Obtain the open-circuit voltage and tab temperature data of the lithium-ion battery samples during the low-pressure test after high-temperature storage.

[0019] Optionally, the steps of obtaining the open-circuit voltage and tab temperature data of the lithium-ion battery samples during the low-pressure test after high-temperature storage include:

[0020] During the high-temperature storage process, judge whether the open-circuit voltage has no abnormal jump and whether the increase in tab temperature does not exceed 2°C;

[0021] During the low-pressure process, judge whether the lithium-ion battery samples are not cracked and deflated, and whether the lithium-ion battery samples do not catch fire, explode, or leak liquid after the test;

[0022] If the lithium-ion battery samples meet the above requirements, continue with the subsequent evaluation, otherwise terminate.

[0023] Optionally, the steps of performing a short-circuit test on the lithium-ion battery samples and obtaining the tab heating and spark phenomenon data of the lithium-ion battery samples during the short-circuit test include:

[0024] Short-circuit the positive and negative electrodes of the lithium-ion battery sample, and observe the heat generation and spark phenomena at the tab during the short-circuit test of the lithium-ion battery sample;

[0025] Judge whether the lithium-ion battery sample catches fire, explodes, or leaks after the short circuit ends, and there is no sparking phenomenon at the tab;

[0026] If the lithium-ion battery sample meets the above requirements, continue with the subsequent evaluation; otherwise, terminate the process.

[0027] Optionally, the step of judging the thermal safety state of the lithium-ion battery sample after fast charge cycling according to the open-circuit voltage at the end, tab temperature data, and tab heat generation and spark phenomenon data includes:

[0028] Judge the thermal safety state of the lithium-ion battery sample during the low-pressure test after high-temperature storage according to the open-circuit voltage at the end and tab temperature data;

[0029] Judge the thermal safety state of the lithium-ion battery sample during the short-circuit test according to the tab heat generation and spark phenomenon data;

[0030] If the lithium-ion battery sample meets the requirements in both the low-pressure test after high-temperature storage and the short-circuit test, the thermal safety state of the lithium-ion battery sample after fast charge cycling is qualified.

[0031] Optionally, the step of outputting the thermal safety evaluation result of the lithium-ion battery sample includes:

[0032] Generate a thermal safety evaluation report for the lithium-ion battery sample according to the thermal safety state of the lithium-ion battery sample during the low-pressure test after high-temperature storage and the short-circuit test;

[0033] Output the thermal safety evaluation report to a preset storage device or display device.

[0034] In a second aspect, the present application provides a high-temperature and high-altitude thermal safety test device for lithium-ion batteries after fast charge cycling, including:

[0035] An acquisition module for acquiring a lithium-ion battery sample after fast charge cycling and grouping the lithium-ion battery sample;

[0036] A test module for performing a low-pressure test on the lithium-ion battery sample after high-temperature storage to obtain the open-circuit voltage at the end and tab temperature data of the lithium-ion battery sample during the low-pressure test after high-temperature storage;

[0037] Perform a short-circuit test on the lithium-ion battery sample to obtain the tab heat generation and spark phenomenon data of the lithium-ion battery sample during the short-circuit test;

[0038] An evaluation module, configured to determine the thermal safety state of the lithium-ion battery sample after fast charge cycling based on the open-circuit voltage at the end, tab temperature data, tab heating, and spark phenomenon data;

[0039] Output the thermal safety evaluation result of the lithium-ion battery sample.

[0040] Optionally, the acquisition module is further configured to:

[0041] Prepare 8 lithium-ion battery samples after fast charge cycling, divide the lithium-ion battery samples into 4 groups, with 2 lithium-ion battery samples in each group;

[0042] The fast charge cycling is defined as the charge rate ≥ 3C, and the lithium-ion battery sample undergoes 300 cycles of 3C fast charge and 1C fast discharge full charge and full discharge, or completes the fast charge cycle according to the number of times specified by the preset standard.

[0043] Optionally, the test module is further configured to:

[0044] Place the lithium-ion battery sample in a low-pressure chamber with a high-temperature function, perform storage at a high temperature of 45°C under normal pressure, and synchronously install and arrange sensors to measure the open-circuit voltage at the end and the temperatures of the two tabs of the lithium-ion battery sample;

[0045] After keeping the lithium-ion battery sample stored in the high-temperature environment for 30 days, adjust the temperature in the low-pressure chamber to room temperature of 25°C, and adjust the air pressure level to 61.2 Kpa at an altitude of 4000 meters for 5 hours;

[0046] Obtain the open-circuit voltage at the end and tab temperature data of the lithium-ion battery sample during the low-pressure test after high-temperature storage.

[0047] Optionally, the test module is further configured to:

[0048] During the high-temperature storage process, determine whether the open-circuit voltage has no abnormal jump and whether the increase in tab temperature does not exceed 2°C;

[0049] During the low-pressure process, determine whether the lithium-ion battery sample has no rupture or air leakage, and whether the lithium-ion battery sample does not catch fire, explode, or leak liquid after the test;

[0050] If the lithium-ion battery sample meets the above requirements, continue with the subsequent evaluation, otherwise terminate.

[0051] Optionally, the test module is further configured to:

[0052] Short-circuit the positive and negative electrodes of the lithium-ion battery sample, and observe the heating and spark phenomenon at the tabs of the lithium-ion battery sample during the short-circuit test;

[0053] Determine whether the lithium-ion battery sample catches fire, explodes, leaks liquid, and has no sparking phenomenon at the tab after the short circuit ends;

[0054] If the lithium-ion battery sample meets the above requirements, continue with subsequent evaluations; otherwise, terminate.

[0055] Optionally, the evaluation module is further configured to:

[0056] Based on the open-circuit voltage at the end and the tab temperature data, determine the thermal safety status of the lithium-ion battery sample in the low-pressure test after high-temperature storage;

[0057] Based on the tab heating and spark phenomenon data, determine the thermal safety status of the lithium-ion battery sample in the short-circuit test;

[0058] If the lithium-ion battery sample meets the requirements in both the low-pressure test after high-temperature storage and the short-circuit test, the thermal safety status of the lithium-ion battery sample after fast charge cycling is qualified.

[0059] Optionally, the evaluation module is further configured to:

[0060] Generate a thermal safety evaluation report for the lithium-ion battery sample based on the thermal safety status of the lithium-ion battery sample in the low-pressure test after high-temperature storage and the short-circuit test;

[0061] Output the thermal safety evaluation report to a preset storage device or display device.

[0062] In a third aspect, the present application provides a computer device, including: a memory, a processor, and a computer program stored on the memory and executable on the processor, where the processor executes the computer program to implement the steps of the lithium-ion battery fast charge cycling and post-high-temperature plateau thermal safety test method described in any one of the above.

[0063] In a fourth aspect, the present application provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the steps of the lithium-ion battery fast charge cycling and post-high-temperature plateau thermal safety test method described in any one of the above.

[0064] In a fifth aspect, the present application provides a computer program product, including a computer program, and when the computer program is executed by a processor, it implements the steps of the lithium-ion battery fast charge cycling and post-high-temperature plateau thermal safety test method described in any one of the above.

[0065] According to the specific embodiments provided by the present application, the following technical effects are disclosed:

[0066] The present application provides a method and device for high-temperature and high-altitude thermal safety testing of lithium-ion batteries after fast charging cycles. Through low-pressure testing and short-circuit testing after high-temperature storage, the thermal safety performance of lithium-ion batteries after fast charging cycles is comprehensively evaluated, simulating the actual scenario of new energy vehicles experiencing high-altitude low pressure after being used in a high-temperature environment in summer, ensuring the reliability of the battery under extreme working conditions. Through grouped testing and repeated experiments, the accuracy and consistency of the test results are improved, avoiding errors that may be caused by single-sample testing. The short-circuit test effectively detects the thermal runaway risk of the battery under short-circuit conditions, preventing safety hazards such as fire, explosion, or leakage. The systematic evaluation process from sample preparation, grouping, testing to final evaluation has clear operation steps and judgment criteria for each step, ensuring the scientificity and standardization of the evaluation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0068] Figure 1 It is a schematic flow chart of a method for high-temperature and high-altitude thermal safety testing of lithium-ion batteries after fast charging cycles provided by an embodiment of the present application;

[0069] Figure 2 It is a schematic circuit diagram of a method for high-temperature and high-altitude thermal safety testing of lithium-ion batteries after fast charging cycles provided by an embodiment of the present application;

[0070] Figure 3 It is a schematic diagram of functional modules of a device for high-temperature and high-altitude thermal safety testing of lithium-ion batteries after fast charging cycles provided by an embodiment of the present application;

[0071] Figure 4 It is a schematic diagram of the structure of a computer device provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0072] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all embodiments. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0073] As Figure 1As shown, some embodiments of the present application provide a method for high-temperature plateau thermal safety testing of lithium-ion batteries after fast charging cycles. In the embodiments of the present application, the method includes the following steps 101 to 105. Among them:

[0074] Step 101: Obtain lithium-ion battery samples after fast charging cycles and group the lithium-ion battery samples.

[0075] In the embodiments of the present application, it is necessary to prepare lithium-ion battery samples required for the experiment. These samples are battery cores after fast charging cycles. The fast charging cycle is defined as the charging rate ≥ 3C. The samples to be analyzed are samples after 300 cycles of 3C fast charging and 1C fast discharging full charge and full discharge, or samples that have completed the fast charging cycle according to the enterprise regulations. After obtaining the samples, they need to be grouped for subsequent experimental operations and data analysis. In the file example, the samples are divided into four groups: A, B, C, and D, with each group containing 2 battery cores.

[0076] Step 102: Conduct a low-pressure test on the lithium-ion battery samples after high-temperature storage, and obtain the open-circuit voltage at the terminals and the tab temperature data of the lithium-ion battery samples during the low-pressure test after high-temperature storage.

[0077] In the embodiments of the present application, the purpose of the test is to simulate the process of the battery expanding during high-temperature in summer on the plain for 30 days after fast charging cycles of new energy vehicles, and then experiencing battery contraction due to low atmospheric pressure on the plateau. This is to evaluate the safety status of the battery under such extreme working conditions. During the test, the fully charged samples need to be placed in a low-pressure chamber with a high-temperature function for 45°C high-temperature and normal-pressure storage, and sensors need to be installed and arranged synchronously to measure the open-circuit voltage at the terminals and the temperatures of the two tabs of the battery. Special attention needs to be paid to the arrangement positions of the open-circuit voltage sampling heads at the terminals and the temperature sensor sensing heads to prevent the sensor adhesion points from loosening and falling off due to the expansion of the battery after heating at high temperature. After the test is completed, the open-circuit voltage at the terminals and the tab temperature data of the samples during the low-pressure test after high-temperature storage can be obtained.

[0078] Specifically, place the samples after 100% SOC fast charging cycles in a low-pressure chamber with a high-temperature function for 45°C high-temperature and normal-pressure storage, and install and arrange sensors synchronously to measure the open-circuit voltage at the terminals and the temperatures of the two tabs of the battery. For soft-packaged batteries, the open-circuit voltage sampling heads at the terminals are arranged on the tab metal sheets, and the temperature sensor sensing heads are arranged at the central positions on the tab metal sheets, rather than on the soft-packaged battery body or the tab insulating adhesive layer. This can prevent the sensor adhesion points from loosening and falling off due to the expansion of the battery after heating at high temperature. For the detailed arrangement positions, see Figure 2 As shown. After maintaining in this high-temperature environment for 30 days, adjust the temperature in the low-pressure chamber to room temperature of 25°C, and adjust the air pressure level to 61.2 Kpa at an altitude of 4000 meters for 5 hours.

[0079] Step 103: Conduct a short-circuit test on the lithium-ion battery sample to obtain data on the ear heating and spark phenomenon of the lithium-ion battery sample during the short-circuit test.

[0080] In the embodiment of the present application, the purpose of the test is to observe the reaction of the battery under short-circuit conditions to evaluate the safety of the battery. During the test, it is necessary to short-circuit the positive and negative electrodes of the fully charged sample and observe the heating and spark phenomenon at the battery ears. After the test is completed, data on the ear heating and spark phenomenon of the sample during the short-circuit test can be obtained.

[0081] Step 104: Determine the thermal safety state of the lithium-ion battery sample after fast charge cycling based on the open-circuit voltage at the end, ear temperature data, and data on the ear heating and spark phenomenon.

[0082] In the embodiment of the present application, based on the open-circuit voltage at the end, ear temperature data, and data on the ear heating and spark phenomenon, the thermal safety state of the lithium-ion battery sample after fast charge cycling can be evaluated. Specifically, it can be determined whether there is an abnormal jump in the open-circuit voltage at the end during high-temperature storage of the battery, whether the ear temperature rises above the specified value, and whether the battery catches fire, explodes, or leaks after the short-circuit test. These data combined can form a comprehensive evaluation of the thermal safety state of the battery.

[0083] Step 105: Output the thermal safety evaluation result of the lithium-ion battery sample.

[0084] In the embodiment of the present application, according to the evaluation result of the thermal safety state of the lithium-ion battery sample after fast charge cycling, the corresponding thermal safety evaluation result can be output. This result can provide important reference information for new energy vehicle manufacturers, battery suppliers, and relevant regulatory agencies to help them better understand the safety of the battery and take corresponding measures to improve the safety performance of the battery.

[0085] In the embodiment of the present application, through the low-pressure test and short-circuit test after high-temperature storage, the thermal safety performance of the lithium-ion battery after fast charge cycling is comprehensively evaluated, simulating the actual scenario of new energy vehicles experiencing high-altitude low pressure after being used in a high-temperature environment in summer, ensuring the reliability of the battery under extreme working conditions. Through group testing and repeated experiments, the accuracy and consistency of the test results are improved, avoiding errors that may be brought by single-sample testing. The short-circuit test effectively detects the thermal runaway risk of the battery under short-circuit conditions, preventing safety hazards such as fire, explosion, or leakage. The systematic evaluation process from sample preparation, grouping, testing to final evaluation has clear operation steps and judgment criteria for each step, ensuring the scientificity and standardization of the evaluation process.

[0086] Optionally, step 101 includes:

[0087] Step 1011: Prepare 8 lithium-ion battery samples after fast charge cycles, divide the lithium-ion battery samples into 4 groups, with 2 lithium-ion battery samples in each group.

[0088] In the embodiment of the present application, according to the experimental requirements, 8 lithium-ion battery samples that have undergone fast charge cycles are prepared. These samples are the main objects of the experiment and are used for a series of subsequent tests and evaluations. The 8 prepared samples are grouped into 4 groups, with each group containing 2 lithium-ion battery samples. Such a grouping method helps to perform different test treatments on the samples of different groups in the subsequent experiment, so as to facilitate the comparison and analysis of the experimental results.

[0089] Step 1012: The fast charge cycle is defined as the charge rate ≥ 3C, and the lithium-ion battery samples have undergone 300 full charge and discharge cycles of 3C fast charge and 1C fast discharge or completed the fast charge cycle according to the number of times specified by the preset standard.

[0090] In the embodiment of the present application, the fast charge cycle is defined as a charging process with a charge rate ≥ 3C. Among them, the charge rate refers to the ratio of the charging current of the battery to the rated capacity. For example, a 3C charge rate means that the charging current is 3 times the rated capacity of the battery. Such a high-rate charging can greatly shorten the charging time of the battery, but at the same time poses higher challenges to the performance and safety of the battery.

[0091] The lithium-ion battery samples in the experiment have undergone 300 full charge and discharge cycles of 3C fast charge and 1C fast discharge or completed the fast charge cycle according to the number of times specified by the preset standard. Specifically, this means that in each cycle, the sample is first quickly charged at a charge rate of 3C until the battery is full; then it is quickly discharged at a discharge rate of 1C until the battery is empty; then the full charge and discharge operation is performed again, and so on, until the preset number of cycles (300 times in this example, or the number of times specified by the preset standard) is reached. Such a cycle process aims to simulate the fast charge cycle working conditions that the battery may experience in actual use to evaluate the performance and safety of the battery after a long time of fast charge cycles.

[0092] Optionally, step 102 includes:

[0093] Step 1021: Place the lithium-ion battery samples in a low-pressure chamber with a high-temperature function, perform storage at 45°C under normal pressure, and synchronously install and arrange sensors to measure the open-circuit voltage at the terminals and the temperature of the two pole tabs of the lithium-ion battery samples.

[0094] In the embodiment of the present application, an experimental low-pressure chamber with a high-temperature function is used. This device can simulate a high-temperature environment and store lithium-ion battery samples.

[0095] Place the lithium-ion battery sample in a low-pressure chamber, set the temperature to 45 °C, and store it under normal pressure. This step aims to simulate the use of the battery in a high-temperature environment and evaluate the stability and safety of the battery under high-temperature conditions.

[0096] During the storage process, synchronously install and arrange sensors to measure the open-circuit voltage at the terminals and the temperature of the two tab ears of the lithium-ion battery sample. The open-circuit voltage at the terminals is the potential difference between the positive and negative electrodes when the external circuit is not connected, which can reflect the internal state of the battery; while the temperature of the two tab ears can reflect the thermal effect during the charge and discharge process of the battery. By monitoring these data in real time, the performance changes of the battery during high-temperature storage can be understood.

[0097] Step 1022, after keeping the lithium-ion battery sample stored in a high-temperature environment for 30 days, adjust the temperature in the low-pressure chamber to room temperature of 25 °C, and adjust the air pressure level to 61.2 Kpa at an altitude simulating 4000 meters and hold for 5 hours.

[0098] In the embodiment of the present application, the lithium-ion battery sample is stored in a high-temperature environment for 30 days to simulate the performance changes of the battery after long-term high-temperature use.

[0099] After the storage is completed, adjust the temperature in the low-pressure chamber to room temperature of 25 °C, and adjust the air pressure level to 61.2 Kpa at an altitude simulating 4000 meters. This step aims to simulate the process of the battery transferring from a high-temperature environment to a low-pressure environment and evaluate the stability and safety of the battery under such working conditions.

[0100] Under the adjusted temperature and air pressure conditions, place the lithium-ion battery sample for 5 hours to fully adapt to the new environmental conditions and prepare for subsequent tests and data collection.

[0101] Step 1023, obtain the open-circuit voltage at the terminals and the tab ear temperature data of the lithium-ion battery sample in the low-pressure test after high-temperature storage.

[0102] In the embodiment of the present application, after the battery undergoes high-temperature storage and low-pressure holding, use the previously arranged sensors to obtain the open-circuit voltage at the terminals and the temperature data of the two tab ears of the lithium-ion battery sample. These data can reflect the performance state of the battery after high-temperature storage and low-pressure holding.

[0103] By analyzing the collected data, the performance changes of the battery during high-temperature storage and low-pressure holding, as well as the adaptability of the battery to extreme working conditions, can be evaluated. This is of great significance for understanding the safety performance of the battery and optimizing the battery design.

[0104] Optionally, step 1023 includes:

[0105] Step 10231, during high-temperature storage, determine whether the open-circuit voltage at the terminal has no abnormal jump and whether the temperature rise of the tab does not exceed 2°C.

[0106] In the embodiments of the present application, the open-circuit voltage (OCV) of the battery is the voltage difference between the positive electrode and the negative electrode when the battery is not connected to an external load or power supply. During high-temperature storage, if the open-circuit voltage of the battery shows an abnormal jump, this may mean that some adverse reactions have occurred inside the battery, such as the decomposition of the electrolyte, the shedding of the electrode material, etc., which will affect the performance and safety of the battery. At the same time, the temperature rise of the tab is also an important indicator for evaluating the thermal stability of the battery. If the temperature of the tab rises by more than 2°C, it may mean that too much heat is generated inside the battery, which will also affect the performance and safety of the battery. Therefore, the purpose of this step is to ensure that during high-temperature storage, the open-circuit voltage of the battery remains stable and the temperature rise of the tab is within an acceptable range.

[0107] Step 10232, during the low-pressure process, determine whether the lithium-ion battery sample is not cracked or deflated and whether the lithium-ion battery sample does not catch fire, explode, or leak liquid after the test.

[0108] In the embodiments of the present application, in a low-pressure environment, due to the decrease in gas pressure, the gas inside the battery may expand and cause the battery casing to crack or deflate. In addition, if the battery undergoes an internal short circuit or thermal runaway in a low-pressure environment, it may cause serious consequences such as fire, explosion, or liquid leakage. Therefore, the purpose of this step is to ensure that during the low-pressure process, the battery does not crack or deflate and remains intact and safe after the test.

[0109] Step 10233, if the lithium-ion battery sample meets the above requirements, continue with the subsequent evaluation; otherwise, terminate the process.

[0110] In the embodiments of the present application, if the lithium-ion battery sample meets the predetermined requirements during high-temperature storage and low-pressure testing, that is, the open-circuit voltage is stable, the temperature rise of the tab is within an acceptable range, there is no cracking or deflation, and the battery remains intact and safe after the test, then the subsequent evaluation work can be continued. This includes, but is not limited to, further testing and analysis of the battery's electrical performance, cycle life, safety, etc. However, if the battery fails to meet the requirements at any step, then the subsequent evaluation work should be terminated because this means that the battery may have some defects or safety hazards and requires further research and improvement.

[0111] Optionally, step 103 includes:

[0112] Step 1031: Short-circuit the positive and negative electrodes of the lithium-ion battery sample, and observe the heat generation and spark phenomena at the tab during the short-circuit test of the lithium-ion battery sample.

[0113] In the embodiments of the present application, the short-circuit test is an important part of evaluating the battery safety, which simulates the behavior of the battery under extreme conditions (such as accidental contact between the positive and negative electrodes). The specific operation is to directly connect (i.e., short-circuit) the positive and negative electrodes of the lithium-ion battery sample through wires or other means, and then observe the reaction of the battery during the short-circuit process.

[0114] The heat generation at the tab is that at the moment of short-circuit, due to the sharp increase in current, a large amount of heat will be generated inside the battery, and these heats will be conducted to the outside through the tab (i.e., the lead-out ends of the positive and negative electrodes of the battery), so the phenomenon of heat generation at the tab can be observed. The spark phenomenon is that if there is a short-circuit point or poor contact of the electrode material inside the battery, electric sparks may be generated during the short-circuit. The electric spark is the manifestation of the instantaneous release of the internal energy of the battery and is also a phenomenon that needs special attention in the battery safety evaluation.

[0115] Step 1032: Judge whether the lithium-ion battery sample does not catch fire, explode, leak liquid after the short-circuit ends, and there is no sparking phenomenon at the tab.

[0116] In the embodiments of the present application, not catching fire, not exploding, and not leaking liquid are the basic requirements for the battery safety evaluation. After the short-circuit test, the battery should remain intact and not occur serious safety accidents such as catching fire, exploding, or leaking liquid.

[0117] The absence of sparking phenomenon at the tab means that in addition to observing the overall safety of the battery, special attention should also be paid to whether there are still electric sparks generated at the tab. If there are still electric sparks at the tab after the short-circuit ends, it indicates that there may be problems such as continuous short-circuit or damage of the electrode material inside the battery, and further inspection and treatment are required.

[0118] Step 1033: If the lithium-ion battery sample meets the above requirements, continue with the subsequent evaluation, otherwise terminate.

[0119] In the embodiments of the present application, if the lithium-ion battery sample performs well in the short-circuit test, without occurring safety accidents such as catching fire, exploding, or leaking liquid, and there is no sparking phenomenon at the tab, then it can be considered that the safety of the battery under the short-circuit condition is reliable, and the subsequent evaluation work can be continued, such as electrical performance test, cycle life test, etc.

[0120] If the lithium-ion battery sample fails to meet the above requirements in the short-circuit test, then the subsequent evaluation work should be terminated. Because this means that there are safety hazards in the battery under the short-circuit condition, and further research and improvement are required to ensure its safety in actual use.

[0121] Optionally, step 104 includes:

[0122] Step 1041: Based on the open-circuit voltage at the end and the tab temperature data, determine the thermal safety status of the lithium-ion battery sample during the low-pressure test after high-temperature storage.

[0123] In the embodiments of the present application, the open-circuit voltage (OCV) at the end is the voltage of the battery when it is not connected to an external load, which reflects the internal electrochemical state of the battery. During high-temperature storage and low-pressure tests, if the open-circuit voltage at the end changes abnormally, it may mean that adverse reactions have occurred inside the battery, such as electrolyte decomposition, changes in the structure of the electrode material, etc., which may all affect the thermal safety of the battery.

[0124] The tab temperature is the temperature of the positive and negative electrode lead-out ends (i.e., tabs) of the battery during operation or testing. The increase in the tab temperature can reflect the thermal effect inside the battery. During high-temperature storage and low-pressure tests, if the tab temperature rises too quickly or too high, it may mean that the heat inside the battery cannot be effectively dissipated, posing a risk of thermal runaway.

[0125] Step 1042: Based on the tab heating and spark phenomenon data, determine the thermal safety status of the lithium-ion battery sample during the short-circuit test.

[0126] In the embodiments of the present application, during the short-circuit test, due to the sharp increase in current, a large amount of heat will be generated inside the battery, and this heat will be conducted to the outside through the tabs, resulting in tab heating. The degree and speed of tab heating can reflect the thermal effect and thermal management ability of the battery under short-circuit conditions.

[0127] The spark phenomenon is generated when the battery is short-circuited due to instantaneous discharge between the electrodes. The appearance of a spark means that there is a short-circuit point inside the battery or poor contact between the electrode materials, which may cause local overheating of the battery and even lead to fire or explosion.

[0128] Step 1043: If the lithium-ion battery sample meets the requirements in both the low-pressure test after high-temperature storage and the short-circuit test, then the thermal safety status of the lithium-ion battery sample after fast charge cycling is qualified.

[0129] In the embodiments of the present application, meeting the requirements in both the low-pressure test after high-temperature storage and the short-circuit test means that the thermal safety performance of the lithium-ion battery sample under extreme conditions (high temperature, low pressure, short circuit) is good, and no safety accidents such as thermal runaway, fire, or explosion have occurred.

[0130] Fast charging cycle is a common charging method in the actual use of the battery, which requires the battery to absorb a large amount of electricity in a short time. If the battery can still maintain good thermal safety performance after low-pressure test and short-circuit test after high-temperature storage, then it can be considered that the thermal safety state of the battery after fast charging cycle is also qualified.

[0131] Optionally, step 105 includes:

[0132] Step 1051, generate a thermal safety evaluation report for the lithium-ion battery sample according to the thermal safety state of the lithium-ion battery sample in the low-pressure test and short-circuit test after high-temperature storage.

[0133] In the embodiments of the present application, the thermal safety state refers to the thermal stability, thermal management ability of the lithium-ion battery sample during the test, and the state of whether thermal runaway, fire, explosion and other safety accidents occur. These states are obtained by observing, measuring and analyzing the test data.

[0134] Generating a thermal safety evaluation report is based on the thermal safety state of the lithium-ion battery sample in the test. The evaluator will compile a detailed thermal safety evaluation report. This report usually includes test objectives, test methods, test data, analysis results, evaluation conclusions and other contents. The evaluation conclusion is the overall evaluation of the thermal safety performance of the lithium-ion battery sample, indicating whether it meets the relevant safety standards and requirements.

[0135] Step 1052, output the thermal safety evaluation report to a preset storage device or display device.

[0136] In the embodiments of the present application, the preset storage device can be a computer hard disk, a removable storage device (such as a USB flash drive, a portable hard disk) or a network storage device (such as cloud storage), etc. Outputting the thermal safety evaluation report to the storage device can facilitate storage, backup, transmission and sharing, ensuring the security and traceability of the report.

[0137] The preset display device can be a computer monitor, a projector or other visualization devices. Outputting the thermal safety evaluation report to the display device can intuitively display the content of the report, facilitating the evaluator, R & D personnel, production personnel or users to view and understand.

[0138] Based on the same inventive concept, an embodiment of the present application further provides a high-temperature and high-altitude thermal safety test device for a lithium-ion battery after fast charge cycling for implementing the high-temperature and high-altitude thermal safety test method for a lithium-ion battery after fast charge cycling involved above. The solution provided by this device for solving problems is similar to the solution described in the above method. Therefore, the specific limitations in one or more embodiments of the high-temperature and high-altitude thermal safety test device for a lithium-ion battery after fast charge cycling provided below can refer to the limitations on the high-temperature and high-altitude thermal safety test method for a lithium-ion battery after fast charge cycling in the above text, and will not be elaborated here.

[0139] In an exemplary embodiment, as Figure 3 shown, a high-temperature and high-altitude thermal safety test device 20 for a lithium-ion battery after fast charge cycling is provided, including:

[0140] An acquisition module 201, configured to acquire lithium-ion battery samples after fast charge cycling and group the lithium-ion battery samples;

[0141] A test module 202, configured to perform a low air pressure test on the lithium-ion battery samples after high-temperature storage, and acquire the open-circuit voltage at the terminals and the data of the tab temperature of the lithium-ion battery samples in the low air pressure test after high-temperature storage;

[0142] Perform a short-circuit test on the lithium-ion battery samples, and acquire the data of tab heating and spark phenomena of the lithium-ion battery samples in the short-circuit test;

[0143] An evaluation module 203, configured to judge the thermal safety state of the lithium-ion battery samples after fast charge cycling according to the open-circuit voltage at the terminals, the data of the tab temperature, the data of tab heating and the spark phenomena;

[0144] Output the thermal safety evaluation result of the lithium-ion battery samples.

[0145] Optionally, the acquisition module 201 is further configured to:

[0146] Prepare 8 lithium-ion battery samples after fast charge cycling, divide the lithium-ion battery samples into 4 groups, with 2 lithium-ion battery samples in each group;

[0147] The fast charge cycling is defined as the charge rate ≥ 3C, and the lithium-ion battery samples are subjected to 300 full charge and discharge cycles of 3C fast charge and 1C fast discharge or complete the fast charge cycle according to the number of times specified by the preset standard.

[0148] Optionally, the test module 202 is further configured to:

[0149] Place the lithium-ion battery sample in a low-pressure chamber with a high-temperature function, and perform high-temperature storage at 45°C under normal pressure. Synchronously install and arrange sensors to measure the open-circuit voltage at the terminals and the temperatures of the two pole tabs of the lithium-ion battery sample.

[0150] After maintaining the lithium-ion battery sample in the high-temperature environment for 30 days, adjust the temperature in the low-pressure chamber to room temperature of 25°C, and adjust the air pressure level to 61.2 Kpa at an altitude of 4000 meters for 5 hours.

[0151] Obtain the open-circuit voltage at the terminals and the pole tab temperature data of the lithium-ion battery sample in the low-pressure test after high-temperature storage.

[0152] Optionally, the test module 202 is further configured to:

[0153] During the high-temperature storage process, determine whether the open-circuit voltage has no abnormal jump, and whether the increase in the pole tab temperature does not exceed 2°C;

[0154] During the low-pressure process, determine whether the lithium-ion battery sample has no rupture and air leakage, and whether the lithium-ion battery sample does not catch fire, explode, or leak liquid after the test;

[0155] If the lithium-ion battery sample meets the above requirements, continue with the subsequent evaluation, otherwise terminate.

[0156] Optionally, the test module 202 is further configured to:

[0157] Short-circuit the positive and negative electrodes of the lithium-ion battery sample, and observe the heat generation and spark phenomena at the pole tabs of the lithium-ion battery sample during the short-circuit test;

[0158] Determine whether the lithium-ion battery sample does not catch fire, explode, or leak liquid after the short-circuit, and there is no sparking phenomenon at the pole tabs;

[0159] If the lithium-ion battery sample meets the above requirements, continue with the subsequent evaluation, otherwise terminate.

[0160] Optionally, the evaluation module 203 is further configured to:

[0161] Based on the open-circuit voltage and pole tab temperature data, determine the thermal safety state of the lithium-ion battery sample in the low-pressure test after high-temperature storage;

[0162] Based on the pole tab heat generation and spark phenomenon data, determine the thermal safety state of the lithium-ion battery sample in the short-circuit test;

[0163] If the lithium-ion battery sample meets the requirements in both the low-pressure test and the short-circuit test after high-temperature storage, the thermal safety state of the lithium-ion battery sample after fast charge cycling is qualified.

[0164] Optionally, the evaluation module 203 is further configured to:

[0165] Generate a thermal safety evaluation report for the lithium-ion battery sample according to the thermal safety state of the lithium-ion battery sample in the low-pressure test and the short-circuit test after high-temperature storage;

[0166] Output the thermal safety evaluation report to a preset storage device or display device.

[0167] In the embodiments of the present application, through the low-pressure test and the short-circuit test after high-temperature storage, the thermal safety performance of the lithium-ion battery after fast charge cycling is comprehensively evaluated, simulating the actual scenario of new energy vehicles experiencing high-altitude low pressure after being used in a high-temperature environment in summer, ensuring the reliability of the battery under extreme working conditions. Through grouped testing and repeated experiments, the accuracy and consistency of the test results are improved, avoiding errors that may be brought by single-sample testing. The short-circuit test effectively detects the thermal runaway risk of the battery under short-circuit conditions, preventing safety hazards such as fire, explosion, or liquid leakage. The systematic evaluation process from sample preparation, grouping, testing to final evaluation has clear operation steps and judgment criteria for each step, ensuring the scientificity and standardization of the evaluation process.

[0168] In an exemplary embodiment, a computer device is provided. The computer device can be a server or a terminal, and its internal structure diagram can be as Figure 4 shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O), and a communication interface. Among them, the processor, the memory, and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store the thermal safety test data of the lithium-ion battery after fast charge cycling at high temperature and high altitude. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with external terminals through a network connection. When the computer program is executed by the processor, it implements a method for testing the thermal safety of a lithium-ion battery after fast charge cycling at high temperature and high altitude.

[0169] Those skilled in the art can understand, Figure 4The structure shown is only a block diagram of some structures related to the solution of this application, and does not constitute a limitation on the computer device to which the solution of this application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine some components, or have a different component layout.

[0170] In an exemplary embodiment, a computer device is further provided, including a memory and a processor. A computer program is stored in the memory, and when the processor executes the computer program, the steps in the above method embodiments are implemented.

[0171] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0172] In an exemplary embodiment, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0173] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use, and processing of relevant data need to comply with relevant regulations.

[0174] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memories can include read-only memory (ROM), magnetic tapes, floppy disks, flash memories, optical memories, high-density embedded non-volatile memories, resistive random access memories (ReRAM), magnetoresistive random access memories (MRAM), ferroelectric random access memories (FRAM), phase change memories (PCM), graphene memories, etc. Volatile memories can include random access memories (RAM) or external cache memories, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0175] The databases involved in the embodiments provided in the present application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the embodiments provided in the present application can be general-purpose processors, central processors, graphics processors, digital signal processors, programmable logics, data processing logics based on quantum computing, etc., without limitation.

[0176] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0177] Specific examples are used in this article to elaborate on the principles and implementation manners of the present application. The descriptions of the above embodiments are only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A high temperature and plateau thermal safety test method for lithium ion batteries after fast charging cycles, characterized in that: The high temperature and plateau thermal safety test method for a lithium-ion battery after fast charging cycles includes: Obtaining lithium-ion battery samples after fast charging cycles, and grouping the lithium-ion battery samples; Performing a low-pressure test after high-temperature storage on the lithium-ion battery sample to obtain terminal open-circuit voltage and lug temperature data of the lithium-ion battery sample in the low-pressure test after high-temperature storage; Performing a short circuit test on the lithium ion battery sample to obtain data on lug heating and spark phenomena of the lithium ion battery sample during the short circuit test; According to the terminal open circuit voltage, the tab temperature data, the tab heating and spark phenomenon data, the thermal safety state of the lithium-ion battery sample after the fast charging cycle is determined; The thermal safety evaluation result of the lithium-ion battery sample is output.

2. The high temperature and plateau thermal safety test method for lithium ion batteries after fast charging cycles according to claim 1, characterized in that: The step of obtaining lithium-ion battery samples after fast charging cycles and grouping the lithium-ion battery samples comprises: 8 lithium-ion battery samples after fast charging cycles were prepared, and the lithium-ion battery samples were divided into 4 groups, with 2 lithium-ion battery samples in each group; The fast charging cycle is defined as a charging rate ≥ 3C, and the lithium-ion battery sample undergoes 300 cycles of 3C fast charging and 1C fast discharging, or completes the fast charging cycle according to the number of times specified by the preset standard.

3. The high temperature and plateau thermal safety test method for lithium ion batteries after fast charging cycles according to claim 1, characterized in that: The step of performing a low-pressure test on the lithium-ion battery sample after high-temperature storage to obtain terminal open circuit voltage and tab temperature data of the lithium-ion battery sample in the low-pressure test after high-temperature storage comprises: The lithium-ion battery sample is placed in a low-pressure chamber with a high-temperature function, and stored at 45°C at normal pressure. Sensors are installed and arranged to measure the end open-circuit voltage and the two-electrode ear temperature of the lithium-ion battery sample; After the lithium-ion battery sample is stored in a high temperature environment for 30 days, the temperature in the low-pressure chamber is adjusted to room temperature 25° C., and the air pressure level is adjusted to a simulated air pressure of 61.2 KPa at an altitude of 4,000 meters for 5 hours; The terminal open circuit voltage and the tab temperature data of the lithium-ion battery sample in the low pressure test after high temperature storage are obtained.

4. The high temperature and plateau thermal safety test method for lithium ion batteries after fast charging cycles according to claim 3, characterized in that: The step of obtaining the terminal open circuit voltage and the tab temperature data of the lithium ion battery sample in the low pressure test after high temperature storage comprises: During high-temperature storage, determine whether the terminal open-circuit voltage has no abnormal jump and whether the tab temperature rises by no more than 2°C; During the low pressure process, determine whether the lithium ion battery sample has no rupture or leakage, and whether the lithium ion battery sample does not catch fire, explode, or leak after the test; If the lithium-ion battery sample meets the above requirements, the subsequent evaluation will continue, otherwise it will be terminated.

5. The high temperature and plateau thermal safety test method for lithium ion batteries after fast charging cycles according to claim 1, characterized in that: The step of performing a short circuit test on the lithium ion battery sample to obtain the data of lug heating and spark phenomena of the lithium ion battery sample in the short circuit test comprises: Short-circuit the positive and negative electrodes of the lithium-ion battery sample, and observe the heating and sparking phenomena at the tabs of the lithium-ion battery sample in the short-circuit test; Determine whether the lithium-ion battery sample does not catch fire, explode, or leak after the short circuit is completed, and whether there is no spark at the tab; If the lithium-ion battery sample meets the above requirements, the subsequent evaluation will continue, otherwise it will be terminated.

6. The high temperature and plateau thermal safety test method for lithium ion batteries after fast charging cycles according to claim 1, characterized in that: The step of judging the thermal safety state of the lithium-ion battery sample after the fast charging cycle according to the terminal open circuit voltage, the tab temperature data, and the tab heating and spark phenomenon data comprises: According to the terminal open circuit voltage and the tab temperature data, determining the thermal safety state of the lithium-ion battery sample in the low pressure test after high temperature storage; According to the ear heating and spark phenomenon data, judging the thermal safety state of the lithium-ion battery sample in the short-circuit test; If the lithium-ion battery sample meets the requirements in both the low pressure test and the short circuit test after high-temperature storage, the thermal safety state of the lithium-ion battery sample after the fast charging cycle is qualified.

7. The high temperature and plateau thermal safety test method for lithium ion batteries after fast charging cycles according to claim 1, characterized in that: The step of outputting the thermal safety evaluation result of the lithium-ion battery sample comprises: Generate a thermal safety evaluation report of the lithium-ion battery sample according to the thermal safety status of the lithium-ion battery sample in the low-pressure test and the short-circuit test after high-temperature storage; The thermal safety evaluation report is output to a preset storage device or display device.

8. A high temperature and plateau thermal safety test device for lithium-ion batteries after fast charging cycles, characterized in that: The high temperature and plateau thermal safety test device for lithium-ion batteries after fast charging cycles comprises: An acquisition module, used for acquiring lithium-ion battery samples after fast charging cycles, and grouping the lithium-ion battery samples; A testing module, used for performing a low-pressure test after high-temperature storage on the lithium-ion battery sample, and obtaining the terminal open-circuit voltage and lug temperature data of the lithium-ion battery sample in the low-pressure test after high-temperature storage; Performing a short circuit test on the lithium ion battery sample to obtain data on lug heating and spark phenomena of the lithium ion battery sample during the short circuit test; An evaluation module, used to determine the thermal safety state of the lithium-ion battery sample after a fast charging cycle according to the terminal open circuit voltage, the tab temperature data, and the tab heating and spark phenomenon data; The thermal safety evaluation result of the lithium-ion battery sample is output.

9. A computer device comprising: 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 high-temperature and high-altitude thermal safety testing method for lithium-ion batteries after fast charging cycles as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the high-temperature and high-altitude thermal safety testing method for lithium-ion batteries after fast charging cycles described in any one of claims 1 to 7 are implemented.

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