Safety performance evaluation method for cooling liquid

Abstract

The invention discloses a safety performance evaluation method for a cooling liquid. The method comprises the following steps: measuring the flash point temperature and the ignition point temperature of the cooling liquid; respectively adjusting the measured flash point temperature and ignition point temperature of the cooling liquid to temperatures under standard atmospheric pressure to obtain a cooling liquid standard flash point temperature and a cooling liquid standard ignition point temperature corresponding to the cooling liquid; obtaining a mixture of the cooling liquid and the electrolyte; the flash point temperature and the ignition point temperature of the mixture are measured, the measured flash point temperature and the measured ignition point temperature of the mixture are adjusted to the temperature under the standard atmospheric pressure, and the mixture standard flash point temperature and the mixture standard ignition point temperature corresponding to the mixture are obtained; and evaluating the influence of electrolyte leakage on the safety performance of the cooling liquid based on the standard flash point temperature of the cooling liquid, the standard ignition point temperature of the cooling liquid, the standard flash point temperature of the mixture and the standard ignition point temperature of the mixture. According to the safety performance evaluation scheme of the cooling liquid, the influence of electrolyte leakage on the safety performance of the cooling liquid can be accurately evaluated, and an important technical support is provided for design and operation of an energy storage system.

Description

Technical Field

[0001] This application relates to the technical field of equipment heat dissipation, and specifically relates to a method for evaluating the safety performance of coolant, an electronic device, and a storage medium. Background Art

[0002] In an immersion energy storage system, the normal operation of the battery cells is crucial. As a key medium to ensure the stable temperature of the battery cells, the safety performance of the coolant is directly related to the safety, reliability, and service life of the entire energy storage system. With the continuous development of energy storage technology, the operating conditions of energy storage systems are becoming increasingly complex. During long-term use, the coolant may be interfered by various potential risk factors, thereby affecting its safety performance.

[0003] However, in the field of immersion energy storage, there is currently no perfect analysis and research on the potential risk of electrolyte leakage from the battery cells. There is a possibility of liquid leakage during the operation of the battery cells. Once the electrolyte leaks, the solvents, lithium salts, additives, and other various substances contained in it may partially or completely dissolve in the coolant. This unexpected change in composition is very likely to have a serious adverse impact on the safety performance of the coolant, thereby affecting the safe and stable operation of the entire energy storage system. However, existing technical means have not fully paid attention to this key issue, and there is also a lack of effective evaluation methods to explore the relationship between the degree of electrolyte leakage and the safety performance of the coolant, which to a certain extent limits the improvement and optimization of the safety performance of energy storage systems. Therefore, there is an urgent need for a method that can accurately evaluate the safety performance of the coolant to address potential risks such as electrolyte leakage, fill the gap in this field of current technology, and provide strong technical support for the safe and reliable operation of immersion energy storage systems.

[0004] The foregoing description is for general background information and does not necessarily constitute prior art. Summary of the Invention

[0005] An embodiment of this application provides a method for evaluating the safety performance of coolant, which can accurately evaluate the impact of electrolyte leakage on the safety performance of coolant, fill the technical gap in this aspect in the field of immersion energy storage, and provide important technical support for the design and operation of energy storage systems.

[0006] An embodiment of this application provides a method for evaluating the safety performance of coolant, including:

[0007] Measuring the flash point temperature and the ignition point temperature of the coolant;

[0008] Adjusting the measured flash point temperature and ignition point temperature of the coolant to the temperature under standard atmospheric pressure respectively to obtain the standard flash point temperature and standard ignition point temperature of the coolant corresponding to the coolant;

[0009] Obtain the mixture of the coolant and the electrolyte;

[0010] Determine the flash point temperature and the ignition point temperature of the mixture, and adjust the determined flash point temperature and ignition point temperature of the mixture to the temperature under standard atmospheric pressure respectively to obtain the mixture standard flash point temperature and the mixture standard ignition point temperature corresponding to the mixture;

[0011] Based on the coolant standard flash point temperature, the coolant standard ignition point temperature, the mixture standard flash point temperature and the mixture standard ignition point temperature, evaluate the influence of electrolyte leakage on the safety performance of the coolant.

[0012] Optionally, in some embodiments of the present application, the determining the flash point temperature and the ignition point temperature of the coolant includes:

[0013] Add the coolant to the test device;

[0014] Heat up the coolant in the test device at a first heating rate;

[0015] During the heating process, determine the flash point temperature and the ignition point temperature of the coolant.

[0016] Optionally, in some embodiments of the present application, the determining the flash point temperature and the ignition point temperature of the coolant during the heating process includes:

[0017] During the heating process, when the temperature reaches a first preset temperature, adjust the heating rate from the first heating rate to a second heating rate;

[0018] When the temperature reaches a second preset temperature, use a test flame to sweep across the coolant in the test device;

[0019] When a flash fire appears on the liquid surface of the coolant in the test device, record the temperature at which the flash fire appears as the flash point temperature;

[0020] After a flash fire appears on the liquid surface of the coolant in the test device, use a test flame to sweep across the coolant in the test device based on a preset temperature interval until a fire appears on the liquid surface of the coolant in the test device, and record the temperature at which the fire appears as the ignition point temperature.

[0021] Optionally, in some embodiments of the present application, the range of the first heating rate is 14°C / min to 17°C / min, and the range of the second heating rate is 5°C / min to 6°C / min.

[0022] Optionally, in some embodiments of the present application, the sweeping path of the test flame is a straight line or a circle with a radius of at least 150 mm.

[0023] Optionally, in some embodiments of the present application, adjusting the flash point temperature and the ignition point temperature of the coolant to be measured to the temperature under standard atmospheric pressure, and adjusting the flash point temperature and the ignition point temperature of the mixture to be measured to the temperature under standard atmospheric pressure are both implemented based on a preset formula, and the preset formula is: T C = T0 + 0.25(101.3 - P);

[0024] wherein, T C is the temperature of the flash point or the ignition point measured under standard atmospheric pressure, T0 is the temperature of the flash point or the ignition point measured, and P is the ambient atmospheric pressure.

[0025] Optionally, in some embodiments of the present application, before obtaining the mixture of the coolant and the electrolyte, it further includes:

[0026] Mixing the coolant and the electrolyte in a preset ratio to obtain mixtures with multiple concentration gradients;

[0027] Using a high-speed stirrer to stir the mixture for a preset duration.

[0028] Optionally, in some embodiments of the present application, the rotation speed range of the high-speed stirrer is 4000 r / min to 5000 r / min, and the range of the preset duration is 20 min to 40 min.

[0029] Optionally, in some embodiments of the present application, measuring the flash point temperature and the ignition point temperature of the mixture, and respectively adjusting the flash point temperature and the ignition point temperature of the mixture to the temperature under standard atmospheric pressure based on the preset formula to obtain the mixture standard flash point temperature and the mixture standard ignition point temperature corresponding to the mixture, includes:

[0030] Measuring the flash point temperature and the ignition point temperature of the mixture;

[0031] After the mixture is left standing at room temperature for a preset time, measuring the flash point temperature and the ignition point temperature of the upper layer liquid of the mixture;

[0032] Based on the preset formula, respectively adjusting the flash point temperature and the ignition point temperature of the mixture, and the flash point temperature and the ignition point temperature of the upper layer liquid of the mixture to the temperature under standard atmospheric pressure to obtain the mixture standard flash point temperature and the mixture standard ignition point temperature corresponding to the mixture, and the upper mixture standard flash point temperature and the upper mixture standard ignition point temperature corresponding to the upper layer liquid of the mixture.

[0033] Optionally, in some embodiments of the present application, evaluating the impact of electrolyte leakage on the safety performance of the coolant based on the standard flash point temperature of the coolant, the standard ignition point temperature of the coolant, the standard flash point temperature of the corresponding mixture, and the standard ignition point temperature of the mixture includes:

[0034] Evaluating the impact of electrolyte leakage on the safety performance of the coolant based on the standard flash point temperature of the coolant, the standard ignition point temperature of the coolant, the standard flash point temperature of the corresponding mixture, the standard ignition point temperature of the mixture, the standard flash point temperature of the upper-layer mixture, and the standard ignition point temperature of the upper-layer mixture.

[0035] The embodiments of the present application provide a method for evaluating the safety performance of a coolant. First, measure the flash point temperature and ignition point temperature of the coolant; then, adjust the measured flash point temperature and ignition point temperature of the coolant to the temperature under standard atmospheric pressure respectively to obtain the standard flash point temperature and standard ignition point temperature of the corresponding coolant; next, obtain the mixture of the coolant and the electrolyte; measure the flash point temperature and ignition point temperature of the mixture, and adjust the flash point temperature and ignition point temperature of the mixture to the temperature under standard atmospheric pressure respectively to obtain the standard flash point temperature and standard ignition point temperature of the corresponding mixture; finally, evaluate the impact of electrolyte leakage on the safety performance of the coolant based on the standard flash point temperature of the coolant, the standard ignition point temperature of the coolant, the standard flash point temperature of the mixture, and the standard ignition point temperature of the mixture. The safety performance evaluation scheme of the coolant provided by the present application provides a systematic evaluation means for the safety performance of the coolant, can effectively quantify the specific impact of electrolyte leakage on the safety performance of the coolant, and can accurately evaluate the impact degree of electrolyte leakage on the safety performance of the coolant by measuring the flash point and ignition point of the coolant and its mixture with the electrolyte and adjusting them to the temperature under standard atmospheric pressure. It not only fills the blank in the analysis of the impact of electrolyte leakage in the field of immersion energy storage in the current technology, but also provides important safety performance data support for the design and operation of the energy storage system, helping to improve the safety and reliability of the entire energy storage system. Description of the Drawings

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can be obtained according to these drawings.

[0037] Figure 1 It is a schematic flowchart of a method for evaluating the safety performance of a coolant provided by the embodiments of the present application;

[0038] Figure 2It is a schematic flowchart of step S1 provided by an embodiment of the present application;

[0039] Figure 3 It is a schematic flowchart of step S13 provided by an embodiment of the present application;

[0040] Figure 4 It is a schematic flowchart of step S4 provided by an embodiment of the present application. Detailed implementation manners

[0041] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present application.

[0042] The following will be described in detail respectively. It should be noted that the description order of the following embodiments does not limit the priority order of the embodiments.

[0043] A method for evaluating the safety performance of a coolant, including: measuring the flash point temperature and the ignition point temperature of the coolant; respectively adjusting the measured flash point temperature and ignition point temperature of the coolant to the temperature under standard atmospheric pressure to obtain the coolant standard flash point temperature and the coolant standard ignition point temperature corresponding to the coolant; obtaining a mixture of the coolant and the electrolyte; measuring the flash point temperature and the ignition point temperature of the mixture, and respectively adjusting the measured flash point temperature and ignition point temperature of the mixture to the temperature under standard atmospheric pressure to obtain the mixture standard flash point temperature and the mixture standard ignition point temperature corresponding to the mixture; evaluating the influence of electrolyte leakage on the safety performance of the coolant based on the coolant standard flash point temperature, the coolant standard ignition point temperature, the mixture standard flash point temperature, and the mixture standard ignition point temperature.

[0044] Please refer to Figure 1 , Figure 1 which is a schematic flowchart of the method for evaluating the safety performance of the coolant provided by an embodiment of the present application. The specific process of the method for evaluating the safety performance of the coolant can be as follows:

[0045] S1. Measure the flash point temperature and the ignition point temperature of the coolant;

[0046] Specifically, for step S1, first, measure the flash point temperature of the coolant. Fill the coolant into the test cup, ensuring that the sample volume is not less than 50% of the container volume. Heat the sample at a heating rate of 14°C / min to 17°C / min. When the sample temperature reaches approximately 56°C before the expected flash point, slow down the heating rate to 5°C / min to 6°C / min. When the temperature is at least 23°C ± 5°C before the expected flash point, start to sweep the test flame. Sweep once every 2°C increase until a flash appears on the liquid surface of the sample. Record the temperature at this time as the flash point temperature. After measuring the flash point temperature, continue to heat at a rate of 5°C / min to 6°C / min and sweep once every 2°C increase until the sample catches fire and can continuously burn for no less than 5 s. Record the temperature at this time as the ignition point temperature. By precisely controlling the heating rate and the sweeping frequency, ensure the accuracy and reliability of the measured flash point and ignition point, providing basic data for subsequent evaluation of the safety performance of the coolant and ensuring the scientificity and accuracy of the evaluation results.

[0047] Optionally, as Figure 2 shown, in some embodiments, step S1, "measuring the flash point temperature and ignition point temperature of the coolant", may specifically include:

[0048] S11. Add the coolant to the test device;

[0049] Specifically, select a suitable test device, usually a dedicated flash point and ignition point tester. The test device should have precise temperature control and measurement functions, as well as safe heating and ignition devices. Add the coolant to the test cup of the test device, ensuring that the sample volume is not less than 50% of the container volume. The purpose of this step is to ensure that there is enough sample in the test cup for testing, while avoiding inaccurate test results caused by too little sample.

[0050] In this embodiment, by ensuring that the sample volume is not less than 50% of the container volume, test errors caused by insufficient sample volume can be avoided, ensuring the accuracy and reliability of the test results; an appropriate sample volume can ensure uniform temperature distribution during the test, reduce the test time, and improve the test efficiency.

[0051] S12. Heat the coolant in the test device at a first heating rate;

[0052] Specifically, at the beginning of the test, the coolant in the test device is heated at a first heating rate (14°C / min to 17°C / min). This heating rate is selected to ensure a uniform temperature distribution of the coolant during the heating process and avoid local overheating caused by too rapid heating. By controlling the heating rate, the test conditions can be ensured to be consistent for each test, avoiding differences in test results caused by different heating rates, and improving the repeatability and reliability of the test; an appropriate heating rate can prevent accidents such as sudden boiling or splashing of the coolant due to too rapid heating, ensuring the safety of the test process.

[0053] S13. During the heating process, measure the flash point temperature and the ignition point temperature of the coolant;

[0054] Specifically, during the heating process, continuously monitor the temperature of the coolant to ensure the stability and consistency of the heating rate.

[0055] Optionally, as Figure 3 shown, in some embodiments, step S13, "During the heating process, measure the flash point temperature and the ignition point temperature of the coolant", may specifically include:

[0056] S131. During the heating process, when the temperature reaches the first preset temperature, adjust the heating rate from the first heating rate to the second heating rate;

[0057] Specifically, during the heating process, when the temperature reaches approximately 56°C before the expected flash point, adjust the heating rate from the first heating rate (14°C / min to 17°C / min) to the second heating rate (5°C / min to 6°C / min). This adjustment is to more precisely control the temperature change when approaching the flash point and avoid test errors caused by too rapid heating. By slowing down the heating rate when approaching the flash point, the appearance of the flash point can be captured more accurately, improving the accuracy of the test results; precise temperature control helps to ensure the consistency of test conditions for each test and improve the repeatability and reliability of the test results.

[0058] S132. When the temperature reaches the second preset temperature, use the test flame to sweep across the coolant in the test device;

[0059] Specifically, when the temperature is at least 23°C ± 5°C before the expected flash point, start to sweep the coolant in the test device with a test flame. The time required for the test flame to pass through the test cup each time is about 1 second. The flame should pass through the center of the test cup at a position perpendicular to the diameter of the test cup through which the thermometer passes. The sweeping should be carried out in a straight line or along a circle with a radius of at least 150 mm. Sweep once every 2°C increase in temperature until a flash fire appears on the liquid surface of the sample. By sweeping with the test flame, the actual ignition conditions are simulated to ensure that the test results can reflect the ignition characteristics of the coolant in actual use; by controlling the sweeping frequency and path, accidental ignition caused by improper operation is avoided to ensure the safety of the test process.

[0060] S133. When a flash fire appears on the liquid surface of the coolant in the test device, record the temperature at the time of the flash fire as the flash point temperature;

[0061] Specifically, during the sweeping process, when a flash fire appears on the liquid surface of the coolant in the test device, immediately record the temperature reading of the thermometer. The recorded temperature reading is the flash point temperature of the coolant. By real-time monitoring of the flash fire phenomenon on the liquid surface, the flash point temperature can be accurately recorded to ensure the accuracy of the test results; immediately recording the flash point temperature can avoid temperature changes caused by delayed recording and improve the reliability of the test results.

[0062] S134. After a flash fire appears on the liquid surface of the coolant in the test device, use the test flame to sweep the coolant in the test device based on a preset temperature interval until a fire appears on the liquid surface of the coolant in the test device, and record the temperature at the time of the fire as the ignition point temperature;

[0063] Specifically, after a flash fire appears on the liquid surface of the coolant in the test device, continue to increase the temperature at a rate of 5°C / min to 6°C / min. Sweep once every 2°C increase in temperature until the sample catches fire and can continuously burn for no less than 5 seconds; when a fire appears on the liquid surface of the coolant in the test device, immediately record the temperature reading of the thermometer. The recorded temperature reading is the ignition point temperature of the coolant. By continuously monitoring the fire phenomenon on the liquid surface, the ignition point temperature can be accurately recorded to ensure the accuracy of the test results; through continuous testing from the flash point to the ignition point, the integrity and comprehensiveness of the test results are ensured, providing reliable data support for subsequent evaluations.

[0064] It can be seen that in this embodiment, by adjusting the heating rate when approaching the flash point, the appearance of the flash point can be captured more accurately; through the sweeping operation of the test flame, the actual ignition conditions are simulated to ensure the reliability of the test results; by real-time recording of the flash point and ignition point temperatures, the accuracy and integrity of the test results are ensured. This not only improves the accuracy and reliability of the test results but also provides a solid foundation for subsequent evaluations of the impact of electrolyte leakage on the safety performance of the coolant.

[0065] Optionally, in some embodiments, the range of the first heating rate is 14°C / min to 17°C / min, and the range of the second heating rate is 5°C / min to 6°C / min.

[0066] Specifically, at the start of the test in this embodiment, the coolant is heated at a relatively fast heating rate (14°C / min to 17°C / min) to quickly reach the temperature range before the expected flash point. When approaching the flash point, the heating rate is slowed down to 5°C / min to 6°C / min to more precisely control the temperature change and ensure the accurate determination of the flash point.

[0067] In addition, different types of coolants may have different flash points and ignition points. By adjusting the heating rate, it is possible to better adapt to the characteristics of different coolants and ensure the accuracy of the test results. According to the specific characteristics of the coolant, the range of the heating rate can be further optimized to improve the accuracy and reliability of the test.

[0068] Optionally, in some embodiments, the sweeping path of the test flame is a straight line or a circle with a radius of at least 150 mm.

[0069] In a specific embodiment, the shape of the sweeping path can be a straight path or an arc path. The straight path means that the test flame can move along a straight path during sweeping; the arc path means that the test flame can move along an arc path with a radius of at least 150 mm during sweeping. When the test flame sweeps along a straight path, it should pass through the center of the test cup in a straight line to ensure that the flame evenly sweeps across the surface of the coolant. When the test flame sweeps along an arc path, it should move along an arc path with a radius of at least 150 mm to ensure that the flame is evenly distributed on the surface of the coolant. The sweeping frequency can be one sweep per 2°C increase in temperature until a flash fire appears on the surface of the test sample. The time required for the test flame to pass through the test cup for each sweep action is about 1 second to ensure that the residence time of the flame on the surface of the coolant is consistent. The sweeping position of the test flame should pass through the center of the test cup at a position perpendicular to the diameter of the test cup passing through the thermometer to ensure that the flame is evenly distributed on the surface of the coolant.

[0070] This embodiment ensures the uniform distribution of the test flame on the surface of the coolant by specifying the shape and size of the sweeping path, avoiding test errors caused by uneven flame distribution; through standardized sweeping operations, the flash point of the coolant can be captured more accurately, improving the accuracy of the test results.

[0071] S2. Adjust the measured flash point temperature and ignition point temperature of the coolant to the temperature under standard atmospheric pressure respectively to obtain the coolant standard flash point temperature and coolant standard ignition point temperature corresponding to the coolant;

[0072] Specifically, for step S2, the measured flash point temperature and ignition point temperature are substituted into the preset formula to calculate the standard flash point temperature and standard ignition point temperature under the standard atmospheric pressure (101.3 kPa) (i.e., the coolant standard flash point temperature and coolant standard ignition point temperature corresponding to the coolant), thereby eliminating the influence of the ambient atmospheric pressure on the measurement result and making the data comparable and consistent. Through standardization processing, it is ensured that the evaluation result is not interfered by environmental factors, and the accuracy and reliability of the evaluation are improved.

[0073] Optionally, in some embodiments, the preset formula is: T C = T0 + 0.25(101.3 - P);

[0074] Wherein, T C is the coolant standard flash point temperature or coolant standard ignition point temperature measured under the standard atmospheric pressure, T0 is the temperature of the measured flash point or ignition point, and P is the ambient atmospheric pressure.

[0075] Specifically, the preset formula adopted in this embodiment is T C = T0 + 0.25(101.3 - P). Substitute the measured flash point and ignition point temperatures into this formula to calculate the flash point and ignition point temperatures of the coolant under the standard atmospheric pressure (101.3 kPa) (i.e., the coolant standard flash point temperature and coolant standard ignition point temperature corresponding to the coolant). Since the change of the ambient atmospheric pressure will affect the flash point and ignition point of the liquid. For example, in high-altitude areas, the atmospheric pressure is low, the boiling point of the liquid will decrease, and the flash point and ignition point will also change accordingly. By adjusting the measured flash point and ignition point to the temperature under the standard atmospheric pressure, the influence of the ambient atmospheric pressure can be eliminated, making the test results comparable and consistent, and improving the accuracy and reliability of the test results. By using the preset formula for adjustment, the test method and process are simplified, and the operation steps and time are reduced.

[0076] S3. Obtain a mixture of coolant and electrolyte;

[0077] Specifically, for step S3, according to the actual design situation, the coolant and the electrolyte are mixed in different proportions to prepare a series of mixtures with different concentration gradients. Use a high-speed stirrer to stir the mixture for 20 - 40 minutes until it forms an emulsion state. By preparing mixtures with different concentration gradients, the actual usage situation of the coolant after electrolyte leakage is simulated. High-speed stirring ensures the uniformity of the mixture and avoids the influence of local concentration differences on the measurement result.

[0078] Optionally, in some embodiments, before step S3 "obtain a mixture of coolant and electrolyte", specifically, it may further include:

[0079] Mix the coolant and the electrolyte in a preset ratio to obtain mixtures with multiple concentration gradients;

[0080] Specifically, in order to simulate the actual usage of the coolant after electrolyte leakage, by configuring mixtures with different concentration gradients, the impact of electrolyte leakage on the safety performance of the coolant is evaluated. According to the actual design situation, the coolant and the electrolyte are mixed in different proportions to configure a series of mixtures with different concentration gradients. For example, mixtures with the mass percentage of the electrolyte being 10%, 20%, 30%, etc. can be configured to comprehensively evaluate the impact of different leakage degrees on the safety performance of the coolant. Through experimental data, the selection of the concentration gradient is optimized to ensure that the test results are representative and comprehensive.

[0081] Use a high-speed stirrer to stir the mixture for a preset duration;

[0082] Optionally, in some embodiments, the rotation speed range of the high-speed stirrer is 4000 r / min to 5000 r / min, and the range of the preset duration is 20 min to 40 min.

[0083] Specifically, in order to ensure the uniformity of the mixture and avoid test errors caused by local concentration differences. Use a high-speed stirrer to stir the mixture for a preset duration, usually 20 - 40 minutes, and the rotation speed range of the stirrer is 4500 ± 500 r / min. Stir until the mixture forms an emulsion state to ensure that the electrolyte and the coolant are fully mixed. According to the properties of the mixture and the performance of the stirrer, optimize the stirring time. For example, for mixtures with higher viscosity, the stirring time can be appropriately extended to ensure full mixing of the mixture. According to the properties of the mixture and the performance of the stirrer, optimize the stirring speed. For example, for mixtures with higher viscosity, the stirring speed can be appropriately reduced to avoid splashing or stratification of the mixture caused by too fast stirring.

[0084] Finally, in order to simulate the static condition of the coolant in actual use, observe the stratification phenomenon of the mixture, and further evaluate the impact of electrolyte leakage on the safety performance of the coolant. Let the stirred mixture stand at room temperature for 2 - 3 hours. After sufficient stratification, take the upper liquid for flash point and fire point tests. According to the properties of the mixture and the actual use conditions, optimize the standing time. For example, for mixtures with faster stratification, the standing time can be appropriately extended to ensure sufficient stratification. According to the actual use conditions, optimize the standing conditions. For example, standing can be carried out under different temperature and pressure conditions to simulate different working conditions in actual use.

[0085] This embodiment configures mixtures with different concentration gradients, simulates different working conditions in actual use, and comprehensively evaluates the impact of electrolyte leakage on the safety performance of the coolant. Through the high-speed stirrer and standing operations, ensure the uniformity and sufficient stratification of the mixture, and improve the accuracy and reliability of the test results.

[0086] S4. Measure the flash point temperature and the ignition point temperature of the mixture, and adjust the measured flash point temperature and ignition point temperature of the mixture to the temperature under standard atmospheric pressure respectively, to obtain the standard flash point temperature and the standard ignition point temperature of the mixture corresponding to the mixture;

[0087] Specifically, for step S4, measure the flash point temperature and the ignition point temperature of the mixture by the same method as in step S1, and use the same preset formula to adjust the measured flash point and ignition point temperatures to the temperature under standard atmospheric pressure, to obtain the standard flash point temperature and the standard ignition point temperature of the mixture corresponding to the mixture, ensuring that the measurement results of the flash point and ignition point of the mixture are comparable with the results measured for the coolant alone, eliminating the influence of the ambient atmospheric pressure, and ensuring the accuracy and reliability of the evaluation results.

[0088] Optionally, as Figure 4 shown, in some embodiments, step S4 "Measure the flash point temperature and the ignition point temperature of the mixture, and based on a preset formula, adjust the flash point temperature and the ignition point temperature of the mixture to the temperature under standard atmospheric pressure respectively" may specifically include:

[0089] S41. Measure the flash point temperature and the ignition point temperature of the mixture;

[0090] Specifically, fill the mixture into the test cup, ensuring that the sample volume is not less than 50% of the container volume. Heat the specimen at a heating rate of 14°C / min to 17°C / min. When the specimen temperature reaches about 56°C before the expected flash point, slow down the heating rate to 5°C / min to 6°C / min. When the temperature is at least 23°C ± 5°C before the expected flash point, start to sweep the test flame, sweeping once every 2°C increase until a flash fire appears on the liquid surface of the specimen, and record the temperature at this time as the flash point temperature. After measuring the flash point temperature, continue to heat at a rate of 5°C / min to 6°C / min, sweeping once every 2°C increase until the specimen catches fire and can continuously burn for not less than 5 seconds, and record the temperature at this time as the ignition point temperature.

[0091] In addition, to ensure the uniformity of the mixture, various stirring methods can be adopted, such as mechanical stirring, magnetic stirring, etc. In addition, the mixing effect can be optimized by controlling the stirring speed and time. According to the properties of the mixture and the test requirements, different types of test devices can be selected, such as a closed-cup flash point tester, an open-cup flash point tester, etc. At the same time, the test device can also be improved to improve the accuracy and reliability of the test. The heating rate has a greater impact on the measurement results of the flash point and ignition point. The test accuracy can be improved by precisely controlling the heating rate. In addition, the influence law of different heating rates on the flash point and ignition point can also be studied to provide a basis for optimizing the test method.

[0092] S42. After allowing the mixture to stand at room temperature for a preset time, measure the flash point temperature and the ignition point temperature of the upper layer liquid of the mixture;

[0093] Specifically, since the electrolyte contains some cyclic solvents, the mixture will show a layering phenomenon after standing still. Therefore, it is necessary to let the mixture stand still for a preset time at room temperature to allow the mixture to fully separate into layers. Then, take the upper liquid and measure its flash point temperature and ignition point temperature in the same way. Substitute the measured flash point and ignition point temperatures into a preset formula to calculate the flash point and ignition point temperatures under standard atmospheric pressure (101.3 kPa). By measuring the flash point and ignition point of the upper liquid, the impact of electrolyte leakage on the safety performance of the coolant can be evaluated more comprehensively. Considering the influence of the layering phenomenon, the safety performance of the mixture in actual use can be evaluated more accurately.

[0094] In addition, the length of the standing time will affect the layering effect. The influence of different standing times on the layering effect can be studied through experiments to determine the optimal standing time. Further study the layering mechanism of the mixture to understand the distribution law of different components in the mixture. This helps to better understand the impact of electrolyte leakage on the safety performance of the coolant. When taking the upper liquid, it is necessary to pay attention to avoiding bringing in the lower liquid to ensure the accuracy of the test results. Special sampling tools such as pipettes and sampling spoons can be used.

[0095] S43. Based on the preset formula, adjust the flash point temperature and ignition point temperature of the mixture, and the flash point temperature and ignition point temperature of the upper liquid of the mixture to the temperatures under standard atmospheric pressure respectively, to obtain the standard flash point temperature and standard ignition point temperature of the mixture corresponding to the mixture, and the standard flash point temperature and standard ignition point temperature of the upper mixture corresponding to the upper liquid of the mixture;

[0096] Specifically, let the mixture stand still for 2 - 3 hours at room temperature. After full layering, take the upper liquid. Follow the same steps as above to measure the flash point and ignition point temperatures of the upper liquid, and adjust the results to the temperatures under standard atmospheric pressure (i.e., the standard flash point temperature and standard ignition point temperature of the upper mixture corresponding to the upper liquid of the mixture). By adjusting the measured results to standard atmospheric pressure, the consistency of the evaluation results under different experimental conditions can be improved. Considering the influence of the ambient atmospheric pressure, the reliability and comparability of the evaluation results can be improved.

[0097] In addition, in order to accurately adjust the temperature, it is necessary to precisely measure the atmospheric pressure of the test environment. A high-precision barometer can be used to improve the measurement accuracy. Although the preset formula can be used for temperature adjustment, its accuracy may be affected by other factors. The applicability of the formula can be verified through experiments and optimized according to the actual situation. After temperature adjustment, the accuracy of the adjustment can be verified by comparing the test results under standard atmospheric pressure. If a large deviation is found between the adjusted result and the actual result, it is necessary to further analyze the reasons and improve the adjustment method.

[0098] It can be seen that in this embodiment, by measuring the flash point temperature and the ignition point temperature of the mixture and adjusting them to the temperature under standard atmospheric pressure, the influence of electrolyte leakage on the safety performance of the coolant can be evaluated more accurately; by measuring the flash point temperature and the ignition point temperature of the upper-layer liquid after the mixture is left standing for a preset time at room temperature, the stratification phenomenon of the mixture can be considered, and the reliability of the test results can be improved.

[0099] S5. Evaluate the influence of electrolyte leakage on the safety performance of the coolant based on the standard flash point temperature of the coolant, the standard ignition point temperature of the coolant, the standard flash point temperature of the mixture, and the standard ignition point temperature of the mixture;

[0100] Specifically, for step S5, compare the standard flash point temperature of the coolant and the standard ignition point temperature of the coolant with the standard flash point temperature of the mixture and the standard ignition point temperature of the mixture, analyze the influence degree of electrolyte leakage on the flash point and ignition point of the coolant, and evaluate its influence on the safety performance of the coolant. Through data comparison, quantitatively analyze the specific influence degree of electrolyte leakage on the safety performance of the coolant, provide a scientific basis for the design and operation of the energy storage system, help optimize the usage ratio of the coolant and the electrolyte, and improve the safety and reliability of the system.

[0101] Optionally, in some embodiments, step S5, "Evaluate the influence of electrolyte leakage on the safety performance of the coolant based on the standard flash point temperature of the coolant, the standard ignition point temperature of the coolant, the standard flash point temperature of the mixture, and the standard ignition point temperature of the mixture", may specifically include:

[0102] Evaluate the influence of electrolyte leakage on the safety performance of the coolant based on the standard flash point temperature of the coolant, the standard ignition point temperature of the coolant, the standard flash point temperature of the mixture, the standard ignition point temperature of the mixture, as well as the standard flash point temperature of the upper-layer mixture and the standard ignition point temperature of the upper-layer mixture.

[0103] In a specific embodiment, first, the measured standard flash point temperature and standard ignition point temperature of the coolant are used as reference values. Then, the standard flash point temperature and standard ignition point temperature of the mixture are compared with the reference values. Through this comparison, the degree of influence of electrolyte leakage on the safety performance of the coolant can be preliminarily judged. If the standard flash point temperature and standard ignition point temperature of the mixture are significantly lower than the reference values, it indicates that the electrolyte leakage has a greater impact on the safety performance of the coolant. Since the electrolyte contains some cyclic solvents, the mixture will show a layering phenomenon after standing still. Therefore, the mixture needs to be left standing for a preset time at room temperature, and then the upper layer liquid is taken and its flash point temperature and ignition point temperature under standard atmospheric pressure are measured (i.e., the standard flash point temperature and standard ignition point temperature of the upper layer mixture). Comparing the standard flash point temperature and standard ignition point temperature of the upper layer mixture with the reference values can further understand the influence of electrolyte leakage on the safety performance of the coolant. If the standard flash point temperature and standard ignition point temperature of the upper layer mixture are also significantly lower than the reference values, it indicates that the electrolyte leakage has a greater impact on the safety performance of the coolant. By comparing the standard flash point temperature of the coolant, the standard ignition point temperature of the coolant, the standard flash point temperature of the mixture, the standard ignition point temperature of the mixture, as well as the standard flash point temperature and standard ignition point temperature of the upper layer mixture, the influence of electrolyte leakage on the safety performance of the coolant can be comprehensively evaluated. Among them, specific evaluation methods may include: calculating the decrease amplitude of the flash point temperature and ignition point temperature of the mixture and the upper layer liquid relative to the reference values; analyzing the change rules of the flash point temperature and ignition point temperature of the mixture and the upper layer liquid under different concentration gradients; and combining the actual application scenarios to determine the degree of influence of electrolyte leakage on the safety performance of the coolant.

[0104] In addition, in addition to the flash point temperature and ignition point temperature, other evaluation indicators can also be considered, such as the viscosity, density, conductivity, etc. of the mixture. These indicators can reflect the influence of electrolyte leakage on the performance of the coolant from different angles, further improving the comprehensiveness and accuracy of the evaluation. A mathematical model can be established to quantify the degree of influence of electrolyte leakage on the safety performance of the coolant. For example, a multiple linear regression model can be used, taking indicators such as flash point temperature, ignition point temperature, viscosity, density, etc. as independent variables and the electrolyte leakage amount as the dependent variable to establish a quantification model. Through model prediction, the degree of influence of electrolyte leakage on the safety performance of the coolant can be evaluated more accurately. The evaluation method can also be optimized according to actual needs. For example, multiple statistical analysis methods can be used to comprehensively analyze multiple evaluation indicators to improve the accuracy and reliability of the evaluation. In addition, different evaluation criteria and thresholds can be formulated in combination with the actual application scenarios to meet the evaluation needs under different scenarios.

[0105] In this embodiment, by comprehensively considering the standard flash point temperature of the coolant, the standard ignition point temperature of the coolant, the standard flash point temperature of the mixture, the standard ignition point temperature of the mixture, as well as the standard flash point temperature and the standard ignition point temperature of the upper-layer mixture, the impact of electrolyte leakage on the safety performance of the coolant can be evaluated more comprehensively, which helps to promptly detect and address the potential safety hazards caused by electrolyte leakage, and improve the safety and reliability of the energy storage system. By accurately measuring and adjusting the flash point temperature and the ignition point temperature, and conducting detailed tests on the mixture and the upper-layer liquid, the accuracy and reliability of the evaluation can be improved, which helps to provide a more reliable reference for the design and operation of the energy storage system and reduce the safety risks caused by electrolyte leakage.

[0106] To facilitate the understanding of the method for evaluating the safety performance of the coolant provided in this embodiment, this embodiment also provides a specific implementation manner of the method for evaluating the safety performance of the coolant, and the detailed process is as follows:

[0107] Before the start of the test, the test cup should be cleaned. Clean the test cup with a cleaning solvent to remove all traces of gum and residue left from the previous test. Then dry the test cup with clean air to ensure that all the used solvent is removed. Cool the test cup to at least 56 °C below the expected flash point before use; calibrate the test instrument. Calibrate the instrument at least once a year with a certified reference sample. The difference between the obtained result and the certified value of the reference sample should be less than or equal to R / √2, where R is the reproducibility of this standard. It is recommended to calibrate the instrument regularly with a working reference sample.

[0108] The test steps are as follows: First, the flash point and fire point of the coolant should be tested. The sample at room temperature or that has been heated is filled into the test cup, and the volume of the sample in the container should not be less than 50% of the container volume. Ignite the test flame. When starting to heat, the heating rate of the sample is 14°C / min to 17°C / min. When the sample temperature reaches about 56°C before the expected flash point, slow down the heating rate so that the heating rate is 5°C / min to 6°C / min when the sample is within the last 23°C ± 5°C before reaching the flash point. At least 23°C ± 5°C before the expected flash point, start to sweep the test flame, and sweep once every 2°C increase in temperature. Use a smooth and continuous movement to sweep. The time required for the test flame to pass through the test cup each time is about 1 s. The test flame should pass through the center of the test cup at a position perpendicular to the diameter of the test cup passing through the thermometer. The sweep is carried out in a straight line or along a circle with a radius of at least 150 mm. The center of the test flame must move on a plane within 2 mm above the upper edge surface of the test cup. First, sweep in one direction, and then sweep in the opposite direction next time. If a film forms on the surface of the sample, the oil film should be pushed to one side and the test should continue. When flash fire occurs at any point on the liquid surface of the sample, immediately record the temperature reading of the thermometer as the observed flash point. Then, according to the actual design of the system, at 25°C ± 2°C, mix the synthetic oil and the electrolyte of the corresponding grade in proportion to prepare an electrolyte-coolant mixture with a certain concentration gradient, and use a high-speed stirrer (rotation speed 4500 ± 500 r / min) to stir the mixture for 20 - 40 min until it becomes an emulsion state. Conduct the flash point determination according to the same experimental steps as above.

[0109] After determining the flash point according to the above steps, continue to heat at a rate of 5°C / min to 6°C / min. Sweep once every 2°C increase in the sample until the sample catches fire and can continuously burn for no less than 5 s. Record this temperature as the observed fire point of the sample.

[0110] Correct the observed flash point or fire point to standard atmospheric pressure. Use Equation (1) to correct the observed flash point or fire point to standard atmospheric pressure (101.3 kPa), that is, determine the standard flash point temperature and standard fire point temperature of the coolant.

[0111] T C = T0 + 0.25(101.3 - P) (1)

[0112] In the formula: T0 is the observed flash point or fire point, °C; P is the ambient atmospheric pressure, kPa.

[0113] Because the electrolyte contains some cyclic solvents, stratification will occur after standing. Let the tested sample of the mixture that has been sampled stand at room temperature for 2 - 3 h. After sufficient stratification, take the upper liquid and conduct flash point and fire point tests according to the same test steps, that is, determine the standard flash point temperature of the upper mixture and the standard fire point temperature of the upper mixture corresponding to the upper liquid of the mixture.

[0114] Analysis of test results: The flash point (open cup) of the coolant > 200°C, and the ignition point > 210°C. This experiment examines the influence of the electrolyte leakage amount on the safety performance of the coolant. The data shows that as the amount of electrolyte added increases, the flash points of the mixture and the upper-layer liquid continuously decrease. When the mass proportion of the electrolyte is the largest (with a relatively low occurrence probability), the flash point and ignition point of the mixture decrease by approximately 8%. The flash point of the mixture (i.e., the standard flash point temperature of the mixture corresponding to the mixture) > 180°C, the ignition point (i.e., the standard ignition point temperature of the mixture corresponding to the mixture) > 190°C, the flash point of the upper-layer liquid (i.e., the standard flash point temperature of the upper-layer mixture corresponding to the upper-layer liquid of the mixture) > 190°C, and the ignition point (i.e., the standard ignition point temperature of the upper-layer mixture corresponding to the upper-layer liquid of the mixture) > 200°C. It can be analyzed that for the design of this system, liquid leakage has a certain impact on the safety of the coolant.

[0115] In summary, for the method for evaluating the safety performance of the coolant provided by the embodiments of the present application, first, measure the flash point temperature and ignition point temperature of the coolant; then, based on a preset formula, adjust the measured flash point temperature and ignition point temperature of the coolant to the temperature under standard atmospheric pressure respectively to obtain the standard flash point temperature and standard ignition point temperature of the coolant corresponding to the coolant; next, obtain the mixture of the coolant and the electrolyte; measure the flash point temperature and ignition point temperature of the mixture, and based on the preset formula, adjust the flash point temperature and ignition point temperature of the mixture to the temperature under standard atmospheric pressure respectively to obtain the standard flash point temperature and standard ignition point temperature of the mixture corresponding to the mixture; finally, based on the standard flash point temperature of the coolant, the standard ignition point temperature of the coolant, the standard flash point temperature of the mixture, and the standard ignition point temperature of the mixture, evaluate the influence of electrolyte leakage on the safety performance of the coolant. The safety performance evaluation scheme of the coolant provided by the embodiments of the present application can effectively quantify the specific influence of electrolyte leakage on the safety performance of the coolant. By measuring the flash points and ignition points of the coolant and its mixture with the electrolyte and adjusting them to the temperature under standard atmospheric pressure, the influence degree of electrolyte leakage on the safety performance of the coolant can be accurately evaluated. It not only fills the blank in the analysis of the influence of electrolyte leakage in the field of immersion energy storage in the current technology, but also provides important safety performance data support for the design and operation of the energy storage system, which helps to improve the safety and reliability of the entire energy storage system.

[0116] The above has introduced in detail a method for evaluating the safety performance of a coolant provided by the embodiments of the present application. Specific examples are used in this article to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those skilled in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A method for evaluating the safety performance of a coolant, characterized in that: include: Determine the flash point temperature and ignition point temperature of the coolant; Respectively adjusting the measured flash point temperature and ignition point temperature of the coolant to the temperature under standard atmospheric pressure to obtain the coolant standard flash point temperature and coolant standard ignition point temperature corresponding to the coolant; Obtaining a mixture of the coolant and the electrolyte; Determine the flash point temperature and the ignition point temperature of the mixture, and adjust the measured flash point temperature and the ignition point temperature of the mixture to the temperature under standard atmospheric pressure, respectively, to obtain a standard flash point temperature of the mixture and a standard ignition point temperature of the mixture corresponding to the mixture; Based on the standard flash point temperature of the coolant, the standard ignition point temperature of the coolant, the standard flash point temperature of the mixture and the standard ignition point temperature of the mixture, the impact of electrolyte leakage on the safety performance of the coolant is evaluated.

2. The safety performance evaluation method according to claim 1, characterized in that: The method of measuring the flash point temperature and the ignition point temperature of the coolant comprises: Add coolant to the test rig; Heating the coolant in the test device at a first heating rate; During the heating process, the flash point temperature and ignition point temperature of the coolant are measured.

3. The safety performance evaluation method according to claim 2, characterized in that: The method of measuring the flash point temperature and the ignition point temperature of the coolant during the temperature increase process comprises: During the heating process, when the temperature reaches a first preset temperature, the heating speed is adjusted from the first heating speed to the second heating speed; When the temperature reaches a second preset temperature, sweeping the coolant of the test device with a test flame; When flash fire appears on the surface of the coolant in the test device, the temperature at which the flash fire appears is recorded as the flash point temperature; After a flash fire occurs on the surface of the coolant in the test device, the coolant in the test device is swept with a test flame based on a preset temperature interval until the surface of the coolant in the test device catches fire, and the temperature when the fire occurs is recorded as the ignition temperature.

4. The safety performance evaluation method according to claim 3, characterized in that: The first heating rate ranges from 14°C / min to 17°C / min, and the second heating rate ranges from 5°C / min to 6°C / min.

5. The safety performance evaluation method according to claim 3, characterized in that: The sweeping path of the test flame is a straight line or a circle with a radius of at least 150 mm.

6. The safety performance evaluation method according to claim 1, characterized in that: The adjusting of the measured flash point temperature and ignition point temperature of the coolant to the temperature under standard atmospheric pressure, and the adjusting of the measured flash point temperature and ignition point temperature of the mixture to the temperature under standard atmospheric pressure are both implemented based on a preset formula, and the preset formula is: T C =T0+0.25(101.3-P); Wherein, Tc is the temperature of the flash point or the ignition point measured under standard atmospheric pressure, T0 is the temperature of the flash point or the ignition point measured, and P is the ambient atmospheric pressure.

7. The safety performance evaluation method according to claim 1, characterized in that: Before obtaining the mixture of the coolant and the electrolyte, the method further includes: The coolant and the electrolyte are mixed in a preset ratio to obtain a mixture with multiple concentration gradients; The mixture is stirred for a preset time using a high-speed stirrer.

8. The safety performance evaluation method according to claim 7, characterized in that: The rotation speed range of the high-speed agitator is 4000 r / min to 5000 r / min, and the preset time range is 20 min to 40 min.

9. The safety performance evaluation method according to claim 1, characterized in that: The method of measuring the flash point temperature and the ignition point temperature of the mixture, and adjusting the measured flash point temperature and the ignition point temperature of the mixture to the temperature under standard atmospheric pressure, respectively, to obtain the standard flash point temperature and the standard ignition point temperature of the mixture corresponding to the mixture, comprises: Determining the flash point temperature and the ignition point temperature of the mixture; After the mixture is allowed to stand for a preset time at room temperature, the flash point temperature and the ignition point temperature of the liquid on the upper layer of the mixture are measured; Based on the preset formula, the flash point temperature and the ignition point temperature of the mixture, and the flash point temperature and the ignition point temperature of the upper liquid of the mixture are respectively adjusted to the temperature under standard atmospheric pressure to obtain the standard flash point temperature of the mixture and the standard ignition point temperature of the mixture corresponding to the mixture, as well as the standard flash point temperature of the upper mixture and the standard ignition point temperature of the upper mixture corresponding to the upper liquid of the mixture.

10. The safety performance evaluation method according to claim 9, characterized in that: The method of evaluating the influence of electrolyte leakage on the safety performance of the coolant based on the coolant standard flash point temperature, the coolant standard ignition point temperature, the mixture standard flash point temperature and the mixture standard ignition point temperature includes: Based on the standard flash point temperature of the coolant, the standard ignition point temperature of the coolant, the standard flash point temperature of the mixture, the standard ignition point temperature of the mixture, the standard flash point temperature of the upper mixture and the standard ignition point temperature of the upper mixture, the impact of electrolyte leakage on the safety performance of the coolant is evaluated.

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