Battery mixed flue gas explosion limit test equipment and method
By designing a battery mixed flue gas explosion limit test equipment, accurately generate and control the mixing of electrolyte vapor with thermal runaway gas, the problem of inaccurate simulation of thermal runaway gas in lithium-ion batteries is solved, the accuracy and safety of the test are improved, and data support is provided for the safety design of lithium battery.
Patent Information
- Application Number
- CN202510538695.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-27
- Publication Date
- 2025-07-22
AI Technical Summary
The prior art cannot effectively simulate the real flue gas generated when the thermal runaway of lithium-ion batteries, especially the lack of electrolyte vapor components, resulting in inaccurate test of the explosive characteristics of the thermal runaway flue gas of lithium-ion batteries.
A battery mixed flue gas explosion limit test equipment was designed, including fixed-capacity bombs, electrolyte evaporation device and vacuum pump system. By accurately generating and controlling the mixing of electrolyte vapor with thermal runaway gas, it simulates the thermal runaway gas of real lithium battery, and combines multi-parameter correction methods to improve the test accuracy.
It realizes accurate simulation of thermal runaway smoke of lithium batteries, improves the accuracy and safety of explosion limit testing, provides reliable data support, and provides a basis for the safety design of lithium batteries.
Smart Images
Figure CN120352475A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the technical field of combustible flue gas combustion and explosion testing, and specifically relates to a battery hybrid flue gas explosion limit testing device and method. Background Art
[0002] Fires and explosions in lithium-ion battery energy storage systems occur frequently, and safety issues have become the key restricting the development of the lithium-ion battery energy storage industry. Most of the fires and explosions in lithium-ion battery energy storage systems are caused by battery thermal runaway. Under abusive conditions such as overcharging, over-discharging, short-circuiting, physical collision, and overheating, lithium batteries will experience thermal runaway. The battery casing will deform and rupture due to the increased internal pressure, causing the electrolyte in the battery to vaporize and leak. At the same time, the thermal runaway reaction occurring inside the battery will generate a large amount of heat and release a large amount of toxic and harmful gases, which are likely to trigger fires or even explosion accidents.
[0003] The flue gas generated by lithium-ion battery thermal runaway includes low-boiling-point electrolyte vapor, H2, CO, CO2, and low-carbon alkane molecules, etc. However, in current lithium battery thermal runaway gas explosion tests, pure gas mixing is mainly used to simulate thermal runaway flue gas or real battery thermal runaway flue gas is collected using gas cylinders. The pure gas mixing method makes the simulated thermal runaway flue gas lack electrolyte vapor. In the gas cylinder collection method, the electrolyte vapor will cool into a liquid. In both cases, the mixed gas lacks electrolyte vapor and cannot simulate real lithium battery thermal runaway flue gas. Summary of the Invention
[0004] In view of the above problems, this application provides a battery hybrid flue gas explosion limit testing device and method, aiming to solve the problem of the variation law of the explosion characteristics of real thermal runaway flue gas, and provide theoretical and data support for the design of lithium-ion battery energy storage fire extinguishing systems and the formulation of explosion suppression and venting strategies.
[0005] To solve the above technical problems, the technical solutions adopted in this application are as follows: In a first aspect, this application provides a battery hybrid flue gas explosion limit testing device, including: A constant volume bomb; A gas cylinder filled with thermal runaway gas, and the gas cylinder is connected to the constant volume bomb; A first vacuum pump, and the first vacuum pump is connected to the constant volume bomb; An electrolyte evaporation device, which includes a micro-injection pump, a liquid atomizer, a heating and mixing device, and a second vacuum pump. The micro-injection pump, the liquid atomizer, and the heating and mixing device are connected in sequence. The second vacuum pump is connected to the heating and mixing device; the heating and mixing device is connected to the constant volume bomb; A control system, which is electrically connected to the constant volume bomb for data recording.
[0006] As a further improvement of the present application, an ignition device, a pressure sensor and a temperature sensor are arranged inside the constant volume bomb, which are used to monitor the explosion overpressure, pressure change rate and temperature data during the ignition process.
[0007] As a further improvement of the present application, a gas flowmeter is arranged on the pipeline connecting the heating and mixing device and the constant volume bomb.
[0008] As a further improvement of the present application, a first electromagnetic valve is arranged on the pipeline connecting the gas cylinder and the constant volume bomb; A third electromagnetic valve is arranged on the pipeline connecting the first vacuum pump and the constant volume bomb; A fourth electromagnetic valve is arranged on the pipeline connecting the heating and mixing device and the constant volume bomb; The second vacuum pump is connected to the heating chamber through a second electromagnetic valve.
[0009] As a further improvement of the present application, the heating and mixing device is internally provided with a heating chamber, a temperature control heater and a pressure sensor, which are used for electrolyte evaporation, gas heating, gas premixing and gas transmission.
[0010] As a further improvement of the present application, the heating chamber is connected to the ambient air through a fifth electromagnetic valve.
[0011] As a further improvement of the present application, the surfaces of the constant volume bomb and the transmission pipeline are wound and covered with glass fiber heating tapes.
[0012] In a second aspect, the present application provides a method for testing the explosion limit of battery hybrid flue gas, based on the battery hybrid flue gas explosion limit testing equipment, including: Using an electrolyte evaporation device to inject electrolyte vapors with different concentrations into the constant volume bomb, and mixing gas to produce a thermal runaway mixed gas containing electrolyte vapors to simulate the real thermal runaway flue gas of a lithium battery.
[0013] Using the pressure and temperature in the constant volume bomb at different stages to correct the volume fraction of the thermal runaway gas.
[0014] As a further improvement of the present application, the step of using an electrolyte evaporation device to inject electrolyte vapors with different concentrations into the constant volume bomb, and mixing gas to produce a thermal runaway mixed gas containing electrolyte vapors to simulate the real thermal runaway flue gas of a lithium battery includes: Vacuum the inside of the constant volume bomb until the pressure reaches , and introduce the thermal runaway gas with a set concentration in the gas cylinder into the constant volume bomb until the pressure in the constant volume bomb reaches and then stop. Then the theoretical ratio of the thermal runaway gas is:
[0015] In the formula, is the theoretical proportion of thermal runaway gas in the constant volume bomb; is the pressure after evacuating the constant volume bomb; is the pressure after introducing thermal runaway gas into the constant volume bomb; is the pressure after gas distribution in the constant volume bomb, = 100 kPa.
[0016] The micro-injection pump injects the electrolyte with a fixed concentration quantitatively; The heating chamber of the heating and mixing device is evacuated to a pressure reaching P3, the injection pump injects the electrolyte at a set injection rate, the electrolyte is atomized by the liquid atomizer and then enters the heating chamber, and then the temperature control heater is energized to heat according to the set temperature until all the electrolyte is vaporized and the pressure in the heating chamber no longer changes. At this time, the pressure in the heating chamber is P4; The electrolyte vapor is introduced into the constant volume bomb with air as the carrier gas. The gas flow rate of the gas flowmeter is adjusted according to the amount of the electrolyte used to ensure that all the electrolyte vapor is introduced. Then, air is continuously introduced into the constant volume bomb until the pressure reaches the target pressure; The ignition device is used to ignite the constant volume bomb to conduct the explosion characteristic test of the thermal runaway mixed flue gas, and the explosion overpressure, pressure change rate and temperature data during the ignition process are monitored and recorded in the control system.
[0017] As a further improvement of the present application, it further includes: The heating chamber is connected to the ambient air to control the inlet and outlet of the air; The second vacuum pump is connected to the heating chamber to evacuate the heating chamber.
[0018] As a further improvement of the present application, the fiberglass heating tape wound around the surface of the constant volume bomb and the transmission pipeline is energized to heat, so as to maintain the set temperature during the experiment.
[0019] As a further improvement of the present application, the volume fraction of the thermal runaway gas is corrected by using the pressure and temperature in the constant volume bomb at different stages, including: The proportion of the thermal runaway gas is corrected according to the pressure and temperature in the constant volume bomb at different stages. The correction method is as follows:
[0020] In the formula, is the theoretical proportion of thermal runaway gas in the constant volume bomb; is the actual proportion of thermal runaway gas in the constant volume bomb; is the temperature after evacuating the constant volume bomb; is the temperature after introducing thermal runaway gas into the constant volume bomb; is the temperature after gas distribution in the constant volume bomb.
[0021] As a further improvement of this application, it further includes: Calculate the volume fraction of the electrolyte vapor by using the pressure and temperature in the heating chamber and the constant volume bomb, specifically including: Obtain the proportion of the electrolyte vapor from the pressures and temperatures before and after evacuating the heating chamber and the pressure and temperature after gas distribution in the constant volume bomb 1. :
[0022] In the formula, is the proportion of the electrolyte vapor in the constant volume bomb; is the pressure after evacuating the heating chamber; The pressure after the electrolyte vaporization in the heating chamber ends; is the pressure after gas distribution in the constant volume bomb, = 100 kPa; is the temperature after evacuating the heating chamber; is the temperature after the electrolyte vaporization in the heating chamber ends, with the unit of K, measured by the thermocouple in the heating chamber; is the volume of the heating chamber; is the volume of the constant volume bomb 1; The explosion overpressure under the mixture gas ratio , is the proportion of the electrolyte vapor and the actual proportion of the thermal runaway gas.
[0023] As a further improvement of this application, it further includes: After conducting the flue gas explosion characteristic test in the constant volume bomb, calculate the explosion overpressure of the thermal runaway mixed flue gas at room temperature, specifically including: When conducting the explosion characteristic test of the thermal runaway mixed flue gas, heat the constant volume bomb 1. If the explosion overpressure data of the thermal runaway mixed flue gas at room temperature is to be obtained, correct the explosion overpressure data obtained from the test. The correction method is as follows:
[0024] In the formula, is the corrected explosion overpressure; is the explosion overpressure obtained from the test; is the absolute temperature at room temperature; is the temperature in the constant volume bomb 1 when the thermal runaway mixed flue gas ignites and explodes; n is the correction coefficient, and the value range is 0.5 to 1.0.
[0025] The beneficial effects of this application compared with the prior art are: This application proposes a test device for the explosion limit of battery hybrid flue gas. The electrolyte evaporation device is integrated. Through the series design of a micro-injection pump, a liquid atomizer, a heating and mixing device, and a second vacuum pump, precise generation, control, and transportation of electrolyte vapor are achieved, enabling the simulation of electrolyte vapor environments with different concentrations and compositions. The dual vacuum pumps have a synergistic effect. The first vacuum pump is used for the initial vacuuming of the constant-volume bomb, and the second vacuum pump assists the heating and mixing device to quickly discharge residual gases, improving the system response speed and experimental efficiency. The micro-injection pump can precisely control the injection volume of the liquid electrolyte (such as at the microliter level). Combined with the atomization efficiency of the liquid atomizer, continuous adjustable control of the vapor concentration is realized. Through temperature control, uniform vaporization of the electrolyte is promoted, and it is fully mixed with the thermal runaway gas to ensure the composition uniformity and stability of the simulated flue gas. The thermal runaway gas cylinder directly provides the characteristic gases (such as CO, H2, CH4, etc.) generated by the thermal runaway of lithium batteries. After being mixed with the electrolyte vapor, the complex components of the real battery thermal runaway flue gas can be reproduced. The fixed-volume design avoids gas leakage and ensures the accuracy and repeatability of the gas distribution process. Key parameters such as the pressure and temperature inside the constant-volume bomb are recorded in real time, supporting the dynamic correction of the volume fraction later. At the same time, the experimental process can be automatically controlled (such as triggering the ignition source, adjusting the power of the vacuum pump, etc.).
[0026] The method for testing the explosion limit of battery hybrid flue gas in this application improves the result accuracy through multi-parameter coupling correction. By real-time monitoring the pressure and temperature changes inside the constant-volume bomb, the actual volume fraction of the thermal runaway gas is corrected using the ideal gas state equation to eliminate the influence of temperature fluctuations on the calculation of the explosion limit. The staged gas distribution strategy first injects electrolyte vapor and then mixes the thermal runaway gas, controlling the mixing ratio step by step to avoid experimental errors caused by uneven gas premixing. The electrolyte vapor and the thermal runaway gas are synergistically simulated. Traditional methods only focus on the explosion limit of a single gas (such as H2), while this application reproduces the coupling effect of the electrolyte and the thermal runaway gas (such as the vapor participating in the chain reaction), which is closer to the actual failure scenario of lithium batteries and highly restores the real thermal runaway scenario. Compared with the open-space test, the risk of dangerous gas leakage is significantly reduced. At the same time, the residual gas is quickly cleaned by the vacuum pump, shortening the experimental preparation time. Combining with the control system, the precise regulation of the ignition source energy is realized to avoid damage to the equipment caused by overly violent reactions. Breaking through the limitations of single-parameter correction, through multi-dimensional data correlation analysis, the credibility of the explosion limit prediction is improved, providing a reliable basis for battery safety design. It significantly improves the accuracy, safety, and efficiency of the explosion limit test, providing a test method closer to the real scenario for the safety performance evaluation of lithium batteries. Description of the Drawings
[0027] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following introduces the accompanying drawings of the relevant technical solutions in the embodiments of the present application or the prior art. It should be understood that the accompanying drawings in the following introduction are only for conveniently and clearly presenting some embodiments of the technical solutions in the present application. For those skilled in the art, without creative efforts, other accompanying drawings can also be obtained based on these drawings.
[0028] Figure 1 is a schematic diagram of the thermal runaway flue gas explosion characteristic test equipment of the present application; Figure 2 is a flowchart of a method for testing the explosion limit of a battery hybrid flue gas provided by the present invention. Detailed implementation manners
[0029] The following details the embodiments of the present application. The examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and should not be construed as a limitation to the present application. For the step numbers in the following embodiments, they are only set for the convenience of elaboration and explanation, and no limitation is imposed on the order between the steps. The execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.
[0030] In the description of the present application, unless otherwise clearly defined, words such as "set", "installed", and "connected" should be understood in a broad sense. Those skilled in the art can reasonably determine the specific meanings of the above words in the present application in combination with the specific content of the technical solution.
[0031] When the present application studies the variation law of the explosion characteristics of real lithium battery thermal runaway flue gas, it improves the problem that the prior art is not applicable to the combustion and explosion characteristics of the thermal runaway mixed gas containing electrolyte vapor. The following is a detailed description.
[0032] Figure 1 is a schematic diagram of the thermal runaway flue gas explosion characteristic test equipment containing electrolyte vapor provided by the present application, including a constant volume bomb 1, a gas cylinder 3 filled with thermal runaway gas, a first vacuum pump 4, a control system 19, an electrolyte evaporation device, etc.
[0033] Among them, the gas cylinder 3 is connected to the constant volume bomb 1; the first vacuum pump 4 is connected to the constant volume bomb 1; the control system 19 is electrically connected to the constant volume bomb 1 for data recording.
[0034] Among them, an ignition device 16, a pressure sensor 17 and a temperature sensor 18 are arranged inside the constant volume bomb 1, which can monitor data such as explosion overpressure, pressure change rate and temperature during the ignition process. The electrolyte evaporation device consists of a high-precision micro-injection pump 5, a liquid atomizer 6, a heating and mixing device 7, a second vacuum pump 8 and a gas flow meter 9. The micro-injection pump 5, the liquid atomizer 6 and the heating and mixing device 7 are connected in sequence, and the second vacuum pump 8 is communicated with the heating and mixing device 7; the heating and mixing device 7 is communicated with the constant volume bomb 1; a gas flow meter 9 is arranged on the pipeline where the heating and mixing device 7 is communicated with the constant volume bomb 1.
[0035] The heating and mixing device 7 is internally provided with a heating chamber 10, a temperature control heater 11 and a pressure sensor 12, and can perform electrolyte evaporation, gas heating, gas premixing and gas transmission.
[0036] A first solenoid valve 2 is arranged on the pipeline where the gas cylinder 3 is communicated with the constant volume bomb 1; a third solenoid valve 16 is arranged on the pipeline where the first vacuum pump 4 is communicated with the constant volume bomb 1; a fourth solenoid valve 20 is arranged on the pipeline where the heating and mixing device 7 is communicated with the constant volume bomb 1. The second vacuum pump 8 is connected to the heating chamber 10 through a second solenoid valve 14. The fourth solenoid valve 20: controls the opening and closing of the gas passage between the heating and mixing device and the constant volume bomb. The fifth solenoid valve 13: connects the heating chamber and the ambient air and is used to adjust the composition of the mixed gas.
[0037] Furthermore, the heating chamber 10 is connected to the ambient air through a fifth solenoid valve 13. The surfaces of the constant volume bomb 1 and the transmission pipeline 21 are wound and covered with a glass fiber heating tape. The glass fiber heating tape: is wound on the surfaces of the constant volume bomb and the transmission pipeline and is used to simulate the experimental environment under different temperature conditions.
[0038] The test equipment for the explosion characteristics of the thermal runaway flue gas containing electrolyte vapor mainly simulates the generation, transmission and explosion process of the thermal runaway flue gas, and monitors and records key parameters through various sensors and control systems. The specific principle analysis is as follows: The constant volume bomb 1: serves as the core experimental chamber, used to accommodate the mixture of thermal runaway flue gas and electrolyte vapor, and simulate the explosion environment. It is internally equipped with: an ignition device 16: used to trigger an explosion and simulate the ignition conditions of the thermal runaway flue gas. A pressure sensor 17: monitors the overpressure and pressure change rate during the explosion process in real time. A temperature sensor 18: records the temperature change during the explosion process.
[0039] The gas cylinder 3: stores the thermal runaway gas (such as the gas generated by battery thermal runaway), is communicated with the constant volume bomb through a pipeline, and a first solenoid valve 2 is arranged on the pipeline to control the on-off of the thermal runaway gas.
[0040] Electrolyte evaporation device: used to generate electrolyte vapor, consisting of the following components: Micro-injection pump 5: precisely controls the injection volume of the electrolyte. Liquid atomizer 6: atomizes the electrolyte into tiny droplets to increase the evaporation surface area. Heating and mixing device 7: equipped with a heating chamber 10, a temperature-controlled heater 11, and a pressure sensor 12, used to evaporate the electrolyte, heat and mix the gas, and ensure uniform gas mixing.
[0041] Second vacuum pump 8: connected to the heating chamber through the second solenoid valve 14, used to control the pressure and gas flow during the evaporation process. Gas flow meter 9: located on the pipeline connecting the heating and mixing device to the constant volume bomb, used to measure the gas flow entering the constant volume bomb.
[0042] First vacuum pump 4: connected to the constant volume bomb 1 through the third solenoid valve 16, used to evacuate the air in the constant volume bomb before the experiment to ensure the purity of the experimental environment. Control system 19: electrically connected to the constant volume bomb 1, used for data recording and analysis, and real-time monitoring and storage of sensor data such as pressure and temperature.
[0043] The main steps in the gas preparation stage include: Introduction of thermal runaway gas: Open the first solenoid valve 2, and the thermal runaway gas enters the constant volume bomb 1 from the gas cylinder 3.
[0044] Generation of electrolyte vapor: The micro-injection pump 5 precisely injects the electrolyte into the liquid atomizer 6, which forms tiny droplets after atomization. The droplets enter the heating chamber 10 of the heating and mixing device 7, and the temperature-controlled heater 11 provides heat to evaporate the droplets into vapor. The second vacuum pump 8 controls the pressure in the heating chamber through the second solenoid valve 14 to promote the evaporation process. The evaporated electrolyte vapor is fully mixed with other gases in the heating and mixing device to form a uniform mixed gas.
[0045] The main steps in the environmental control and explosion simulation stage include: Vacuum pumping of the constant volume bomb: Open the third solenoid valve 16 and start the first vacuum pump 4 to evacuate the constant volume bomb to a vacuum and exclude interfering gases. Injection of the mixed gas: Open the fourth solenoid valve 20, and the mixed gas (containing electrolyte vapor) in the heating and mixing device 7 enters the constant volume bomb 1.
[0046] The main steps in ignition and data acquisition include: Trigger an explosion through the ignition device 16 to simulate the explosion process of thermal runaway smoke. The pressure sensor 17 and temperature sensor 18 continuously monitor the overpressure, pressure change rate, and temperature change during the explosion process. The control system 19 records and analyzes this data for evaluating the explosion characteristics of thermal runaway smoke.
[0047] The main steps in environmental regulation and expandability include: Temperature control: The fiberglass heating tape can heat the constant volume bomb and the transmission pipeline to simulate the explosion environment under different temperature conditions. Gas composition adjustment: Introduce ambient air through the fifth solenoid valve 13 to adjust the composition of the mixed gas and study the influence of different gas ratios on the explosion characteristics.
[0048] Components such as the micro-injection pump, solenoid valve, and vacuum pump in the embodiments of this application achieve precise control of gas flow, pressure, and composition, ensuring the repeatability of experimental conditions. The pressure sensor and temperature sensor can monitor the key parameters during the explosion process in real time, providing comprehensive data for the study of the explosion characteristics of thermal runaway flue gas. By adjusting the experimental environment with the heating tape and solenoid valve, the explosion process under different temperature and gas composition conditions can be simulated, enhancing the applicability of the equipment.
[0049] This equipment provides an effective experimental platform for the research of battery thermal safety, electrolyte vapor explosion risk, etc., and helps to develop safer battery technologies and electrolyte formulations. By integrating functions such as thermal runaway gas supply, electrolyte vapor generation, environmental control, and data acquisition, it is possible to systematically study the explosion characteristics of thermal runaway flue gas containing electrolyte vapor, providing important support for safety research and product development in related fields.
[0050] The method for testing the explosion limit of battery mixed flue gas using the above equipment includes the following steps: Use the electrolyte evaporation device to inject electrolyte vapor with different concentrations into the constant volume bomb to prepare a thermal runaway mixed gas containing electrolyte vapor to simulate the real thermal runaway flue gas of lithium batteries.
[0051] Vacuum the constant volume bomb 1 until the pressure reaches , open the first solenoid valve 2, and introduce a certain concentration of thermal runaway gas in the gas cylinder 3 into the constant volume bomb 1. When the pressure in the constant volume bomb 1 reaches , close the first solenoid valve 2, and the increased pressure in the constant volume bomb 1 is the theoretical proportion of the thermal runaway gas .
[0052] Vacuum the constant volume bomb until the pressure reaches , introduce the thermal runaway gas with a set concentration in the gas cylinder into the constant volume bomb until the pressure in the constant volume bomb reaches and then stop. Then the theoretical proportion of the thermal runaway gas is:
[0053] In the formula, is the theoretical proportion of the thermal runaway gas in the constant volume bomb; is the pressure after the constant volume bomb is evacuated; is the pressure after the thermal runaway gas is introduced into the constant volume bomb; is the pressure after the gas distribution in the constant volume bomb ends. = 100 kPa.
[0054] Electrify and heat the fiberglass heating tape wrapped around the surface of the constant volume bomb 1 and the transmission pipeline 21, and maintain a certain temperature during the experiment to prevent the electrolyte vapor from condensing and liquefying during transmission and experimentation.
[0055] The electrolyte evaporation device consists of a high-precision micro-injection pump 5, a liquid atomizer 6, a heating and mixing device 7, a second vacuum pump 8, and a gas flow meter 9. The heating and mixing device 7 is internally provided with a heating chamber 10, a temperature control heater 11, and a pressure sensor 12. The heating and mixing device 7 is connected to the liquid atomizer 6 and the high-precision micro-injection pump 5 to accurately introduce the electrolyte with a fixed concentration by the method of quantitative injection. The heating chamber 10 is connected to the ambient air through a fifth solenoid valve 13, and the air inlet and outlet are controlled by a valve. The second vacuum pump 8 is connected to the heating chamber 10 through a second solenoid valve 14, and the heating chamber 10 can be evacuated.
[0056] Evacuate the heating chamber 10 of the heating and mixing device 7 to a pressure of P3. Use a syringe to extract an appropriate amount of electrolyte, remove the air bubbles in the syringe and the pipeline, and the injection pump 5 injects the electrolyte at the set injection rate. After the electrolyte is atomized by the liquid atomizer 6, it enters the heating chamber 10. Subsequently, the temperature control heater 11 is electrified and heated according to the set temperature until all the electrolyte is vaporized and the pressure in the heating chamber 10 no longer changes. At this time, the pressure in the heating chamber 10 is P4.
[0057] Open the fifth solenoid valve 13 and the sixth solenoid valve 15, introduce the electrolyte vapor into the constant volume bomb 1 with air as the carrier gas, adjust the gas flow rate of the gas flow meter 9 according to the amount of electrolyte used to ensure that all the electrolyte vapor is introduced, and then continue to introduce air into the constant volume bomb 1 until the pressure reaches 100 kPa. The gas distribution is completed, and the fifth solenoid valve 13 and the sixth solenoid valve 15 are closed.
[0058] Use the ignition device 16 to ignite the constant volume bomb 1, conduct the explosion characteristic test of the thermal runaway mixed flue gas, and use the pressure sensor 17 and the temperature sensor 18 to monitor data such as the explosion overpressure, pressure change rate, and temperature during the ignition process, and record them in the control system 19.
[0059] Among them, as Figure 2 shown, this experiment simulates the thermal runaway flue gas environment of lithium batteries through a controllable gas distribution system, and its principle is: 1) Quantitative configuration of thermal runaway gas: Use the differential pressure method to inject the thermal runaway gas with a known concentration into the constant volume bomb: Through the difference between the initial vacuum (P1) and the pressure after ventilation (P2), accurately calculate the volume ratio φ of the thermal runaway gas gas , and establish the basic flue gas atmosphere.
[0060] 2) Precise generation of electrolyte vapor: Adopt the "vacuum flash evaporation - carrier gas transportation" technology: The micro-injection pump and the liquid atomizer work together to achieve rapid vaporization of the nano-level electrolyte in the quantitative feeding vacuum chamber (P3), and combined with pressure monitoring (P4) to ensure complete vaporization; The air carrier gas realizes lossless transmission of the vapor through flow control, and finally returns to normal pressure (100 kPa).
[0061] 3) Dynamic maintenance of temperature and humidity: The glass fiber heating tape conducts constant temperature control on the entire pipeline, and prevents the condensation of high-boiling electrolyte components through surface temperature field management (maintaining above the dew point throughout the experiment) to ensure the stable transmission of all components of the gaseous substance.
[0062] 4) Closed-loop test of explosion characteristics: After the mixed gas in the constant volume bomb is ignited by an electric spark, characteristic parameters such as the peak overpressure, pressure rise rate, and temperature mutation are collected in real time through high-frequency pressure sensors and temperature sensors, and the dynamic characterization of the deflagration characteristics of the thermal runaway flue gas is completed in combination with the data acquisition system.
[0063] This principle system realizes the construction of a fully parameter-programmable experimental environment from electrolyte vaporization to the reproduction of thermal runaway scenarios through multi-dimensional coupling control of pressure - temperature - flow.
[0064] Among them, the proportion of thermal runaway gas is corrected according to the pressure and temperature in the constant volume bomb 1 at different stages, and the correction method is as follows:
[0065] In the formula, is the theoretical proportion of thermal runaway gas in the constant volume bomb 1; is the actual proportion of thermal runaway gas in the constant volume bomb 1; is the temperature after the constant volume bomb 1 is evacuated, in K; is the temperature after the thermal runaway gas is introduced into the constant volume bomb 1, in K; is the temperature after the gas distribution in the constant volume bomb 1 is completed, in K.
[0066] This application also corrects the volume fraction of thermal runaway gas according to the pressure and temperature in the constant volume bomb at different stages.
[0067] The proportion of electrolyte vapor is obtained from the pressure and temperature before and after the heating chamber 10 is evacuated and the pressure and temperature after the gas distribution in the constant volume bomb 1 is completed:
[0068] In the formula, is the proportion of electrolyte vapor in the constant volume bomb 1; is the pressure after the heating chamber 10 is evacuated, in kPa; The pressure after the electrolyte vaporization in the heating chamber 10, in kPa; is the pressure after the gas distribution in the constant volume bomb; = 100 kPa; is the temperature after the heating chamber 10 is evacuated, in K; is the temperature after the electrolyte vaporization in the heating chamber 10, in K, measured by the thermocouple in the heating chamber 10; is the volume of the heating chamber 10, in m 3 ; is the volume of the constant volume bomb 1, in m 3 .
[0069] The explosion overpressure under the mixed gas ratio is obtained through the test, where is the sum of the electrolyte vapor ratio and the actual ratio of the thermal runaway gas.
[0070] Based on the method of correcting the electrolyte vapor ratio in the constant volume bomb, the volume fraction of the electrolyte vapor can be calculated using the pressure and temperature in the heating chamber and the constant volume bomb.
[0071] The method of correcting the explosion overpressure of the thermal runaway mixed flue gas considering the temperature factor can calculate the explosion overpressure of the thermal runaway mixed flue gas at room temperature after the explosion characteristics test of the flue gas in the constant volume bomb.
[0072] When conducting the explosion characteristics test of the thermal runaway mixed flue gas, to prevent the electrolyte vapor from cooling and condensing, the constant volume bomb 1 is heated. If the explosion overpressure data of the thermal runaway mixed flue gas at room temperature is to be obtained, the explosion overpressure data obtained from the test needs to be corrected for temperature. The correction method is as follows:
[0073] In the formula, is the corrected explosion overpressure, in kPa; is the explosion overpressure obtained from the test, in kPa; is the absolute temperature at room temperature, in K, usually taken as 298.15 K; is the temperature in the constant volume bomb 1 when the thermal runaway mixed flue gas ignites and explodes, in K; n is the correction coefficient, and the value range is 0.5 - 1.0.
[0074] Obviously, the described embodiments are only part of the embodiments of the present application, not all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.
[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and not to limit them. Although the present application has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications or equivalent replacements can still be made to the specific implementation manners of the present application, and any modification or equivalent replacement that does not depart from the spirit and scope of the present application should be covered within the protection scope of the claims of the present application.
Claims
1. A testing device for the explosion limit of battery hybrid flue gas, characterized in that, Comprising: Constant volume bomb; Gas cylinder filled with thermal runaway gas; the gas cylinder is connected to the constant volume bomb; First vacuum pump; The first vacuum pump is connected to the constant volume bomb; Electrolyte evaporation device; the electrolyte evaporation device includes a micro-injection pump, a liquid atomizer, a heating and mixing device and a second vacuum pump, the micro-injection pump, the liquid atomizer, and the heating and mixing device are connected in sequence, and the second vacuum pump is connected to the heating and mixing device; the heating and mixing device is connected to the constant volume bomb; Control system, the control system is electrically connected to the constant volume bomb for data recording.
2. The battery mixed flue gas explosion limit test equipment according to claim 1, wherein An ignition device, a pressure sensor and a temperature sensor are arranged in the constant volume bomb for monitoring the explosion overpressure, pressure change rate and temperature data during the ignition process.
3. The battery mixed flue gas explosion limit test equipment according to claim 1, wherein A gas flow meter is arranged on the pipeline where the heating and mixing device is connected to the constant volume bomb.
4. The battery mixed flue gas explosion limit test equipment according to claim 1, wherein A first solenoid valve is arranged on the pipeline where the gas cylinder is connected to the constant volume bomb; A third solenoid valve is arranged on the pipeline where the first vacuum pump is connected to the constant volume bomb; A fourth solenoid valve is arranged on the pipeline where the heating and mixing device is connected to the constant volume bomb; The second vacuum pump is connected to the heating chamber through a second solenoid valve.
5. The battery mixed flue gas explosion limit test equipment according to claim 1, wherein The heating and mixing device is internally provided with a heating chamber, a temperature control heater and a pressure sensor for electrolyte evaporation, gas heating, gas premixing and gas transmission.
6. The battery mixed flue gas explosion limit test equipment according to claim 1, wherein The heating chamber is connected to ambient air through a fifth solenoid valve.
7. The battery mixed flue gas explosion limit test equipment according to claim 1, wherein The surface of the constant volume bomb and the transmission pipeline is wound and covered with a glass fiber heating tape.
8. A method for testing the explosion limit of battery hybrid flue gas, based on the battery hybrid flue gas explosion limit testing equipment described in claims 1 to 8, characterized in that, Comprising: Using the electrolyte evaporation device to inject electrolyte vapors with different concentrations into the constant volume bomb, and mixing gas to produce a thermal runaway mixed gas containing electrolyte vapors to simulate the real thermal runaway flue gas of a lithium battery; Using the pressure and temperature in the constant volume bomb at different stages to correct the volume fraction of the thermal runaway gas.
9. The method for testing the explosion limit of the battery hybrid flue gas according to claim 8, characterized in that, The using the electrolyte evaporation device to inject electrolyte vapors with different concentrations into the constant volume bomb, and mixing gas to produce a thermal runaway mixed gas containing electrolyte vapors to simulate the real thermal runaway flue gas of a lithium battery, includes: Vacuum the constant volume bomb until the pressure reaches , and introduce the thermal runaway gas with a set concentration in the gas cylinder into the constant volume bomb until the pressure in the constant volume bomb reaches , then stop; The micro-injection pump injects a fixed concentration of electrolyte in a quantitative manner; The heating chamber of the heating and mixing device is evacuated to a pressure of P3, the injection pump injects the electrolyte at a set injection rate, the electrolyte is atomized by the liquid atomizer and then enters the heating chamber, and then the temperature control heater is energized and heated at a set temperature until all the electrolyte is vaporized and the pressure in the heating chamber no longer changes. At this time, the pressure in the heating chamber is P4; Introduce the electrolyte vapor into the constant-volume bomb with air as the carrier gas. Adjust the gas flow rate of the gas flowmeter according to the amount of the electrolyte to ensure that the electrolyte vapor is completely introduced. Then continue to introduce air into the constant-volume bomb until the pressure reaches the target pressure; Use an ignition device to ignite the constant-volume bomb and conduct an explosion characteristic test on the thermal runaway mixed flue gas. Monitor the explosion overpressure, pressure change rate and temperature data during the ignition process and record them in the control system.
10. The method for testing the explosion limit of the battery hybrid flue gas according to claim 9, wherein, When the pressure in the constant volume bomb reaches and stops, the theoretical proportion of thermal runaway gas is as follows: In the formula, is the theoretical proportion of the thermal runaway gas in the constant volume bomb; is the pressure after the constant volume bomb is evacuated; is the pressure after the thermal runaway gas is introduced into the constant volume bomb; is the pressure after the gas distribution in the constant volume bomb is completed.
11. The method for testing the explosion limit of battery hybrid flue gas according to claim 9, characterized in that, It also includes: The heating chamber is connected to the ambient air to control the inlet and outlet of the air; The second vacuum pump is connected to the heating chamber to evacuate the heating chamber.
12. The method for testing the explosion limit of battery hybrid flue gas according to claim 9, wherein, Energize the fiberglass heating tape wrapped around the surface of the constant-volume bomb and the transmission pipeline to heat it, so as to maintain the set temperature during the experiment.
13. The method for testing and calculating the explosion limit of the battery hybrid flue gas according to claim 8, wherein, The correction of the volume fraction of the thermal runaway gas by using the pressure and temperature in the constant-volume bomb at different stages includes: Correct the proportion of the thermal runaway gas according to the pressure and temperature in the constant-volume bomb at different stages. The correction method is as follows: In the formula, is the theoretical proportion of the thermal runaway gas in the constant volume bomb; is the actual proportion of the thermal runaway gas in the constant volume bomb; is the temperature after the constant volume bomb is evacuated; is the temperature after the thermal runaway gas is introduced into the constant volume bomb; is the temperature after the gas distribution in the constant volume bomb is completed.
14. The method for calculating the explosion limit of the battery hybrid flue gas according to claim 8, wherein, It also includes: Calculate the volume fraction of the electrolyte vapor by using the pressure and temperature in the heating chamber and the constant-volume bomb. Specifically, it includes: The proportion of electrolyte vapor is obtained from the pressures and temperatures before and after evacuating the heating chamber, and the pressures and temperatures after the gas distribution in the constant volume bomb : Wherein, is the proportion of electrolyte vapor in the constant volume bomb; is the pressure after the heating chamber is evacuated; is the pressure after the electrolyte vaporization in the heating chamber ends; is the pressure after the gas distribution in the constant volume bomb ends; is the temperature after the heating chamber is evacuated; is the temperature after the electrolyte vaporization in the heating chamber ends; is the volume of the heating chamber; is the volume of the constant volume bomb 1; The explosion overpressure under the mixed gas ratio is , which is the sum of the proportion of electrolyte vapor and the actual proportion of thermal runaway gas .
15. The method for testing the explosion limit of the battery hybrid flue gas according to claim 8, characterized in that It also includes: After conducting the explosion characteristic test of the flue gas in the constant-volume bomb, calculate the explosion overpressure of the thermal runaway mixed flue gas at room temperature. Specifically, it includes: When conducting the explosion characteristic test of the thermal runaway mixed flue gas, heat the constant-volume bomb. If the explosion overpressure data of the thermal runaway mixed flue gas at room temperature is to be obtained, correct the explosion overpressure data obtained from the test. The correction method is as follows: In the formula, is the corrected explosion overpressure; is the explosion overpressure obtained from the test; is the absolute temperature at room temperature; is the temperature in the constant volume bomb during the ignition explosion of the thermal runaway mixed flue gas; n is the correction coefficient.