Method for collecting and verifying gas generated by thermal runaway of battery in closed pressure container

Abstract

The invention discloses a method for collecting and verifying gas generated by thermal runaway of a battery in a closed pressure container, which comprises the following steps of: 1, starting a power supply of an experimental device, debugging each component and trying to act, putting the battery with a clamp into the closed pressure container 1, and closing a cabin door of the container; step 2, vacuumizing the transformed large-volume closed pressure container 1 until the transformed large-volume closed pressure container 1 reaches a vacuum environment, then filling nitrogen, monitoring and recording the nitrogen concentration through a nitrogen concentration sensor 1-2, and inputting data into a control system 6; a plurality of nitrogen concentration sensors are arranged at a plurality of gas sampling ports of a closed pressure container, a nitrogen concentration sensor is arranged in a premixing cabin, and an ideal gas state equation, a gas homogenization calculation method and an automatic adjustment algorithm are integrated in a control system. By utilizing the flow rate adjusting function of the sampling pipeline and actually measured concentration data, the automatic detection, adjustment and verification of the uniformity degree of the thermal runaway mixed gas sample are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of battery safety testing, and in particular to a method for collecting and verifying gas generated by thermal runaway of a battery in a sealed pressure container. Background Art

[0002] As the "new three things" of my country's foreign trade, lithium-ion batteries have become a new business card in recent years to show that China's manufacturing is moving towards high-end, intelligent and green. The scale of the lithium battery industry is also showing a trend of continuous development and growth; according to incomplete statistics, my country's total lithium battery output in 2023 will exceed 940GWh, a year-on-year increase of 25%, and the total output value of the industry will exceed 1.4 trillion yuan; however, as an energy carrier, lithium batteries will experience thermal runaway under conditions of electrical, thermal and mechanical abuse, generating a large amount of heat and releasing mixed flammable gases; once the flammable gas accumulates in a confined space and reaches the explosion limit, it is likely to cause an explosion accident; therefore, it is of great practical significance to study the explosion characteristics of the mixed gas generated by thermal runaway of lithium batteries;

[0003] At present, researchers mostly use non-in-situ methods to test and study the explosion characteristics of thermal runaway gas, mainly triggering thermal runaway of battery cells in a closed pressure vessel, collecting the mixed gas in the container into a sampling bag through a sampling port after the thermal runaway gas is completely released, and then analyzing the components of the mixed gas produced by thermal runaway through equipment such as gas chromatographs and chromatography-mass spectrometry. On this basis, further test the explosion sensitivity index parameters such as the explosion limit and minimum ignition energy of the mixed gas, as well as the explosion intensity index parameters such as the maximum explosion pressure and the maximum explosion pressure rise rate. However, with the emergence and widespread application of longer single cells such as BYD's "blade" battery, the volume of closed pressure vessels used for thermal runaway gas production testing has become larger and larger. In such a large-volume pressure vessel, the mixed gas produced by thermal runaway will show a non-uniform distribution characteristic, resulting in differences in the components of the mixed gas collected at different positions, which further affects the accuracy and reliability of subsequent explosion characteristic tests. However, there is still no method and corresponding sampling device that can achieve uniform collection of mixed gas produced by thermal runaway in large-volume closed pressure vessels.

[0004] Based on this, a method for collecting and verifying the gas generated by thermal runaway of batteries in a closed pressure vessel is needed. Summary of the invention

[0005] To achieve the above object, the present invention provides the following solution: a method for collecting and verifying gas generated by thermal runaway of a battery in a closed pressure vessel, comprising the following steps:

[0006] Step 1: Turn on the power of the experimental device, debug each component and test the operation, put the battery with the clamp into the sealed pressure container, and close the container hatch;

[0007] Step 2: Evacuate the modified large-volume closed pressure vessel to a vacuum environment and then fill it with nitrogen; monitor and record the nitrogen concentration through a nitrogen concentration sensor, and input the data into a control system;

[0008] Step 3: Trigger battery thermal runaway and monitor the pressure change in the modified large-volume closed pressure vessel until it stabilizes, and record the amount of mixed gas released;

[0009] Step 4: Evacuate the gas collection premixing chamber and ensure that a vacuum environment is reached using a vacuum pressure gauge;

[0010] Step 5: Control gas delivery through the output solenoid valve and input solenoid valve of the multi-channel gas collection system, and use the gas flow meter and flow control valve to adjust the flow of each gas path to ensure that the gas volume in the collected gas premixing cabin is uniform;

[0011] Step 6: After the pressure in the gas premixing chamber returns to the standard atmospheric pressure, close the relevant valves of the multi-channel gas collection system, record the gas input volume of each channel, start the explosion-proof fan, stir the gas in the chamber to achieve uniform mixing, turn off the explosion-proof fan after stirring, let it stand, and read and record the data of the nitrogen concentration sensor;

[0012] Step 7: The control system calculates the gas volume Vgas generated by thermal runaway through the ideal gas state equation, and calculates the nitrogen concentration in the homogenized gas, and verifies the uniformity of the mixed gas by comparing it with the data measured by the nitrogen concentration sensor in the gas premixing chamber;

[0013] Step 8: If the gas does not reach a uniform condition, the control system automatically adjusts the input volume ratio of different gas paths according to the gas volume of each gas path input into the gas premixing chamber of the multi-path gas collection system and the nitrogen concentration in the gas premixing chamber, as well as the data of each concentration sensor in the modified large-volume closed pressure vessel, and repeats steps 4 and 7 until a uniform condition is reached;

[0014] Step 9. If the mixed gas in the gas premixing chamber reaches a uniform condition, turn on the suction pump of the sampling total output system to collect the homogenized mixed gas sample into the gas sampling bag to complete the collection and sampling. Otherwise, repeat the steps and automatically adjust through the control system until a uniform condition is reached.

[0015] In some embodiments, in step 2, after the battery is placed in the modified sealed pressure vessel, a vacuum operation is immediately performed to reach a preset vacuum level, and then pure nitrogen is filled to a specific pressure. The nitrogen concentration is monitored and recorded in real time by a nitrogen concentration sensor to ensure the standardization of the initial test environment.

[0016] In some embodiments, in step five, the system is equipped with an automatically controlled output solenoid valve and flow meter to accurately control the amount of gas collected from different parts of the modified large-volume closed pressure vessel. The control system automatically adjusts the flow regulating valve according to the flow data obtained from the gas flow meter to ensure that the amount of gas collected at each sampling port is uniform.

[0017] In some embodiments, in step six, the explosion-proof fan automatically adjusts the rotation speed and stirring time according to the instructions of the control system and the feedback from the gas concentration sensor to ensure thorough and uniform mixing of the gas and optimize the homogeneity of the gas.

[0018] In some embodiments, in step 7 and step 8, the volume Vgas of the gas generated by thermal runaway is calculated using the ideal gas state equation and compared with the measured nitrogen concentration to verify the uniformity of the mixed gas. In addition, if it is detected that the gas mixture does not achieve the expected uniformity, the control system will adjust the acquisition parameters;

[0019] According to the following formula algorithm, the concentration of mixed gas in the premixing chamber of the collected gas is automatically adjusted by changing the input volume ratio of different gas paths, and steps six and seven are further repeated;

[0020]

[0021] In the formula, They are the nitrogen concentrations measured by modifying the nitrogen concentration sensor in a large-volume closed pressure vessel. The nitrogen concentration in the gas premixing chamber is measured by the nitrogen concentration sensor. V, V, and V are the gas volumes recorded by the flow meters of each gas path in the multi-path gas collection system.

[0022] A self-verifying battery thermal runaway gas homogenization collection device comprises a modified large-volume closed pressure vessel, a multi-channel gas collection system, a collection gas premixing cabin, a sampling total output system, a data collection system and a control system, wherein the modified large-volume closed pressure vessel is a steel cylindrical container, equipped with a thermocouple, a pressure sensor, an air inlet, an exhaust valve and at least one gas sampling port, and the sampling ports are distributed at different positions of the container, and a gas concentration sensor 1-2 is arranged at the position of the gas collection port cabin wall to convert the collected mixed gas concentration; the multi-channel gas collection system is connected to each gas sampling port on the modified large-volume closed pressure vessel through a pipeline, and each The pipelines are provided with output solenoid valves, flow regulating valves, gas flow meters and input solenoid valves, and are connected to the control system to control the volume of gas output in each route. The gas collection premixing cabin is a steel cylindrical container with a volume controlled within 10L. The internal explosion-proof fan is used to stir the input mixed gas, and the vacuum valve and vacuum pump are used to create a vacuum environment, and the pressure in the cabin is monitored by setting a vacuum pressure gauge. The total sampling output system is connected to the gas collection premixing cabin, and is equipped with a suction pump for outputting and collecting the homogenized thermal runaway mixed gas; and a gas concentration sensor 1-2 is set at the wall of the gas collection port to convert the collected mixed gas concentration.

[0023] The control system includes a host computer and a programmable controller, which are integrated in a control cabinet and are used to control a multi-channel gas collection system, an explosion-proof fan in a gas premixing cabin, a vacuum valve, a vacuum pump, a sampling total output system and a data acquisition system to calculate, adjust and verify the uniformity of the gas, and trigger the sampling total output system to collect samples.

[0024] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0025] 1. The present invention realizes uniform collection of battery thermal runaway mixed gas by adding a small-volume sampling gas premixing chamber that can be evacuated and stirred in the chamber, as well as multiple sampling pipelines that can automatically adjust the gas flow rate and flow rate.

[0026] 2. The present invention sets multiple nitrogen concentration sensors at the multi-channel gas sampling ports of the closed pressure vessel and sets a nitrogen concentration sensor in the premixing chamber, integrates the ideal gas state equation, gas homogenization calculation method and automatic adjustment algorithm in the control system, and utilizes the flow rate adjustment function of the sampling pipeline and the measured concentration data to realize automatic detection, adjustment and verification of the uniformity of the thermal runaway mixed gas sample. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 For the present invention;

[0029] Figure 2 It is a schematic diagram of the main body of the experimental device of the present invention;

[0030] Figure 3 Schematic diagram of the control system of the experimental device of the present invention.

[0031] Figure numerals: 1. Modification of large-volume closed pressure vessel; 1-1. Gas sampling port; 1-2. Nitrogen concentration sensor; 2. Multi-channel gas collection system; 3. Collection gas premixing chamber; 4. Sampling total output system; 5. Data acquisition system; 6. Control system; 2-1. Output solenoid valve; 2-2. Flow regulating valve; 2-3. Gas flow meter; 2-4. Input solenoid valve; 3-1. Explosion-proof fan; 3-2. Vacuum valve; 3-3. Vacuum pump; 3-4. Vacuum pressure gauge; Nitrogen concentration sensor 3-5; 4-1. Suction pump; 6-1. Host computer; 6-2. Controller; 6-3. Control cabinet. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] Example

[0035] like Figure 1-2 As shown, a method for collecting and verifying gas generated by thermal runaway of a battery in a closed pressure container in this embodiment includes the following steps:

[0036] Step 1: First, turn on the power of the experimental device, debug all components including thermocouples, pressure sensors, air inlets, and exhaust valves, and perform test actions to check the functional integrity and operational response of the device. Then, install the battery fixed with a specific fixture into the closed pressure vessel 1 to ensure that the battery is fixed in the correct position to avoid displacement during the experiment. Finally, close the hatch of the modified large-volume closed pressure vessel 1 to ensure that there is no leakage in all sealing links, and complete all preparations before the experiment;

[0037] Step 2: After the battery is installed and fixed in the modified large-volume sealed pressure vessel 1, the vacuum system is immediately started to perform the vacuum operation on the container 1 to ensure that the air in the modified large-volume sealed pressure vessel 1 is quickly and effectively removed to reach the preset vacuum level. The modified large-volume sealed pressure vessel 1 is evacuated to a vacuum environment and then filled with nitrogen. After the vacuum is completed, pure nitrogen is slowly and accurately filled until the pressure in the cabin reaches the specific pressure standard required by the experiment. During the nitrogen filling process, the nitrogen concentration sensor 1-2 continuously monitors the concentration change of the gas in the cabin, records the data in real time, and inputs the data into the control system 6. The control system 6 adjusts the inflation speed and amount according to the real-time data of the nitrogen concentration to ensure the standardization of the environment in the modified large-volume sealed pressure vessel 1 and its adaptation to the needs of subsequent experimental steps;

[0038] By controlling the vacuum degree and nitrogen filling process, a stable and predictable test environment is established to ensure the repeatability of the initial conditions of the experiment, which is crucial to the accuracy and safety of the battery thermal runaway experiment. The accurate reading and real-time feedback of the nitrogen concentration sensor 1-2 can ensure that the gas composition in the modified large-volume closed pressure vessel 1 reaches an ideal state, thereby providing a strictly controlled environment for the thermal runaway triggering of the battery.

[0039] Step 3. After ensuring that the environment in the modified large-volume sealed pressure vessel 1 is stable, the thermal runaway trigger of the battery is started, which is achieved by external heating or overcharging to simulate the thermal runaway phenomenon of the battery under extreme conditions. After the thermal runaway is triggered, the sensor system in the experimental device begins to intensively monitor the pressure and temperature changes in the modified large-volume sealed pressure vessel, and records the data in real time to capture any slight changes in pressure. The change in pressure is due to the rapid generation and release of the mixed gas in the thermal runaway reaction. During the monitoring process, pay attention to whether the pressure reaches the predetermined safety limit and the speed of pressure change. The pressure sensor continues to provide pressure readings throughout the process until the data shows that the pressure is stable. At this time, it means that the thermal runaway reaction has reached a relative equilibrium state and the main release stage of the mixed gas has been completed. At the same time, the total amount of the released mixed gas is calculated using the ideal gas state method through the recorded pressure and temperature data information before and after the test;

[0040] Step 4: After completing the battery thermal runaway experiment and preliminary gas release monitoring, enter the gas collection and pretreatment stage. First, thoroughly evacuate the gas collection premixing cabin 3 to prepare the cabin environment for subsequent gas mixing and homogenization. Start the vacuum pump 3-3 connected to the gas collection premixing cabin 3 to extract all existing gases from the cabin to create a complete vacuum state. During the vacuuming process, monitor the reading of the vacuum pressure gauge 3-4 in real time. The vacuum pressure gauge 3-4 is used to record and display the pressure state in the gas collection premixing cabin 3 to help the operator accurately grasp the vacuuming progress. The vacuuming operation continues until the vacuum pressure gauge 3-4 indicates that the pressure in the gas collection premixing cabin 3 reaches a preset vacuum level, which is usually close to or equal to a very small part of the external atmospheric pressure.

[0041] Step 5: Control gas delivery through the output solenoid valve 2-1 and the input solenoid valve 2-4 of the multi-channel gas collection system 2, and use the gas flowmeter 2-3 and the flow control valve 2-2 to adjust the flow of each gas path to ensure that the gas volume in the collected gas premixing chamber 3 is uniform. The output solenoid valve 2-1 and the flowmeter 2-3 that are automatically controlled by the equipment are used to accurately control the amount of gas collected from different parts of the modified large-volume closed pressure vessel 1. The control system 6 automatically adjusts the flow control valve 2-2 according to the flow data obtained from the gas flowmeter 2-3 to ensure that the amount of gas collected at each sampling port is uniform;

[0042] Step six, when the gas is transported into the gas premixing cabin 3 through the multi-channel gas collection system 2, and the pressure in the cabin is gradually restored to the standard atmospheric pressure through meticulous control, immediately ensure the uniform mixing of the gas. After the pressure in the gas premixing cabin 3 is restored to the standard atmospheric pressure, close the relevant valves of the multi-channel gas collection system 2, and record the input volume of each gas, start the explosion-proof fan 3-1, and start to vigorously stir the gas in the cabin. The operation of the explosion-proof fan 3-1 is to ensure that different gases can be fully mixed, and stir the gas in the cabin to achieve uniform mixing. After the stirring is completed, turn off the explosion-proof fan 3-1 and let it stand, read and record the data of the nitrogen concentration sensor 3-5, and the explosion-proof fan 3-1 automatically adjusts the speed and stirring time according to the instructions of the control system 6 and the feedback of the gas concentration sensor 3-5 to ensure thorough and uniform mixing of the gas and optimize the homogeneity of the gas;

[0043] Step 7, the control system 6 calculates the gas volume Vgas generated by thermal runaway through the ideal gas state equation, and calculates the nitrogen concentration in the homogenized gas, and verifies the uniformity of the mixed gas by comparing it with the data measured by the nitrogen concentration sensor 3-5 in the gas premixing chamber 3;

[0044] Step 8: If the gas does not reach a uniform condition, the control system 6 automatically adjusts the input volume ratio of different gas paths according to the gas volume of each gas path input into the gas premixing chamber 3 of the multi-path gas collection system and the nitrogen concentration in the gas premixing chamber 3, as well as the data of each concentration sensor in the modified large-volume closed pressure vessel 1, and repeats steps 4 and 7 until a uniform condition is reached;

[0045] In step 7 and step 8, the volume Vgas of the gas generated by thermal runaway is calculated using the ideal gas state equation and compared with the measured nitrogen concentration to verify the uniformity of the mixed gas. In addition, if it is detected that the gas mixture does not achieve the expected uniformity, the control system 6 will adjust the acquisition parameters;

[0046] According to the following formula algorithm, the concentration of mixed gas in the premixing chamber of the collected gas is automatically adjusted by changing the input volume ratio of different gas paths, and steps six and seven are further repeated;

[0047]

[0048] In the formula, They are the nitrogen concentrations measured by three nitrogen concentration sensors in the modified large-volume closed pressure vessel 1. To collect the nitrogen concentration measured by the nitrogen concentration sensor in the gas premixing chamber 3, V1, V2 and V3 are the gas volumes recorded by the gas flow meters 2-3 in the multi-channel gas collection system 2 respectively.

[0049] Step nine, after confirming that the mixed gas in the gas premixing chamber 3 has reached a uniform state, enter the final sample collection stage. If the mixed gas in the gas premixing chamber 3 has reached a uniform condition, turn on the suction pump 4-1 of the sampling total output system 4, collect the homogenized mixed gas sample into the gas sampling bag, and complete the collection and sampling. Otherwise, repeat step 8 and automatically adjust through the control system 6 until a uniform condition is reached.

[0050] A self-verifying battery thermal runaway gas homogenization collection device comprises a modified large-volume closed pressure vessel 1, a multi-channel gas collection system 2, a collection gas premixing cabin 3, a sampling total output system 4, a data collection system 5 and a control system 6, wherein the modified large-volume closed pressure vessel 1 is a steel cylindrical container, equipped with a thermocouple, a pressure sensor, an air inlet, an exhaust valve and at least three gas sampling ports 1-1, and the sampling ports are distributed at different positions of the container, and a gas concentration sensor 1-2 is arranged at the position of the gas collection port cabin wall to convert the collected mixed gas concentration;

[0051] The multiple gas sampling ports 1-1 are configured and distributed at different positions of the modified large-volume closed pressure vessel 1 to ensure that multi-point sampling data is obtained from the gas generated by the thermal runaway of the battery, and the spatial distribution differences of the gas composition can be fully captured, thereby providing a more accurate basis for data analysis. The data acquisition system 5 and the control system 6 integrated in the device allow real-time monitoring and automatic adjustment of experimental parameters, such as pressure and gas concentration, to ensure that the experimental conditions are always kept in the best state. The steel cylindrical modified large-volume closed pressure vessel 1 increases the safety of high-pressure and high-temperature environments. In addition, the exhaust valve and the air inlet are provided to quickly adjust the internal pressure in the event of thermal runaway to prevent the container from being dangerous due to excessive pressure. In addition, the explosion-proof fan 3-1 in the gas premixing chamber 3 improves the safety of operation and ensures that stirring and homogenization can be carried out safely even when the gas is flammable. The gas premixing chamber 3 stirs the gas in the chamber through the explosion-proof fan 3-1 to ensure that various gas components can be fully mixed, thereby improving the accuracy of subsequent analysis. The stirred gas is evenly collected through the suction pump 4-1 of the sampling total output system 4, thereby avoiding gas stratification or segregation in the sample.

[0052] The multi-channel gas collection system 2 is connected to each gas sampling port 1-1 on the modified large-volume closed pressure vessel 1 through a pipeline, and each pipeline is provided with an output solenoid valve 2-1, a flow regulating valve 2-2, a gas flow meter 2-3 and an input solenoid valve 2-4, and is connected to a control system 6 to control the gas volume of each output;

[0053] By controlling the initial release of gas from the modified large-volume closed pressure vessel 1 to the gas collection premixing chamber 3 through the output solenoid valve 2-1, the release time and opening degree of the gas can be precisely regulated to ensure the controllability and safety of the gas release;

[0054] The flow regulating valve 2-2 is responsible for regulating the flow rate of the gas when the gas flows through the pipeline, so that the flow rate of each gas can be accurately adjusted according to the experimental requirements to ensure the consistency of the input amount of each gas;

[0055] The gas flow meter 2-3 monitors the total amount of gas passing through each pipeline in real time, providing accurate data support for the control system 6;

[0056] The gas entering the gas collection premixing chamber 3 is controlled by input solenoid valves 2-4, allowing the timing and amount of gas intake to be finely adjusted to optimize the uniformity of the gas in the gas collection premixing chamber 3 and the overall sampling efficiency.

[0057] The gas collection premixing cabin 3 is a steel cylindrical container with a volume controlled within 10L. The explosion-proof fan 3-1 configured inside is used to stir the input mixed gas, and the vacuum valve 3-2 and the vacuum pump 3-3 are used to create a vacuum environment. The pressure in the cabin is monitored by setting a vacuum pressure gauge 3-4. The vacuum environment helps to effectively extract gas samples from the modified large-volume closed pressure vessel 1 to the gas collection premixing cabin 3. It is also to ensure that there is no other gas residue in the gas collection premixing cabin before the gas is input to avoid cross contamination. The vacuum pressure gauge 3-4 is set on the gas collection premixing cabin 3 for real-time monitoring and displaying the pressure state in the cabin. A gas concentration sensor 3-5 is set at the connection position between the rear end of the gas collection premixing cabin 3 and the total output system 4 to monitor the final output nitrogen concentration and verify the uniformity of the output gas;

[0058] The gas collection premixing chamber 3 is made of steel material to form a cylindrical container, which increases the internal pressure resistance and is easy to maintain and clean. The volume is controlled within 10 liters, and can effectively mix the gas evenly without causing excessive gas waste;

[0059] The internally configured explosion-proof fan 3-1 is used to stir the input mixed gas. The explosion-proof design of the explosion-proof fan 3-1 ensures safe operation even when handling gases that may be flammable and explosive. Through high-speed rotation, the airflow generated by the fan quickly and evenly mixes the different gas components in the cabin, eliminating gas stratification and ensuring that the collected samples represent the overall gas state.

[0060] The sampling total output system 4 is connected to the sampling gas premixing chamber 3 and is equipped with an air suction pump 4-1 for outputting and collecting the homogenized thermal runaway mixed gas.

[0061] By adding a small-volume sampling gas premixing chamber that can be evacuated and stirred in the chamber, and multiple sampling pipelines that can automatically adjust the gas flow and flow rate, the uniform collection of the battery thermal runaway mixed gas can be achieved. By setting multiple nitrogen concentration sensors at the multi-channel gas sampling ports of the closed pressure vessel and setting a nitrogen concentration sensor in the premixing chamber, the ideal gas state equation, gas homogenization calculation method and automatic adjustment algorithm are integrated in the control system, and the flow rate adjustment function of the sampling pipeline and the measured concentration data are used to achieve automatic detection, adjustment and verification of the uniformity of the thermal runaway mixed gas samples.

[0062] The control system 6 includes a host computer 6-1 and a programmable controller 6-2, which are integrated in a control cabinet 6-3 and are used to control a multi-channel gas collection system 2, an explosion-proof fan 3-1 in a gas premixing chamber, a vacuum valve 3-2, a vacuum pump 3-3, a sampling total output system 4 and a data acquisition system 5, to calculate, adjust and verify the uniformity of the gas, and trigger the sampling total output system 4 to collect samples.

[0063] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0064] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for collecting and verifying gas generated by thermal runaway of a battery in a closed pressure vessel, characterized in that: The following steps are involved: Step 1: Turn on the power of the experimental device, debug each component and test the operation, put the battery with the clamp into the sealed pressure container 1, and close the container door; Step 2: Evacuate the modified large-volume sealed pressure vessel 1 to a vacuum environment and then fill it with nitrogen. Monitor and record the nitrogen concentration through the nitrogen concentration sensor 1-2, and input the data into the control system 6; Step 3, triggering battery thermal runaway and monitoring the pressure change in the modified large-volume sealed pressure vessel 1 until it stabilizes, and recording the amount of mixed gas released; Step 4: Vacuum the gas collection premixing chamber 3 and ensure that a vacuum environment is reached through the vacuum pressure gauge 3-4; Step 5: Control gas delivery through the output solenoid valve 2-1 and the input solenoid valve 2-4 of the multi-channel gas collection system 2, and use the gas flow meter 2-3 and the flow regulating valve 2-2 to adjust the flow of each gas path to ensure that the gas volume in the collected gas premixing chamber 3 is uniform; Step 6: After the pressure in the gas premixing chamber 3 returns to the standard atmospheric pressure, close the relevant valves of the multi-channel gas collection system 2, and record the gas input volume of each channel, start the explosion-proof fan 3-1, stir the gas in the chamber to achieve uniform mixing, turn off the explosion-proof fan 3-1 after stirring, let it stand, and read and record the data of the nitrogen concentration sensor 3-5; Step 7, the control system 6 calculates the gas volume Vgas generated by thermal runaway through the ideal gas state equation, and calculates the nitrogen concentration in the homogenized gas, and verifies the uniformity of the mixed gas by comparing it with the data measured by the nitrogen concentration sensor 3-5 in the gas premixing chamber 3; Step 8: If the gas does not reach a uniform condition, the control system 6 automatically adjusts the input volume ratio of different gas paths according to the gas volume of each gas path input into the gas premixing chamber 3 of the multi-path gas collection system and the nitrogen concentration in the gas premixing chamber 3, as well as the data of each concentration sensor in the modified large-volume closed pressure vessel 1, and repeats steps 4 and 7 until a uniform condition is reached; Step nine, if the mixed gas in the gas premixing chamber 3 reaches a uniform condition, turn on the suction pump 4-1 of the sampling total output system 4, collect the homogenized mixed gas sample into the gas sampling bag, and complete the collection and sampling, otherwise repeat step 8, and automatically adjust through the control system 6 until a uniform condition is reached.

2. The method for collecting and verifying gas generated by thermal runaway of a battery in a closed pressure container according to claim 1, characterized in that: In the step 2, after the battery is placed in the modified sealed pressure vessel 1, a vacuum operation is immediately performed to reach a preset vacuum level, and then pure nitrogen is filled to a specific pressure. The nitrogen concentration is monitored and recorded in real time by the nitrogen concentration sensor 1-2 to ensure the standardization of the initial test environment.

3. The method for collecting and verifying gas generated by thermal runaway of a battery in a closed pressure container according to claim 1, characterized in that: In step five, the system is equipped with an automatically controlled output solenoid valve 2-1 and a flow meter 2-3 to accurately control the amount of gas collected from different parts of the modified large-volume closed pressure vessel 1. The control system 6 automatically adjusts the flow regulating valve 2-2 according to the flow data obtained from the gas flow meter 2-3 to ensure that the amount of gas collected at each sampling port is uniform.

4. The method for collecting and verifying gas generated by thermal runaway of a battery in a closed pressure container according to claim 1, characterized in that: In step six, the explosion-proof fan 3-1 automatically adjusts the rotation speed and stirring time according to the instructions of the control system 6 and the feedback of the gas concentration sensor 3-5.

5. The method for collecting and verifying gas generated by thermal runaway of a battery in a closed pressure container according to claim 1, characterized in that: In step 7 and step 8, the volume Vgas of the gas generated by thermal runaway is calculated using the ideal gas state equation and compared with the measured nitrogen concentration to verify the uniformity of the mixed gas. In addition, if it is detected that the gas mixture does not achieve the expected uniformity, the control system 6 will adjust the acquisition parameters; - Is it possible to highlight that the flow meter, solenoid valve and gas concentration sensor are used to achieve this? According to the following formula algorithm, the concentration of mixed gas in the premixing chamber of the collected gas is automatically adjusted by changing the input volume ratio of different gas paths, and steps six and seven are further repeated; In the formula, They are the nitrogen concentrations measured by three nitrogen concentration sensors in the modified large-volume closed pressure vessel 1. To collect the nitrogen concentration measured by the nitrogen concentration sensor in the gas premixing chamber 3, V1, V2 and V3 are the gas volumes recorded by the gas flow meters 2-3 in the multi-channel gas collection system 2 respectively.

6. A self-verifying battery thermal runaway gas homogenization collection device according to the method for collecting and verifying the gas generated by battery thermal runaway in a closed pressure container as described in claims 1-5, characterized in that: The system comprises a modified large-volume closed pressure vessel 1, a multi-channel gas collection system 2, a collection gas premixing cabin 3, a sampling total output system 4, a data collection system 5 and a control system 6, wherein the modified large-volume closed pressure vessel 1 is a steel cylindrical container, equipped with a thermocouple, a pressure sensor, an air inlet, an exhaust valve and at least three gas sampling ports 1-1, and the sampling ports are distributed at different positions of the container, and a gas concentration sensor 1-2 is arranged at the position of the gas collection port cabin wall to convert the collected mixed gas concentration.

7. The self-verifying battery thermal runaway gas homogenization collection device according to claim 6, characterized in that: The multi-channel gas collection system 2 is connected to each gas sampling port 1-1 on the modified large-volume closed pressure vessel 1 through a pipeline. Each pipeline is provided with an output solenoid valve 2-1, a flow regulating valve 2-2, a gas flow meter 2-3 and an input solenoid valve 2-4, and is connected to a control system 6 to control the gas volume of each output.

8. The self-verifying battery thermal runaway gas homogenization collection device according to claim 1, characterized in that: The gas collection premixing cabin 3 is a steel cylindrical container with a volume controlled within 10L. The explosion-proof fan 3-1 configured inside is used to stir the input mixed gas, and the vacuum valve 3-2 and the vacuum pump 3-3 are used to create a vacuum environment. The pressure in the cabin is monitored by setting a vacuum pressure gauge 3-4. A gas concentration sensor 3-5 is set at the connection position between the rear end of the gas collection premixing cabin 3 and the total output system 4 to monitor the final output nitrogen concentration and verify the uniformity of the output gas.

9. The self-verifying battery thermal runaway gas homogenization collection device according to claim 1, characterized in that: The sampling total output system 4 is connected to the sampling gas premixing chamber 3 and is equipped with an air suction pump 4-1 for outputting and collecting the homogenized thermal runaway mixed gas.

10. The self-verifying battery thermal runaway gas homogenization collection device according to claim 1, characterized in that: The control system 6 includes a host computer 6-1 and a programmable controller 6-2, which are integrated in a control cabinet 6-3, and are used to control a multi-channel gas collection system 2, an explosion-proof fan 3-1 in a gas premixing chamber, a vacuum valve 3-2, a vacuum pump 3-3, a sampling total output system 4 and a data acquisition system 5, to calculate, adjust and verify the uniformity of the gas, and trigger the sampling total output system 4 to collect samples.

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