A multi-dimensional signal coupling test device for thermal runaway of a lithium ion battery and a test method thereof

Abstract

The application discloses a lithium ion battery thermal runaway multi-dimensional signal coupling test device in the technical field of lithium ion battery thermal safety, which comprises a sealed test container, a signal acquisition system, an optical visualization system, a temperature control system, a gas acquisition system and a gas charging system. The sealed test container is a cuboid, four through holes are formed in the front and back and left and right outer walls of the cuboid, and optical glass is arranged on two through holes among the four through holes. The signal acquisition system comprises an impact force sensor, a pressure sensor, a thermocouple, a battery test system, a data acquisition card and an analysis device. The optical visualization system comprises a camera, a point light source, a reflecting mirror, a concave mirror and a blade. The temperature control system comprises a heating rod, a heating sheet, a power supply and a controller. The gas acquisition system comprises an exhaust passage, a gas sampling bag and a gas chromatograph. The gas charging system comprises a gas charging pipeline, a pressure regulating valve and an inert gas tank. The application can directly reflect the jet state of the battery or the battery module during the thermal runaway process.

Description

Technical Field

[0001] This invention relates to a testing device in the field of lithium-ion battery thermal safety technology, and in particular to a multi-dimensional signal coupling testing device and method for lithium-ion battery thermal runaway under multiple abuse modes. Background Technology

[0002] Lithium-ion batteries are widely used in new energy vehicles and energy storage, but fires and explosions caused by thermal runaway occur frequently during their widespread use. The main causes include a variety of complex factors such as thermal abuse, electrical abuse, and mechanical abuse. Thermal runaway is a complex multi-field coupling process involving dynamic changes in signals such as temperature, pressure, current, voltage, and impact force. These signals change sequentially during the development of thermal runaway. Current detection methods primarily rely on temperature signals, which cannot provide a comprehensive characterization to accurately reflect the entire thermal runaway process. To achieve early warning of lithium battery thermal runaway, it is necessary to analyze the spatiotemporal coupling relationships of multi-dimensional signals and clarify the coupling mechanisms between different characteristic signals. Therefore, how to innovatively design multi-dimensional signal coupling measurement for lithium-ion battery thermal runaway under multiple abuse modes is a pressing technical challenge in this field. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention proposes a multi-dimensional signal coupling test device and method for lithium-ion battery thermal runaway, which can conveniently measure multi-dimensional signals of lithium-ion battery thermal runaway under multiple abuse modes.

[0004] This invention is achieved through the following technical solution: This invention includes a multi-dimensional signal coupling testing device for thermal runaway of lithium-ion batteries. The testing device includes a sealed testing container, a multi-dimensional signal acquisition system, an optical visualization system, a temperature control system, a gas acquisition system, and a gas filling system. The sealed testing container is a hollow cube with mounting grooves and mounting through holes on its outer wall. Four orthogonal through holes are opened on its front, back, left, and right outer walls, with optical glass installed in the left and right through holes. Inside the container are a testing platform and a battery fixing device. The battery fixing device is installed on the testing platform, and the battery or battery module is installed onto the battery. The mounting device consists of a heat insulation plate, a flange, and a chassis arranged sequentially at the bottom of the test platform. The chassis is embedded in the bottom wall of the sealed test container, and an aviation connector is mounted on the chassis. The multi-dimensional signal acquisition system includes an impact sensor, a pressure sensor, thermocouples, a battery testing system, a data acquisition card, and an analysis device. The impact sensor is located at the bottom of the flange, the pressure sensor at the top of the sealed test container, and the thermocouples on the battery or battery module. The battery testing system is connected to the battery or battery module via an aviation connector using wires. The impact sensor, thermocouples, and battery testing system are all connected via aviation connectors using wires. The plug connects to the data acquisition card, which in turn connects to the analysis device via wires. The optical visualization system includes a high-speed camera, a point light source, a first reflector, a second reflector, a first concave mirror, a second concave mirror, and a blade. The point light source, the first reflector, and the first concave mirror are all positioned on the left side of the sealed test container, while the high-speed camera, the second concave mirror, the second reflector, and the blade are all positioned on the right side of the sealed test container. The beam generated by the point light source passes sequentially through the first reflector and the first concave mirror, becoming a parallel beam. The beam then passes through the optical glass of the sealed test container and illuminates the test platform. The beam then passes sequentially through the second concave mirror and the second... The reflector and blade are captured by a high-speed camera. The temperature control system includes heating rods, heating elements, a power supply, and a controller. The heating rods are evenly inserted on the surface of the sealed container, and the heating elements are arranged at the bottom of the test platform and above the heat insulation plate. The heating rods and heating elements are connected to the power supply via wires. The gas collection system includes an exhaust channel, a gas collection bag, and a gas chromatograph. The exhaust channel is located at the top of the sealed test container. The gas filling system includes a gas filling pipeline, a pressure regulating valve, and an inert gas tank. One end of the gas filling pipeline is connected to the inert gas tank, and the other end of the gas filling pipeline is connected to the sealed test container. The pressure regulating valve is located on the gas filling pipeline.

[0005] Furthermore, in this invention, the inflation system also includes a gas flow controller, which is connected in series on the inflation pipeline.

[0006] Furthermore, in this invention, the two through holes on the left and right walls of the sealed test container are circular, and the heating element, heat insulation plate, flange, and base are also circular.

[0007] Furthermore, in this invention, the inert gas container is filled with nitrogen.

[0008] This invention also includes a test method for a multidimensional signal coupling test device for thermal runaway of lithium-ion batteries, specifically comprising the following steps:

[0009] Step 1: Install and calibrate the equipment. Connect the current leads to the electrodes of the lithium-ion battery, then fix the battery on the test bench, ensuring a stable connection with the sealed test container. Attach two thermocouples to the surface of the battery. Then calibrate the multi-dimensional signal acquisition system to ensure that each sensor is operating normally. Seal the sealed container, align the light source and high-speed camera with the optical observation windows on the left and right sides of the test container, adjust the position and focal length of the high-speed camera, and adjust the relative positions of the reflector and blade to capture a clear macroscopic morphology image during spraying. Start the high-speed camera.

[0010] Step 2: Calibrate the temperature control system to ensure stable control of temperature changes in the test environment during the experiment. Once all systems in the test device are running normally, begin coupling and measuring the multidimensional signals generated after thermal runaway of the lithium-ion battery.

[0011] Step 3: To couple and measure the multidimensional signals generated by the thermal runaway reaction of lithium-ion batteries or battery modules under thermal abuse mode, the temperature management system needs to be activated after sealing the container, the power supply turned on, and the temperature inside the sealed container gradually and uniformly increased using heating rods to initiate the thermal runaway process; or the heating element can be activated to heat the individual battery cells or battery modules to initiate the thermal runaway process; then the temperature, pressure, current, voltage, and impact force signals output during the entire thermal runaway process are recorded, and the intensity of the explosion is calculated; after the thermal runaway process ends, the generated gas is collected through the exhaust channel, and the gas composition is determined using a gas chromatograph, while the mass loss of gas and solids is recorded, and the flammability limit of the thermally released gas is calculated; the jet state captured by schlieren during the thermal runaway process is analyzed and processed;

[0012] If you want to couple and measure the multidimensional signals generated by the thermal runaway reaction of lithium-ion batteries under the electric abuse mode, you need to start the battery test system, connect the current leads to the positive and negative terminals of the battery, put the battery or battery module into a sealed container, seal the container, control the battery to overcharge or short circuit to induce thermal runaway, and then collect, analyze and process the multidimensional signals, gas composition and jet state according to the above procedure.

[0013] If you want to perform coupled measurement on the multidimensional signals generated by the thermal runaway reaction of lithium-ion batteries under thermoelectric coupled abuse mode, you need to seal the container, turn on the power, start the heating program, and at the same time start the battery test system to control the battery to overcharge or short circuit, so that it can start the thermal runaway process under the coupled effect of thermal abuse and electrical abuse. Then, follow the above procedure to collect, analyze and process the multidimensional signals and gas composition.

[0014] Furthermore, in step three above, the intensity of the explosion is calculated using the pressure rise rate, as shown in the following formula:

[0015] K st =(dP / dt) max ·V 1 / 3

[0016] Among them, K st dP / dt is the explosion index; P is the gas pressure inside the constant-volume bomb, in Pa; dP / dt is the pressure rise rate, in Pa / s; V is the volume of the constant-volume bomb, in L.

[0017] The flammability limit of the heat-released gas is calculated using the LC formula, which is as follows:

[0018]

[0019] Among them, (LFL) mix This is the flammability limit value (LFL) of the mixture. i X is the flammability limit value of component i; i Let i be the volume fraction of component i.

[0020] Compared with existing technologies, the beneficial effects of this invention are as follows: The optical visualization system included in this invention utilizes schlieren to intuitively reflect the jetting state generated by the battery or battery module during thermal runaway, including jetting speed, direction, and airflow changes. This provides rich data support for analyzing the interaction and coupling mechanism between gas jetting generated during battery thermal runaway and other signals such as temperature and pressure. Unlike traditional single-signal monitoring technologies, this invention, through the combination of a multi-dimensional signal acquisition system and an optical visualization system, can comprehensively capture multiple signals such as temperature, current, voltage, pressure, impact force, gas jetting speed, jetting cone angle, and gas composition, reflecting the entire process of thermal runaway in real time, thereby providing more accurate data support for battery safety performance evaluation. This invention can measure multi-dimensional signals generated by battery thermal runaway under various abuse modes, comprehensively and accurately capturing the dynamic changes of the battery under different operating conditions, providing a more scientific and comprehensive safety assessment. By acquiring these signals in real time, the repeatability and authenticity of experiments can be improved, while providing data-driven decision support for battery management systems. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall system structure according to an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of the implementation method in an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the installation structure of the aviation plug and the impact sensor in an embodiment of the present invention;

[0024] Figure 4 This is a schematic diagram of the structure of the bottom components of the test platform in an embodiment of the present invention;

[0025] In the diagram, 1. Test platform, 2. Optical glass, 3. Exhaust channel, 4. Battery fixing device, 5. Aviation plug, 6. Pressure sensor, 7. Thermocouple, 8. Force sensor, 9. High-speed camera, 10. Point light source, 11. Second reflector, 12. Blade and adjustment bracket, 13. Pressure reducing valve, 14. Heating rod, 15. Power supply, 16. Battery testing system, 17. Analysis device, 18. Heating element, 19. Gas chromatograph, 20. Insulation plate, 21. Data acquisition card, 22. Chassis, 23. Flange, 24. Battery or battery module, 25. Second concave mirror, 26. Sealed test container, 27. First reflector, 28. Second concave mirror, 29. Gas filling pipeline, 30. Inert gas tank. Detailed Implementation

[0026] To facilitate understanding of the present invention, the technical solutions described below are further illustrated with specific embodiments. These examples are for illustrative purposes only and are not limited to this scope.

[0027] Example

[0028] like Figures 1 to 4 As shown, the present invention includes a sealed test container 26, a multi-dimensional signal acquisition system, an optical visualization system, a temperature control system, a gas acquisition system, and a gas filling system. The multi-dimensional signal acquisition system includes a pressure sensor 6, an impact sensor 8, a thermocouple 7, a battery testing system 16, a data acquisition card 21, and an analysis device 17. The optical visualization system includes a high-speed camera 9, a point light source 10, a first reflector 27, a second reflector 11, a first concave mirror 28, a second concave mirror 25, and a blade 12. The temperature control system includes a heating rod 14, a heating element 18, a power supply 15, and a controller. The gas acquisition system includes an exhaust channel 3, a gas sampling bag, and a gas chromatograph 19. The gas filling system includes a gas filling pipeline 29, a pressure regulating valve 13, and an inert gas tank 30.

[0029] The sealed test container 26 is a hollow cube with mounting grooves and through holes on its outer wall. Four orthogonal through holes are formed on its front, back, left, and right outer walls, with optical glass 2 installed in the left and right through holes. Inside, a test platform 1 and a battery fixing device 4 are arranged. The battery fixing device 4 is mounted on the test platform 1, and the battery or battery module 24 is mounted on the battery fixing device 4. At the bottom of the test platform 1, a heating element 18, a heat insulation plate 20, a flange 23, and a base 22 are arranged in sequence. The base 22 is embedded in the bottom wall of the sealed test container 1, and an aviation connector 5 is arranged on the base 22. A point light source 10, a first reflector 27, and a first concave mirror 28 are all arranged on the left side of the sealed test container 1, while a high-speed camera 9, a second concave mirror 25, a second reflector 11, and a blade 12 are all arranged on the right side of the sealed test container 1. Impact sensor 8 is located at the bottom of flange 23, thermocouple 7 is located on battery or battery module 24, battery testing system 16 is connected to battery or battery module 24 via aviation connector 5, and pressure sensor 6 is located at the top of sealed test container 26. Impact sensor 8, thermocouple 7, and battery testing system 16 are all connected to data acquisition card 21 via aviation connector 5, and data acquisition card 21 is connected to analysis device 17 via guide. The beam of light generated by point light source 15 passes through first reflector 27 and first concave mirror 28 in sequence and becomes a parallel beam. The beam of light shines on test platform 1 through optical glass 2 of sealed test container 26, and then passes through second concave mirror 25, second reflector 11, and blade 12 in sequence before being captured by high-speed camera 9. Heating rods 14 are evenly inserted on the surface of sealed container 26, and heating rods 14 and heating plates 18 are connected to power supply via wires. The exhaust channel 3 is located at the top of the sealed test container 26. One end of the inflation pipe 29 is connected to the inert gas tank 30, and the other end of the inflation pipe 29 is connected to the sealed test container 26. The pressure regulating valve 13 is located on the inflation pipe 29. The inert gas tank 30 is filled with nitrogen.

[0030] In the implementation of this invention, two through holes are opened on the left and right outer walls of the sealed test container 26. Optical glass 2 is installed on the through holes as an observation window for detecting the jet state by schlieren method. The sealed test container 26 contains a test platform 1. An aviation plug 5 is installed below the test platform 1. The signal acquisition devices such as the thermocouple 7 and the wires of the external battery test system 16 are connected to the external data acquisition system by the aviation plug 5. The impact sensor 8 is also connected to the aviation plug 5 through a flange to maintain the connection seal.

[0031] One end of thermocouple 7 is mounted on test platform 1 via an aviation connector, and the other end is connected to the battery or battery module 24 to measure the surface temperature of the battery or battery module 24 during thermal runaway. Battery testing system 16 is connected to battery or battery module 24 via aviation connector 5 using wires. Impact force sensor 8 is mounted below test platform 1 to measure the impact force generated by the battery during thermal runaway. The collected force signal, temperature signal, current and voltage signal, and pressure signal are transmitted to data acquisition card 21 for analysis and processing.

[0032] A point light source 15 is placed at one end of the system. The generated light beam is transformed into a parallel beam by the first reflecting mirror 27 and the first concave mirror 28, illuminating the test platform 1. The collimation and angle of the beam are ensured by adjusting the relative position of the first reflecting mirror 27. After the light shines into the test area, fluid is generated due to the thermal runaway reaction within the platform. The light is refracted or deflected at different refractive indices, forming schlieren. The formed schlieren is then refracted by the second concave mirror 25. The optical contrast is improved by adjusting the relative position of the blades 12, enhancing the visualization of the flow characteristics. The obtained image is uploaded to the analysis device 17 for analysis and processing of the jet state.

[0033] One end of the heating rod 14 is evenly inserted into the surface of the sealed container 26 to ensure uniform temperature inside the sealed test container 26 during heating. The other end of the heating rod 14 is connected to the power supply 15, and the temperature inside the sealed test container 26 is controlled by adjusting the heating power. The heating element 18 is placed below the test platform 1 and is controlled by the power supply 15 and the controller. It is used to heat the battery cells or battery modules 24 to achieve thermal runaway of the battery under thermal abuse. The battery testing system 16 is an integrated system that is connected to the positive and negative terminals of the battery through current leads. It can monitor the changes in current and voltage of the battery in real time and perform responsible testing on the battery.

[0034] The implementation method of the present invention includes the following steps:

[0035] First, install and calibrate the equipment. Connect the current leads to the electrodes of the lithium-ion battery, then fix the battery on the test platform 1 to ensure a stable connection with the constant-capacity incendiary bomb. Attach two thermocouples 7 to the battery surface. Then calibrate the multi-dimensional signal acquisition system to ensure the normal operation of each sensor. Next, seal the sealed test container 26. Align the point light source 10 and the high-speed camera 9 with the optical observation windows on the left and right sides of the sealed test container 26, respectively. Adjust the position and focal length of the high-speed camera 9, and adjust the relative positions of the second reflector 11 and the blade 12 to capture a clear macroscopic morphological image during spraying. Start the high-speed camera 9.

[0036] Then, the temperature control system was calibrated to ensure that the temperature changes of the test environment could be stably controlled during the experiment. After all the systems in the test device were running normally, the multidimensional signals generated after the thermal runaway of the lithium-ion battery were coupled and measured.

[0037] Finally, to perform coupled measurement of the multidimensional signals generated by the thermal runaway reaction of the lithium-ion battery or battery module 24 under thermal abuse mode, the temperature management system needs to be activated after sealing the test container 26, the power supply 15 needs to be turned on, and the temperature inside the sealed container needs to be gradually and uniformly increased using the heating rod 14 to initiate the thermal runaway process. Alternatively, the heating element 18 can be activated to heat the individual battery cells or battery module 24 to initiate the thermal runaway process. Then, the output temperature during the entire thermal runaway process should be recorded.

[0038] Pressure, current, voltage, and impact force signals. The intensity of the explosion is calculated using the pressure rise rate, as shown in the following formula:

[0039] K st =(dP / dt) max ·V 1 / 3

[0040] Among them, K st dP / dt is the explosion index; P is the gas pressure inside the constant-volume bomb, in Pa; dP / dt is the pressure rise rate, in Pa / s; V is the volume of the constant-volume bomb, in L.

[0041] After the thermal runaway process ends, the generated gas is collected through exhaust pipe 13, and its composition is determined using gas chromatograph 19. Simultaneously, the mass loss of both gas and solids is recorded. The flammability limit of the thermally released gas can be calculated using the LC formula, as follows:

[0042]

[0043] Among them, (LFL) mix This is the flammability limit value (LFL) of the mixture. i X is the flammability limit value of component i; i Let i be the volume fraction of component i.

[0044] The jetting state during the thermal runaway process, captured by schlieren imaging, was analyzed and processed.

[0045] If you want to perform coupled measurement of the multidimensional signals generated by the thermal runaway reaction of lithium-ion batteries under the electric abuse mode, you need to start the battery test system 16, connect the current leads to the positive and negative terminals of the battery, put the battery or battery module 24 into the sealed test container 26, seal the container, control the battery to overcharge or short circuit to induce thermal runaway, and then collect, analyze and process the multidimensional signals, gas composition and jet state according to the above procedure.

[0046] To perform coupled measurements of multidimensional signals generated by the thermal runaway reaction of a lithium-ion battery under thermoelectric coupled abuse mode, the power supply should be turned on and the heating program started after sealing the test container 26. Simultaneously, the battery testing system should be activated to control overcharging or short-circuiting of the battery. This initiates the thermal runaway process under the coupled effects of thermal and electrical abuse. Then, the multidimensional signals and gas composition should be collected, analyzed, and processed according to the above procedure.

[0047] The above description is only a preferred embodiment of the present invention. Any equivalent changes and modifications made by those skilled in the art within the scope of the patent application of the present invention shall also fall within the scope covered by the appended claims.

Claims

1. A multi-dimensional signal coupling test device for thermal runaway of lithium-ion batteries, comprising a sealed test container, characterized in that... It also includes a multi-dimensional signal acquisition system, an optical visualization system, a temperature control system, a gas acquisition system, and an inflation system; The sealed test container is a hollow cube with mounting grooves and mounting through holes on its outer wall. Four orthogonal through holes are opened on its front, back, left, and right outer walls, with optical glass installed in the left and right through holes. Inside, a test platform and a battery fixing device are arranged. The battery fixing device is installed on the test platform, and the battery or battery module is installed on the battery fixing device. At the bottom of the test platform, a heat insulation plate, a flange, and a base are arranged in sequence. The base is embedded in the bottom wall of the sealed test container, and an aviation plug is arranged on the base. The multi-dimensional signal acquisition system includes an impact sensor, a pressure sensor, a thermocouple, a battery testing system, a data acquisition card, and an analysis device. The impact sensor is located at the bottom of the flange, the pressure sensor is located at the top of the sealed test container, the thermocouple is located on the battery or battery module, and the battery testing system is connected to the battery or battery module via an aviation connector using wires. The impact sensor, thermocouple, and battery testing system are all connected to the data acquisition card via aviation connectors using wires, and the data acquisition card is connected to the analysis device via wires. The optical visualization system includes a high-speed camera, a point light source, a first reflector, a second reflector, a first concave mirror, a second concave mirror, and a blade. The point light source, the first reflector, and the first concave mirror are all arranged on the left side of the sealed test container, while the high-speed camera, the second concave mirror, the second reflector, and the blade are all arranged on the right side of the sealed test container. The light beam generated by the point light source passes through the first reflector and the first concave mirror in sequence, becoming a parallel light beam. The light beam then passes through the optical glass of the sealed test container and illuminates the test platform. After passing through the second concave mirror, the second reflector, and the blade in sequence, the light beam is captured by the high-speed camera. The temperature control system includes heating rods, heating elements, a power supply, and a controller. The heating rods are evenly inserted on the surface of the sealed container, and the heating elements are arranged at the bottom of the test platform and above the heat insulation plate. The heating rods and heating elements are connected to the power supply through wires. The gas collection system includes an exhaust channel, a gas collection bag, and a gas chromatograph. The exhaust channel is located at the top of the sealed test container. The inflation system includes an inflation pipeline, a pressure regulating valve, and an inert gas tank. One end of the inflation pipeline is connected to the inert gas tank, and the other end of the inflation pipeline is connected to a sealed test container. The pressure regulating valve is located on the inflation pipeline.

2. The lithium-ion battery thermal runaway multidimensional signal coupling test device according to claim 1, characterized in that... The inflation system also includes a gas flow controller, which is connected in series on the inflation pipeline.

3. The lithium-ion battery thermal runaway multidimensional signal coupling test device according to claim 2 is characterized in that... The two through holes on the left and right walls of the sealed test container are circular, as are the heating element, heat insulation plate, flange, and base.

4. The lithium-ion battery thermal runaway multidimensional signal coupling test device according to claim 1, characterized in that... The inert gas container is filled with nitrogen.

5. The test method of the lithium-ion battery thermal runaway multidimensional signal coupling test device according to claim 1, comprising the following steps: Step 1: Install and calibrate the equipment. Connect the current leads to the electrodes of the lithium-ion battery, then fix the battery on the test bench, ensuring a stable connection with the sealed test container. Attach two thermocouples to the surface of the battery. Then calibrate the multi-dimensional signal acquisition system to ensure that each sensor is operating normally. Seal the sealed container, align the light source and high-speed camera with the optical observation windows on the left and right sides of the test container, adjust the position and focal length of the high-speed camera, and adjust the relative positions of the reflector and blade to capture a clear macroscopic morphology image during spraying. Start the high-speed camera. Step 2: Calibrate the temperature control system to ensure stable control of temperature changes in the test environment during the experiment. Once all systems in the test device are running normally, begin coupling and measuring the multidimensional signals generated after thermal runaway of the lithium-ion battery. Step 3: If you want to perform coupled measurement of the multidimensional signals generated by the thermal runaway reaction of lithium-ion batteries or battery modules under thermal abuse mode, you need to start the temperature management system after sealing the container, turn on the power, and use the heating rod to gradually and evenly increase the temperature inside the sealed container to initiate the thermal runaway process; or start the heating element to heat the battery cell or battery module to initiate the thermal runaway process; then record the temperature, pressure, current, voltage and impact force signals output during the entire thermal runaway process, and calculate the severity of the explosion; after the thermal runaway process ends, collect the generated gas through the exhaust channel, use a gas chromatograph to determine the gas composition, record the gas and solid mass loss, and calculate the flammability limit of the thermally released gas; The jetting state during the thermal runaway process was analyzed and processed using schlieren imaging. If you want to couple and measure the multidimensional signals generated by the thermal runaway reaction of lithium-ion batteries under the electric abuse mode, you need to start the battery test system, connect the current leads to the positive and negative terminals of the battery, put the battery or battery module into a sealed container, seal the container, control the battery to overcharge or short circuit to induce thermal runaway, and then collect, analyze and process the multidimensional signals, gas composition and jet state according to the above procedure. If you want to perform coupled measurement on the multidimensional signals generated by the thermal runaway reaction of lithium-ion batteries under thermoelectric coupled abuse mode, you need to seal the container, turn on the power, start the heating program, and at the same time start the battery test system to control the battery to overcharge or short circuit, so that it can start the thermal runaway process under the coupled effect of thermal abuse and electrical abuse. Then, follow the above procedure to collect, analyze and process the multidimensional signals and gas composition.

6. The test method of the lithium-ion battery thermal runaway multidimensional signal coupling test device according to claim 5, characterized in that in step three, the calculation of the severity of the explosion is performed using the pressure rise rate, as shown in the following formula: K st =(dP / dt) max ·V 1 / 3 in, K st dP / dt is the explosion index; P is the gas pressure inside the constant-volume bomb, in Pa; dP / dt is the pressure rise rate, in Pa / s; V is the volume of the constant-volume bomb, in L. The calculation of the flammability limit of the heat-released gas is performed using the LC formula, which is as follows: Among them, (LFL) mix This is the flammability limit (LFL) of the mixture. i X is the flammability limit value of component i; i Let i be the volume fraction of component i.

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