An apparatus and method for determining surface heat flux distribution of a battery module under fire

Abstract

The application discloses a device and method for measuring surface heat flow distribution of a battery module under fire, wherein the device comprises a test platform, a mixed battery module, a data acquisition module and a central control system; the mixed battery module is composed of a real battery and simulation batteries symmetrically arranged on two sides of the real battery; the simulation battery is a hollow shell with the same shape and surface characteristics, and a heat flow meter and a thermocouple are arrayed and embedded on the surface of the simulation battery; the data acquisition module synchronously acquires heat flow density and temperature data, and the central control system remotely controls an experimental process. The method reconstructs the heat flow density space-time distribution field of the surface of the simulation battery by pretreating the real battery, assembling the module, triggering thermal runaway and ignition, and synchronously collecting data. The application can directly and quantitatively measure the heat flow density space-time distribution of the module, significantly reduces the test cost, improves the experimental safety, and provides a standardized platform for the research and numerical simulation verification of the thermal spread of the battery module.

Description

Technical Field

[0001] This invention belongs to the field of battery safety technology, and in particular relates to an apparatus and method for measuring the heat flow distribution on the surface of a battery module during a fire. Background Technology

[0002] In large-scale energy storage power stations, batteries are typically integrated and arranged in high-density modules. The spacing between individual cells within the module is extremely small, resulting in significant thermal coupling effects. When a single cell in the module experiences thermal runaway due to internal short circuits, overcharging, external heating, or manufacturing defects, it rapidly releases a large amount of heat from the chemical reaction. The battery casing temperature rises sharply, and the safety valve ruptures, ejecting high-temperature flammable gas and electrolyte vapor, forming a high-temperature jet flame or high-temperature plume of smoke. This heat, through a combination of convection and radiation, violently impacts the surfaces of adjacent battery cells, easily triggering thermal runaway in adjacent cells, leading to heat propagation, and ultimately causing a large-scale fire or explosion accident involving the entire module or even the entire battery system. Therefore, in the thermal safety design phase of battery modules, it is essential to accurately understand the heat flux density distribution of the thermally runaway cell on the surrounding battery surfaces. This is crucial for providing accurate boundary conditions for numerical simulations and for providing quantitative basis for thermal protection structure design and safety spacing optimization.

[0003] Currently, testing devices and methods for battery thermal runaway characteristics are mainly divided into two categories: The first category is single-cell level testing devices. These devices typically focus only on intrinsic thermal runaway characteristic parameters of a single cell, such as the thermal runaway triggering conditions, temperature rise rate, gas production, and heat production. For example, they use equipment such as accelerating calorimeters (ARC), differential scanning calorimeters (DSC), or cone calorimeters to perform thermal runaway tests on single cells. Although this type of testing can obtain the thermal runaway characteristic parameters of a single cell, the test environment is an open space or adiabatic environment, which cannot reflect the thermal coupling effect and heat transfer boundary conditions between adjacent cells in a real module. Therefore, it cannot provide quantitative data on heat transfer between cells, let alone obtain information on the surface heat flux density distribution at the module level. The second category is module-level testing devices. These devices often use the method of arranging thermocouple temperature sensors inside a real module to indirectly infer the thermal propagation process by monitoring the temperature changes at a few discrete measurement points within the module. However, thermocouples can only measure the temperature time history data of local points and cannot directly measure the surface heat flux density, which characterizes the degree of thermal hazard. Heat flux density is a key physical quantity describing the rate of heat transfer per unit area. It directly reflects the intensity of thermal shock experienced by adjacent battery surfaces and is a core parameter for assessing thermal propagation risk and designing thermal protection systems. Temperature data alone cannot accurately quantify the thermal shock intensity of a thermally runaway battery on surrounding batteries, nor can it provide direct thermal boundary condition inputs for computational fluid dynamics numerical simulations.

[0004] Therefore, there is an urgent need for a standardized test device and method that can economically, accurately and repeatedly determine the spatiotemporal distribution of heat flux density on the surface of adjacent batteries under thermal runaway conditions of module batteries, under real module stacking and surface characteristics. Summary of the Invention

[0005] To address the problems mentioned in the background art, this invention discloses an apparatus and method for measuring the surface heat flow distribution of a battery module in a fire. This provides a standardized experimental platform and testing method for studying the mechanism of thermal runaway in battery modules, optimizing safety design, and verifying numerical models. To achieve the above objectives, the technical solution adopted by this invention is as follows: An apparatus for measuring the heat flow distribution on the lower surface of a battery module in a fire, characterized in that the apparatus comprises a test platform, a hybrid battery module, a data acquisition module, and a central control system; The test platform includes a steel box with an opening at the top, inside which the hybrid battery module is placed. The test platform is also equipped with a bracket, on which an ignition needle is installed. The ignition needle is located above the safety valve port of the actual battery. The hybrid battery module includes a real battery and simulated batteries symmetrically arranged on both sides of the real battery at a predetermined interval. The simulated batteries are hollow shells with the same external dimensions, surface material, and surface emissivity as the real battery, and their interiors are hollow. The large surface of the simulated battery is attached to the large surface of the real battery, and an aerogel adhesive is provided between the real battery and the simulated battery. The surface of the simulated battery has arrayed heat flow meter holes and thermocouple holes, and heat flow meters and thermocouples are respectively embedded in the heat flow meter holes and thermocouple holes. The sensing surface of the heat flow meter is precisely flush with the surface of the simulated battery shell. Wiring holes are also provided on the side of the simulated battery, through which the signal lines of the heat flow meter and thermocouple, as well as the coolant circulation pipe on the back of the heat flow meter, are led out. The data acquisition module includes a multi-channel synchronous acquisition instrument, which is electrically connected to the heat flow meter and the thermocouple, respectively, and is used to synchronously acquire the heat flux density and temperature data of the simulated battery surface during thermal runaway. The central control system is communicatively connected to the ignition needle and the data acquisition module, and is used to remotely control the start and stop of the experimental process, the triggering of the ignition needle, and the synchronous acquisition of data by the data acquisition module, and to display the multi-dimensional parameters acquired by the data acquisition module in real time.

[0006] Furthermore, the steel housing of the test platform has holes at both ends for leading out the signal lines and cooling pipes of the heat flow meter and thermocouple.

[0007] Furthermore, preferably, the spacing between the real battery and the simulated batteries on both sides is set to 1mm to 20mm.

[0008] Furthermore, the heat flow meter is a Schmidt-Belth type total heat flow meter or a Gordon type total heat flow meter; the thermocouple includes a patch thermocouple for measuring the surface temperature of the simulated battery and a K-type thermocouple for measuring the temperature of the gas phase region above the surface.

[0009] Furthermore, the multi-channel synchronous acquisition instrument is connected to the central control system via wired or wireless communication. The central control system is pre-installed with customized measurement and control software, which integrates experimental process control, real-time display of multi-source data, and data storage management modules.

[0010] This invention also discloses a method for measuring the heat flow distribution on the lower surface of a battery module in a fire, implemented based on the aforementioned apparatus for measuring the heat flow distribution on the lower surface of a battery module in a fire, characterized by comprising the following steps: S1. Discharge the real battery to 0% state of charge, let it stand, and then charge it to 100% state of charge to complete the sample pretreatment. S2, place the pre-treated real battery in the middle of the test platform, cover the two sides of the real battery with aerogel adhesive in the thickness direction, arrange the simulated battery symmetrically on both sides of the real battery according to the preset spacing, install the heat flow meter and thermocouple in the heat flow meter hole and thermocouple hole of the simulated battery according to the preset array, and lead out the signal lines of the heat flow meter and thermocouple, as well as the coolant circulation pipe on the back of the heat flow meter through the wiring hole on the side of the simulated battery and the through hole on the side wall of the test platform and connect them to the multi-channel synchronous acquisition instrument and the coolant circulation system; S3, start the multi-channel synchronous acquisition instrument and high-speed camera, remotely trigger the thermal runaway of the real battery through the central control system, after the real battery safety valve ruptures and sprays out combustible gas, remotely open the ignition needle to ignite the combustible gas, and synchronously collect the heat flux density time history data and temperature time history data of each measuring point. After the battery combustion process ends and the surface temperature cools down naturally, stop all data acquisition. S4. The collected data is filtered and denoised, and time synchronization is calibrated. Based on the spatial coordinates and heat flux density time history data of each measuring point, the spatial interpolation algorithm is used to reconstruct the spatiotemporal distribution field of heat flux density on the surface of the simulated battery pack. The spatiotemporal distribution field of heat flux density is used as the thermal boundary condition and input into the battery module fire numerical simulation program for simulation verification.

[0011] Furthermore, in step S1, the battery is fully discharged to 0% SOC on a standard charging and discharging device, left to stand at room temperature for at least 4 hours, and then charged to 100% SOC using a 0.5C constant current charging to the cutoff voltage and a constant voltage charging to the cutoff current method.

[0012] Furthermore, in step S2, the heat flow meter is installed so that its sensing surface is precisely flush with the outer surface of the simulated battery. The patch thermocouple is attached to the surface of the simulated battery using high-temperature resistant adhesive, and the K-type thermocouple probe is inserted into the corresponding hole and fixed.

[0013] Furthermore, in step S3, actual battery thermal runaway is triggered by overcharging or external heating.

[0014] Furthermore, in step S4, the spatial interpolation algorithm is either bilinear interpolation or spline interpolation. If the predicted temperature rise curve of the adjacent battery obtained by numerical simulation deviates significantly from the experimentally measured temperature rise curve, the numerical model parameters are adjusted through parameter inversion and model correction methods until the simulation results and experimental data achieve satisfactory agreement.

[0015] The present invention has the following beneficial effects: (1) Significantly reduces testing costs and improves experimental safety and controllability. This invention constructs a hybrid battery module using a real battery and several highly realistic simulated battery casings with built-in sensors. Compared to destructive testing using a fully real battery module, this significantly reduces battery consumption costs. More importantly, because the simulated battery has a hollow structure and does not contain active electrochemical materials, it will not experience thermal runaway due to heat, thus completely eliminating the risk of uncontrollable experimental processes caused by heat propagation igniting adjacent real batteries. Experimenters can remotely control the entire experimental process from a safe distance through a central control system, significantly improving experimental safety and process controllability, while also ensuring the standardization of experimental conditions and the high repeatability of results.

[0016] (2) For the first time, direct quantitative measurement of the spatiotemporal distribution of heat flux density at the module level has been achieved. This invention innovatively integrates a heat flux meter, which can directly reflect the degree of thermal hazard, and a thermocouple array on the surface of a simulated battery casing that is highly consistent with the appearance, surface roughness, and radiation characteristics of a real battery. For the first time, direct, multi-point, and high-precision quantitative measurement of the transient heat flux density distribution during thermal runaway at the battery module level has been achieved. The obtained heat flux density data has a clear physical meaning and does not need to be indirectly calculated from temperature data. It can be directly used as the input boundary condition or verification basis for numerical models such as computational fluid dynamics, effectively solving the technical bottleneck of lacking measured heat flux boundary condition verification in numerical simulations in the prior art.

[0017] (3) Multi-dimensional data synchronous acquisition and spatiotemporal distribution reconstruction. The device of this invention integrates the synchronous acquisition function of multi-dimensional physical parameters such as heat flux density, surface temperature, and gas phase temperature. All sensor data are recorded through a unified time scale, which facilitates the subsequent reconstruction of the spatiotemporal distribution field of heat flux and temperature field on the surface of the simulated battery pack using interpolation algorithms. This spatiotemporal distribution data can not only intuitively show the propagation law of thermal shock on the module surface during thermal runaway, but also provide rich experimental evidence for a deeper understanding of the thermal propagation mechanism.

[0018] (4) Modular structure and standardized testing platform. The device of this invention has a highly modular structure. The number, spacing, and sensor density of the simulated batteries in the hybrid battery module can be flexibly adjusted according to research needs. The entire operation can be remotely controlled through a central control system, which reduces the risk of human operation and experimental errors. It provides a standardized, reproducible, and scalable testing platform for the thermal safety research of battery modules, and has good prospects for promotion and application and practical engineering value. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the system for measuring the heat flow distribution on the lower surface of a battery module during a fire, as described in a specific embodiment.

[0020] Figure 2 This is an isometric view of the device for measuring the heat flow distribution on the lower surface of a battery module during a fire, as described in a specific embodiment.

[0021] Figure 3 This is a cross-sectional view along the short side centerline of the device for measuring the heat flow distribution on the lower surface of a battery module during a fire, as described in a specific embodiment.

[0022] Figure 4 This is a flowchart illustrating the experimental procedure for determining the surface heat flow distribution of a battery module during a fire, as described in a specific embodiment.

[0023] Explanation of reference numerals in the attached diagram: 1. Test platform; 2. Hybrid battery module; 3. Data acquisition module; 4. Central control system; 11. Steel cuboid experimental platform; 12. Through hole; 13. Aluminum alloy bracket; 14. Ignition needle; 21. Real battery; 22. Simulated battery; 23. Aerogel adhesive; 24. Hole; 25. K-type thermocouple probe. Detailed Implementation

[0024] To facilitate understanding by those skilled in the art, the present invention will be further described below in conjunction with embodiments and accompanying drawings.

[0025]

Example 1

[0026] See Figure 2 The test platform 1 is a rectangular steel experimental platform 11 with an open top, made of high-temperature resistant alloy steel, possessing good structural strength and thermal stability, used to support and protect the internal hybrid battery modules. Through holes 12 are provided along the arrangement direction of the hybrid battery modules on the test platform for laying the signal lines of the heat flow meter and thermocouples, as well as the coolant circulation pipes on the back of the heat flow meter, ensuring that the wiring is neatly arranged and does not affect the thermal environment flow field inside the chamber. An aluminum alloy bracket 13 is welded to the side of the test platform, and an ignition needle 14 is fixedly installed on the bracket. The tip of the ignition needle 14 is precisely aligned and positioned at an appropriate height directly above the safety valve of the actual battery, so that when the safety valve ruptures and sprays out the mixed combustible gas after thermal runaway of the actual battery, it can promptly and reliably ignite the combustible gas, simulating a real fire scenario, while preventing unburned combustible gas from accumulating inside the chamber and forming an explosive mixture.

[0027] See Figure 2 and Figure 3The hybrid battery module 2 consists of a real battery 21 and several simulated batteries 22. The simulated batteries 22 are symmetrically distributed at equal intervals on both sides of the real battery 21 along its thickness, forming a stacked structure of "simulated battery-real battery-simulated battery". A fire-resistant and heat-insulating aerogel adhesive 23 is placed between the real battery 21 and adjacent simulated batteries 22. This aerogel adhesive 23 is typically 1mm to 10mm thick and possesses excellent heat insulation and electrical insulation properties. It effectively blocks heat transfer from the real battery to the simulated battery through solid heat conduction during thermal runaway, ensuring that the measured heat flow data primarily reflects the contributions of heat convection and heat radiation, thus more accurately simulating the heat transfer mechanism in the real module. The simulated batteries 22 use a cuboid shell made of the same material as the real battery 21. Their dimensions, surface roughness, and surface oxidation treatment process are consistent with the real battery to ensure consistency in surface emissivity and appearance characteristics. The simulated battery 22 has a hollow internal structure with wiring holes on its bottom side. The signal lines of the heat flow meter and thermocouples, as well as the coolant circulation pipes on the back of the heat flow meter, are introduced into the hollow cavity inside the simulated battery through these wiring holes and extend along the cavity to the various measuring points on the surface of the simulated battery. At the same location as the terminals of the real battery 21, a hole 24 of the same size as the sensing surface of the heat flow meter is formed on the surface of the simulated battery 22. The heat flow meter is embedded in this hole 24, and the sensing surface of the heat flow meter is precisely flush with the outer surface of the simulated battery casing to avoid airflow boundary layer disturbances and measurement errors caused by surface unevenness. Adjacent to each heat flow meter, a K-type thermocouple hole with the same diameter as the K-type thermocouple probe 25 is formed. The K-type thermocouple probe 25 is inserted into this K-type thermocouple hole, with its temperature measuring end slightly protruding from the surface of the simulated battery, for measuring the temperature distribution in the gas phase region above the surface of the simulated battery. In addition, high-temperature resistant silicone or ceramic adhesive is used to attach patch thermocouples near the K-type thermocouple hole to simulate the surface temperature of the battery during thermal runaway.

[0028] Data acquisition module 3 is used to achieve synchronous acquisition and processing of multi-source heterogeneous data. A high-speed multi-channel data acquisition unit is connected to each heat flux meter and thermocouple via signal lines. The data acquisition unit features a high sampling frequency and multi-channel synchronous triggering function, capable of synchronously converting analog signals output from all sensors into digital signals and assigning a unified timestamp to all channel data, ensuring strict alignment of heat flux density data and temperature data in the time dimension. The data acquisition unit also features signal conditioning, noise filtering, and automatic range switching functions to adapt to drastic changes in signal amplitude during thermal runaway.

[0029] The central control system 4 communicates with the multi-channel synchronous data acquisition unit via a high-speed USB interface. The central computer is pre-installed with customized measurement and control software, which integrates the following functional modules: experimental process control module, multi-source data real-time display module, data storage management module, anomaly alarm module, and post-processing analysis module. Through this central control system 4, researchers can achieve remote, fully automated control of the entire experimental process, real-time display of multi-source data, and unified time-stamped storage from a remote observation room, maximizing personnel safety and improving experimental efficiency.

[0030]

Example 2

[0031] S2, Hybrid Battery Module Assembly and Sensor Placement. Place the pre-treated real battery stably in the center of the test platform, ensuring the battery surface is horizontal and centered. Evenly apply aerogel adhesive to both sides of the real battery's thickness direction, covering the main contact area between the real and simulated batteries. Then, arrange simulated batteries symmetrically on both sides of the real battery at preset intervals, ensuring the simulated battery surface is parallel and opposite to the real battery surface. Install the heat flow meter and thermocouples at the heat flow meter holes and thermocouple holes of the simulated batteries according to the preset array arrangement. During installation, ensure the heat flow meter's sensing surface is precisely flush with the outer surface of the simulated battery; the K-type thermocouple probe should be securely fixed after insertion into the hole, with the measuring end in good contact with the bottom or wall of the hole; the patch thermocouple should be firmly adhered to the simulated battery surface near the thermocouple hole using high-temperature resistant adhesive. The signal lines of the heat flow meter and thermocouples, as well as the coolant circulation pipes on the back of the heat flow meter, are all led out through wiring holes opened at the bottom side of the simulated battery. These holes then connect to the corresponding channels of the multi-channel synchronous acquisition instrument and the coolant circulation system through through-holes in the side wall of the test platform. The wiring hole design avoids interference with the thermal flow and temperature fields caused by lines leading from the front or top, ensuring the accuracy of the measurement data. It also makes the external wiring of the module simple and neat, facilitating quick assembly and disassembly.

[0032] S3, Thermal Runaway Data Acquisition. Start the multi-channel synchronous acquisition instrument, set the sampling frequency, and perform zero-point calibration and full-scale calibration on each channel to ensure measurement accuracy. Set up a high-speed camera, adjusting the viewing angle and focal length to cover the entire hybrid battery module area to record the entire thermal runaway process. Start the host computer monitoring and control software, check the communication status of each channel, and confirm that the system is operating normally. After all preparations are completed, the operators evacuate to the remote observation room, close the fire doors of the experimental area, and ensure personnel safety. Remotely operate the host computer monitoring and control software to trigger thermal runaway of a real battery through overcharging or external heating. Once the real battery safety valve ruptures and begins to eject flammable gas, immediately remotely activate the ignition needle to ignite the flammable gas, forming a stable flame jet. Simultaneously, start the multi-channel synchronous acquisition instrument via the host computer to record the heat flux density time history data and temperature time history data at each measuring point. The high-speed camera is simultaneously started to record visible light images of the thermal runaway and combustion process. During the experiment, the operators monitored the changes in data and video footage at each measuring point in real time through the central control system. Once the battery combustion process was basically over and the battery surface temperature had cooled down naturally, all data acquisition was stopped, and the data acquisition instrument and high-speed camera were turned off.

[0033] S4, Data Processing and Model Validation. After the experiment, the raw data from each channel were post-processed using the host computer monitoring and control software. First, the data was filtered and denoised to eliminate high-frequency noise and electromagnetic interference. Second, all channel data were time-aligned and synchronized based on a unified timestamp. Then, based on the spatial coordinates (x, y) of each measuring point and the measured heat flux density time history data q(x, y, t), spatial interpolation algorithms such as bilinear interpolation or spline interpolation were used to reconstruct the spatiotemporal distribution field of heat flux density Q(x, y, t) on the simulated battery pack surface. Similarly, the spatiotemporal distribution of the temperature field T(x, y, t) could be reconstructed. The reconstructed spatiotemporal distribution field of heat flux was used as the thermal boundary condition and input into the battery module fire numerical simulation program. The same initial and boundary conditions as the experiment were set, and the numerical simulation was run to obtain the predicted temperature rise curves of adjacent batteries. The predicted values ​​were compared and analyzed with the experimentally measured temperature rise curves to evaluate the accuracy of the numerical model. If the two match well, the rationality of key parameters in the numerical model, such as the convective heat transfer coefficient, radiation model parameters, and jet heat source model, is verified. If there is a significant deviation, the relevant parameters in the numerical model are adjusted through parameter inversion and model correction methods until the simulation results and experimental data achieve a satisfactory degree of agreement, thereby establishing a high-precision numerical model of battery module thermal spread that has been experimentally verified.

[0034] The apparatus and method provided in this invention overcome the limitations of traditional single-cell testing, which cannot reflect the thermal boundary conditions of battery modules, and the shortcomings of fully realistic battery module testing, such as uncontrollability, difficulty in measurement, and high cost, by innovatively constructing a hybrid battery module composed of real and simulated batteries. This invention provides a standardized, reproducible, economical, and safe experimental platform and testing method for the study of battery module thermal propagation mechanisms, optimization of thermal protection design, and numerical simulation verification. It has significant theoretical and engineering application value for promoting the advancement of thermal safety technology in battery energy storage systems.

[0035] The above embodiments are merely illustrative of the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of this invention.

Claims

1. A device for measuring the heat flow distribution on the lower surface of a battery module during a fire, characterized in that, The device includes: a test platform, a hybrid battery module, a data acquisition module, and a central control system; The test platform includes a steel box with an opening at the top, inside which the hybrid battery module is placed. The test platform is also equipped with a bracket, on which an ignition needle is installed. The ignition needle is located above the safety valve port of the actual battery. The hybrid battery module includes a real battery and simulated batteries symmetrically arranged on both sides of the real battery at a predetermined interval. The simulated batteries are hollow shells with the same external dimensions, surface material, and surface emissivity as the real battery, and their interiors are hollow. The large surface of the simulated battery is attached to the large surface of the real battery, and an aerogel adhesive is provided between the real battery and the simulated battery. The surface of the simulated battery has arrayed heat flow meter holes and thermocouple holes, and heat flow meters and thermocouples are respectively embedded in the heat flow meter holes and thermocouple holes. The sensing surface of the heat flow meter is precisely flush with the surface of the simulated battery shell. Wiring holes are also provided on the side of the simulated battery, through which the signal lines of the heat flow meter and thermocouple, as well as the coolant circulation pipe on the back of the heat flow meter, are led out. The data acquisition module includes a multi-channel synchronous acquisition instrument, which is electrically connected to the heat flow meter and the thermocouple, respectively, and is used to synchronously acquire the heat flux density and temperature data of the simulated battery surface during thermal runaway. The central control system is communicatively connected to the ignition needle and the data acquisition module, and is used to remotely control the start and stop of the experimental process, the triggering of the ignition needle, and the synchronous acquisition of data by the data acquisition module, and to display the multi-dimensional parameters acquired by the data acquisition module in real time.

2. The apparatus for measuring the heat flow distribution on the lower surface of a battery module in a fire, as described in claim 1, is characterized in that... The steel housing of the test platform has holes at both ends for leading out the signal lines and cooling pipes of the heat flow meter and thermocouple.

3. The apparatus for measuring the heat flow distribution on the lower surface of a battery module in a fire, as described in claim 1, is characterized in that... The set distance between the real battery and the simulated batteries on both sides is 1mm to 20mm.

4. The apparatus for measuring the heat flow distribution on the lower surface of a battery module in a fire, as described in claim 1, is characterized in that... The heat flow meter is a Schmidt-Belth type total heat flow meter or a Gordon type total heat flow meter; the thermocouple includes a patch thermocouple for measuring the surface temperature of the simulated battery and a K-type thermocouple for measuring the temperature of the gas phase region above the surface.

5. The apparatus for measuring the heat flow distribution on the lower surface of a battery module in a fire, according to any one of claims 1 to 4, is characterized in that, The multi-channel synchronous acquisition instrument is connected to the central control system via wired or wireless communication. The central control system has pre-installed customized measurement and control software, which integrates experimental process control, real-time display of multi-source data, and data storage management modules.

6. A method for measuring the heat flow distribution on the lower surface of a battery module in a fire, implemented based on the apparatus for measuring the heat flow distribution on the lower surface of a battery module in a fire as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Discharge the real battery to 0% state of charge, let it stand, and then charge it to 100% state of charge to complete the sample pretreatment. S2, place the pre-treated real battery in the middle of the test platform, cover the two sides of the real battery with aerogel adhesive in the thickness direction, arrange the simulated battery symmetrically on both sides of the real battery according to the preset spacing, install the heat flow meter and thermocouple in the heat flow meter hole and thermocouple hole of the simulated battery according to the preset array, and lead out the signal lines of the heat flow meter and thermocouple, as well as the coolant circulation pipe on the back of the heat flow meter through the wiring hole on the side of the simulated battery and the through hole on the side wall of the test platform and connect them to the multi-channel synchronous acquisition instrument and the coolant circulation system; S3, start the multi-channel synchronous acquisition instrument and high-speed camera, remotely trigger the thermal runaway of the real battery through the central control system, after the real battery safety valve ruptures and sprays out combustible gas, remotely open the ignition needle to ignite the combustible gas, and synchronously collect the heat flux density time history data and temperature time history data of each measuring point. After the battery combustion process ends and the surface temperature cools down naturally, stop all data acquisition. S4. The collected data is filtered and denoised, and time synchronization is calibrated. Based on the spatial coordinates and heat flux density time history data of each measuring point, the spatial interpolation algorithm is used to reconstruct the spatiotemporal distribution field of heat flux density on the surface of the simulated battery pack. The spatiotemporal distribution field of heat flux density is used as the thermal boundary condition and input into the battery module fire numerical simulation program for simulation verification.

7. The method for determining the heat flow distribution on the lower surface of a battery module in a fire, as described in claim 6, is characterized in that... In step S1, the battery is fully discharged to 0% SOC on a standard charging and discharging device, left to stand at room temperature for at least 4 hours, and then charged to 100% SOC using a 0.5C constant current charging to the cutoff voltage and a constant voltage charging to the cutoff current method.

8. The method for determining the heat flow distribution on the lower surface of a battery module in a fire, as described in claim 6, is characterized in that... In step S2, the thermocouple is installed so that its sensing surface is precisely flush with the outer surface of the simulated battery. The patch thermocouple is attached to the surface of the simulated battery using high-temperature resistant adhesive. The K-type thermocouple probe is inserted into the corresponding hole and fixed.

9. The method for determining the heat flow distribution on the lower surface of a battery module in a fire, as described in claim 6, is characterized in that... In step S3, actual battery thermal runaway is triggered by overcharging or external heating.

10. The method for determining the heat flow distribution on the lower surface of a battery module in a fire, as described in claim 6, is characterized in that... In step S4, the spatial interpolation algorithm is either bilinear interpolation or spline interpolation. If the predicted temperature rise curve of the adjacent battery obtained by numerical simulation deviates significantly from the experimentally measured temperature rise curve, the numerical model parameters are adjusted by parameter inversion and model correction methods until the simulation results and experimental data achieve satisfactory agreement.

Images