Method and system for testing influence of battery cell thermal runaway on safety performance of insulating oil

Abstract

The invention discloses a method and system for testing the influence of thermal runaway of a battery cell on the safety performance of insulating oil, and the method comprises the steps: introducing an explosion source at a preset test position near the insulating oil in an open environment; and detonating the explosion source to simulate out-of-control of a battery cell in the immersed energy storage battery pack, and monitoring whether the insulating oil is combusted or not. According to the method, the thermal runaway scene of the battery cell can be simulated by detonating the explosion source, the influence of the thermal runaway of the battery cell on the safety performance of the insulating oil is analyzed by monitoring whether the insulating oil is burnt or not in the scene, the whole testing process is easy and safe to operate, and the testing result is high in reliability; the test result can also provide support for insulating oil formula optimization and energy storage system safety design.

Description

Technical Field

[0001] The present application relates to the technical field of safety performance testing, and in particular to a method and system for testing the impact of thermal runaway of a battery cell on the safety performance of insulating oil. Background Art

[0002] Insulating oil, the core dielectric of submerged energy storage systems, is typically composed of materials such as polyalphaolefins, silicone oil, synthetic esters, or natural gas synthetic oil. It performs a dual function within the energy storage battery pack: first, it effectively dissipates heat through direct contact with the battery cells; second, it utilizes its high dielectric strength to isolate the electrical path between live components and the battery pack. This liquid dielectric requires long-term immersion in the battery module surface and terminal area, and its performance directly impacts the thermal safety and operational reliability of the energy storage system.

[0003] The safety performance of insulating oil is particularly important for submerged energy storage systems. In addition to basic thermal conductivity and electrical insulation properties, it must also possess: high-temperature stability to maintain chemical inertness at both the battery cell's operating temperature and the extreme temperatures of thermal runaway; flame retardancy to suppress the spread of flames in the event of a combustible gas explosion; and low volatility to prevent mixing with gases like hydrogen and methane released during thermal runaway, creating an explosive oil and gas environment.

[0004] Insulating oil that does not meet safety standards will significantly increase system risks. When a battery cell experiences thermal runaway, the combustible gas released will mix with the volatiles of the insulating oil, creating a highly explosive environment. For example, some low-quality insulating oils will flash under the impact of flames, and the benzene-containing substances released during the combustion process will further poison the fire extinguishing medium. What's more serious is that the carbonized deposits generated by such oils after high-temperature cracking will reduce the insulation resistance between battery cells, leading to cascading short-circuit failures. The current industry lacks testing methods for the safety of insulating oil in battery cell thermal runaway scenarios, making it difficult to assess the impact of thermal runaway on insulating oil. This is precisely the technical pain point that urgently needs to be addressed in this field. Summary of the Invention

[0005] One purpose of the present application is to provide a test method and test system for the impact of thermal runaway of battery cells on the safety performance of insulating oil, which aims to solve the technical problem that the current industry lacks a test method for the safety of insulating oil in the scenario of thermal runaway of battery cells, and it is difficult to evaluate the impact of thermal runaway of battery cells on insulating oil.

[0006] To achieve the above-mentioned objectives, the present application provides a method for testing the impact of thermal runaway of battery cells on the safety performance of insulating oil. The method comprises: introducing an explosion source at a preset test position near the insulating oil set in an open environment; detonating the explosion source to simulate the runaway of the battery cells in an immersed energy storage battery pack, and monitoring whether the insulating oil burns.

[0007] According to one embodiment of the present application, the insulating oil is located in a container having an open mouth; the surface liquid surface formed after the insulating oil is spread in the container is the test contact surface of the insulating oil; the preset test position is a position in the open mouth area of the container at a preset height from the test contact surface.

[0008] According to one embodiment of the present application, the preset height is set with reference to the distance between the battery cells and the insulating oil in the battery pack.

[0009] According to one embodiment of the present application, the preset height is in the range of 20 mm to 100 mm.

[0010] According to one embodiment of the present application, the method further includes: determining the contact area between the insulating oil and the battery cells in the battery pack and determining the volume of the insulating oil in advance based on the specifications of the battery pack; determining the specifications of the container so that after the insulating oil is poured into the container according to the determined volume, the area of the test contact surface is not less than the contact area.

[0011] According to one embodiment of the present application, the method further includes: selecting a container based on the number of battery cells in the battery pack and the arrangement of the battery cell modules in the battery pack, including: the more battery cells in the battery pack, the larger the volume of the container; under the premise that the number of battery cells in the battery pack is the same, the smaller the number of battery cells in a single module, the larger the volume of the container.

[0012] According to one embodiment of the present application, the explosion source is an explosive gas.

[0013] According to one embodiment of the present application, introducing the explosion source includes: providing a gas tank for storing explosive gas, connecting the gas tank with an extension pipe, and introducing the outlet of the extension pipe to a preset test position.

[0014] According to one embodiment of the present application, the explosive gas includes at least the following gases (which the present application also provides): hydrogen and methane.

[0015] According to one embodiment of the present application, the method further includes: providing a temperature detection device in the insulating oil, and monitoring the temperature change of the insulating oil in real time based on the temperature detection device.

[0016] According to one embodiment of the present application, the method further includes: setting an image acquisition device in an open space, acquiring images of the insulating oil and its surrounding areas based on the image acquisition device, determining whether the insulating oil is burning based on the acquired images, and when the insulating oil is burning, obtaining the spread of the flame based on the acquired images.

[0017] According to one embodiment of the present application, the method further includes: pre-installing an ignition device at a preset test position; detonating the explosion source, including: starting the ignition device to ignite and controlling the ignition temperature to ignite the explosion source.

[0018] According to one embodiment of the present application, the method further includes: if the insulating oil does not burn after the ignition device is ignited, controlling the ignition device to increase the ignition temperature and / or supplement the explosion source until the insulating oil burns.

[0019] According to one embodiment of the present application, the ignition temperature is in the range of 700°C to 800°C.

[0020] According to one embodiment of the present application, the method further includes: configuring an oil and gas collection device above the insulating oil to collect the oil and gas above the insulating oil during the test, and quantitatively analyzing the composition of the collected oil and gas, and generating an oil and gas composition analysis report based on the analysis results to quantify the risk.

[0021] According to one embodiment of the present application, the method further includes: when the insulating oil is not burned, sampling and analyzing the insulating oil.

[0022] The present application also provides a testing system for the impact of thermal runaway of battery cells on the safety performance of insulating oil used in any of the above-mentioned testing methods, comprising: insulating oil set in an open environment; and an explosion source introduced into a preset test position.

[0023] According to one embodiment of the present application, the testing system further includes: a container for containing insulating oil;

[0024] and / or, an oil and gas collecting device, disposed above the insulating oil level, for collecting oil and gas above the insulating oil during the test;

[0025] and / or, an ignition device provided at the preset test position, for detonating the explosion source;

[0026] and / or, a gas tank and an extension pipe, wherein the gas tank is used to store the explosion source, one end of the extension pipe is connected to the gas tank, and the other end of the extension pipe is directed toward the preset test position;

[0027] And / or, the testing system further includes: an image acquisition device, configured to acquire images of the insulating oil and its surrounding areas.

[0028] The present application has at least one of the following beneficial effects:

[0029] The test method for the impact of thermal runaway of battery cells on the safety performance of insulating oil in the present application simulates thermal runaway of battery cells by detonating an explosion source at a preset test position near the insulating oil in an open environment, and monitors whether the insulating oil is burning, thereby realizing the safety performance analysis of the insulating oil during thermal runaway of the battery cells. In this way, the present application simulates the complex thermal runaway process inside the battery pack using a test method that can be standardized. The entire test process is simple and safe to operate, and the test results are highly reliable. The test results can also provide support for the optimization of insulating oil formulation and the safety design of energy storage systems.

[0030] In addition, the contact area between the explosion shock wave and the oil surface can be controlled to reproduce the energy release intensity during thermal runaway of the battery cell group; combined with multi-dimensional monitoring systems such as temperature detection devices and image detection devices, real-time temperature changes of the insulating oil and recording of the flame propagation process can be achieved during the test; an oil and gas collection device can be configured to collect low-molecular-weight oil and gas above the insulating oil during the test, and the composition of the collected oil and gas can be quantitatively analyzed. Based on the analysis results, an oil and gas composition analysis report can be generated to quantify the risk. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0032] Figure 1 1 is a flow chart of a method for testing the impact of thermal runaway of a battery cell on the safety performance of insulating oil in an embodiment of the present application;

[0033] Figure 2 Schematic diagram of the structure of the test system for the impact of thermal runaway of battery cells on the safety performance of insulating oil in an embodiment of the present application;

[0034] Figure 3 It is along Figure 2 Schematic diagram of the cross section along line AA;

[0035] Figure 4 Schematic diagram of the relationship between components of a test system for the impact of thermal runaway of a battery cell on the safety performance of insulating oil in an embodiment of the present application.

[0036] Description of Figure Numbers:

[0037] 1. Insulating oil; 2. Explosion source; 3. Container; 4. Gas tank; 5. Extension pipe; 6. Image acquisition device; 7. Ignition device; 8. Oil and gas collection device. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0039] In modern energy storage technology, insulating oil plays a vital role as the core medium of immersed energy storage systems. It is usually composed of advanced materials such as polyalphaolefins, silicone oil, synthetic esters, or natural gas synthetic oil. These liquid media have a dual function in energy storage battery packs: on the one hand, they achieve efficient heat conduction through direct contact with the battery cells, helping the system maintain an optimal operating temperature; on the other hand, they use their high dielectric strength properties to isolate the electrical path between live components and the box, ensuring the safe operation of the entire system. This type of liquid medium needs to be immersed in the surface of the battery module and the pole area for a long time. The quality of its performance directly determines the thermal safety and operational reliability of the energy storage system, which in turn affects the stability and life of the entire system.

[0040] For submerged energy storage systems, the safety performance of insulating oil is particularly critical. In addition to basic thermal conductivity and electrical insulation, insulating oil must possess a range of specialized properties: high-temperature stability, ensuring that the oil remains chemically inert and does not decompose or react at the normal operating temperature of the battery cell, even at extreme temperatures associated with thermal runaway; flame retardancy, meaning that in the event of a combustible gas explosion, the insulating oil can effectively suppress the spread of flames and prevent the fire from spreading; and low volatility, preventing mixing with gases like hydrogen and methane released during thermal runaway, which could create a potentially explosive oil and gas environment. The combined performance of these properties is the cornerstone of ensuring the safe operation of energy storage systems.

[0041] When the safety performance of insulating oil does not meet the standards, it will significantly increase the risk of the system. Taking thermal runaway of battery cells as an example, if the volatiles of insulating oil mix with the combustible gases released by the battery cells, a highly explosive environment will be formed. For example, some low-quality insulating oils will flash under the impact of flames. The benzene ring-containing substances released during the combustion process will not only poison the fire extinguishing medium, but may also have serious impacts on the environment and human health. Even if the extreme case of thermal runaway of single cells is not considered, the carbonized deposits generated by such oils after high-temperature cracking will reduce the insulation resistance between battery cells, leading to cascading short-circuit failures, thereby triggering the collapse of the entire system. Currently, the industry lacks testing methods for the safety of insulating oil in battery cell thermal runaway scenarios, which makes it difficult for technical personnel in this field to evaluate the impact of thermal runaway of battery cells on insulating oil.

[0042] In order to solve the above technical problems, this application provides a test method for the impact of thermal runaway of battery cells on the safety performance of insulating oil 1, please refer to Figures 1 to 3 As shown, Figure 1 1 is a flow chart of a method for testing the impact of thermal runaway of a battery cell on the safety performance of insulating oil in an embodiment of the present application; Figure 2 Schematic diagram of the structure of the test system for the impact of thermal runaway of battery cells on the safety performance of insulating oil in an embodiment of the present application; Figure 3 It is along Figure 2A schematic cross-sectional view taken along line AA. The method includes introducing an explosion source 2 at a predetermined test location near insulating oil 1 in an open environment; detonating the explosion source 2 to simulate a runaway cell in an immersed energy storage battery pack; and monitoring whether the insulating oil 1 ignites.

[0043] This embodiment simulates thermal runaway of a battery cell by setting up and detonating an explosion source 2 in an open environment. The explosion energy simulates the combustion effect of the flammable gas released during actual thermal runaway, reproducing the energy impact scenario that occurs when a battery cell fails within an immersion energy storage battery pack. After detonating explosion source 2 at a preset test location, the resulting flame propagation path and heat release characteristics effectively represent the direct thermal shock to insulating oil 1 during a runaway battery cell. By monitoring whether insulating oil 1 burns, the safety of insulating oil 1 during a runaway battery cell can be analyzed.

[0044] This solution simulates an explosion in an open environment to simulate the combustion scenario of the combustible gas released when the reduction battery cell loses control and the mixture of the volatile substances of the insulating oil 1, providing a repeatable and low-cost experimental path for quickly verifying the reliability of the insulating oil 1 under extreme thermal runaway conditions.

[0045] According to one embodiment of the present application, the insulating oil 1 is located in a container 3 having an open mouth; the surface liquid surface formed after the insulating oil 1 is spread in the container 3 is the test contact surface of the insulating oil 1; the preset test position is a position in the open mouth area of the container 3 at a preset height from the test contact surface.

[0046] This embodiment places the insulating oil 1 in an open-mouth container 3 and limits the relative position between the test contact surface and the explosion source 2. After the explosion source 2 is detonated at this distance, the diffusion of its shock wave is consistent with the path of energy release through the gap in the battery pack shell or the pressure relief valve when the battery cell thermal runaway occurs, ensuring that the effect of the explosion energy on the oil surface is similar to that in the real scene, thereby accurately reflecting the combustion risk of the insulating oil 1 caused by battery cell runaway in actual application.

[0047] Furthermore, the preset height is set based on the distance between the battery cells and the insulating oil in the battery pack. For example, under normal circumstances, the insulating oil in the battery pack does not completely immerse the battery cells, and the preset height can be the minimum distance between the upper surface of the battery cells and the lower surface of the insulating oil.

[0048] Therefore, the location of the explosion source needs to be adjusted for battery cells of different specifications.

[0049] This embodiment directly correlates the preset height with the actual distance between the battery cells and the insulating oil 1 in the battery pack, and the distance between the battery cells and the synthetic oil when thermal runaway occurs, thereby further making the detonation position of the explosion source 2 consistent with the spatial distribution of energy released by the battery cells in the actual thermal runaway scenario, ensuring that key parameters such as the flame propagation path, thermal radiation intensity and heated area of the oil surface strictly correspond to the actual operating conditions of the energy storage system, further ensuring the accuracy of the test results.

[0050] Furthermore, the preset height is within a range of 20 mm to 100 mm.

[0051] Based on the actual installation spacing distribution characteristics of the battery cells and the insulating oil 1 in the energy storage battery pack, this embodiment limits the preset height to a range of 20mm to 100mm, covering both compact design and conventional design. It can simulate various thermal runaway scenarios of medium-sized battery cells in the range of 20mm low gap to 100mm medium and high gap.

[0052] Optionally, the method also includes: determining the contact area between the insulating oil 1 and the battery cell in the battery pack and determining the volume of the insulating oil 1 in advance according to the specifications of the battery pack; determining the specifications of the container 3 so that after the insulating oil 1 is poured into the container 3 according to the determined volume, the area of the test contact surface is not less than the contact area.

[0053] The contact area is generally the area of the top surface of the battery cell (including the surface area of the battery cell poles), which is determined by the rigidity of the battery cell structure and can be calculated by measuring the dimensions of the top surface of the battery cell. The contact area varies from battery cell to battery cell.

[0054] In this embodiment, by accurately calculating the contact area and volume between the insulating oil 1 and the battery cell based on the battery pack specifications in advance and matching the specifications of the container 3 accordingly, the physical parameters of the oil volume and contact area during the test are ensured to be consistent with the actual internal operating conditions of the battery pack. This not only avoids the false increase of local heat flux density due to a small contact surface, but also eliminates the heat capacity distortion caused by oil quantity deviation, such as excessive temperature rise when the oil quantity is insufficient or abnormal heat dissipation when the oil quantity is excessive. As a result, the flame retardancy test of the insulating oil 1 is strictly constrained within the thermal boundary conditions of the actual operation of the battery pack, so that the test results can truly reflect the ability of the insulating oil 1 to suppress flame spread and the thermal balance characteristics during thermal runaway of the battery cell, providing a high-fidelity experimental basis for the selection of insulating media and safety redundancy design of energy storage systems of different specifications.

[0055] Furthermore, the method also includes: selecting container 3 according to the number of battery cells in the battery pack and the arrangement of the battery cell modules in the battery pack, including: the more battery cells in the battery pack, the larger the volume of container 3; under the premise that the number of battery cells in the battery pack is the same, the smaller the number of battery cells in a single module, the larger the volume of container 3.

[0056] In this embodiment, the volume of container 3 is dynamically adjusted based on the number of cells in the battery pack and the module layout. Because the container primarily simulates the battery space, the greater the number of cells in the battery pack, the larger the battery space, and therefore the larger the volume of container 3. Because each module requires structural components such as end plates and steel strips to secure it, given the same number of cells in the battery pack, the more cells in a single battery module, the smaller the container volume can be. If the module has fewer cells, the volume will increase, requiring a larger container volume.

[0057] According to one embodiment of the present application, the explosion source 2 is an explosive gas.

[0058] Explosion source 2 is set to explosive gas because the battery cell will produce a large amount of flammable and explosive gas under thermal runaway conditions. Therefore, by detonating the explosive gas, the real battery cell thermal runaway scenario can be simulated more accurately.

[0059] Furthermore, introducing the explosion source 2 includes: providing a gas tank 4 for storing explosive gas, connecting the gas tank 4 with an extension pipe 5, and introducing the outlet of the extension pipe 5 to a preset test position.

[0060] In a specific implementation, safety is significantly improved by physically isolating the explosive gas storage tank 4 from the test area and connecting it to the predetermined explosion point via an extended pipeline 5. This long pipeline buffers fluctuations in gas delivery pressure, reducing the risk of leakage or deflagration caused by sudden pressure changes in the front-end gas tank 4. Furthermore, operators can remotely control the valve to regulate gas release from a safe area, avoiding direct exposure to the explosion source 2.

[0061] For example, a quick-shut device can be pre-installed at the end of the pipeline to immediately cut off the gas line under abnormal operating conditions, preventing the accumulation of unburned gas in the test space and the potential for secondary explosions. Furthermore, this design decouples the high-risk gas storage unit from the dynamic testing environment, complying with hazardous material zoning control requirements.

[0062] Furthermore, the explosive gas includes at least one of the following gases: hydrogen and methane.

[0063] The decomposition of lithium battery electrolytes often releases hydrogen, while the carbonization of organic materials or the decomposition of SEI films may generate methane. Introducing hydrogen and methane into the explosion source 2 can highly simulate the typical combustible gas components of the battery thermal runaway scenario, making the explosion shock wave intensity, flame propagation path and gas penetration behavior faced by the insulating oil 1 at the gas-liquid interface closer to the actual working conditions, ensuring that the test results can effectively reflect the safety performance of the insulating oil 1 during thermal runaway of the battery cell, and avoiding distortion of the explosion-proof performance evaluation caused by the deviation between the simulated gas and the actual gas production components.

[0064] According to one embodiment of the present application, the method further includes: providing a temperature detection device in the insulating oil 1 , and monitoring the temperature change of the insulating oil 1 in real time based on the temperature detection device.

[0065] A temperature detection device such as a thermocouple is provided in the insulating oil 1, which can monitor the oil temperature change in real time during the battery thermal runaway simulation process, and provide more detailed reference data for optimizing the explosion-proof design.

[0066] According to one embodiment of the present application, the method further includes: setting an image acquisition device 6 in an open space, acquiring images of the insulating oil 1 and its surrounding areas based on the image acquisition device 6, judging whether the insulating oil 1 is burning based on the acquired images, and when the insulating oil 1 is burning, obtaining the spread of the flame based on the acquired images.

[0067] In this embodiment, the image acquisition device 6 is deployed in an open space to capture the combustion state and flame propagation image of the insulating oil 1 and the surrounding area in real time. The tester can directly obtain the test results by observing the image, and can also cooperate with image recognition software.

[0068] According to one embodiment of the present application, the method further includes: pre-installing an ignition device 7 at a preset test position to detonate the explosion source 2, including: starting the ignition device 7 to ignite and controlling the ignition temperature to ignite the explosion source 2.

[0069] In this embodiment, a controllable ignition device 7 is installed at a preset test position, and the repeatability and safety of the explosion simulation experiment can be improved by accurately controlling the ignition temperature.

[0070] Furthermore, the method further includes: if the insulating oil 1 does not burn after the ignition device 7 is ignited, controlling the ignition device 7 to increase the ignition temperature and / or replenish the explosion source 2 until the insulating oil 1 burns.

[0071] In this preferred embodiment, through a closed-loop feedback control mechanism, the combustion state of the insulating oil 1 is detected in real time after the ignition device 7 is ignited. If combustion is not triggered, the ignition temperature can be automatically increased in a step-by-step manner or the concentration of the explosion source 2 can be dynamically supplemented. This not only ensures that the detonation operation can be effectively carried out, but also ensures the safety of the operation and avoids operational risks that may be caused by manual intervention.

[0072] Optionally, the ignition temperature is in the range of 700°C to 800°C.

[0073] The ignition temperature is controlled in the range of 700℃ to 800℃, which is significantly higher than the auto-ignition threshold of common combustibles, and can ensure that the explosion source can be detonated after ignition.

[0074] According to one embodiment of the present application, the method further includes: configuring an oil and gas collection device 8 above the insulating oil 1 to collect the oil and gas above the insulating oil 1 during the test, and quantitatively analyzing the composition of the collected oil and gas, and generating an oil and gas composition analysis report based on the analysis results to quantify the risk.

[0075] In this embodiment, the volatile mixture released from the surface of the insulating oil 1 is collected in real time during the test process, and the collected oil and gas composition is detected by methods such as GC-MS quantitative analysis, so that the risk can be quantified.

[0076] According to one embodiment of the present application, the method further includes: when the insulating oil 1 is not burning, sampling and analyzing the insulating oil 1 .

[0077] In this embodiment, after the test is terminated, the unburned insulating oil 1 is sampled and analyzed, for example, the composition and density of the insulating oil are analyzed.

[0078] To solve the above technical problems, the present application also provides a test system for the impact of thermal runaway of battery cells on the safety performance of insulating oil 1 for use in any of the above test methods, comprising: insulating oil 1 set in an open environment; an explosion source 2, introduced into a preset test position.

[0079] Because the test system for the impact of thermal runaway of a battery cell on the safety performance of the insulating oil 1 provided in this embodiment is applied to the above-mentioned test method, the test system of this embodiment also has the technical effects of the above-mentioned test method.

[0080] According to one embodiment of the present application, the testing system further includes: a container 3 for containing the insulating oil 1 .

[0081] The container 3 may be a simulated battery space for containing the insulating oil 1 so as to limit the contact area between the insulating oil 1 and the explosion flame, reduce test errors, and improve the accuracy and repeatability of data collection.

[0082] According to one embodiment of the present application, the testing system further includes: an oil and gas collecting device 8, which is arranged above the liquid level of the insulating oil 1 and is used to collect the oil and gas above the insulating oil during the test.

[0083] The provision of the oil / gas collection device 8 facilitates the real-time collection of volatile compounds released from the surface of the insulating oil 1 and the quantitative analysis of the collected oil / gas composition. The oil / gas collection device 8 can be fixed to the open mouth area of the container using a separate bracket or directly fixed to the container wall in the open mouth area.

[0084] According to one embodiment of the present application, the test system also includes: an ignition device 7 arranged at the preset test position, used to detonate the explosion source 2; and / or a gas tank 4 and an extension pipe 5, the gas tank 4 is used to store the explosion source 2, one end of the extension pipe 5 is connected to the gas tank 4, and the other end of the extension pipe 5 is facing the preset test position.

[0085] The provision of an ignition device 7 improves the repeatability and safety of explosion simulation experiments. The provision of an extended pipe 5 significantly enhances safety by physically isolating the explosive gas storage tank 4 from the test area and connecting it to the predetermined explosion point. According to one embodiment of the present application, the testing system further includes an image acquisition device 6 for capturing images of the insulating oil 1 and its surrounding area.

[0086] In this embodiment, the image acquisition device 6 is configured to provide visualization parameters for optimizing the formulation of the insulating oil 1 and the response strategy of the explosion-proof system.

[0087] Please refer to Figure 4 As shown, Figure 4 Schematic diagram of the relationship between components of a test system for the impact of thermal runaway of a battery cell on the safety performance of insulating oil in an embodiment of the present application.

[0088] In one embodiment of the present application, the container is a rectangular box with a size of 737.5 mm * 1307.7 mm * 32.5 mm. The contact area between the insulating oil 1 and the air is approximately 1 m2, and the oil consumption is approximately 30 L, which is used to simulate the actual working conditions of the insulating oil 1. The gas tank 4 is set with reference to the pressure vessel standard GB 150-2011. The image acquisition device 6 uses an industrial detection infrared thermal imager that complies with GB / T 19870-2018. The test system also includes a thermocouple as a temperature detection device.

[0089] It is conceivable that in order to ensure the safety of the test process, the test system may also include fire extinguishing equipment, such as a fire extinguisher that complies with GB 4351-2023.

[0090] It should be noted that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship and movement status between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0091] It should also be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or indirectly connected to the other element through an intervening element.

[0092] In addition, the descriptions of "first", "second", etc. in this application are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0093] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0094] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0095] The above description is only a preferred embodiment of the present application and does not limit the patent scope of the present application. All equivalent structural transformations made based on the design concept of the present application and the contents of the present application description and drawings, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A method for testing the impact of thermal runaway of a battery cell on the safety performance of insulating oil, characterized in that: The method comprises: Introducing an explosion source at a pre-set test location near insulating oil in an open environment; The explosion source is detonated to simulate the loss of control of the battery cells in the immersed energy storage battery pack, and the burning of the insulating oil is monitored.

2. The method for testing the impact of thermal runaway of a battery cell on the safety performance of insulating oil according to claim 1, characterized in that: The insulating oil is placed in a container with an open mouth; the surface liquid surface formed after the insulating oil is spread in the container is the test contact surface of the insulating oil; The preset test position is a position at a preset height from the test contact surface in the open area of the container.

3. The method for testing the impact of thermal runaway of a battery cell on the safety performance of insulating oil according to claim 2, characterized in that: The preset height is set with reference to the distance between the battery cells and the insulating oil in the battery pack.

4. The method for testing the impact of thermal runaway of a battery cell on the safety performance of insulating oil according to claim 3, characterized in that: The preset height is in the range of 20 mm to 100 mm.

5. The method for testing the impact of thermal runaway of a battery cell on the safety performance of insulating oil according to claim 2, characterized in that: The method further comprises: Determining in advance the contact area between the insulating oil and the battery cells in the battery pack and the volume of the insulating oil according to the specifications of the battery pack; The specifications of the container are determined so that after the insulating oil is poured into the container according to the determined volume, the area of the test contact surface is not less than the contact area.

6. The method for testing the impact of thermal runaway of a battery cell on the safety performance of insulating oil according to claim 5, characterized in that: The method further comprises: The container is selected according to the number of battery cells in the battery pack and the arrangement of the battery cell modules in the battery pack, including: the more battery cells in the battery pack, the larger the volume of the container; under the premise that the number of battery cells in the battery pack is the same, the smaller the number of battery cells in a single module, the larger the volume of the container.

7. The method for testing the impact of thermal runaway of a battery cell on the safety performance of insulating oil according to claim 1, characterized in that: The explosion source is explosive gas.

8. The method for testing the impact of thermal runaway of a battery cell on the safety performance of insulating oil according to claim 7, characterized in that: The introduction of the explosion source comprises: A gas tank for storing the explosive gas is provided, the gas tank is connected with an extension pipe, and the outlet of the extension pipe is introduced into the preset test position.

9. The method for testing the safety performance of insulating oil according to claim 8, characterized in that: The explosive gas includes at least one of the following gases: hydrogen and methane.

10. The method for testing the impact of thermal runaway of a battery cell on the safety performance of insulating oil according to claim 1, characterized in that: The method further comprises: A temperature detection device is provided in the insulating oil, and temperature changes of the insulating oil are monitored in real time based on the temperature detection device; And / or, an image acquisition device is provided in the open space, and images of the insulating oil and its surrounding area are acquired by the image acquisition device. Based on the acquired images, it is determined whether the insulating oil is burning, and when the insulating oil is burning, the propagation of the flame is obtained based on the acquired images.

11. The method for testing the impact of thermal runaway of a battery cell on the safety performance of insulating oil according to claim 1, characterized in that: The method further comprises: Pre-install an ignition device at the preset test position; Detonating the explosion source includes: starting the ignition device to ignite and controlling the ignition temperature to ignite the explosion source.

12. The method for testing the impact of thermal runaway of a battery cell on the safety performance of insulating oil according to claim 11, characterized in that: The method further comprises: If the insulating oil does not burn after the ignition device is ignited, controlling the ignition device to increase the ignition temperature and / or replenish the explosion source until the insulating oil burns; And / or, the ignition temperature is in the range of 700°C to 800°C.

13. The method for testing the impact of thermal runaway of a battery cell on the safety performance of insulating oil according to claim 1, characterized in that: The method further comprises: An oil and gas collection device is arranged above the insulating oil to collect the oil and gas above the insulating oil during the test, and the composition of the collected oil and gas is quantitatively analyzed. An oil and gas composition analysis report is generated based on the analysis results to quantify the risk. And / or, when the insulating oil does not burn, sampling and analyzing the insulating oil.

14. A testing system for the impact of thermal runaway of a battery cell on the safety performance of insulating oil used in the testing method according to any one of claims 1 to 13, characterized in that: include: Insulating oil set in open environment; An explosion source is introduced into the preset test location.

15. The testing system for the impact of thermal runaway of battery cells on the safety performance of insulating oil according to claim 14, characterized in that: Also includes: a container for containing the insulating oil; and / or, an ignition device, disposed at the preset test position, for detonating the explosion source; and / or, a gas tank and an extension pipe, wherein the gas tank is used to store the explosion source, one end of the extension pipe is connected to the gas tank, and the other end of the extension pipe is directed toward the preset test position; and / or, a temperature detection device, disposed in the insulating oil, for monitoring temperature changes of the insulating oil in real time; and / or, an image acquisition device for acquiring images of the insulating oil and its surrounding area; And / or, an oil and gas collection device is provided above the insulating oil liquid level, for collecting the oil and gas above the insulating oil during the test process.

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