Method and device for measuring jet impact force of battery thermal runaway

Abstract

The application provides a battery thermal runaway jet impact force measuring method and device. The battery thermal runaway jet impact force measuring method comprises the following steps: obtaining the actual mass M of a baffle, placing the baffle at a preset height h above a battery to be measured, and supporting the baffle through a support structure; heating the battery to open the pressure relief valve of the battery, and generating a thermal runaway jet of the battery; obtaining the minimum support force F of the support structure on the baffle during the generation of the thermal runaway jet min ; according to force balance, calculating the maximum jet impact force Q max experienced by the baffle through a jet impact force obtaining step, wherein Q max =Mg-F min . The technical scheme of the application can obtain the maximum jet impact force Q max experienced by the baffle at the preset height h when the battery is in thermal runaway jet, so that a battery module capable of bearing the maximum jet impact force Q max of the battery can be designed according to the measurement result, thereby ensuring the safety performance of the battery module.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more specifically, to a method and apparatus for measuring the impact force of a thermal runaway jet in a battery. Background Technology

[0002] Lithium-ion batteries are currently widely used in important fields such as electric vehicles, electric cars, and energy storage power stations. However, lithium-ion batteries pose a risk of thermal runaway under abuse conditions such as short circuits, impacts, punctures, and overheating.

[0003] In existing technologies, lithium-ion battery modules include a casing and battery cells housed within the casing. When thermal runaway occurs, the battery's pressure relief valve opens and jets air, creating a jet impact force on the top plate of the casing. If the top plate cannot withstand a large jet impact force, it will be damaged, posing a safety hazard. Furthermore, due to the high energy density requirements of some applications (such as energy storage containers and electric vehicle battery modules), the internal space of battery modules is becoming increasingly limited. When the jet impact force is too large and the internal space of the casing is too small, it can further lead to combustion and explosion problems.

[0004] In conclusion, due to the inability to predict the magnitude of the jet impact force in advance, batteries pose significant safety risks during thermal runaway. Summary of the Invention

[0005] The main objective of this invention is to provide a method and apparatus for measuring the jet impact force during battery thermal runaway, in order to solve the problem in the prior art where the size of the jet impact force during battery thermal runaway cannot be predicted, resulting in the battery module design being unable to withstand the jet impact force, thus posing a significant safety hazard.

[0006] To achieve the above objectives, according to one aspect of the present invention, a method for measuring the impact force of a battery thermal runaway jet is provided, comprising: obtaining the actual mass M of a baffle; placing the baffle at a preset height h above the battery to be measured, such that the central axis of the baffle coincides with the central axis of the battery's pressure relief valve, and supporting the baffle by a support structure; heating the battery until the battery's pressure relief valve opens, and generating a jet of thermal runaway jet; and obtaining the minimum value F of the supporting force F of the support structure on the baffle during the generation of the thermal runaway jet. min The steps to obtain the minimum support force are as follows: Based on the force balance, calculate the maximum jet impact force Q on the baffle. max The steps for obtaining the jet impact force, where Q max =Mg-F min .

[0007] Furthermore, in the step of supporting the baffle with a support structure, the support structure is a suspension frame, and the baffle is suspended on the suspension frame by a tension sensor. After the battery is heated, the minimum supporting force F of the support structure on the baffle can be obtained based on the real-time measurement value of the tension sensor. min .

[0008] Furthermore, before heating the battery, the measurement method also includes a step of placing the battery on a liftable telescopic platform, and the measurement method also includes fixing a heating element to one side of the battery and heating the battery through the heating element.

[0009] Furthermore, the measurement method also includes: changing the size of the preset height h, and repeatedly executing the jet generation step, the minimum support force acquisition step, and the jet impact force acquisition step, in order to obtain the maximum jet impact force Q of the battery on the baffle located at different preset heights h when thermal runaway jet occurs. max Size.

[0010] Furthermore, the measurement method also includes: obtaining the force-bearing area A of the baffle, which is the projected area of ​​the baffle on a plane perpendicular to its own central axis; and calculating the maximum jet impact force P experienced per unit area of ​​the baffle. max =Q max / A, to obtain the maximum jet impact force P per unit area of ​​the baffle located at a preset height h during thermal runaway jet. max .

[0011] According to another aspect of the present invention, a design method for a battery module thermal runaway protection system is also provided, the design method comprising: obtaining the maximum jet impact force Q during battery thermal runaway according to the above-described measurement method. max Obtain the force-bearing area A of the baffle, which is the projected area of ​​the baffle on a plane perpendicular to its central axis; calculate the maximum jet impact force P experienced per unit area of ​​the baffle. max =Q max / A, to obtain the maximum jet impact force P per unit area of ​​the baffle during thermal runaway jet of the battery. max ; and the material used for the battery module casing, wherein the tensile strength of the material is greater than or equal to the maximum jet impact force P per unit area on the baffle located at a preset height h during thermal runaway. max Furthermore, the distance between the top plate of the casing and the battery cell of the battery module is a preset height h.

[0012] According to another aspect of the present invention, a measuring device for measuring the impact force of a battery thermal runaway jet is also provided. The measuring device is applied to the above-described method for measuring the impact force of a battery thermal runaway jet. The measuring device includes: a mounting platform for placing the battery to be measured; a baffle located above the mounting platform, and the baffle is configured such that its central axis coincides with the central axis of the battery's pressure relief valve; a support structure for supporting the baffle; a sensor connected to the support structure, the sensor being used to measure the supporting force F of the support structure on the baffle; and a heating element disposed on the mounting platform, the heating element being used to heat the battery.

[0013] Furthermore, the sensor is a tension sensor, and the support structure is a suspension frame. The suspension frame includes: a support frame body and multiple support beams arranged on the support frame body, the multiple support beams being parallel to each other; at least three tension sensors, one end of each tension sensor being connected to one of the multiple support beams, and the other end of each tension sensor being connected to a baffle, so that the suspension frame supports the baffle through at least three tension sensors and measures the tension value of the suspension frame on the baffle.

[0014] Furthermore, there are four tension sensors, which are spaced apart at the four corners of the baffle; and / or, the suspension also includes a lead screw for connecting the tension sensors and the baffle, one end of the lead screw being fixedly connected to the tension sensor and the other end of the lead screw being threadedly connected to the baffle.

[0015] Furthermore, the installation platform is a telescopic platform that can be raised and lowered. The telescopic platform includes a fixed plate, a movable plate that can be raised and lowered in the vertical direction relative to the fixed plate, and a linkage assembly disposed between the fixed plate and the movable plate.

[0016] By applying the technical solution of this invention and based on force balance, the maximum jet impact force Q of the battery on the baffle located at a preset height h during thermal runaway jet can be obtained. max This allows for the estimation of the impact force exerted on the top plate of the casing during thermal runaway, providing data support for subsequent battery module design. Specifically, when designing the battery module, the measured values ​​can be used to select a casing material that meets strength requirements and optimize the casing dimensions (i.e., the height distance between the top plate of the casing and the battery cell). This enables the design of a thermal runaway suppression system and a thermal runaway protection system that match the battery cell, ensuring that the battery module can withstand the maximum jet impact force Q from the battery. max This avoids the problem of the battery damaging the casing during thermal runaway jets, as well as the problem of the battery exploding due to the excessively small internal space of the casing. This reduces the safety hazards during battery thermal runaway and ensures the safety performance of the battery module. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0018] Figure 1 A partial flowchart illustrating an embodiment of the method for measuring the impact force of a battery thermal runaway jet according to the present invention is shown.

[0019] Figure 2 It shows Figure 1 A flowchart illustrating an embodiment of a method for measuring the impact force of a battery thermal runaway jet;

[0020] Figure 3 A flowchart illustrating an embodiment of the design method for a battery module thermal runaway protection system according to the present invention is shown.

[0021] Figure 4 A schematic diagram of a measuring device for measuring the impact force of a battery thermal runaway jet according to the present invention is shown; and

[0022] Figure 5 A schematic diagram showing the change of jet impact force over time during battery thermal runaway, obtained by the method for measuring the jet impact force of the battery thermal runaway according to the present invention.

[0023] The above figures include the following reference numerals:

[0024] 10. Installation platform; 20. Baffle; 30. Support structure; 31. Support frame; 32. Support beam; 34. Lead screw; 40. Heating element; 50. Tension sensor; 60. Fixture; 100. Battery. Detailed Implementation

[0025] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] In this invention and its embodiments, it is preferable to measure the jet impact force during thermal runaway of a lithium battery. This provides experimental data for subsequent battery module design, allowing for better optimization of the battery module structure.

[0027] It should be noted that, Figure 5 A schematic diagram of the change of jet impact force during battery thermal runaway jet as a function of time is shown, obtained by the method of measuring the impact force of battery thermal runaway jet according to the present invention, wherein exp(1), exp(2) and exp(3) represent the measurement curves of three different battery samples when the baffle is located 2 cm (i.e. 20 mm) above the battery.

[0028] like Figure 1 As shown, an embodiment of the present invention provides a method for measuring the impact force of a battery thermal runaway jet. The method includes: obtaining the actual mass M of a baffle; placing the baffle at a preset height h above the battery to be measured, aligning the central axis of the baffle with the central axis of the battery's pressure relief valve, and supporting the baffle with a support structure; heating the battery until the pressure relief valve opens, causing the battery to generate a thermal runaway jet; and during the generation of the thermal runaway jet, obtaining the minimum value F of the supporting force F exerted by the support structure on the baffle. min The steps to obtain the minimum support force are as follows: Based on the force balance, calculate the maximum jet impact force Q on the baffle. max The steps for obtaining the jet impact force, where Q max =Mg-F min .

[0029] It should be noted that in the above formula, g represents gravitational acceleration, with units of N / kg; M represents mass, with units of kg; F min The unit is N. "Place the baffle at a preset height h above the battery to be measured" refers to the height distance between the lower surface of the baffle and the upper surface of the battery cell.

[0030] Based on the above settings and the principle of force balance, the maximum jet impact force Q of the battery on the baffle located at a preset height h during thermal runaway jet can be obtained. max This allows for the estimation of the impact force on the top plate of the casing during thermal runaway, providing support for subsequent battery module design and enabling optimization of the battery module structure. Specifically, when designing the battery module, the measured values ​​can be used to select a casing material that meets strength requirements and optimize the casing dimensions (i.e., the height distance between the top plate of the casing and the battery cell). This allows for the design of a thermal runaway suppression system and a thermal runaway protection system that match the battery cell, ensuring that the battery module can withstand the maximum jet impact force Q from the battery. max This avoids the problem of the battery damaging the casing during thermal runaway jets, as well as the problem of the battery exploding due to the excessively small internal space of the casing. This reduces the safety hazards during battery thermal runaway and ensures the safety performance of the battery module.

[0031] Optionally, the power range of the heating element used when heating the battery is from 300W to 1000W, preferably 500W, so as to cause thermal runaway and jetting phenomenon in the battery.

[0032] In another embodiment of the present invention, before the jet generation step, the actual weight G of the baffle can be directly obtained by acquiring the supporting force of the supporting structure on the baffle (for example, by weighing using a weighing sensor or tension sensor installed on the supporting structure). In this case, the equilibrium equation in the jet impact force acquisition step is Q.max =GF min .

[0033] like Figure 2 As shown in the embodiment of the present invention, in the step of supporting the baffle by a support structure, the support structure is a suspension frame, and the baffle is suspended on the suspension frame by a tension sensor. After the battery is heated, the minimum value F of the supporting force F of the support structure on the baffle can be obtained according to the real-time measurement value of the tension sensor. min .

[0034] With the above settings, the tension sensor can measure the supporting tension of the suspension on the baffle in real time. Thus, for a period of time after the battery experiences thermal runaway, the changes in the supporting force of the suspension on the baffle can be obtained based on the measured values. This allows for the acquisition of a curve showing the change in supporting force over a preset time period (from the generation of the jet to its near disappearance). Based on this curve, the minimum supporting force F of the suspension on the baffle can then be determined. min At this point, the jet impact force of the battery on the baffle is at its maximum.

[0035] In another embodiment of the invention, Figure 5 This diagram illustrates the change in jet impact force over time during thermal runaway of a lithium battery. The horizontal axis represents time (seconds), and the vertical axis represents impact force (Newtons). Experiments show that the jet impact force reaches its maximum value approximately 25 seconds after thermal runaway. Therefore, based on these experiments, reading the tension sensor value 25 seconds after heating the battery can also yield the minimum supporting force F of the suspension bracket on the baffle. min .

[0036] like Figure 2 As shown, in an embodiment of the present invention, before heating the battery, the measurement method further includes a step of placing the battery on a liftable telescopic platform, and the measurement method further includes fixing a heating element to one side of the battery and heating the battery through the heating element.

[0037] With the above setup, the battery is placed on a height-adjustable telescopic platform. By adjusting the height of the telescopic platform, the height distance h between the lower surface of the baffle and the upper surface of the battery cell can be changed. The height can be adjusted according to different testing requirements, making operation convenient.

[0038] In an embodiment of the present invention, the measurement method further includes: changing the size of the preset height h, and repeatedly executing the jet generation step, the minimum support force acquisition step, and the jet impact force acquisition step, so as to obtain the maximum jet impact force Q of the battery on the baffle located at different preset height h when thermal runaway jet occurs. max Size.

[0039] In the above technical solution, adjusting the height of the telescopic platform can change the height distance h between the lower surface of the baffle and the upper surface of the battery cell. This allows for multiple adjustments of the preset height h to be measured according to different testing requirements, thus providing a basis for the subsequent design of battery modules of different specifications.

[0040] like Figure 2 As shown, in an embodiment of the present invention, the measurement method further includes: obtaining the force-bearing area A of the baffle, where the force-bearing area is the projected area of ​​the baffle on a plane perpendicular to its own central axis; and calculating the maximum jet impact force P experienced per unit area of ​​the baffle. max =Q max / A, to obtain the maximum jet impact force P per unit area of ​​the baffle located at a preset height h during thermal runaway jet. max .

[0041] With the above settings, the maximum jet impact force P per unit area of ​​the baffle located at a preset height h can be obtained when the battery experiences thermal runaway jet. max .

[0042] like Figure 3 As shown, embodiments of the present invention also provide a design method for a battery module thermal runaway protection system. The design method includes: obtaining the maximum jet impact force Q during battery thermal runaway using the above-described measurement method. max Obtain the force-bearing area A of the baffle, which is the projected area of ​​the baffle on a plane perpendicular to its own central axis; calculate the maximum jet impact force P per unit area of ​​the baffle. max =Q max / A, to obtain the maximum jet impact force P per unit area of ​​the baffle located at a preset height h during thermal runaway jet. max The material used for the battery module housing is selected such that the tensile strength of the material is greater than or equal to the maximum jet impact force Pmax per unit area on the baffle located at a preset height h when the battery is in thermal runaway, and the distance between the top plate of the housing and the battery cell of the battery module is the preset height h.

[0043] With the above settings, when designing the battery module, the maximum jet impact force P per unit area of ​​the baffle can be used as a reference. max By selecting the casing material and optimizing its dimensions (i.e., the height distance between the casing top plate and the battery cell), a thermal runaway suppression system and a thermal runaway protection system that match the battery cell are designed to ensure that the battery module can withstand the maximum jet impact force P from the battery to the unit area of ​​the battery module. max To prevent the battery from being unable to withstand the maximum jet impact force P per unit area of ​​the battery module due to the low tensile strength of the casing material during thermal runaway jetting. maxThis addresses the issues of casing damage and battery explosion due to excessively confined internal space, thereby reducing safety hazards during battery thermal runaway and ensuring the safety performance of the battery module.

[0044] In another embodiment of the invention, when the area of ​​the baffle is large, the jet impact force from the battery on different positions of the baffle is not uniform. The area of ​​the baffle directly opposite the battery pressure relief valve experiences the most concentrated force; that is, the area of ​​the baffle directly opposite the battery pressure relief valve can be considered the force-bearing area of ​​the baffle, and the cross-sectional area of ​​the battery pressure relief valve is equivalent to the force-bearing area of ​​the baffle. In this case, the step of obtaining the size of the force-bearing area of ​​the baffle can also be to obtain the size of the cross-sectional area S of the battery pressure relief valve, where the cross-sectional area is the projected area of ​​the battery pressure relief valve on a plane perpendicular to its own central axis. Then, the maximum jet impact force P per unit area of ​​the baffle is... max =Q max / S.

[0045] like Figure 4 As shown, an embodiment of the present invention also provides a measuring device for measuring the impact force of a battery thermal runaway jet. The measuring device is applied to the above-described method for measuring the impact force of a battery thermal runaway jet. The measuring device includes a mounting platform 10, a baffle 20, a support structure 30, a sensor, and a heating element 40. The mounting platform 10 is used to place the battery 100 to be measured. The baffle 20 is located above the mounting platform 10, and the baffle 20 is configured such that its central axis coincides with the central axis of the pressure relief valve of the battery 100. The support structure 30 is used to support the baffle 20. The sensor is connected to the support structure 30 and is used to measure the supporting force F of the support structure on the baffle. The heating element 40 is disposed on the mounting platform 10 and is used to heat the battery 100.

[0046] With the above setup, the heating element 40 heats the battery 100, causing it to jet after thermal runaway. The impact force generated by the jet from the battery 100 can impact the baffle 20. According to the principle of force balance, the sum of the jet impact force on the baffle 20 and the supporting force of the supporting structure 30 on the baffle 20 is equal to the weight of the baffle 20. In this way, the magnitude of the jet impact force on the baffle 20 during thermal runaway can be calculated.

[0047] Preferably, the baffle 20 is made of steel plate, which can ensure that the baffle 20 has a certain strength and avoid damage to the baffle 20 after being impacted by the jet of the battery 100 during the experiment.

[0048] like Figure 4As shown, in an embodiment of the present invention, the sensor is a tension sensor 50, the support structure 30 is a suspension frame, and the suspension frame includes: a support frame body 31 and multiple support beams 32 disposed on the support frame body 31, the multiple support beams 32 being parallel to each other; at least three tension sensors 50, one end of each tension sensor 50 being connected to one of the multiple support beams 32, and the other end of each tension sensor 50 being connected to a baffle 20, so that the suspension frame supports the baffle 20 through at least three tension sensors 50 and measures the tension value of the suspension frame on the baffle 20.

[0049] In the above technical solution, the support frame 31 includes four columns and four connecting rods connected end to end on the top of the four columns. Two parallel support beams 32 are spaced apart on the connecting rods in the horizontal direction. Both support beams 32 can move horizontally relative to the support frame 31, which can be used to connect baffles 20 of different sizes, thus making it suitable for measuring batteries 100 of different sizes.

[0050] With the above settings, the measured value of the tension sensor 50 is the supporting tension of the suspension frame on the baffle 20.

[0051] In one embodiment of the present invention, the support frame 31 is an iron frame with a length of 75cm, a width of 53cm, and a height of 103cm.

[0052] In another embodiment of the present invention, the support structure 30 can also be a support platform. The support platform includes a base and a support plate disposed on top of the base. An clearance through hole is provided on the support plate. A baffle 20 is located on the support plate and covers the clearance through hole, so that the central axis of the baffle 20 coincides with the central axis of the pressure relief valve of the battery 100. A pressure sensor is provided on the support plate. According to the principle of force balance, the measured value of the pressure sensor (i.e., the pressure of the baffle 20 on the support plate) is equal to the supporting force F of the support plate on the baffle 20. Thus, according to the balance equation: Q max =Mg-F min It can also calculate the magnitude of the jet impact force on the baffle 20 when the current thermal runaway occurs.

[0053] Preferably, four tension sensors 50 are arranged at intervals at the four corners of the baffle 20. Thus, when the battery 100 does not experience thermal runaway, and ignoring friction, the sum of the tension values ​​displayed by the four tension sensors 50 is the actual weight of the baffle 20. Similarly, when the battery 100 experiences thermal runaway and generates a jet, the actual weight of the baffle 20 minus the sum of the values ​​displayed by the four tension sensors yields the jet impact force of the battery 100 on the baffle 20. By using four tension sensors 50, the baffle 20 can be suspended more stably on the suspension frame, preventing the baffle 20 from swaying or rotating in the horizontal direction, thereby ensuring accurate measurement results.

[0054] like Figure 4 As shown, in an embodiment of the present invention, the suspension frame further includes a lead screw 34 for connecting the tension sensor 50 and the baffle 20. One end of the lead screw 34 is fixedly connected to the tension sensor 50, and the other end of the lead screw 34 is threadedly connected to the baffle 20.

[0055] In the above technical solution, the baffle 20 is provided with a threaded hole for threaded connection with the lead screw 34, and the lead screw 34 is fixedly connected to the support beam 32 by a hook. In this way, the lead screw 34 can restrain the horizontal sway of the baffle 20 and prevent the baffle from rotating or swaying laterally or laterally.

[0056] like Figure 4 As shown, in an embodiment of the present invention, the installation platform 10 is a telescopic platform that can be raised and lowered. The telescopic platform includes a fixed plate, a movable plate that can be raised and lowered relative to the fixed plate in the vertical direction, and a connecting rod assembly disposed between the fixed plate and the movable plate.

[0057] By adjusting the above settings, the preset height h can be adjusted by changing the height of the telescopic platform, making operation easier.

[0058] like Figure 4 As shown, in an embodiment of the present invention, the mounting platform 10 is also provided with a clamp 60, which is used to fix the battery 100 to be measured and the heating element 40. The top of the clamp 60 is provided with an opening, and the battery pressure relief valve corresponds to the opening so that the impact force of the pressure relief valve jet can be ejected through the opening and impact the baffle 20.

[0059] In one embodiment of the present invention, the installation platform 10 is a height-adjustable telescopic platform with a length of 30cm, a width of 30cm, and a height of 10cm to 46cm.

[0060] In one embodiment of the present invention, the baffle 20 is a carbon steel plate with a length of 300 mm, a width of 200 mm, and a thickness of 30 mm. Threaded holes with a depth of 25 mm are opened at the four corners of the baffle 20. The maximum jet impact force Q on the baffle 20 located 2 cm above the battery 100 during thermal runaway of the battery 100 (specifically a 50 Ah lithium battery) is obtained according to the aforementioned measurement method. max 10N (e.g.) Figure 5 (As shown). Due to the large area of ​​baffle 20, the jet impact force from the battery on different positions of baffle 20 is not uniform. The area of ​​baffle 20 directly opposite the battery pressure relief valve experiences the most concentrated force (i.e., the area of ​​baffle 20 directly opposite the battery pressure relief valve can be considered the force-bearing area of ​​baffle 20, and the cross-sectional area of ​​the battery pressure relief valve is equivalent to the force-bearing area of ​​baffle 20). The battery pressure relief valve is 15mm long and 20mm wide. Therefore, according to calculations, the jet impact force P per unit area on baffle 20 during thermal runaway of battery 100 can be obtained. max3.3*10 -2 N / mm 2 Therefore, when designing the battery module casing, if the distance between the lower surface of the casing top plate and the upper surface of the battery cell is 2cm, the material capable of withstanding the jet impact force during battery thermal runaway is determined based on the above measurement results. The casing needs to be selected with a shear strength greater than 3.3*10 at high temperatures (approximately 1000℃). -2 N / mm 2 The material is designed to ensure that the casing will not be damaged in the event of thermal runaway of the battery.

[0061] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects: based on the force balance, the maximum jet impact force Q of the battery on the baffle located at a preset height h during thermal runaway jet can be obtained. max This allows for the estimation of the impact force exerted on the top plate of the casing during thermal runaway. When designing the battery module, the selected casing material and dimensions (i.e., the height distance between the top plate of the casing and the battery cell) can be optimized based on these measurements. This enables the design of a thermal runaway suppression system and a thermal runaway protection system that match the battery cell, ensuring that the battery module can withstand the maximum jet impact force Q from the battery. max To prevent the battery from experiencing thermal runaway due to the tensile strength of the casing material being less than the battery's maximum jet impact force Q. max This addresses the issues of casing damage and battery explosion due to excessively confined internal space, thereby reducing safety hazards during battery thermal runaway and ensuring the safety performance of the battery module.

[0062] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for measuring the impact force of a battery thermal runaway jet, characterized in that, include: Obtain the actual mass M of the baffle, place the baffle at a preset height h above the battery to be measured, so that the central axis of the baffle coincides with the central axis of the pressure relief valve of the battery, and support the baffle through a support structure; The jet generation step involves heating the battery until the battery's pressure relief valve opens, causing the battery to generate a thermal runaway jet. The steps to obtain the actual weight G of the baffle by obtaining the supporting force of the supporting structure on the baffle; During the generation of the thermal runaway jet, the minimum value F of the supporting force F of the support structure on the baffle is obtained. min The steps to obtain the minimum support force; Based on the force balance, the maximum jet impact force Q on the baffle is calculated. max The steps for obtaining the jet impact force, where Q max = Mg- F min ; In the step of supporting the baffle using the support structure, the support structure is a suspension frame, and the baffle is suspended from the suspension frame by a tension sensor. After heating the battery, the minimum supporting force F of the support structure on the baffle can be obtained based on the real-time measurement value of the tension sensor. min ; Before heating the battery, the measurement method further includes a step of placing the battery on a liftable telescopic platform, and the measurement method further includes fixing a heating element to one side of the battery and heating the battery through the heating element; The measurement method further includes: Obtain the force-bearing area A of the baffle, where the force-bearing area is the projected area of ​​the baffle on a plane perpendicular to its own central axis; Calculate the maximum jet impact force P per unit area of ​​the baffle. max =Q max / A, to obtain the maximum jet impact force P per unit area of ​​the baffle located at a preset height h during thermal runaway jet. max .

2. The method for measuring the impact force of a battery thermal runaway jet according to claim 1, characterized in that, The measurement method further includes: changing the size of the preset height h, and repeatedly executing the jet generation step, the minimum support force acquisition step, and the jet impact force acquisition step, to obtain the maximum jet impact force Q of the battery on the baffle located at different preset height h when thermal runaway jet occurs. max Size.

3. A design method for a battery module thermal runaway protection system, characterized in that, The design method include: The measurement method according to claim 1 or 2 is used to obtain the maximum jet impact force Q during battery thermal runaway. max ; Obtain the force-bearing area A of the baffle, where the force-bearing area is the projected area of ​​the baffle on a plane perpendicular to its own central axis; Calculate the maximum jet impact force P per unit area of ​​the baffle. max =Q max / A, to obtain the maximum jet impact force P per unit area of ​​the baffle located at a preset height h during thermal runaway jet. max ; as well as The material used for the battery module housing is selected such that its tensile strength is greater than or equal to the maximum jet impact force P experienced per unit area by the baffle during thermal runaway of the battery. max Furthermore, the distance between the top plate of the casing and the cell of the battery module is a preset height h.

4. A measuring device for measuring the impact force of a jet during thermal runaway of a battery, characterized in that, The measuring device is applied to the method for measuring the impact force of a battery thermal runaway jet as described in claim 1 or 2, and the measuring device comprises: Mounting platform (10) for placing the battery to be measured; A baffle (20) is located above the mounting platform (10), and the baffle (20) is configured such that its central axis coincides with the central axis of the battery's pressure relief valve; Support structure (30) for supporting the baffle (20); A sensor is connected to the support structure (30) and is used to measure the supporting force F of the support structure on the baffle. A heating element (40) is disposed on the mounting platform (10) and is used to heat the battery.

5. The measuring device for measuring the impact force of a battery thermal runaway jet according to claim 4, characterized in that, The sensor is a tension sensor (50), and the support structure (30) is a suspension frame, which includes: The support frame (31) and multiple support beams (32) arranged on the support frame (31) are parallel to each other; At least three of the tension sensors (50) are provided, one end of each tension sensor (50) is connected to one of the plurality of support beams (32), and the other end of each tension sensor (50) is connected to the baffle (20), so that the suspension supports the baffle (20) by at least three of the tension sensors (50) and measures the tension value of the suspension on the baffle (20).

6. The measuring device for measuring the impact force of a battery thermal runaway jet according to claim 5, characterized in that, There are four tension sensors (50), which are spaced apart at the four corners of the baffle (20); and / or, The suspension frame also includes a lead screw (34) for connecting the tension sensor (50) and the baffle (20), one end of the lead screw (34) is fixedly connected to the tension sensor (50), and the other end of the lead screw (34) is threadedly connected to the baffle (20).

7. The measuring device for measuring the impact force of a battery thermal runaway jet according to claim 4, characterized in that, The installation platform (10) is a telescopic platform that can be raised and lowered. The telescopic platform includes a fixed plate, a movable plate that can be raised and lowered in the vertical direction relative to the fixed plate, and a connecting rod assembly disposed between the fixed plate and the movable plate.

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