An in-situ battery separator impact testing device for impact process visualization

Abstract

The application relates to an in-situ battery diaphragm impact testing device for impact process visualization, and belongs to the technical field of impact testing. The device comprises an electromagnetic ballistic acceleration mechanism, an impact clamp mechanism, a high-speed camera, an oscilloscope and a plurality of projectiles; the electromagnetic ballistic acceleration mechanism is a coil acceleration gun or a high-voltage electromagnetic gun; the impact clamp mechanism comprises an upper electrolytic tank, a lower electrolytic tank and a pair of clamping pipes; the upper electrolytic tank and the lower electrolytic tank are both made of transparent materials and are both provided with electrolyte; the positive and negative electrodes of the oscilloscope are respectively connected with the electrolyte in the upper electrolytic tank and the electrolyte in the lower electrolytic tank through wires; and the high-speed camera is arranged on one side of the impact clamp mechanism. During impact testing, the impact testing device is arranged in a glove box; the measured battery diaphragm is clamped between the pair of clamping pipes, the projectile is shot into the upper electrolytic tank from the ballistic gun chamber and penetrates the measured battery diaphragm to enter the lower electrolytic tank; the high-speed camera records the impact process; and the oscilloscope records the battery voltage change in the impact process.

Description

Technical Field

[0001] This invention belongs to the field of impact testing technology, specifically relating to a testing device for visualizing the impact process of in-situ battery separators. Background Technology

[0002] In recent years, with the booming development of new energy vehicles, the safety performance of automobiles has gradually attracted widespread attention. It can be said that battery collision safety has become a crucial factor affecting the safety of new energy vehicles. Therefore, battery collision avoidance testing and the evolution of the battery's internal structure during high-speed external impacts have received increasingly extensive research and attention. On the other hand, battery fires / explosions during collisions occur because the maximum stress at the separator exceeds its allowable stress, leading to separator damage and mechanical failure, which further causes internal short circuits and thermal runaway, ultimately resulting in battery fires and explosions.

[0003] Currently, researchers often study the impact resistance of lithium-ion batteries by conducting impact tests on pouch cells and observing whether the battery pack remains intact before and after the impact. However, due to the packaging requirements of pouch cells and the opaque nature of the aluminum-plastic film, traditional impact testing methods cannot allow researchers to observe and track the evolution of the battery's internal structure in real time, nor can they grasp the dynamic damage process of the separator. Furthermore, traditional impact testing devices for pouch lithium-ion batteries can only evaluate their impact resistance based on the total energy loss during the impact process, failing to identify internal components or materials that generate energy dissipation characteristics during the impact, and also unable to observe changes in the electrolyte diffusion rate before and after the impact. Therefore, there is an urgent need for an in-situ battery impact testing device that allows for visual observation during the impact process, enabling a more detailed study of the impact resistance characteristics of pouch lithium-ion batteries. Summary of the Invention

[0004] To enable a more detailed study of the impact resistance characteristics of pouch lithium-ion batteries, this invention provides an in-situ impact testing device for battery separators that visualizes the impact process.

[0005] An in-situ battery separator impact testing device for visualizing the impact process includes an electromagnetic ballistic acceleration mechanism, an impact clamp mechanism, a high-speed camera, an oscilloscope, and several projectiles.

[0006] The electromagnetic ballistic acceleration mechanism is a coil-accelerated gun or a high-pressure electromagnetic gun.

[0007] The impact clamping mechanism includes an upper electrolytic cell 14, a lower electrolytic cell 16, and a pair of clamping tubes; both the upper electrolytic cell 14 and the lower electrolytic cell 16 are made of transparent material, and both the upper electrolytic cell 14 and the lower electrolytic cell 16 are filled with electrolyte; one end of one clamping tube is connected to the impact hole at the bottom of the upper electrolytic cell 14, and the other clamping tube is connected to the impact hole at the top of the lower electrolytic cell 16;

[0008] The lower end of the ballistic gun barrel 9 is connected to the top of the upper electrolytic cell 14.

[0009] The positive electrode of the oscilloscope is in contact with the electrolyte in the upper electrolytic cell 14 via a wire, and the negative electrode of the oscilloscope is in contact with the electrolyte in the lower electrolytic cell 16 via a wire.

[0010] The high-speed camera is located on one side of the impact clamp mechanism, and the camera of the high-speed camera corresponds to a pair of clamping tubes of the impact clamp mechanism.

[0011] When used for impact testing, the impact testing device is housed inside a glove box;

[0012] First, dye is added to the electrolyte in the upper electrolytic cell 14 and the lower electrolytic cell 16 respectively, and dispersed evenly to obtain an electrolyte with dye concentration of 400 mg / L.

[0013] The battery separator under test is clamped between a pair of clamping tubes. The projectile 18 is fired from the ballistic gun barrel 9 into the dye-containing electrolyte in the upper electrolytic cell 14, and passes through the battery separator under test into the dye-containing electrolyte in the lower electrolytic cell 16. The initial velocity of the projectile 18 is accelerated to 10m / s to 100m / s. The high-speed camera captures and records the impact process, and the oscilloscope records the changes in battery voltage during the impact process.

[0014] The further defined technical solution is as follows:

[0015] The core material of the projectile is a ferromagnetic material, and a hydrophobic shell 17 is provided on the surface of the ferromagnetic material. The hydrophobic shell 17 is made of an organic hydrophobic material.

[0016] The coil-driven gun includes a ballistic barrel 9, a boost control mechanism 10, and a battery pack 1. The upper part of the ballistic barrel 9 is fixed to a circuit board 2 by a first electromagnetic coil 6 and a first capacitor 11, a second electromagnetic coil 7 and a second capacitor 12, and a third electromagnetic coil 8 and a third capacitor 13, all of which are evenly distributed. A first photoelectric trigger 3 is provided on the circuit board 2 corresponding to the first electromagnetic coil 6, a second photoelectric trigger 4 is provided corresponding to the second electromagnetic coil 7, and a third photoelectric trigger 5 is provided corresponding to the third electromagnetic coil 8. The boost control mechanism 10 is electrically connected to the circuit board 2 and to the battery pack 1.

[0017] The electrolyte is a hydrophilic liquid, a 1 mol / L lithium hexafluorophosphate (LiPF6) solution prepared from lithium salt and organic solvent, with a specific gravity of 1.2 g / cm³. 3 The organic solvent is prepared by uniformly mixing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio of 1:1:1.

[0018] The dye is Rhodamine B.

[0019] The oscilloscope is a model MDO4104C oscilloscope with an operating voltage of 0-15V.

[0020] The high-speed camera is a Phantom V2512 model.

[0021] The beneficial technical effects of this invention are reflected in the following aspects:

[0022] 1. Traditional impact testing methods cannot provide researchers with real-time observation and tracking of the evolution of the battery's internal structure, nor can they grasp the dynamic damage process of the separator. In other words, traditional impact loading devices lack a direct design for loading the battery. This invention assesses battery safety by observing bullet energy loss and the internal damage process of the battery, while simultaneously enabling real-time monitoring of battery safety performance by monitoring changes in the battery's internal voltage. Compared to traditional battery impact testing methods, this invention offers advantages such as visualization, real-time monitoring, and in-situ observation. Specifically, it connects the electromagnetic gun to the electrolytic cell, thereby achieving direct loading of the battery. The innovations and beneficial technical effects are as follows: (1) Connecting the electromagnetic acceleration device to the battery electrolytic cell enables direct high-speed loading of the battery; (2) The electrolytic cell is a transparent device, so the trajectory of the bullet in the electrolyte and the process of penetrating the diaphragm can be observed completely; (3) A high-speed camera is installed on the side of the electrolytic cell, so that the bullet's incident velocity and exit velocity can be calculated, thereby calculating energy loss and analyzing the mechanical properties of the battery; (4) Electrodes are led out in the electrode slot and connected to an oscilloscope to monitor the electrical signals during the impact process; (5) Adding dye to the electrolyte causes the electrolyte on both sides to diffuse into each other after the battery diaphragm breaks, and the degree of damage to the diaphragm can be analyzed based on the diffusion of the dye.

[0023] 2. This invention uses hydrophobic projectiles for impact testing, which minimizes energy loss during impact as the projectile passes through the electrolyte, resulting in better impact test results. The main innovation lies in the modification of the projectile; ordinary projectiles are made of iron, but to reduce energy loss in the electrolyte, a hydrophobic organic layer is added to the surface.

[0024] 3. This invention uses a transparent electrolytic cell as an impact clamp, allowing complete observation of the bullet's trajectory in the electrolyte and its penetration of the diaphragm. Simultaneously, high-speed photography is used to observe the entire impact process, clearly demonstrating the bullet's trajectory in the electrolyte and its passage through the battery diaphragm. This effectively assesses the in-situ battery's impact resistance and allows for calculation of the bullet's velocity changes.

[0025] 4. In this invention, dye is added to the electrolyte being tested. When the bullet penetrates the battery separator, the electrolyte diffuses through the damaged separator. The diffusion of color on both sides of the impacted device can be used to measure the degree of damage to the battery separator.

[0026] 5. The present invention leads electrodes from the electrolyte at both ends of the impacted device and connects them to an oscilloscope. The oscilloscope is used to monitor the changes in battery voltage during the impact process, thereby clearly determining the voltage changes of the in-situ battery during the impact process. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the present invention.

[0028] Figure 2 yes Figure 1 Rear view.

[0029] Figure 3 This is a cross-sectional schematic diagram of the impact clamp mechanism.

[0030] Figure 4 This is a schematic diagram showing a projectile passing through the gun barrel and entering the electrolyte in the upper electrolytic cell.

[0031] Figure 5 This is a schematic diagram showing a projectile penetrating the battery separator and entering the lower electrolyte layer.

[0032] Figure 6 This is a schematic diagram of a hydrophobic ferromagnetic projectile.

[0033] Figure 1-2 Serial number: Battery pack 1, Circuit board 2, First photoelectric trigger 3, Second photoelectric trigger 4, Third photoelectric trigger 5, First electromagnetic coil 6, Second electromagnetic coil 7, Third electromagnetic coil 8, Ballistic gun barrel 9, Boosting device 10, First capacitor 11, Second capacitor 12, Third capacitor 13, First electrolytic cell 14, Clamping tube 15, Second electrolytic cell 16, Hydrophobic shell of projectile 17, Projectile 18. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0035] See Figure 1 and Figure 2An in-situ battery separator impact testing device for visualizing the impact process includes an electromagnetic ballistic acceleration mechanism, an impact fixture mechanism, a high-speed camera, an oscilloscope, and several projectiles.

[0036] The electromagnetic ballistic acceleration mechanism is a coil-driven cannon, comprising a ballistic gun barrel 9, a boost control mechanism 10, and a battery pack 1. The upper part of the ballistic gun barrel 9 is fixed to a circuit board 2 via evenly distributed first electromagnetic coils 6 and 11, second electromagnetic coils 7 and 12, and third electromagnetic coils 8 and 13. A first photoelectric trigger 3 is mounted on the circuit board 2 corresponding to the first electromagnetic coil 6, a second photoelectric trigger 4 corresponding to the second electromagnetic coil 7, and a third photoelectric trigger 5 corresponding to the third electromagnetic coil 8. The boost control mechanism 10 is electrically connected to both the circuit board 2 and the battery pack 1.

[0037] See Figure 2 The impact clamping mechanism includes an upper electrolytic cell 14, a lower electrolytic cell 16, and a pair of clamping tubes 15. Both the upper and lower electrolytic cells 14 and 16 are made of transparent engineering plastic; both cells are filled with electrolyte. One end of one clamping tube 15 is connected to an impact hole at the bottom of the upper electrolytic cell 14, and the other clamping tube is connected to an impact hole at the top of the lower electrolytic cell 16. (See also...) Figure 3 The lower end of the ballistic gun chamber 9 is connected to the top of the upper electrolytic cell 14.

[0038] The positive electrode of the oscilloscope is in contact with the electrolyte in the upper electrolytic cell 14 via a wire, and the negative electrode of the oscilloscope is in contact with the electrolyte in the lower electrolytic cell 16 via a wire. The oscilloscope is a model MDO4104C oscilloscope with an operating voltage of 0–15V.

[0039] The electrolyte is a hydrophilic liquid, a 1 mol / L lithium hexafluorophosphate (LiPF6) solution prepared from lithium salt and organic solvent, with a specific gravity of 1.2 g / cm³. 3 The organic solvent is prepared by uniformly mixing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio of 1:1:1 to form a shear-thickening electrolyte.

[0040] A high-speed camera is mounted on one side of the impact clamp mechanism, and the camera lens of the high-speed camera corresponds to a pair of clamping tubes 15 of the impact clamp mechanism. The high-speed camera is a Phantom V2512 model.

[0041] See Figure 6 The core material of the projectile is a ferromagnetic material, and a hydrophobic shell 17 is provided on the surface of the ferromagnetic material. The hydrophobic shell 17 is made of an organic hydrophobic material.

[0042] The working principle of this invention is explained in detail below:

[0043] When used for impact testing, the impact testing device of the present invention is installed inside a glove box.

[0044] First, dye was added to the electrolyte in the upper electrolytic cell 14 and the lower electrolytic cell 16 respectively. Then, 100 mg of dye Rhodamine B was added to 281.25 g of electrolyte and dispersed evenly to obtain an electrolyte with dye concentration of 400 mg / L.

[0045] The battery separator to be tested is clamped between a pair of clamping tubes 15.

[0046] Pressing the launch button of the electromagnetic ballistic acceleration mechanism energizes the first electromagnetic coil 6, generating a magnetic field that attracts the projectile 18 forward. The initial velocity of the projectile 18 is 10m / s to 100m / s. The projectile 18 passes through the first photoelectric trigger 3 between the first electromagnetic coil 6 and the second electromagnetic coil 7, which triggers the second electromagnetic coil 7 to energize, attracting the projectile 18 to continue accelerating. The three-stage guns work in the same way, allowing the projectile 18 to accelerate continuously.

[0047] See Figure 3 After being accelerated, the bullet is fired from the ballistic chamber 9 into the dye-containing electrolyte in the upper electrolytic cell 14, such as... Figure 4 And it breaks through the separator of the battery under test and enters the electrolyte containing dye in the lower electrolytic cell 16, such as Figure 5 This process dynamically loads the battery separator. A high-speed camera records the impact, and a computer calculates the projectile's incident and exit velocities to determine the energy dissipation. In this embodiment, the shear-thickened electrolyte exhibits significant energy dissipation characteristics due to its phase change behavior under dynamic loading. Compared to ordinary electrolytes, the shear-thickened electrolyte dissipates more energy as the projectile passes through it, thus providing significant protection for the battery separator. The quantification and evaluation of this protective effect can be achieved using this device.

[0048] In this embodiment, by adding dye to the electrolyte, the leakage of electrolyte after the battery separator is damaged can be assessed.

[0049] In this embodiment, an oscilloscope is used to monitor the changes in the battery's output voltage during the impact process.

[0050] The impact testing device of this invention evaluates battery safety by visualizing the impact process and monitoring energy loss in real time, thereby better predicting its stability in collision application environments.

[0051] Those skilled in the art will readily understand that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An in-situ impact testing device for battery separators that visualizes the impact process, characterized in that: It includes an electromagnetic ballistic acceleration mechanism, an impact clamp mechanism, a high-speed camera, an oscilloscope, and several projectiles; The electromagnetic ballistic acceleration mechanism is a coil-accelerated gun or a high-pressure electromagnetic gun. The impact clamp mechanism includes an upper electrolytic cell (14), a lower electrolytic cell (16), and a pair of clamping tubes; both the upper electrolytic cell (14) and the lower electrolytic cell (16) are made of transparent material, and both the upper electrolytic cell (14) and the lower electrolytic cell (16) are filled with electrolyte; one end of one clamping tube is connected to the impact hole at the bottom of the upper electrolytic cell (14), and the other clamping tube is connected to the impact hole at the top of the lower electrolytic cell (16); The coil-driven gun includes a ballistic gun barrel (9), a boost control mechanism (10), and a battery pack (1). The lower end of the ballistic gun barrel (9) is connected to the top of the upper electrolytic cell (14); The positive electrode of the oscilloscope is in contact with the electrolyte in the upper electrolytic cell (14) through a wire, and the negative electrode of the oscilloscope is in contact with the electrolyte in the lower electrolytic cell (16) through a wire; The high-speed camera is located on one side of the impact clamp mechanism, and the camera of the high-speed camera corresponds to a pair of clamping tubes of the impact clamp mechanism. When used for impact testing, the impact testing device is housed inside a glove box; First, add dye to the electrolyte in the upper electrolytic cell (14) and the lower electrolytic cell (16) respectively, and disperse it evenly to obtain an electrolyte with dye concentration of 400 mg / L. The battery separator under test is clamped between a pair of clamping tubes. The projectile (18) is fired from the ballistic gun barrel (9) into the dye-containing electrolyte in the upper electrolytic cell (14), and passes through the battery separator under test into the dye-containing electrolyte in the lower electrolytic cell (16). The initial velocity of the projectile (18) is accelerated to 10m / s to 100m / s. The high-speed camera records the impact process, and the battery voltage change during the impact process is recorded by the oscilloscope. The core material of the projectile is a ferromagnetic material, and a hydrophobic shell (17) is provided on the surface of the ferromagnetic material. The hydrophobic shell (17) is made of an organic hydrophobic material. The upper part of the ballistic gun barrel (9) is fixed to the circuit board (2) by the evenly distributed first electromagnetic coil (6) and first capacitor (11), second electromagnetic coil (7) and second capacitor (12), third electromagnetic coil (8) and third capacitor (13); the circuit board (2) is provided with a first photoelectric trigger (3) corresponding to the first electromagnetic coil (6), a second photoelectric trigger (4) corresponding to the second electromagnetic coil (7), and a third photoelectric trigger (5) corresponding to the third electromagnetic coil (8); the boost control mechanism (10) is electrically connected to the circuit board (2) and the boost control mechanism (10) is electrically connected to the battery pack (1); The electrolyte is a hydrophilic liquid, a 1 mol / L lithium hexafluorophosphate (LiPF6) solution prepared from lithium salt and organic solvent, with a specific gravity of 1.2 g / cm³. 3 The organic solvent is prepared by uniformly mixing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio of 1:1:

1. The dye is Rhodamine B.

2. The in-situ battery separator impact testing device for visualizing the impact process according to claim 1, characterized in that: The oscilloscope is a model MDO4104C oscilloscope with an operating voltage of 0-15V.

3. The in-situ impact testing device for visualizing the impact process of a battery separator according to claim 1, characterized in that: The high-speed camera is a Phantom V2512 model.

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