Battery pack fire simulation test device

Abstract

The invention discloses a battery pack fire simulation test device, and relates to the technical field of test devices. The positioning part is arranged in the test bed and is used for fixing a battery pack to be tested; the mechanism simulation component is used for simulating the condition of external impact on the battery pack; the loading component is used for storing potential energy for the mechanism simulation component; the water tank is filled with water and is used for extinguishing the on-fire battery pack after the test is completed; and a release member. The mechanism simulation component is arranged to impact the battery pack, so that the bottom impact test requirement newly added in the new national standard is met, the specific implementation of the test is not beneficial to direct driving of a hydraulic system, and under the condition that the battery pack is fixed by the positioning component, the loading component is firstly utilized to store energy for the mechanism simulation component; and when the double-shaft moving module sends the mechanism simulation part to an impact position, potential energy is released for impact, the spring structure has higher corrosion resistance, and meanwhile, the maintenance cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of test devices, and particularly to a battery pack fire simulation test device. Background Art

[0002] New energy vehicles are in the stage of large-scale popularization and application globally. Among them, pure electric vehicles, as the core technical route, their safety is directly related to public acceptance and industrial development. However, the lithium-ion battery system of pure electric vehicles is prone to spontaneous combustion and even explosion accidents under thermal runaway conditions. According to industry statistics, most new energy vehicle fires originate from battery pack thermal runaway. Such accidents not only increase consumers' safety concerns about electric vehicles but also pose a significant threat to social public safety. It is necessary to propose a special test device to simulate the causes of fires to optimize the protection design.

[0003] Battery pack fire simulation tests include multiple research directions, including simulation of thermal runaway triggering mechanisms, research on fire behavior and heat diffusion kinetics, verification of fire extinguishing and flame retardant systems, multi-physical field coupling failure analysis, environmental adaptability and secondary disaster research, etc. Among them, the thermal runaway triggering mechanism is a key project for preventing fires. The battery packs of pure electric vehicles are usually arranged at the bottom of the vehicle and are vulnerable to intrusion of road debris or impact from bottoming collisions. Such impacts can cause mechanical deformation of the battery pack housing, which in turn squeezes the internal battery cells, leading to rupture of the internal diaphragm of the battery cells and short circuit between the positive and negative electrodes. The Joule heat released instantaneously triggers the thermal runaway of a single cell, and the released combustible gas and high-temperature electrolyte further spread to adjacent modules, forming a chain reaction of "thermal runaway - heat diffusion - vehicle spontaneous combustion".

[0004] In response to the above risks, GB38031-2025 "Safety Requirements for Power Batteries for Electric Vehicles" adds a bottom impact test as a mandatory item, requiring that the battery pack has no leakage, fire or explosion after being impacted by a 30-mm diameter steel ball with 150 J of energy (simulating a vehicle speed of 50 km / h), and it is also required to pass a 2-hour thermal runaway monitoring (temperature ≤ 60°C). At the same time, after retrieval, the Chinese patent with the publication number CN216979257U proposes a fire simulation test device, which uses a hydraulic lifting device to push the impact head to simulate bottom bumping, reproducing the deformation and thermal runaway process of the battery pack after being impacted, providing an experimental basis for the protection design.

[0005] However, since this scheme uses a hydraulic lifting device to directly drive the impact head for testing, the hydraulic system has weak impact resistance: the reaction force at the moment of impact causes the hydraulic cylinder to withstand a peak pressure twice the rated value (>60MPa), causing the sealing ring to burst and the pipe joints to loosen, thereby reducing the overall life of the test device; there is a risk of battery leakage during the test, and the fluorine-containing electrolyte leaked after the battery casing ruptures is highly corrosive, and direct contact with the hydraulic cylinder piston rod may cause surface coating failure and metal corrosion; in addition, the flame temperature of the battery thermal runaway eruption exceeds 1000℃, and the hydraulic oil pipe is prone to aging and bursting at high temperature, causing damage. At the same time, the ignition point of traditional mineral hydraulic oil is only 180℃, which poses a risk of combustion. Summary of the Invention

[0006] The object of the present invention is to provide a battery pack fire simulation test device to solve the problems raised in the above background technology.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: A battery pack fire simulation test device comprises a test bench; further comprising: a positioning component installed inside the test bench and used to fix the battery pack to be tested; a mechanism simulation component for simulating external impact on the battery pack; a loading component for storing potential energy for the mechanism simulation component; a water tank containing water for extinguishing the battery pack in the event of fire after the test is completed; a release component arranged on the top of the test bench and used to release the battery pack in the event of fire, causing the battery pack to fall into the water tank; a two-axis movable module for controlling the movement of the mechanism simulation component to the position at the bottom of the battery pack to be impacted; a thermal feedback component for sensing abnormal heating and driving the release component to operate; the mechanism simulation component comprises a movable platform fixedly connected to the movable end of the two-axis movable module, the top and bottom of the movable platform respectively having an ejection groove and a clearance groove, a pressure rod slidably connected to one side of the inner wall of the ejection groove, the top of the pressure rod fixedly connected to the impact head, the end of the pressure rod away from the impact head extends into the interior of the clearance groove and is fixedly connected to a limit block, and the position of the pressure rod located in the ejection groove is covered with an energy storage spring.

[0008] By adopting the above technical solution, a mechanism simulation component is set up to impact the battery pack, thereby realizing the bottom impact test requirements newly added in the new national standard. The specific implementation of the test is not conducive to direct drive of the hydraulic system. Instead, when the positioning component fixes the battery pack, the loading component is first used to store energy for the mechanism simulation component, and then the potential energy is released to impact when the dual-axis moving module sends the mechanism simulation component to the impact position. The spring structure has higher corrosion resistance and lower replacement cost.

[0009] A further improvement of the technical solution of the present invention lies in that: the loading component includes mounting grooves symmetrically opened inside the ejection groove. A clamping block is slidably connected between the inner walls of the mounting groove. A locking spring is fixedly connected between one side of the inner wall of the mounting groove and the clamping block. Two mounting cylinders are symmetrically and fixedly connected to both sides of the moving platform. One side of the inner wall of the mounting groove is slidably connected with a sliding rod. One end of the sliding rod is fixedly connected to the clamping block, and the other end away from the clamping block extends into the mounting cylinder and is fixedly connected with an iron block. An electromagnet is fixedly connected to one side of the inner wall of the mounting cylinder. The clamping block is arranged as a wedge block. A clamping groove is opened on the side wall of the impact head, and the clamping groove surrounds the periphery of the impact head; a hydraulic cylinder is fixedly installed inside the test bench frame, and the end of the piston rod of the hydraulic cylinder is fixedly connected with a pressing plate.

[0010] With the above technical solution, the moving platform is controlled by the double-axis moving module to move to directly below the hydraulic cylinder, and then the hydraulic cylinder is controlled to work, pushing the pressing plate downward and pushing the impact head downward, so that the energy storage spring is compressed until the clamping block is directly opposite to the clamping groove (when the clamping block is not directly opposite to the clamping groove, the locking spring is in a compressed state). The locking spring rebounds and resets, and ejects the clamping block into the clamping groove. Then, the piston rod of the hydraulic cylinder is controlled to retract to complete energy storage; during the test, by controlling the electromagnet to be energized and generate magnetic force to attract the iron block, the iron block is quickly moved in the direction close to the electromagnet, squeezing the locking spring, and driving the clamping block to move through the sliding rod until the clamping block leaves the clamping groove. At this time, the impact head is no longer restricted, and the potential energy of the energy storage spring is released, pushing the impact head out and hitting the bottom of the battery pack.

[0011] A further improvement of the technical solution of the present invention lies in that: the positioning component includes a mounting frame, the mounting frame is fixedly connected inside the test bench frame. Four guide rods are slidably connected to the top inside the mounting frame. The bottom of the guide rods is fixedly connected with a bracket. The tops of the guide rods all extend above the mounting frame and are fixedly connected with limit heads. Two racks are symmetrically and fixedly connected to both sides of the top of the bracket. A lifting shaft is rotatably connected between the inner sides of the upper part of the test bench frame. Two gears are symmetrically and fixedly connected to the outside of the lifting shaft. The gears are meshed with the racks. A motor for driving the lifting shaft to rotate is fixedly installed on the top of the test bench frame.

[0012] With the above technical solution, by simplifying the fixing process of the battery pack, the preparation operation before the test is facilitated, thereby improving the test efficiency; specifically, when placing the battery pack, the bracket is at a height convenient for operation. The battery pack is placed on the bracket, and then the motor is controlled to work, driving the lifting shaft to rotate, and then driving the two gears to rotate, and making the two racks move upward, so as to lift the battery pack upward until the top of the battery pack touches the top inside the mounting frame to fix the battery pack. At the same time, the lifting and fixing of the battery pack are completed, which is convenient for actual operation.

[0013] A further improvement of the technical solution of the present invention lies in that: the above-mentioned release component includes a side plate fixedly connected to the top of the test bench. One side of the side plate is rotatably connected with a first synchronous pulley. A second synchronous pulley is fixedly connected to the outside of the lifting shaft. A first spline groove is provided on the central shaft of the first synchronous pulley. A first piston cylinder is fixedly connected to the side of the side plate close to the first synchronous pulley. A first piston plate is slidably connected between the inner walls of the first piston cylinder. A linkage rod is slidably connected to one side of the first piston cylinder. One end of the linkage rod extends into the first piston cylinder and is fixedly connected to the first piston plate. The end of the linkage rod far from the first piston plate is fixedly connected with a movable plate. A return spring is sleeved on the part of the linkage rod located in the first piston cylinder. A transmission shaft is rotatably connected through the movable plate. Spline shafts are fixedly connected to both ends of the transmission shaft. The output end of the motor is fixedly connected with a transmission sleeve. A second spline groove is provided at the end of the transmission sleeve far from the motor. The two spline shafts respectively correspond to the first spline groove and the second spline groove one by one and are in plug-in fit; an air inlet pipe, an air outlet pipe and a driving pipe are arranged on the first piston cylinder. Check valves are arranged inside the air inlet pipe, the air outlet pipe and the driving pipe; the diameter of the air outlet pipe is smaller than that of the air inlet pipe and the driving pipe.

[0014] By adopting the above technical solution, by setting the release component, the battery pack can be released after the fire becomes large until the heat feedback component acts, so that the battery pack falls into the water pool, thereby extinguishing the fire on the battery pack, avoiding burning the main structure of the test device, improving the pertinence of the test equipment and the efficiency of conducting this special (fire ignition mechanism) test, and at the same time improving the safety.

[0015] A further improvement of the technical solution of the present invention lies in that: the heat feedback component includes a plurality of feedback cylinders. A second piston plate is slidably connected between the inner walls of the feedback cylinders. A stud is connected to the mouth position of the feedback cylinder by screws. The stud is made of copper and the end located inside the feedback cylinder is of a hollow structure. A thermal expansion block is fixedly connected inside the hollow structure. The volume of the thermal expansion block increases when the temperature rises. One end of the thermal expansion block is fixedly connected with a pressing block. A tension spring is fixedly connected between the second piston plate and the top wall of the feedback cylinder. A lock ring is fixedly connected to the side far from the tension spring. A lock seat is fixedly connected to one side of the inner wall of the feedback cylinder. A lock block is slidably connected between the inner walls of the lock seat. A locking spring is fixedly connected between the lock block and the inner wall of the lock seat. The two corners on the side of the lock block far from the locking spring are both beveled, and the side length of the lock block close to the second piston plate is smaller than the side length of the side far from the second piston plate; a plurality of through holes corresponding to the feedback cylinders one by one are equidistantly arranged at the top of the mounting frame. Threads are provided on the inner walls of the through holes. The feedback cylinders are connected inside the through holes through the internal threaded fit of the studs with the through holes. The internal structure of the feedback cylinders can be maintained by unscrewing the studs. An input pipe and an output pipe are arranged on the feedback cylinders. Check valves are arranged inside the input pipe and the output pipe. The air inlet pipe is communicated with the output pipe.

[0016] The above technical solution is adopted by opening several through holes on the mounting frame and installing thermal feedback components on the through holes. Each thermal feedback component serves as an external heat collection point, and heat collection is achieved through heat conduction. When the battery pack continues to heat up and transmits heat to the thermal expansion block through the copper stud, it expands in volume and pushes the pressure block to move and squeeze the bevel at the lower part of the lock hole, so that the lock block automatically retracts into the lock seat until the lock block is completely disengaged from the lock ring. At this time, the second piston plate moves rapidly and discharges air into the first piston cylinder through the output pipe to prompt the battery pack to be automatically released.

[0017] A further improvement of the technical solution of the present invention is that an air pump is fixedly installed on the top of the test bench, the output end of the air pump is connected to the input pipe, and the diameter of the input pipe is larger than that of the output pipe.

[0018] By adopting the above technical solution, an air pump is set up, which can be used to blow air and inject it into the feedback cylinder through the input pipe. Since the diameter of the input pipe is larger than the output pipe, the air pressure inside the feedback cylinder continues to increase during the operation of the air pump, thereby pushing the second piston plate to move, causing the tension spring to extend. During the process, the lock ring contacts the bevel on the upper part of the locking block, causing the locking block to automatically retract into the lock seat until the locking block is completely facing the inside of the lock ring. At this time, the locking block is inserted into the lock ring to complete the locking. After turning off the air pump, the tension spring pulls back the second piston plate and the lock ring, so that the lock ring and the lock block are pressed tightly.

[0019] A further improvement of the technical solution of the present invention is that: a buffer spring is sleeved on the part of the pressure rod located in the give way groove, the top of the buffer spring is fixedly connected to the top of the give way groove, the give way groove includes a narrow mouth portion arranged at the upper part and a wide mouth portion arranged at the lower part, and a transition portion is arranged between the narrow mouth portion and the wide mouth portion, the cross-sectional shape of the narrow mouth portion matches the cross-sectional shape of the limit block, and a deceleration hole connected to the outside is opened on the narrow mouth portion.

[0020] By adopting the above technical solution and setting a buffer spring, the limit block will enter the narrow mouth when it exceeds its movement range. During this process, the movement of the limit block will be restricted by the air pressure inside the narrow mouth, which can produce a damping effect. At the same time, the buffer spring is contacted to provide a reverse force, causing the limit block to gradually slow down until it stops moving, and then rebound until it resets.

[0021] A further improvement of the technical solution of the present invention is that the diameter of the ejection groove is larger than the impact head, a guide ring is fixedly connected to the outside of the impact head, and the bottom of the guide ring is set to be rounded.

[0022] With the above technical solution, by setting a guiding ring with a larger outer diameter outside the impact head, which is flush with one side of the card slot, when the clamping block leaves the card slot, the card slot must move to the outside of the guiding ring, and only this part of the guiding ring comes into contact and friction with the clamping block during the ejection process of the impact head. Therefore, the wear during the ejection process of the impact head can be reduced, and the accuracy of the test results can be improved.

[0023] Due to the adoption of the above technical solution, the technical progress achieved by the present invention compared with the prior art is as follows: 1. The present invention provides a battery pack fire simulation test device. By setting a mechanism simulation component for impacting the battery pack, the new bottom impact test requirements in the new national standard can be achieved. However, the direct drive of the hydraulic system is not conducive to the specific implementation of the test. Instead, when the positioning component fixes the battery pack, the loading component is first used to store energy for the mechanism simulation component, and the potential energy is released for impact when the biaxial moving module sends the mechanism simulation component to the impact position. The spring structure has higher corrosion resistance and reduces the maintenance cost at the same time.

[0024] 2. The present invention provides a battery pack fire simulation test device. By simplifying the fixing process of the battery pack, the preparation operation before the test is facilitated, thereby improving the test efficiency. Specifically, when placing the battery pack, the bracket is at a convenient operating height. The battery pack is placed on the bracket, and then the motor is controlled to work, driving the lifting shaft to rotate, and then driving two gears to rotate, and making two racks move upward, so as to lift the battery pack upward until the top of the battery pack contacts the top inside the mounting frame to fix the battery pack. At the same time, the lifting and fixing of the battery pack are completed, which is convenient for actual operation.

[0025] 3. The present invention provides a battery pack fire simulation test device. By setting a release component, the battery pack can be released after the fire becomes large until the thermal feedback component acts, so that the battery pack falls into the water pool, thereby extinguishing the fire on the battery pack, preventing it from burning out the main structure of the test device, improving the pertinence of the test equipment and the efficiency of conducting this special (fire ignition mechanism) test, and improving the safety at the same time.

[0026] 4. The present invention provides a battery pack fire simulation test device. By opening a number of through holes on the mounting frame and installing thermal feedback components on the through holes, each thermal feedback component serves as an external heat collection point, and heat collection is achieved by means of heat conduction. When the battery pack continuously generates heat and is transmitted to the thermal expansion block through the copper stud, its volume expands, and the pressing block is pushed to move and squeeze the bevel at the lower part of the lock hole, so that the lock block automatically retracts into the lock seat until the lock block is completely separated from the lock ring. At this time, the second piston plate moves quickly, and air is discharged into the first piston cylinder through the output pipe to promote the release of the battery pack.

[0027] 5. The present invention provides a battery pack fire simulation test device. By arranging a guide ring with a larger outer diameter outside the impact head, the guide ring is flush with one side of the card slot. When the block leaves the card slot, the card slot must move to the outside of the guide ring. During the ejection process of the impact head, only this part of the guide ring comes into contact and friction with the block. Therefore, the wear during the ejection process of the impact head can be reduced, and the accuracy of the test results is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be further described below with reference to the accompanying drawings.

[0029] Figure 1 is a schematic structural diagram of the whole of the present invention from the first perspective; Figure 2 is a schematic structural diagram of the whole of the present invention from the second perspective; Figure 3 is a schematic structural diagram of the whole of the present invention from the third perspective; Figure 4 is a schematic structural diagram of the mechanism simulation component of the present invention; Figure 5 is a schematic exploded view of the spline shaft, the first spline groove and the second spline groove of the present invention; Figure 6 is a schematic installation structure diagram of the feedback cylinder and the mounting bracket of the present invention; Figure 7 is a schematic exploded view of the feedback cylinder and the mounting bracket of the present invention; Figure 8 is a three-dimensional structural diagram of the thermal feedback component of the present invention; Figure 9 is a schematic state diagram of the action process of the thermal feedback component of the present invention; Figure 10 is a schematic structural diagram of the release component of the present invention; Figure 11 is a schematic structural diagram of the bracket of the present invention; Figure 12 of the present invention Figure 10 is the enlarged view at A in

[0030] In the figure: 1. Test bench; 2. Water tank; 3. Mounting rack; 4. Biaxial moving module; 5. Moving platform; 6. Hydraulic cylinder; 7. Pressure plate; 8. Pressure rod; 9. Impact head; 10. Limit block; 11. Energy storage spring; 12. Installation groove; 13. Installation cylinder; 14. Electromagnet; 15. Ejection groove; 16. Iron block; 17. Slide bar; 18. Clamping block; 19. Locking spring; 20. Card slot; 21. Buffer spring; 22. Slow-down hole; 23. Guide ring; 24. Through hole; 25. Feedback cylinder; 26. Stud; 27. Second piston plate; 28. Tensile spring; 29. Relief groove; 30. Locking ring; 31. Lock seat; 32. Locking block; 33. Locking spring; 34. Thermal expansion block; 35. Pressing block; 36. Motor; 37. Transmission sleeve; 38. First piston cylinder; 39. First piston plate; 40. Intake pipe; 41. Exhaust pipe; 42. Return spring; 43. Movable plate; 44. Transmission shaft; 45. Spline shaft; 46. First synchronous pulley; 47. Lifting shaft; 48. Second synchronous pulley; 49. First spline groove; 50. Second spline groove; 51. Linking rod; 52. Output pipe; 53. Input pipe; 54. Air pump; 55. Drive pipe; 56. Guide rod; 57. Bracket; 58. Rack; 59. Gear; 60. Side plate. Detailed implementation manners

[0031] The present invention will be further described in detail below in conjunction with embodiments.

[0032] Embodiment 1 As Figure 1 , Figure 3 and Figure 4As shown, the present invention provides a battery pack fire simulation test device, including a test bench 1; further comprising: a positioning component installed inside the test bench 1, used to fix the battery pack to be tested; a mechanism simulation component, used to simulate the situation of external impact on the battery pack; a loading component, used to store potential energy for the mechanism simulation component; a water pool 2, which contains water and is used to extinguish the battery pack on fire after the test is completed; a release component, which is arranged on the top of the test bench 1, used to release the battery pack when a fire occurs, causing the battery pack to fall into the water pool 2; a dual-axis moving module 4, including two linear modules with mutually perpendicular moving paths, one of which is installed on the slider of the other linear module , which can be moved to a certain position in the plane as needed, and is used to control the mechanism simulation component to move to the part of the bottom of the battery pack that needs to be impacted; a thermal feedback component is used to sense abnormal heat and drive the release component to move; the mechanism simulation component includes a mobile platform 5 fixedly connected to the movable end of the dual-axis mobile module 4, and the top and bottom of the mobile platform 5 are respectively provided with an ejection groove 15 and a clearance groove 29. A pressure rod 8 is slidably connected to one side of the inner wall of the ejection groove 15, and the top of the pressure rod 8 is fixedly connected to the impact head 9. The end of the pressure rod 8 away from the impact head 9 extends to the inside of the clearance groove 29 and is fixedly connected to the limiting block 10. The pressure rod 8 is located at the ejection groove 15 and is covered with an energy storage spring 11.

[0033] The battery pack has an internal monitoring system. For battery packs without a monitoring system, an external monitoring system is used to receive battery pack status information, including internal temperature abnormality monitoring.

[0034] In this embodiment, a mechanism simulation component is provided to impact the battery pack, thereby achieving the bottom impact test requirements newly added in the new national standard. However, the specific implementation of the test is not conducive to direct drive of the hydraulic system. Instead, when the positioning component fixes the battery pack, the loading component is first used to store energy for the mechanism simulation component. When the dual-axis moving module 4 moves the mechanism simulation component to the impact position, the potential energy is released to impact. The spring structure has higher corrosion resistance and lower replacement cost. Specifically, by pressing the impact head 9 downward, the pressure rod 8 and the limit block 10 are pushed to move, the energy storage spring 11 is squeezed to accumulate elastic potential energy, and the impact head 9 is released after the impact head 9 moves to the position where it needs to be impacted, thereby simulating an external impact action. The structure that performs the impact action is composed of the impact head 9, the pressure rod 8, the limit block 10 and the energy storage spring 11, and the driving structure is not directly involved, thereby avoiding the influence of the reaction force on the life of the driving structure.

[0035] It should be particularly noted that when the impact head 9 contacts the battery pack, the energy storage spring 11 has already exceeded the normal state and has a small amount of tension (inertia). After the impact, the energy storage spring 11 no longer provides elastic force to the impact head 9, and the impact head 9 impacts completely by inertia. After the impact, the battery pack deforms, and there is no upward supporting force below the impact head 9, so it will not continuously press against the battery pack; Among them, the impact head 9 is a hemispherical shape with a diameter of 30 mm, a mass of 10 kg, and the material is 45# steel; The impact energy of the impact head 9 is about 150 J ± 3 J; The impact positions and times are three bottom protection risk points provided by the manufacturer as the impact positions (covering the front, middle, and rear of the battery); After the impact operation is completed, observe for 2 h at the test environment temperature.

[0036] As Figure 2 、 Figure 3 and Figure 4 As shown, the loading component includes mounting grooves 12 symmetrically opened inside the ejection groove 15. A clamping block 18 is slidably connected between the inner walls of the mounting groove 12. A locking spring 19 is fixedly connected between one side of the inner wall of the mounting groove 12 and the clamping block 18. Mounting cylinders 13 are symmetrically and fixedly connected to both sides of the moving platform 5. A sliding rod 17 is slidably connected to one side of the inner wall of the mounting groove 12. One end of the sliding rod 17 is fixedly connected to the clamping block 18, and the end far from the clamping block 18 extends into the mounting cylinder 13 and is fixedly connected to an iron block 16. An electromagnet 14 is fixedly connected to one side of the inner wall of the mounting cylinder 13. The clamping block 18 is set as a wedge block, and a clamping groove 20 is opened on the side wall of the impact head 9, and the clamping groove 20 surrounds the periphery of the impact head 9; A hydraulic cylinder 6 is fixedly installed inside the test bench 1, and a pressing plate 7 is fixedly connected to the end of the piston rod of the hydraulic cylinder 6.

[0037] In this embodiment, during loading, the moving platform 5 is controlled by the double-axis moving module 4 to move to directly below the hydraulic cylinder 6, and then the hydraulic cylinder 6 is controlled to work, pushing the pressing plate 7 downward and pushing the impact head 9 downward, compressing the energy storage spring 11 until the clamping block 18 is directly opposite to the clamping groove 20 (when the clamping block 18 is not directly opposite to the clamping groove 20, the locking spring 19 is in a compressed state). The locking spring 19 rebounds and resets, and ejects the clamping block 18 into the clamping groove 20. Then, the piston rod of the hydraulic cylinder 6 is controlled to retract to complete energy storage; During the test, by controlling the electromagnet 14 to be energized and generate magnetic force, attracting the iron block 16, making the iron block 16 quickly move in the direction close to the electromagnet 14, squeezing the locking spring 19, and driving the clamping block 18 to move through the sliding rod 17 until the clamping block 18 leaves the clamping groove 20. At this time, the impact head 9 is no longer restricted, and the potential energy of the energy storage spring 11 is released, pushing the impact head 9 out to impact the bottom of the battery pack.

[0038] As Figure 2 、 Figure 3 andFigure 11 As shown, preferably, the positioning component includes a mounting frame 3, the mounting frame 3 is fixedly connected to the inside of the test bench 1, the top of the inner side of the mounting frame 3 is slidably connected with four guide rods 56, the bottom of the guide rods 56 is fixedly connected with a bracket 57, the tops of the guide rods 56 all extend above the mounting frame 3 and are fixedly connected with limit heads, two racks 58 are symmetrically and fixedly connected to both sides of the top of the bracket 57, a lifting shaft 47 is rotatably connected between the inner sides of the upper part of the test bench 1, two gears 59 are symmetrically and fixedly connected to the outside of the lifting shaft 47, the gears 59 are meshed with the racks 58, and a motor 36 for driving the lifting shaft 47 to rotate is fixedly installed on the top of the test bench 1.

[0039] During the operation, not only the battery pack needs to be fixed, but also it needs to be lifted to a height convenient for impact. Since the battery pack itself is relatively large in size, the placement process should not be too high, and multiple sets of control tests need to be carried out in the test. The disassembly and assembly of the battery pack should be convenient, and the operation process should not be too complicated. In this embodiment, by simplifying the fixing process of the battery pack, the preparation operation before the test is facilitated, thereby improving the test efficiency. Specifically, when placing the battery pack, the bracket 57 is at a height convenient for operation. Place the battery pack on the bracket 57, then control the motor 36 to work, drive the lifting shaft 47 to rotate, and then drive the two gears 59 to rotate, and make the two racks 58 move upward, so as to lift the battery pack upward until the top of the battery pack touches the top of the inner side of the mounting frame 3 to fix the battery pack. At the same time, the lifting and fixing of the battery pack are completed, which facilitates the actual operation.

[0040] Embodiment 2 As Figure 5 、 Figure 10 and Figure 12As shown in the figure, on the basis of Embodiment 1, the present invention provides a technical solution: Preferably, the release component includes a side plate 60 fixedly connected to the top of the test bench 1. One side of the side plate 60 is rotatably connected to a first synchronous wheel 46. A second synchronous wheel 48 is fixedly connected to the outside of the lifting shaft 47. A first spline groove 49 is provided on the central axis of the first synchronous wheel 46. A first piston cylinder 38 is fixedly connected to the side of the side plate 60 close to the first synchronous wheel 46. A first piston plate 39 is slidably connected between the inner walls of the first piston cylinder 38. A linkage rod 51 is slidably connected to one side of the first piston cylinder 38. One end of the linkage rod 51 extends into the first piston cylinder 38 and is fixedly connected to the first piston plate 39. The end of the linkage rod 51 far from the first piston plate 39 is fixedly connected to a movable plate 43. A return spring 42 is sleeved on the part of the linkage rod 51 located in the first piston cylinder 38. A transmission shaft 44 is rotatably connected through the movable plate 43. Spline shafts 45 are fixedly connected to both ends of the transmission shaft 44. The output end of the motor 36 is fixedly connected to a transmission sleeve 37. A second spline groove 50 is provided at the end of the transmission sleeve 37 far from the motor 36. The two spline shafts 45 respectively correspond to the first spline groove 49 and the second spline groove 50 one by one and are in plug-in fit; An air inlet pipe 40, an air outlet pipe 41 and a drive pipe 55 are provided on the first piston cylinder 38. Check valves are provided inside the air inlet pipe 40, the air outlet pipe 41 and the drive pipe 55; The diameter of the air outlet pipe 41 is smaller than that of the air inlet pipe 40 and the drive pipe 55.

[0041] Since this solution aims to study the simulated fire inducement, specifically to study the impact of external collision on battery ignition. In order to conduct the above research targeted and avoid damage to the overall device caused by the increase in fire, it is necessary to separate the battery pack and extinguish the fire after the fire increases (the test purpose has been achieved when the state of ignition is reached); In this embodiment, by providing a release component, the battery pack can be released after the fire intensifies until the heat feedback component operates, causing the battery pack to fall into the pool 2, thereby extinguishing the fire on the battery pack and preventing it from burning out the main structure of the test device. Specifically, when a temperature anomaly occurs, the heat feedback component inflates the drive tube 55, and air enters the first piston cylinder 38 through the drive tube 55. Among them, the check valves inside the drive tube 55 and the intake pipe 40 are both unidirectionally conductive from the outside to the first piston cylinder 38, and the check valve inside the outlet pipe 41 is only unidirectionally conductive from the first piston cylinder 38 to the outside. During the process of injecting air into the first piston cylinder 38 through the drive tube 55, part of the air is discharged from the outlet pipe 41. However, since the diameter of the outlet pipe 41 is smaller than that of the drive tube 55, the air pressure inside the first piston cylinder 38 gradually increases. The air pressure pushes the first piston plate 39 to move, compresses the return spring 42, and drives the movable plate 43 to move through the linkage rod 51. At the same time, it drives the transmission shaft 44 and the spline shaft 45 to move away from the first synchronous wheel 46 until the spline shaft 45 disengages from the first spline groove 49. At this time, the first synchronous wheel 46 is no longer restricted by the output end of the motor 36 and can rotate freely, causing the rack 58 to move downward under the gravity of the battery pack and the bracket 57 until it falls into the pool 2 and is supported by the bottom of the pool 2. The pool 2 is filled with water to extinguish the open fire. During the downward movement of the above-mentioned rack 58, the gear 59 and the lifting shaft 47 are driven to rotate.

[0042] After the bracket 57 and the battery pack have fallen to the bottom of the pool 2 for a period of time, since the mounting frame 3 is no longer in contact with the battery pack, the heat feedback component no longer senses heat (it gradually resets inside) and no longer continues to provide positive pressure to the first piston cylinder 38. Instead, the positive pressure inside the first piston cylinder 38 continues to slowly leak from the outlet pipe 41 until the air pressure is insufficient to support the elastic force of the return spring 42. At this time, the first piston plate 39 is pushed to slowly reset, driving the transmission shaft 44 and the spline shaft 45 to reset until the spline shaft 45 is inserted into the first spline groove 49 again (it is highly probable that the spline shaft 45 is not directly opposite the first spline groove 49. During the above process, the motor 36 is controlled to work simultaneously. When the spline shaft 45 is directly opposite the first spline groove 49, the spline shaft 45 naturally inserts into the first spline groove 49), and then the bracket 57 can be lifted upward again by controlling the motor 36 to work (the state is the same as the initial state. The motor 36 can drive the first synchronous wheel 46 to rotate, and through the synchronous belt, drive the second synchronous wheel 48 to rotate. Further, it can drive the lifting shaft 47 to rotate).

[0043] Embodiment 3 As Figure 6 、 Figure 7 and Figure 8As shown, on the basis of Embodiment 2, the present invention provides a technical solution: Preferably, the thermal feedback component includes a plurality of feedback cylinders 25. A second piston plate 27 is slidably connected between the inner walls of the feedback cylinder 25. A stud 26 is connected to the mouth position of the feedback cylinder 25 by screws. The stud 26 is made of copper and the end located inside the feedback cylinder 25 is of a hollow structure. A thermal expansion block 34 is fixedly connected inside the hollow structure. The volume of the thermal expansion block 34 increases when the temperature rises. One end of the thermal expansion block 34 is fixedly connected to a pressing block 35. A tension spring 28 is fixedly connected between the second piston plate 27 and the top wall of the feedback cylinder 25. A locking ring 30 is fixedly connected to the side away from the tension spring 28. A locking seat 31 is fixedly connected to one side of the inner wall of the feedback cylinder 25. A locking block 32 is slidably connected between the inner walls of the locking seat 31. A locking spring 33 is fixedly connected between the locking block 32 and the inner wall of the locking seat 31. Both corners of the side of the locking block 32 away from the locking spring 33 are beveled, and the side length of the locking block 32 on the side close to the second piston plate 27 is smaller than the side length on the side away from the second piston plate 27; A plurality of through holes 24 corresponding to the feedback cylinders 25 one by one are equidistantly opened at the top of the mounting frame 3. The inner wall of the through hole 24 is provided with threads. The feedback cylinder 25 is threadedly connected to the inside of the through hole 24 through the stud 26. The internal structure of the feedback cylinder 25 can be maintained by unscrewing the stud 26. An input pipe 53 and an output pipe 52 are provided on the feedback cylinder 25. Check valves are provided inside both the input pipe 53 and the output pipe 52. The intake pipe 40 is communicated with the output pipe 52.

[0044] It should be particularly noted that under normal conditions (the state where the locking block 32 is inserted into the locking ring 30), the tension spring 28 is in an extended state; In this embodiment, by opening a plurality of through holes 24 on the mounting frame 3 and installing thermal feedback components on the through holes 24, each thermal feedback component serves as an external heat collection point, and heat collection is achieved by means of heat conduction; As Figure 9 shown, the initial state is the leftmost one in the figure. When the battery pack continuously generates heat and is transmitted to the thermal expansion block 34 through the copper stud 26, causing its volume to expand and pushing the pressing block 35 to move and squeeze the bevel at the lower part of the locking hole, the locking block 32 automatically retracts into the locking seat 31 (the locking spring 33 is compressed during the process), until the bottom of the bevel of the locking seat 31 no longer contacts the inside of the locking ring 30. This state is referred to Figure 9 the state shown in the second one from the left in the figure. At this time, the inclined surface part of the bevel contacts the inside of the locking ring 30, and the locking ring 30 and the second piston plate 27 itself have a tendency to be pulled by the tension spring 28. In this state, the tension spring 28 pulls the second piston plate 27 and the locking ring 30 to move, further causing the locking block 32 to retract into the locking seat 31 until the locking block 32 is completely separated from the locking ring 30. The state is referred to Figure 9 the rightmost one in the figure. At this time, the second piston plate 27 moves quickly, and air is discharged into the first piston cylinder 38 through the output pipe 52 to prompt the battery pack to release.

[0045] As Figure 3 , Figure 8 and Figure 9 shown, preferably, an air pump 54 is fixedly installed at the top of the test bench 1. The output end of the air pump 54 is communicated with the input pipe 53, and the diameter of the input pipe 53 is larger than that of the output pipe 52.

[0046] Since the device in the solution needs to perform repeated tests, the thermal feedback component needs to be easily reset after operation; In this embodiment, by setting the air pump 54, the air pump 54 can be used to blow air and inject it into the feedback cylinder 25 through the input pipe 53. Since the diameter of the input pipe 53 is larger than that of the output pipe 52, the air pressure inside the feedback cylinder 25 continuously increases during the operation of the air pump 54, thereby pushing the second piston plate 27 to move, causing the tension spring 28 to elongate. During this process, the locking ring 30 contacts the bevel on the upper part of the locking block, causing the locking block 32 to automatically retract into the lock seat 31 until the locking block 32 is completely opposite to the inside of the locking ring 30. At this time, the locking block 32 is inserted into the locking ring 30 (under the action of the rebound of the locking spring 33) to complete the locking. After the air pump 54 is turned off, the tension spring 28 pulls the second piston plate 27 and the locking ring 30 back, making the locking ring 30 abut against the locking block 32; In the above process, part of the air is discharged into the first piston cylinder 38 through the output pipe 52, resulting in the spline shaft 45 being briefly disengaged from the first spline groove 49. The inflation process using the air pump 54 occurs during the reset operation after the thermal feedback component acts. In this state, the bracket 57 itself is in the water tank 2. Therefore, the operation of the air pump 54 occurs after the thermal feedback component acts.

[0047] It should be particularly noted that since a check valve is provided inside each output pipe 52, when a certain feedback cylinder 25 acts, it will not affect other feedback cylinders 25, and the air (which can be regarded as a signal) in the feedback cylinder 25 will only be transmitted to the first piston cylinder 38.

[0048] In addition, the battery pack itself is equipped with a monitoring system (or an external monitoring system, such as installing multiple temperature sensors inside the mounting frame 3), and both the monitoring system and the air pump 54 are electrically connected to an external controller; the monitoring system can monitor the heat information of the battery pack. When continuous thermal anomalies occur, even if the above thermal feedback component does not detect a fire signal, it can still transmit the signal to the external controller, thereby controlling the operation of the air pump 54 to actively disengage the spline shaft 45 from the first spline groove 49 and release the battery pack into the water tank 2.

[0049] Embodiment 4 As Figure 4As shown, on the basis of Example 3, the present invention provides a technical solution: preferably, the portion of the pressure rod 8 located in the give way groove 29 is sleeved with a buffer spring 21, and the top of the buffer spring 21 is fixedly connected to the top of the give way groove 29, and the give way groove 29 includes a narrow mouth portion arranged at the upper part and a wide mouth portion arranged at the lower part, and a transition portion is provided between the narrow mouth portion and the wide mouth portion, the cross-sectional shape of the narrow mouth portion matches the cross-sectional shape of the limit block 10, and the narrow mouth portion is provided with a deceleration hole 22 connected to the outside.

[0050] The impact head 9 has a large amount of kinetic energy when impacting the battery pack. Therefore, the impact head 9 will not be over-ejected when hammering on the battery pack during the test. However, if the impact head 9 is not loaded or the hammer force is adjusted due to errors, over-ejection may occur. This will cause the impact energy to directly act on the limit block 10, affecting its service life. In this embodiment, by providing a buffer spring 21, the limit block 10 will enter the narrow mouth when it exceeds its range of movement. During this process, the movement of the limit block 10 will be restricted by the air pressure inside the narrow mouth, which can produce a damping effect. At the same time, the process contacts the buffer spring 21 to provide a reverse force, causing the limit block 10 to gradually slow down until it stops moving, and then rebound until it is reset.

[0051] like Figure 4 As shown, preferably, the diameter of the ejection groove 15 is larger than the impact head 9, and a guide ring 23 is fixedly connected to the outside of the impact head 9, and the bottom of the guide ring 23 is set to be rounded.

[0052] Since the ejection process of the impact head 9 requires the block 18 to leave the slot 20, the impact head 9 is freed from its restraint. That is, the impact head 9 will be ejected quickly as soon as the block 18 leaves the slot 20. During this process, the side wall of the impact head 9 continues to slide relative to the block 18, thereby generating friction. This process will lose some energy, making it difficult to control the energy of the impact head 9 when it hits the target. In this embodiment, a guide ring 23 with a larger outer diameter is provided on the outside of the impact head 9. The guide ring 23 is flush with one side of the slot 20. When the block 18 leaves the slot 20, the slot 20 must be moved to the outside of the guide ring 23. During the ejection process of the impact head 9, only this part of the guide ring 23 and the block 18 generate contact friction. Therefore, the wear of the impact head during the ejection process can be reduced, and the accuracy of the test results is improved.

[0053] The working principle of the battery pack fire simulation test device is described in detail below.

[0054] like Figures 1 - 12As shown in the figure, the battery pack is fixed as follows: Place the battery pack on the bracket 57, then control the motor 36 to operate, drive the lifting shaft 47 to rotate, and then drive the two gears 59 to rotate, and make the two racks 58 move upward, so as to lift the battery pack upward until the top of the battery pack touches the top inside the mounting frame 3, so as to fix the battery pack, and at the same time complete the lifting and fixing of the battery pack; Loading of the impact head 9: Control the moving platform 5 to move to directly below the hydraulic cylinder 6 through the double-axis moving module 4, then control the hydraulic cylinder 6 to operate, push the pressure plate 7 downward, and push the impact head 9 downward to compress the energy storage spring 11 until the locking block 18 is directly opposite to the card slot 20 (when the locking block 18 is not directly opposite to the card slot 20, the locking spring 19 is in a compressed state), the locking spring 19 rebounds and resets, and pops the locking block 18 into the card slot 20, and then control the piston rod of the hydraulic cylinder 6 to retract to complete energy storage; Impact test process: Drive the moving platform 5 to move to the position to be impacted through the double-axis moving module 4. By controlling the electromagnet 14 to be energized and generate magnetic force, attract the iron block 16, so that the iron block 16 quickly moves in the direction close to the electromagnet 14, squeeze the locking spring 19, and drive the locking block 18 to move through the slide bar 17 until the locking block 18 leaves the card slot 20. At this time, the impact head 9 is no longer restricted, and the potential energy of the energy storage spring 11 is released, pushing the impact head 9 out to impact the bottom of the battery pack; Repeat the above process of loading the impact head 9 and the impact test three times, and after the impact operation is completed, observe for 2 h at the test environment temperature, and monitor the internal temperature change and ignition situation of the battery pack.

[0055] The above text generally describes the present invention in detail. However, based on the present invention, some modifications or improvements can be made, which are obvious to those of ordinary skill in the art. Therefore, the modifications or improvements made without departing from the spirit of the present invention are within the protection scope of the present invention.

Claims

1. A battery pack fire simulation test device, comprising a test bench (1); characterized in that, Also includes: A positioning component, installed inside the test bench (1), for fixing the battery pack to be tested; Mechanism simulation components, used to simulate external impact on the battery pack; A loading component for storing potential energy for the mechanism simulation component; A water tank (2) containing water for extinguishing a battery pack that has caught fire after the test is completed; A release component is provided on the top of the test bench (1) and is used to release the battery pack in the event of fire, causing the battery pack to fall into the water pool (2); A dual-axis moving module (4) is used to control the movement of the mechanism simulation component to the position on the bottom of the battery pack that needs to be impacted; Thermal feedback component, used to sense abnormal heating and drive the release component to operate; The mechanism simulation component includes a mobile platform (5) fixedly connected to the movable end of the biaxial mobile module (4), the top and bottom of the mobile platform (5) are respectively provided with an ejection groove (15) and a clearance groove (29), one side of the inner wall of the ejection groove (15) is slidably connected to a pressure rod (8), the top of the pressure rod (8) is fixedly connected to an impact head (9), the end of the pressure rod (8) away from the impact head (9) extends to the inside of the clearance groove (29) and is fixedly connected to a limit block (10), and the pressure rod (8) is sleeved with an energy storage spring (11) at the position of the ejection groove (15).

2. The battery pack fire simulation test device according to claim 1, wherein: The loading component includes a mounting groove (12) symmetrically opened inside the ejection groove (15), a clamping block (18) is slidably connected between the inner walls of the mounting groove (12), and a locking spring (19) is fixedly connected between the clamping block (18) and one side of the inner wall of the mounting groove (12), and the two sides of the mobile platform (5) are symmetrically fixedly connected to the mounting cylinder (13), and one side of the inner wall of the mounting groove (12) is slidably connected to a sliding rod (17), and one end of the sliding rod (17) is fixedly connected to the clamping block (18). , one end away from the clamping block (18) extends to the inside of the mounting cylinder (13) and is fixedly connected to an iron block (16), one side of the inner wall of the mounting cylinder (13) is fixedly connected to an electromagnet (14), the clamping block (18) is set as a wedge block, and a clamping groove (20) is opened on the side wall of the impact head (9), and the clamping groove (20) surrounds the periphery of the impact head (9); a hydraulic cylinder (6) is fixedly installed inside the test bench (1), and the end of the piston rod of the hydraulic cylinder (6) is fixedly connected to a pressure plate (7).

3. The battery pack fire simulation test device according to claim 2, wherein: The positioning component includes a mounting frame (3), the mounting frame (3) is fixedly connected inside the test bench frame (1), the top of the inner side of the mounting frame (3) is slidably connected with four guide rods (56), the bottom of the guide rods (56) is fixedly connected with a bracket (57), the tops of the guide rods (56) all extend above the mounting frame (3) and are fixedly connected with limit heads, both sides of the top of the bracket (57) are symmetrically and fixedly connected with two racks (58), the upper part of the inner side of the test bench frame (1) is rotatably connected with a lifting shaft (47), two gears (59) are symmetrically fixedly connected to the outside of the lifting shaft (47), the gears (59) are meshed with the racks (58), and a motor (36) for driving the lifting shaft (47) to rotate is fixedly installed on the top of the test bench frame (1).

4. A battery pack fire simulation test device according to claim 3, characterized in that: The releasing component includes a side plate (60) fixedly connected to the top of the test bench frame (1), a first synchronous pulley (46) is rotatably connected to one side of the side plate (60), a second synchronous pulley (48) is fixedly connected to the outside of the lifting shaft (47), a first spline groove (49) is formed in the central shaft of the first synchronous pulley (46), a first piston cylinder (38) is fixedly connected to the side of the side plate (60) close to the first synchronous pulley (46), a first piston plate (39) is slidably connected between the inner walls of the first piston cylinder (38), a linkage rod (51) is slidably connected to one side of the first piston cylinder (), one end of the linkage rod (51) extends into the first piston cylinder (38) and is fixedly connected with the first piston plate (39), a movable plate (43) is fixedly connected to the end of the linkage rod (51) away from the first piston plate (39), a return spring (42) is sleeved on the part of the linkage rod (51) located in the first piston cylinder (38), a transmission shaft (44) is rotatably connected through the movable plate (43), spline shafts (45) are fixedly connected to both ends of the transmission shaft (44), a transmission sleeve (37) is fixedly connected to the output end of the motor (36), a second spline groove (50) is formed at the end of the transmission sleeve (37) away from the motor (36), the two spline shafts (45) respectively correspond to the first spline groove (49) and the second spline groove (50) one by one and are in plug-in fit; an air inlet pipe (40), an air outlet pipe (41) and a driving pipe (55) are arranged on the first piston cylinder (38), check valves are arranged inside the air inlet pipe (40), the air outlet pipe (41) and the driving pipe (55); the diameter of the air outlet pipe (41) is smaller than that of the air inlet pipe (40) and the driving pipe (55).

5. A battery pack fire simulation test device according to claim 4, characterized in that: The thermal feedback component includes a plurality of feedback cylinders (25), the inner walls of the feedback cylinders (25) are slidably connected to a second piston plate (27), the mouth of the feedback cylinder (25) is connected to a stud (26) by a screw, the stud (26) is made of copper and one end of the stud (26) is located in the feedback cylinder (25) and is a hollow structure, and a thermal expansion block (34) is fixedly connected inside the hollow structure, the volume of the thermal expansion block (34) increases when the temperature rises, one end of the thermal expansion block (34) is fixedly connected to a pressure block (35), a tension spring (28) is fixedly connected between the second piston plate (27) and the top wall of the feedback cylinder (25), and a lock ring (30) is fixedly connected to the side away from the tension spring (28), a lock seat (31) is fixedly connected to one side of the inner wall of the feedback cylinder (25), and the inner walls of the lock seat (31) are slidably connected. A locking block (32) is provided, wherein a locking spring (33) is fixedly connected between the locking block (32) and the inner wall of the lock seat (31), and the two corners of the locking block (32) away from the locking spring (33) are both beveled, and the side length of the locking block (32) close to the second piston plate (27) is smaller than the side length away from the second piston plate (27); a plurality of through holes (24) corresponding to the feedback cylinder (25) are equidistantly provided on the top of the mounting frame (3), and the inner wall of the through hole (24) is provided with a thread, and the feedback cylinder (25) is connected to the inside of the through hole (24) through a stud (26) and the inner thread of the through hole (24), and an input pipe (53) and an output pipe (52) are provided on the feedback cylinder (25), and a one-way valve is provided inside the input pipe (53) and the output pipe (52), and the air inlet pipe (40) is connected to the output pipe (52).

6. A battery pack fire simulation test device according to claim 5, characterized in that: An air pump (54) is fixedly installed on the top of the test bench (1), and the output end of the air pump (54) is connected to the input pipe (53), and the diameter of the input pipe (53) is larger than that of the output pipe (52).

7. An apparatus for simulating a battery pack fire test according to claim 6, wherein: The portion of the pressure rod (8) located in the clearance groove (29) is sleeved with a buffer spring (21), the top of the buffer spring (21) is fixedly connected to the top of the clearance groove (29), the clearance groove (29) includes a narrow mouth portion arranged at the upper part and a wide mouth portion arranged at the lower part, and a transition portion is provided between the narrow mouth portion and the wide mouth portion, the cross-sectional shape of the narrow mouth portion matches the cross-sectional shape of the limit block (10), and the narrow mouth portion is provided with a deceleration hole (22) connected to the outside.

8. A battery pack fire simulation test device according to claim 7, characterized in that: The diameter of the ejection groove (15) is larger than that of the impact head (9), and a guide ring (23) is fixedly connected to the outside of the impact head (9), and the bottom of the guide ring (23) is configured as a rounded corner.

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