Cylindrical battery acupuncture test device and method

Abstract

The invention provides a cylindrical battery needling test device and method, and relates to the field of battery safety testing, and the device comprises a mounting rack, a clamping mechanism, a detection mechanism and a needling mechanism. The clamping mechanism clamps the cylindrical battery, and the detection mechanism is connected with the anti-explosion valve and detects the pressure of gas discharged by the anti-explosion valve. The needling mechanism comprises a driving device and a puncture needle, and the surface of the puncture needle is provided with a sealing layer of low-melting-point alloy and a solidification accelerator. The melting point of the low-melting-point alloy ranges from 80 DEG C to 150 DEG C, and the low-melting-point alloy is melted and fills the gap between the puncture hole and the puncture needle body when the battery is in thermal runaway, so that gas leakage is prevented. The solidification accelerant is evenly dispersed in the low-melting-point alloy, a solidification mechanism is triggered after the sealing layer is melted, a compact sealing structure is formed, and it is ensured that gas is discharged only through the anti-explosion valve instead of leaking through a gap of a puncture hole. The device effectively solves the problem of gas leakage in the traditional acupuncture test, and improves the accuracy and reliability of the explosion-proof pressure relief test.

Description

Technical Field

[0001] This application relates to the field of battery safety testing, and particularly to a cylindrical battery acupuncture test device and method. Background Art

[0002] With the rapid development of new energy vehicles and energy storage industries, cylindrical batteries have become one of the mainstream technical routes in the field of power batteries due to their advantages such as high energy density and standardized manufacturing. However, the safety issues of batteries under extreme working conditions (such as mechanical abuse and thermal runaway) have always been the core concerns of the industry. As a key experimental method for simulating internal short circuits in batteries that trigger thermal runaway, acupuncture testing is widely used in domestic and foreign safety standards such as GB / T31485 and UL1642, and its test results are directly related to core technical aspects such as the design of the bursting pressure of explosion-proof valves and the optimization of module thermal management strategies.

[0003] In the prior art, acupuncture testing triggers an internal short circuit by driving a metal puncture needle to instantaneously pierce the battery housing and monitors key parameters such as the change in internal pressure and gas release during thermal runaway. As the only controllable pressure relief channel during battery thermal runaway, the bursting pressure threshold of the explosion-proof valve needs to strictly match the gas production characteristics of the battery: if the bursting pressure design is too high, it may cause the overall rupture of the housing and trigger secondary accidents; if the design is too low, it may cause battery performance degradation due to frequent mis-opening. Therefore, accurately obtaining the internal pressure-time curve and pressure relief gas flow data during acupuncture is the core basis for the scientific design of explosion-proof valves.

[0004] However, there are still significant technical bottlenecks in the current acupuncture testing devices during actual application. After the puncture needle penetrates the battery housing, gaps often form between the puncture needle and the battery housing, resulting in gas leakage from these gaps. Due to the existence of these gaps, gas not only relieves pressure through the explosion-proof valve but also leaks through the gaps around the puncture hole, forming a parallel pressure relief path. The existence of this parallel path causes gas to leak out of the battery through multiple channels instead of just through the single channel of the explosion-proof valve. Especially in the initial stage of thermal runaway (pressure range of 5 - 20 kPa), due to the parallel pressure relief path of the puncture hole and the explosion-proof valve, the actual pressure relief volume of the explosion-proof valve is severely underestimated by the multi-channel gas leakage, and the measured data fluctuates by up to ±30%, which cannot provide reliable input for bursting pressure calibration. These problems seriously affect the accuracy and reliability of test results.

[0005] Content of the Application

[0006] In view of this, this application proposes a cylindrical battery acupuncture test device and method, aiming to solve the problem of inaccurate pressure relief test results caused by the parallel pressure relief path between the puncture hole and the explosion-proof valve during acupuncture testing.

[0007] The technical solution of this application is realized as follows:

[0008] On the one hand, the present application provides a cylindrical battery acupuncture test device, which is characterized by comprising:

[0009] A mounting frame;

[0010] A clamping mechanism, fixedly arranged on the mounting frame, for clamping and fixing the cylindrical battery;

[0011] A detection mechanism, fixedly arranged on the mounting frame, for connecting with the explosion-proof valve of the cylindrical battery to detect the gas pressure discharged from the explosion-proof valve port;

[0012] An acupuncture mechanism, comprising a driving device and a puncture needle. The driving device is used to drive the puncture needle to move to pierce the cylindrical battery. The puncture needle includes a needle body and a sealing layer arranged on the outer surface of the needle body. The sealing layer includes a low-melting-point alloy and a solidification promoter. The melting point range of the low-melting-point alloy is 80 - 150 °C, and it is used to melt and fill the gap between the puncture hole and the needle body at the high temperature of 80 - 200 °C generated by the thermal runaway of the battery. The solidification promoter is uniformly dispersed in the low-melting-point alloy and is used to trigger the solidification mechanism after the sealing layer melts to form a dense sealing structure in the gap between the puncture hole and the needle body. The triggering condition of the solidification promoter is configured to start solidifying after the sealing layer is fully filled.

[0013] On the basis of the above technical solution, preferably, the low-melting-point alloy is a bismuth-based alloy layer, and its components by mass percentage include: bismuth content is 55% - 60%; tin content is 30% - 38%; indium content is 5% - 10%; silicon carbide whisker content is 5% - 10%, with a length of 10 - 20 μm and a diameter of 0.5 - 1 μm, uniformly dispersed in the alloy; the thickness of the sealing layer is 90 - 110 μm, covering the outer surface of the needle body; the solidification promoter is one or more of a pressure-sensitive polymer, a curing agent microcapsule, and nano-aluminum oxide particles.

[0014] On the basis of the above technical solution, preferably, the puncture needle further includes a transition layer and an impact layer. The transition layer covers the outer surface of the needle body and is used to enhance the bonding force between the needle body and the sealing layer. The impact layer covers the outer surface of the transition layer and is used to improve the hardness and wear resistance of the puncture needle. The sealing layer covers the outer surface of the impact layer.

[0015] On the basis of the above technical solution, preferably, the transition layer is nickel-based, with a thickness of 3 - 8 μm and a bonding force ≥ 40 MPa; the impact layer is silicon carbide, with a thickness of 20 - 40 μm and a hardness ≥ 2200 HV.

[0016] Based on the above technical solution, preferably, the puncture needle further includes a lubricating layer, which covers the outer surface of the sealing layer. The lubricating layer is hexagonal boron nitride with a thickness of 1 ± 3 μm, a friction coefficient ≤ 0.15, and a grain size ≤ 200 nm.

[0017] Based on the above technical solution, preferably, the clamping mechanism includes a radial clamping assembly and an axial clamping assembly. There are two sets of the radial clamping assemblies symmetrically arranged for clamping the radial direction of the cylindrical battery in the horizontal direction. The axial clamping assembly is used for horizontally pushing one end of the cylindrical battery. The detection mechanism is located at the end of the cylindrical battery away from the axial clamping assembly, and it includes a fixed flange and a detection component. The fixed flange is fixedly arranged on the top surface of the support frame, and there is a connection port on it. One end of the connection port is used for sealing connection with the explosion-proof valve of the cylindrical battery, and the other end is communicated with the detection component. The detection component is used for collecting the gas pressure data and gas components released from the explosion-proof valve port.

[0018] Based on the above technical solution, preferably, the radial clamping assembly includes a first clamping cylinder and a first clamping piece. The first clamping cylinder is horizontally fixed on the top surface of the mounting frame and is used to drive the first clamping piece to move along the radial direction of the cylindrical battery. The axial clamping assembly includes a second clamping cylinder and a second clamping piece. The second clamping cylinder is fixedly arranged on the top surface of the mounting frame and is used to drive the second clamping piece to translate towards the connection port.

[0019] Based on the above technical solution, preferably, a temperature sensor is arranged on the surface of the first clamping piece in contact with the cylindrical battery.

[0020] Based on the above technical solution, preferably, the detection component includes a detection cavity, a pressure sensor, and a MEMS mass spectrometry chip. One end of the detection cavity is communicated with the connection port, and the other end extends axially. Its inner cavity includes a contraction section and an expansion section. The contraction section is located between the connection port and the expansion section, and its inner diameter gradually decreases from the connection port to the expansion section. The inner diameter of the expansion section gradually increases from the end of the contraction section towards the direction away from the connection port. The pressure sensor is arranged inside the connection port and is used for collecting the gas pressure data released from the explosion-proof valve port. The MEMS mass spectrometry chip is arranged at one end of the expansion section away from the contraction section and is used for collecting the gas components released from the explosion-proof valve port.

[0021] Based on the above technical solution, preferably, a fire extinguishing device is further included. The fire extinguishing device includes a fire detector and a reservoir. The fire detector is arranged inside the detection port and is used for detecting the fire signal generated when the cylindrical battery undergoes thermal runaway. The reservoir is arranged below the mounting frame, and a through hole is provided on the top surface of the mounting frame for the cylindrical battery to fall into the reservoir when the fire signal is triggered.

[0022] On the basis of the above technical solution, preferably, it further includes a protective box and a support mechanism. The mounting frame is arranged in the protective box, the driving device is fixedly arranged on the inner top surface of the protective box, the water storage tank and the moving device are arranged on the inner bottom surface of the protective box. Two groups of support mechanisms are symmetrically arranged, respectively located below both sides of the length direction of the through hole. The support mechanism includes a fixed frame, a support member, a first telescopic element and a second telescopic element. The fixed frame is fixedly connected to the mounting frame. The first telescopic element is fixedly arranged on the fixed frame and is used to drive the second telescopic element to horizontally move in the length direction of the through hole. The second telescopic element is used to drive the support member to upwardly pass through the through hole and lift the cylindrical battery.

[0023] In a second aspect, the present application discloses a method for testing the puncture of a cylindrical battery, which utilizes the cylindrical battery puncture testing device described in the first aspect, and includes the following steps:

[0024] S1. Horizontally place the cylindrical battery at the through hole on the top surface of the mounting frame, align the explosion-proof valve of the cylindrical battery with the connection port, axially clamp and position the cylindrical battery through the axial clamping assembly, and radially clamp and position the cylindrical battery in the radial direction through the radial clamping assembly;

[0025] S2. Drive the puncture needle to vertically pierce the cylindrical battery through the driving device. The low-melting-point alloy on the sealing layer melts at a high temperature of 80-200 °C generated by the thermal runaway of the battery and fills the gap between the puncture hole and the needle body of the puncture needle. The solidification promoter on the sealing layer triggers the solidification mechanism after the sealing layer melts, and a dense sealing structure is formed in the gap between the puncture hole and the needle body of the puncture needle;

[0026] S3. When thermal runaway occurs inside the cylindrical battery, the pressure relief port of the explosion-proof valve starts to release high-pressure gas. The pressure data of the gas released from the explosion-proof valve port is collected through the pressure sensor in the detection component, and the gas components released from the explosion-proof valve port are collected through the MEMS mass spectrometry chip and are transmitted to the data processing system for analysis in real time;

[0027] S4. When the fire detector detects a fire signal at the explosion-proof valve port, the clamping mechanism releases the clamping of the cylindrical battery, the driving device releases the clamping of the puncture needle, and the puncture needle drops into the water storage tank with the cylindrical battery through the through hole to extinguish the fire.

[0028] The present application has the following beneficial effects compared with the prior art:

[0029] (1) The cylindrical battery puncture test device disclosed in the present application can effectively fill the gap between the puncture hole and the puncture needle during thermal runaway by providing a sealing layer of low-melting-point alloy and solidification accelerator on the surface of the puncture needle to prevent gas leakage through these gaps. This solves the problem of gas leakage caused by the gap between the puncture needle and the battery casing in traditional puncture tests, thereby ensuring the accuracy of the test results. Due to the presence of the sealing layer, the gas will only release pressure through the explosion-proof valve channel, rather than through the puncture hole gap, so that the actual pressure relief of the explosion-proof valve can be accurately measured. This solves the problem of underestimated explosion-proof valve pressure relief due to multi-channel gas leakage, thereby improving the reliability of explosion-proof pressure relief testing.

[0030] (2) Through the synergistic effect of the low-melting-point alloy and the solidification accelerator, the sealing layer quickly melts and fills the gap between the puncture hole and the needle body at the initial stage of thermal runaway of the battery (80-150°C), and then quickly solidifies under the triggering of the solidification accelerator to form a dense sealing structure, effectively blocking the gas leakage path and ensuring that the gas is only released through the explosion-proof valve, thereby improving the accuracy of the explosion-proof pressure relief test.

[0031] (3) By setting a temperature sensor on the side where the first clamping member contacts the cylindrical battery, temperature detection can be performed more intuitively. At the same time, there is no need to manually stick thermocouples or other forms of temperature sensors on the surface of the cylindrical battery, which can avoid excessive temperature causing the thermocouple to slip off the cylindrical battery and affect temperature detection.

[0032] (4) By installing a pressure sensor and a MEMS mass spectrometer chip in the detection component, the deflation pressure and gas composition of the cylindrical battery can be collected simultaneously. These data provide an important basis for improving battery design and manufacturing processes, optimizing battery pack layout, and improving overall safety, ensuring that the battery can still work safely and reliably under extreme working conditions.

[0033] (5) By setting a contraction section and an expansion section in the detection cavity, the inner diameter of the contraction section gradually decreases from the connection port to the expansion section, and its cross-sectional area gradually decreases, the flow rate is accelerated, and the pressure is reduced. The inner diameter of the expansion section gradually increases from the end of the contraction section toward the direction away from the connection port, and its cross-sectional area gradually increases, the flow rate is slowed down, and the pressure is further reduced. Placing a MEMS mass spectrometer chip at the end of the expansion section helps to avoid direct impact of high-pressure airflow on the chip, because the airflow has been significantly decelerated and reduced in pressure when passing through the contraction section and the expansion section, thereby protecting the MEMS mass spectrometer chip from damage and reducing interference from particulate matter.

[0034] (6) By setting through holes on the mounting bracket, a water reservoir is arranged on the bottom surface of the mounting bracket, and a fire detector is arranged in the detection port. When the fire detector triggers the fire extinguishing measure, the clamping of the cylindrical battery is quickly released through the clamping mechanism, and at the same time, the driving device also releases the clamping of the puncture needle. At this time, the cylindrical battery will fall into the water reservoir through the through hole on the top surface of the mounting bracket to achieve the fire extinguishing operation, avoiding damage to the detection components caused by a fire when the cylindrical battery undergoes a needle puncture test.

[0035] (7) By introducing a support mechanism, the clamping and positioning of the cylindrical battery can be efficiently and accurately completed during the implementation process. This not only improves the clamping efficiency and accuracy but also simplifies the operation process and reduces the manual operation burden. The automated support and positioning system ensure the stability of the battery, further improving the safety of the test process and providing guarantee for emergency handling during thermal runaway. This design effectively improves the performance and safety of the test device, making the entire test process smoother and more efficient. Description of the Drawings

[0036] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0037] Figure 1 Schematic perspective view of the cylindrical battery needle puncture test device disclosed in the present application;

[0038] Figure 2 Schematic perspective view of the internal structure of the cylindrical battery needle puncture test device disclosed in the present application;

[0039] Figure 3 Schematic plan view of the puncture needle disclosed in the present application;

[0040] Figure 4 Top view of the internal structure of the cylindrical battery needle puncture test device disclosed in the present application;

[0041] Figure 5 For Figure 4 Cross-sectional view taken along the plane A-A in

[0042] Figure 6 Schematic perspective view of the clamping mechanism disclosed in the present application;

[0043] Figure 7 Schematic perspective view of the radial clamping assembly disclosed in the present application;

[0044] Figure 8Schematic three-dimensional structure diagram of the support mechanism disclosed in this application;

[0045] Reference numerals:

[0046] 1. Mounting frame; 2. Clamping mechanism; P. Cylindrical battery; 3. Detection mechanism; 4. Needling mechanism; 41. Driving device; 42. Puncture needle; 421. Needle body; 422. Sealing layer; 423. Transition layer; 21. Radial clamping assembly; 22. Axial clamping assembly; 211. First clamping cylinder; 212. First clamping member; 221. Second clamping cylinder; 222. Second clamping member; 31. Fixed flange; 32. Detection assembly; 33. Connection port; 321. Detection cavity; 322. Pressure sensor; 323. MEMS mass spectrometry chip; 3211. Shrinkage section; 3212. Expansion section; 324. Filter device; 5. Fire extinguishing device; 51. Fire detector; 52. Water reservoir; 11. Through hole; 6. Protective box; 7. Support mechanism; 71. Fixed frame; 72. Support member; 73. First telescopic element; 74. Second telescopic element; 8. Pulling cylinder; T. Temperature sensor. Detailed implementation manners

[0047] Next, in combination with the implementation manners of this application, the technical solutions in the implementation manners of this application will be clearly and completely described. Obviously, the described implementation manners are only a part of the implementation manners of this application, rather than all the implementation manners. Based on the implementation manners in this application, all other implementation manners obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of this application.

[0048] As Figure 1 shown, in combination with Figure 2 and 3 , an embodiment of this application discloses a cylindrical battery needling test device, including a mounting frame 1, a clamping mechanism 2, a detection mechanism 3, and a needling mechanism 4.

[0049] Among them, the mounting frame 1 is the support structure of the entire device, used to fix the clamping mechanism 2 and the detection mechanism 3, and ensure that each component remains stable during the test.

[0050] The clamping mechanism 2 is fixedly arranged on the mounting frame 1 and is used to clamp and fix the cylindrical battery P to ensure that it does not displace or tilt during the puncture process. In this embodiment, the cylindrical battery is clamped in the horizontal direction, which is convenient for puncture operations in the vertical direction.

[0051] The detection mechanism 3 is fixedly arranged on the mounting frame 1 and is used to connect with the explosion-proof valve of the cylindrical battery to detect the gas pressure released from the explosion-proof valve opening. In some embodiments, by connecting the detection mechanism 3 to a computer, the pressure curve can be displayed in real time, providing accurate pressure relief data when the cylindrical battery undergoes thermal runaway, and providing a basis for evaluating the safety performance of the cylindrical battery.

[0052] The acupuncture mechanism 4 includes a driving device 41 and a puncture needle 42. The driving device 41 is used to drive the puncture needle 42 to pierce the cylindrical battery at a certain speed. In this embodiment, the driving device 41 is arranged above the mounting frame 1 and is used to control the moving speed and depth of the puncture needle 42 in the vertical direction. In some embodiments, the driving device 41 can adopt a stepping motor plus a roller screw structure to achieve accurate displacement control.

[0053] As for the prior art, when the puncture needle 42 pierces the cylindrical battery, a puncture hole will be formed on the shell of the cylindrical battery, and there is a certain gap between the puncture needle 42 and the puncture hole. When the cylindrical battery undergoes thermal runaway, the gas inside the cylindrical battery will leak from the above gap, and at the same time, the gas will also be relieved through the explosion-proof valve, forming a parallel gas leakage path. Since the gas relief amount at the above gap cannot be obtained, the actual pressure relief amount of the explosion-proof valve is seriously underestimated due to multi-channel gas leakage, and the measured data fluctuates as high as ±30%, which cannot provide reliable input for the calibration of the bursting pressure. These problems seriously affect the accuracy and reliability of the test results.

[0054] To solve the above problems, the present application is solved by the following solutions.

[0055] Specifically, the puncture needle 42 of the present application includes a needle body 421 and a sealing layer 422 arranged on the outer surface of the needle body 421. The acupuncture body can adopt high-strength alloy steel with a diameter of 3 mm to 5 mm.

[0056] The sealing layer 422 includes a low-melting-point alloy and a solidification promoter. The melting point range of the low-melting-point alloy is 80 - 150 °C, and it is used to melt and fill the gap between the puncture hole and the needle body 421 at the high temperature of 80 - 200 °C generated by the thermal runaway of the battery. This can effectively prevent gas from leaking through these gaps, avoiding the underestimation of the pressure relief amount of the explosion-proof valve caused by multi-channel gas leakage in the test.

[0057] The solidification promoter is uniformly dispersed in the low-melting-point alloy and is used to trigger the solidification mechanism after the sealing layer 422 melts, so as to form a dense sealing structure in the gap between the puncture hole and the needle body 421. In this way, in the case of thermal runaway, the sealing layer 422 will automatically solidify in a short time to form an effective seal to prevent gas from leaking through this path.

[0058] In this embodiment, the triggering condition of the solidification promoter is configured to start solidifying after the sealing layer 422 is sufficiently filled. As a result, the sealing layer 422 will automatically turn into a solid state within 3 - 10 s, and the sealing strength is ≥20 mpa, with a lasting and reliable effect.

[0059] By providing a sealing layer 422 of low-melting-point alloy and solidification promoter on the surface of the puncture needle 42, the gap between the puncture hole and the puncture needle 42 can be effectively filled during a thermal runaway process, preventing gas from leaking through these gaps. This solves the problem of gas leakage caused by the gap between the puncture needle 42 and the battery housing in traditional puncture tests, thereby ensuring the accuracy of test results. Due to the presence of the sealing layer 422, gas will only relieve pressure through the explosion-proof valve channel rather than through the puncture hole gap, enabling the actual pressure relief amount of the explosion-proof valve to be accurately measured. This solves the problem of underestimation of the explosion-proof valve pressure relief amount caused by multi-channel gas leakage and improves the reliability of the test.

[0060] As some embodiments, the low-melting-point alloy is a bismuth-based alloy layer. As the main material of the sealing layer 422, the bismuth-based alloy layer has a low melting point (80 - 150 °C) and high fluidity, and can quickly melt and fill the gap between the puncture hole and the needle body 421 during battery thermal runaway. The low melting point characteristic of the bismuth-based alloy enables it to melt in the initial stage of battery thermal runaway (80 - 200 °C), ensuring that the sealing layer 422 can function in a timely manner, blocking the parallel gas leakage path, and ensuring that gas is only released through the explosion-proof valve.

[0061] The bismuth-based alloy layer includes bismuth, tin, and silicon carbide whiskers, and its composition by mass percentage includes: bismuth content of 55% - 60%; tin content of 30% - 38%; silicon carbide whisker content of 5% - 10%.

[0062] Among them, bismuth is the main component of the bismuth-based alloy, and its content directly affects the melting point and fluidity of the alloy. The bismuth content of 55% - 60% ensures that the alloy melts within the range of 80 - 150 °C while maintaining good fluidity. It should be noted that too low a bismuth content will cause the melting point to rise, making it difficult to melt in the initial stage of thermal runaway, and too high a bismuth content may lead to insufficient alloy strength and inability to effectively fill the gap.

[0063] Tin, as a secondary component of the bismuth-based alloy, is used to adjust the mechanical properties and solidification rate of the alloy. The tin content of 30% - 38% ensures that the alloy can solidify quickly after melting, forming a dense sealing structure. It should be noted that too low a tin content will cause the alloy solidification rate to be too slow, making it difficult to maintain the seal under the action of high-pressure gas; too high a tin content may lead to a decrease in alloy fluidity and inability to completely fill the gap.

[0064] Indium has a relatively low melting point. When added to the bismuth-based alloy, it can further lower the melting point of the alloy, making it easier to melt in the initial stage of battery thermal runaway (80 - 150 °C). The addition of indium makes the melting temperature range of the alloy closer to the temperature range of battery thermal runaway (80 - 200 °C), ensuring that the sealing layer 422 functions in a timely manner. The indium content is 5% - 10%. If the indium content is too low (<5%), it may lead to insufficient fluidity of the alloy and inability to completely fill the gap; if the indium content is too high (>10%), it may lead to overly strong fluidity of the alloy, increasing the risk of the sealing layer 422 being blown away by high-pressure gas.

[0065] Silicon carbide whiskers are used as reinforcing materials to improve the mechanical strength and wear resistance of the bismuth-based alloy. A silicon carbide whisker content of 5% - 10% ensures that the alloy has sufficient impact resistance during the puncture process. The length of the silicon carbide whiskers is 10 - 20 μm, and the diameter is 0.5 - 1 μm, which are uniformly dispersed in the alloy to ensure a uniform strengthening effect.

[0066] In this embodiment, the total thickness of the sealing layer 422 is 90 - 110 μm, covering the outer surface of the stylet body 421. Setting a certain thickness ensures that the sealing layer 422 can completely fill the gap after melting and at the same time has sufficient mechanical strength to withstand the action of high-pressure gas.

[0067] Although tin can accelerate the solidification rate of the bismuth-based alloy, its solidification rate is still limited by the alloy composition and environmental temperature. Under extreme working conditions (such as the action of high-pressure gas), relying solely on tin may not ensure the rapid solidification of the sealing layer 422. The solidification rate of tin is not sufficient to completely prevent the sealing layer 422 from being blown away under the action of high-pressure gas, which may lead to an increase in the leakage rate.

[0068] Therefore, this application also uniformly disperses a solidification promoter in the low-melting alloy. The solidification promoter is one or more of a pressure-sensitive polymer, a curing agent microcapsule, and nano-aluminum oxide particles. The addition of the solidification promoter can significantly increase the solidification rate of the sealing layer 422. Tin and the solidification promoter have a synergistic effect. Tin regulates the solidification rate of the alloy, while the solidification promoter ensures the rapid solidification of the sealing layer 422 under extreme working conditions.

[0069] The melting point range of the low-melting alloy (bismuth-based alloy) is 80 - 150 °C, and it melts rapidly in the initial stage of battery thermal runaway (80 - 200 °C). The melting temperature of the alloy matches the thermal runaway temperature range, ensuring that the sealing layer 422 plays a role in time in the initial stage of thermal runaway. The low-melting alloy has high fluidity after melting and can quickly fill the gap between the puncture hole and the needle body 421 under the action of gravity or pressure. The fluidity of the alloy ensures that the sealing layer 422 is evenly distributed after melting, forming a dense filling structure. The melted alloy quickly flows into the gap between the puncture hole and the needle body 421 under the pressure generated by thermal runaway to complete the filling. The filling time window is from after the alloy melts to before it solidifies, and it is completed within a few seconds to more than ten seconds.

[0070] The solidification promoter (such as pressure-sensitive polymer, curing agent microcapsule, and nano-aluminum oxide particles) starts to act under specific conditions (such as high temperature or high pressure). The triggering conditions match the melting temperature of the sealing layer 422, ensuring that the sealing layer 422 starts to solidify after being fully filled. For example, the pressure-sensitive polymer undergoes a cross-linking reaction under a pressure of 10 MPa, accelerating the solidification of the sealing layer 422. The curing agent microcapsule ruptures at a high temperature of 150 °C to release the curing agent, triggering the solidification of the sealing layer 422; nano-aluminum oxide particles: by increasing the nucleation points, the solidification rate of the sealing layer 422 is increased. The low-melting alloy fills the gap after melting, and the solidification promoter triggers the solidification mechanism after the sealing layer 422 is fully filled, ensuring that the sealing layer 422 solidifies rapidly. The addition of the solidification promoter can significantly increase the solidification rate of the sealing layer 422, prevent it from being blown away by high-pressure gas, and greatly reduce the leakage amount at the puncture hole gap.

[0071] As some embodiments, the specific substance of the pressure-sensitive polymer is polydimethylsiloxane (PDMS) + cross-linking agent (such as tetraethoxysilane, TEOS). Among them, PDMS can undergo a cross-linking reaction under high pressure to form a three-dimensional network structure, improving the mechanical strength of the sealing layer. The cross-linking agent (such as TEOS) promotes the cross-linking and curing of PDMS under pressure.

[0072] As other embodiments, the specific substance of the pressure-sensitive polymer is epoxy resin (EP) + amine curing agent (such as DETA, TETA). Epoxy resin can accelerate the cross-linking reaction with the amine curing agent under high pressure, increasing the curing speed.

[0073] As some embodiments, the shell material of the curing agent microcapsule is polymethyl methacrylate (PMMA), polystyrene (PS), or urea-formaldehyde resin (UF). The curing agent material in the microcapsule is benzoyl peroxide (BPO) (a free radical initiator for polymerization reaction), diaminodiphenylmethane (DDM) (an epoxy resin curing agent), and dicyandiamide (DICY) (a latent curing agent, released at high temperature).

[0074] Example 1, the composition of the low-melting alloy is 58% Bi, 32% Sn, 10% In, the content of silicon carbide whiskers is 8%, the length is 15 μm, the diameter is 0.8 μm, and it is evenly dispersed in the alloy. The thickness of the sealing layer 422 is 100 μm, the solidification promoter is a pressure-sensitive polymer, the content is 1%, and a cross-linking reaction occurs under a pressure of 10 MPa to accelerate the solidification of the sealing layer 422.

[0075] Example 2, the composition of the low-melting alloy is 55% Bi, 35% Sn, 10% In, the content of silicon carbide whiskers is 10%, the length is 20 μm, the diameter is 1 μm, and it is evenly dispersed in the alloy. The thickness of the sealing layer 422 is 110 μm, the solidification promoter is a microcapsule of curing agent, the diameter is 8 μm, and it contains a curing agent, which ruptures and releases at a high temperature of 150 °C to trigger the solidification of the sealing layer 422.

[0076] Example 3, the composition of the low-melting alloy is 60% Bi, 30% Sn, 10% In, the content of silicon carbide whiskers is 5%, the length is 10 μm, the diameter is 0.5 μm, and it is evenly dispersed in the alloy. The thickness of the sealing layer 422 is 90 μm, the solidification promoter is nano-aluminum oxide particles, the particle size is 80 nm, and the content is 2%, which is used to increase the solidification rate of the sealing layer 422.

[0077] Through the synergistic effect of the low-melting alloy and the solidification promoter, the sealing layer 422 quickly melts and fills the gap between the puncture hole and the puncture needle body 421 at the initial stage of battery thermal runaway (80 - 150 °C), and then quickly solidifies under the trigger of the solidification promoter to form a dense sealing structure, effectively blocking the gas leakage path, ensuring that the gas is only discharged through the explosion-proof valve, thereby improving the accuracy of the explosion-proof pressure relief test.

[0078] As some embodiments, the puncture needle 42 further includes a transition layer 423, the transition layer 423 is arranged between the sealing layer 422 and the puncture body, the transition layer 423 is nickel-based, its thickness is 3 - 8 μm, and the bonding strength is ≥40 Mpa. The transition layer 423 is used to enhance the bonding strength between the puncture needle body 421 and the sealing layer 422 to prevent it from falling off during the puncture process.

[0079] In order to achieve horizontal clamping and positioning of the cylindrical battery, the clamping mechanism 2 of this embodiment includes a radial clamping assembly 21 and an axial clamping assembly 22. There are two groups of symmetrically arranged radial clamping assemblies 21, which are used to clamp the radial direction of the cylindrical battery in the horizontal direction. The symmetrically arranged design can apply force evenly to ensure stable fixation of the cylindrical battery in the radial direction, avoiding displacement or rotation of the battery during the test, thereby improving the test accuracy and repeatability.

[0080] In this embodiment, referring to the appendix Figures 3 - 7As shown, the radial clamping assembly 21 includes a first clamping cylinder 211 and a first clamping member 212. The first clamping cylinder 211 is horizontally fixed on the top surface of the mounting bracket 1 and is used to drive the first clamping member 212 to move along the radial direction of the cylindrical battery. The two first clamping members 212 approach each other in the horizontal direction to clamp the cylindrical battery in the radial direction. The surface of the first clamping member 212 in this embodiment has a V-shaped groove, which can be adapted to clamp cylindrical batteries with a diameter of 14 - 60 mm.

[0081] The axial clamping assembly 22 is used to push one end of the cylindrical battery horizontally. In order to position the cylindrical battery in the axial direction, in this embodiment, the detection mechanism 3 is arranged at the end of the cylindrical battery away from the axial clamping assembly 22. It includes a fixed flange 31 and a detection component 32. The fixed flange 31 is fixedly arranged on the top surface of the support frame, and a connection port 33 is arranged thereon. One end of the connection port 33 is used for sealing connection with the explosion-proof valve of the cylindrical battery, and the other end is communicated with the detection component 32. The detection component 32 is used to collect the gas pressure data and gas composition discharged from the explosion-proof valve port.

[0082] Adopting the above technical solution, the connection port 33 is fixed on the mounting bracket 1 through the fixed flange 31. When the cylindrical battery is placed horizontally, the end of the cylindrical battery with the explosion-proof valve is connected to the connection port 33, and then the other end of the cylindrical battery is pushed horizontally by the axial clamping assembly 22, so as to limit the position of the cylindrical battery in the axial direction.

[0083] In this embodiment, the axial clamping assembly 22 includes a second clamping cylinder 221 and a second clamping member 222. The second clamping cylinder 221 is fixedly arranged on the top surface of the mounting bracket 1 and is used to drive the second clamping member 222 to translate towards the connection port 33. Specifically, the telescopic direction of the second clamping cylinder 221 coincides with the axial line direction of the connection port 33. The second clamping member 222 is a pushing block, preferably a circular block. The second clamping member 222 is driven by the second clamping cylinder 221 to lie flat towards the connection port 33, so as to clamp and position the cylindrical battery in the axial direction.

[0084] It should be noted that providing stable and reliable clamping and fixing in the axial direction can realize the tight fit connection between the connection port 33 and the end face of the cylindrical battery, so that the explosion-proof valve is located at the connection port 33, thereby ensuring the uniqueness of the gas path when the explosion-proof valve relieves pressure.

[0085] In some embodiments, during the puncture test, when the puncture needle 42 pierces the cylindrical battery, thermal runaway occurs after an internal short circuit in the cylindrical battery, and the temperature accumulates and rises. In order to be able to test the temperature change after the thermal runaway of the cylindrical battery, this embodiment sets a temperature sensor T on the first clamping member 212. Specifically, the temperature sensor T is set on the side of the first clamping member 212 that contacts the cylindrical battery. This allows for more intuitive temperature detection. At the same time, there is no need to manually stick other forms of temperature sensors T such as thermocouples on the surface of the cylindrical battery, which can avoid excessive temperature, causing the thermocouple to slip off the cylindrical battery and affect temperature detection.

[0086] In some embodiments, a plurality of temperature sensors T may be disposed on the surface of the first clamping member 212 along the length direction of the cylindrical battery at intervals, so as to obtain temperature data at different positions on the surface of the cylindrical battery, and to collect richer data.

[0087] In this embodiment, the sealing layer 422 is used to self-seal the gap between the puncture needle 42 and the puncture hole of the cylindrical battery, so that the explosion-proof valve of the cylindrical battery becomes the only gas release path. When thermal runaway occurs, the internal pressure of the battery is too high, and the gas breaks through the explosion-proof valve and enters the detection component 32 through the connecting port 33. By collecting the gas pressure relief at the explosion-proof valve, the change of the internal air pressure of the battery during the thermal runaway process can be evaluated, and it can be verified whether the opening pressure of the explosion-proof valve is reasonable and the performance of the explosion-proof valve can be verified.

[0088] Since the gas released by cylindrical batteries during thermal runaway reactions contains multiple components, different gas components reflect different chemical reactions inside the battery (such as electrolyte decomposition, positive and negative electrode material reactions, etc.). By analyzing the gas composition, the specific cause of battery thermal runaway can be identified, providing a basis for improving battery design and manufacturing processes.

[0089] In order to realize the synchronous collection of the deflation pressure and gas composition of the cylindrical battery, this embodiment implements it through the detection component 32.

[0090] Specifically, the detection assembly 32 includes a detection cavity 321, a pressure sensor 322 and a MEMS mass spectrometer chip 323. One end of the detection cavity 321 is connected to the connection port 33, and the other end extends axially. The pressure sensor 322 is arranged inside the connection port 33 to collect gas pressure data discharged from the explosion-proof valve port. In this embodiment, the pressure sensor 322 adopts a SAW pressure sensor 322, which is located inside the connection port 33. When the explosion-proof valve is depressurized, the pressure sensor 322 can respond quickly and collect pressure data. According to the depressurization time, the pressure and time curve data can be obtained.

[0091] In order to obtain the gas composition, in this embodiment, an MEMS mass spectrometry chip 323 is used for detection. However, during the pressure relief process of the explosion-proof valve, the high-pressure gas flow carrying particulate matter will interfere with the MEMS mass spectrometry chip 323, and the high pressure of the gas flow will impact the MEMS mass spectrometry chip 323, resulting in component damage.

[0092] Therefore, in this embodiment, the inner cavity of the detection cavity 321 is set as a contraction section 3211 and an expansion section 3212; the contraction section 3211 is located between the connection port 33 and the expansion section 3212, and its inner diameter gradually decreases from the connection port 33 to the expansion section 3212; the inner diameter of the expansion section 3212 gradually increases in the direction away from the connection port 33 from the end of the contraction section 3211. The MEMS mass spectrometry chip 323 is arranged at one end of the expansion section 3212 far from the contraction section 3211 for collecting the gas composition discharged from the explosion-proof valve port.

[0093] With this setting, through the inner diameter of the contraction section 3211 gradually decreasing from the connection port 33 to the expansion section 3212, its cross-sectional area gradually decreases, the flow rate increases, and the pressure decreases. Through the inner diameter of the expansion section 3212 gradually increasing in the direction away from the connection port 33 from the end of the contraction section 3211, its cross-sectional area gradually increases, the flow rate slows down, and the pressure further decreases. Placing the MEMS mass spectrometry chip 323 at the end of the expansion section 3212 helps to avoid direct impact of the high-pressure gas flow on the chip because the gas flow has been significantly decelerated and depressurized when passing through the contraction section 3211 and the expansion section 3212, thereby protecting the MEMS mass spectrometry chip 323 from damage and reducing the interference of particulate matter.

[0094] As some embodiments, a filtering device 324 is further arranged in the expansion section 3212. The filtering device 324 is located on the front side of the MEMS mass spectrometry chip 323 and is used to filter out the particulate matter carried by the high-pressure gas to avoid damage to the MEMS mass spectrometry chip 323 caused by the particulate matter. In this embodiment, the filtering device 324 includes a metal sintered filter screen and a silicon carbide ceramic filter element. The metal sintered filter screen is located at the outlet of the expansion cavity with a pore diameter of 50 μm to intercept large particles; the silicon carbide ceramic filter element has a pore diameter of 5 μm to further filter micron-sized residues.

[0095] By arranging a pressure sensor 322 and an MEMS mass spectrometry chip 323 in the detection component 32, the pressure of the cylindrical battery during deflation and the gas composition can be synchronously collected. These data provide an important basis for improving the battery design and manufacturing process, optimizing the battery pack layout, and enhancing the overall safety, ensuring that the battery can still work safely and reliably under extreme working conditions.

[0096] When thermal runaway occurs violently, the explosion-proof valve port of the cylindrical battery will spray fire. In order to avoid damage to the detection device in the detection assembly 32, the present embodiment further provides a fire extinguishing device 5. Specifically, the fire extinguishing device 5 includes a fire detector 51 and a water reservoir 52. The fire detector 51 is arranged on the inner side of the detection port to detect the fire signal generated when the cylindrical battery has thermal runaway. The water reservoir 52 is arranged below the mounting frame 1. A through hole 11 is provided on the top surface of the mounting frame 1 to allow the cylindrical battery to fall into the water reservoir 52 when the fire signal is triggered.

[0097] By adopting the above technical scheme, after the cylindrical battery is punctured, the deflation pressure and gas composition of the cylindrical battery during thermal runaway can be tested in real time through the detection component 32, and the temperature data of the real-time changes on the surface of the cylindrical battery can be obtained through the temperature sensor T. When the fire detector 51 detects the presence of a flame at the explosion-proof valve port, it means that the thermal runaway is already quite serious and an explosion may occur at any time. At this time, the fire detector 51 triggers the fire extinguishing measures, and the clamping mechanism 2 quickly releases the clamping of the cylindrical battery. At the same time, the driving device 41 also releases the clamping of the puncture needle 42. At this time, the cylindrical battery will fall into the water reservoir 52 through the through hole 11 on the top surface of the mounting frame 1 to achieve the fire extinguishing operation, thereby preventing the cylindrical battery from causing damage to the detection component 32 due to a fire during the puncture test.

[0098] In this embodiment, perfluoroacetone solution may be added to the water reservoir 52 to ensure that the battery is completely submerged after falling, so that fire can be extinguished more efficiently.

[0099] Although there are fire extinguishing measures in the above embodiments, some cylindrical batteries have violent internal reactions when thermal runaway occurs and may explode without a fire. This may cause certain safety hazards during the test. For this reason, the test device of this embodiment also includes a protective box 6, the mounting frame 1 is arranged in the protective box 6, the driving device 41 is fixedly arranged on the top surface of the protective box 6, and the water tank 52 and the moving device are arranged on the bottom surface of the protective box 6.

[0100] With this arrangement, the entire test process is carried out in the closed protection box 6. Even if an explosion occurs during the needle penetration test, the protection box 6 can be used to protect the surrounding environment, thereby preventing the explosion from spreading to the surrounding environment.

[0101] In some embodiments, the water reservoir 52 is located on the bottom surface of the mounting frame 1, and a pull-out cylinder 8 is also provided on the inner bottom surface of the protective box 6. When a certain amount of cylindrical battery puncture tests are completed and the tested cylindrical batteries need to be regularly recovered, the water reservoir 52 is pulled out of the mounting frame 1 by the pull-out cylinder 8, which is convenient for collecting the tested cylindrical batteries and puncture needles 42, and also convenient for replacing the fire extinguishing solution.

[0102] In some embodiments, in order to facilitate manual clamping and positioning of cylindrical batteries on the mounting rack 1 quickly, a support mechanism 7 is further provided in this embodiment. Through the support mechanism 7, pre-positioning of the cylindrical battery in the initial horizontal direction can be provided, and then it is convenient for the clamping mechanism 2 to perform radial and axial clamping.

[0103] Referring to the attached Figure 5 and 8 As shown, the support mechanism 7 of this embodiment includes a fixed frame 71, a support member 72, a first telescopic element 73 and a second telescopic element 74. The fixed frame 71 is fixedly connected to the mounting rack 1. The first telescopic element 73 is fixedly arranged on the fixed frame 71 and is used to drive the second telescopic element 74 to move horizontally along the length direction of the through hole 11. The second telescopic element 74 is used to drive the support member 72 to move upward through the through hole 11 and lift the cylindrical battery.

[0104] Adopting the above technical solution, before the initial clamping, the telescopic ends of the second telescopic element 74 and the first telescopic element 73 extend in sequence. At this time, the support member 72 vertically moves upward through the through hole 11, and the upper end of the support member 72 is located above the through hole 11. The top surface of the support member 72 has a V-shaped structure. The tester horizontally places the cylindrical battery on the top surfaces of the two support members 72 and connects the explosion-proof valve of the cylindrical battery to the connection port 33. Then, the axial clamping assembly 22 and the radial clamping assembly 21 complete the axial and radial clamping and positioning of the cylindrical battery in sequence. When the cylindrical battery is clamped, the telescopic ends of the second telescopic element 74 and the first telescopic element 73 retract in sequence, so that the lower part of the through hole 11 is in an open environment, which is convenient for the cylindrical battery to fall when it catches fire subsequently.

[0105] The support mechanism 7 of this embodiment can provide preliminary positioning of the cylindrical battery, and the V-shaped structure design of the support member 72 helps to accurately place the battery. This can reduce the error of manual operation, speed up the clamping speed, and improve work efficiency. After the initial positioning, the cylindrical battery is accurately clamped by the axial and radial clamping assemblies 21, so that the battery maintains a stable position during the test and avoids test errors caused by battery offset.

[0106] By introducing the support mechanism 7, the clamping and positioning of the cylindrical battery can be completed efficiently and accurately during the implementation process. It not only improves the clamping efficiency and accuracy, but also simplifies the operation process and reduces the manual operation burden. The automated support and positioning system ensures the stability of the battery, further improves the safety of the test process, and provides guarantee for the emergency treatment during thermal runaway. This design effectively improves the performance and safety of the test device, making the whole test process smoother and more efficient.

[0107] This application also discloses a method for testing the acupuncture of a cylindrical battery, including the following steps:

[0108] S1. Horizontally place the cylindrical battery at the through-hole 11 on the top surface of the mounting bracket 1, align the explosion-proof valve of the cylindrical battery with the connection port 33, axially clamp and position the cylindrical battery through the axial clamping assembly 22, and radially clamp and position the cylindrical battery in the radial direction through the radial clamping assembly 21.

[0109] Between the above steps S1, the support mechanism 7 can provide precise initial positioning for the cylindrical battery in the horizontal direction. After the initial positioning, the cylindrical battery is accurately clamped through the axial and radial clamping assemblies 21, so that the battery maintains a stable position during the test, avoiding test errors caused by battery offset.

[0110] S2. Drive the puncture needle 42 to vertically pierce the cylindrical battery through the driving device 41. The low-melting-point alloy on the sealing layer 422 melts at the high temperature of 80 - 200 °C generated by the thermal runaway of the battery and fills the gap between the puncture hole and the needle body 421. The solidification promoter on the sealing layer 422 triggers the solidification mechanism after the sealing layer 422 melts, forming a dense sealing structure in the gap between the puncture hole and the needle body 421.

[0111] S3. When thermal runaway occurs inside the cylindrical battery, the pressure relief port of the explosion-proof valve starts to release high-pressure gas. The pressure sensor 322 in the detection component 32 collects the gas pressure data released from the explosion-proof valve port, and the MEMS mass spectrometry chip 323 collects the gas components released from the explosion-proof valve port and transmits them to the data processing system for analysis in real time.

[0112] S4. When the fire detector 51 detects a fire signal at the explosion-proof valve port, the clamping mechanism 2 releases the clamping of the cylindrical battery, the driving device 41 releases the clamping of the puncture needle 42, and the puncture needle 42 drops into the reservoir 52 with the cylindrical battery through the through-hole 11 to extinguish the fire.

[0113] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A cylindrical battery puncture test device, characterized in that: include: Mounting frame; A clamping mechanism, fixedly arranged on the mounting frame, for clamping and fixing the cylindrical battery; The detection mechanism is fixedly arranged on the mounting frame and is used to be connected with the explosion-proof valve of the cylindrical battery to detect the gas pressure discharged from the explosion-proof valve port; The puncture mechanism comprises a driving device and a puncture needle, wherein the driving device is used to drive the puncture needle to move so as to puncture a cylindrical battery, wherein the puncture needle comprises a puncture needle body and a sealing layer arranged on the outer surface of the puncture needle body, wherein the sealing layer comprises a low-melting-point alloy and a solidification accelerator, wherein the melting point range of the low-melting-point alloy is 80-150°C, and the low-melting-point alloy is used to melt and fill the gap between the puncture hole and the puncture needle body at a high temperature of 80-200°C generated by thermal runaway of the battery, wherein the solidification accelerator is uniformly dispersed in the low-melting-point alloy, and is used to trigger a solidification mechanism after the sealing layer is melted, so as to form a dense sealing structure in the gap between the puncture hole and the puncture needle body, and the triggering condition of the solidification accelerator is configured to start solidification after the sealing layer is fully filled.

2. The cylindrical battery puncture test device according to claim 1, characterized in that: The low melting point alloy is a bismuth-based alloy layer, and its components, by mass percentage, include: bismuth content of 55%-60%; tin content of 30%-38%; indium content of 5%-10%; silicon carbide whisker content of 5%-10%, length of 10-20 μm, diameter of 0.5-1 μm, uniformly dispersed in the alloy; the sealing layer has a thickness of 90-110 μm and is coated on the outer surface of the needle body; the solidification accelerator is one or more of a pressure-sensitive polymer, a curing agent microcapsule and nano-alumina particles.

3. The cylindrical battery puncture test device according to claim 1 or 2, characterized in that: The puncture needle also includes a transition layer, which is arranged between the sealing layer and the puncture body. The transition layer is used to enhance the bonding force between the puncture needle body and the sealing layer. The transition layer is nickel-based, has a thickness of 3-8 μm, and a bonding force of ≥40 MPa.

4. The cylindrical battery puncture test device according to claim 1, characterized in that: The clamping mechanism includes a radial clamping assembly and an axial clamping assembly. The radial clamping assembly is symmetrically arranged in two groups and is used to clamp the radial direction of the cylindrical battery in the horizontal direction. The axial clamping assembly is used to push one end of the cylindrical battery in the horizontal direction. The detection mechanism is located at the end of the cylindrical battery away from the axial clamping assembly, and includes a fixed flange and a detection assembly. The fixed flange is fixedly arranged on the top surface of the support frame and is provided with a connecting port. One end of the connecting port is used for sealing connection with the explosion-proof valve of the cylindrical battery, and the other end is connected to the detection assembly. The detection assembly is used to collect gas pressure data and gas composition discharged from the explosion-proof valve port.

5. The cylindrical battery puncture test device according to claim 4, characterized in that: The radial clamping assembly includes a first clamping cylinder and a first clamping member, wherein the first clamping cylinder is horizontally fixed on the top surface of the mounting frame and is used to drive the first clamping member to move in the radial direction of the cylindrical battery, and the axial clamping assembly includes a second clamping cylinder and a second clamping member, wherein the second clamping cylinder is fixedly arranged on the top surface of the mounting frame and is used to drive the second clamping member to translate toward the connection port.

6. The cylindrical battery puncture test device according to claim 5, characterized in that: A temperature sensor is disposed on a surface of the first clamping member that contacts the cylindrical battery.

7. The cylindrical battery puncture test device according to claim 4, characterized in that: The detection component includes a detection cavity, a pressure sensor and a MEMS mass spectrometer chip. One end of the detection cavity is connected to the connecting port, and the other end extends axially, and its inner cavity includes a contraction section and an expansion section; the contraction section is located between the connecting port and the expansion section, and its inner diameter gradually decreases from the connecting port to the expansion section; the inner diameter of the expansion section gradually increases from the end of the contraction section toward the direction away from the connecting port; the pressure sensor is arranged on the inner side of the connecting port, and is used to collect gas pressure data discharged from the explosion-proof valve port; the MEMS mass spectrometer chip is arranged at one end of the expansion section away from the contraction section, and is used to collect gas components discharged from the explosion-proof valve port.

8. The cylindrical battery puncture test device according to claim 7, characterized in that: It also includes a fire extinguishing device, which includes a fire detector and a water reservoir. The fire detector is arranged on the inner side of the detection port to detect the fire signal generated when the cylindrical battery is thermally out of control. The water reservoir is arranged under the mounting frame, and a through hole is opened on the top surface of the mounting frame to allow the cylindrical battery to fall into the water reservoir when the fire signal is triggered.

9. The cylindrical battery puncture test device according to claim 8, characterized in that: It also includes a protective box and a supporting mechanism, wherein the mounting frame is arranged in the protective box, the driving device is fixedly arranged on the top surface of the protective box, the water reservoir and the moving device are arranged on the bottom surface of the protective box, and the supporting mechanism is symmetrically arranged in two groups, which are respectively located below both sides of the length direction of the through hole. The supporting mechanism includes a fixed frame, a supporting member, a first telescopic element and a second telescopic element. The fixed frame is fixedly connected to the mounting frame. The first telescopic element is fixedly arranged on the fixed frame and is used to drive the second telescopic element to move horizontally in the length direction of the through hole. The second telescopic element is used to drive the supporting member to pass through the through hole upward and lift the cylindrical battery.

10. A cylindrical battery puncture test method, which utilizes the cylindrical battery puncture test device described in any one of 8 or 9, characterized in that: The steps include: S1. Place the cylindrical battery horizontally at the through hole on the top surface of the mounting frame, dock the explosion-proof valve of the cylindrical battery with the connection port, clamp and position the cylindrical battery axially through the axial clamping assembly, and clamp and position the cylindrical battery in the radial direction through the radial clamping assembly; S2. The puncture needle is driven vertically downward to pierce the cylindrical battery through a driving device. The low-melting-point alloy on the sealing layer melts at a high temperature of 80-200°C generated by thermal runaway of the battery and fills the gap between the puncture hole and the puncture needle body. The solidification accelerator on the sealing layer triggers the solidification mechanism after the sealing layer melts, forming a dense sealing structure in the gap between the puncture hole and the puncture needle body. S3. When thermal runaway occurs inside the cylindrical battery, the explosion-proof valve pressure relief port begins to release high-pressure gas. The gas pressure data released from the explosion-proof valve port is collected through the pressure sensor in the detection component, and the gas composition released from the explosion-proof valve port is collected through the MEMS mass spectrometer chip, and transmitted to the data processing system in real time for analysis; S4. When a fire signal is detected by the fire detector at the explosion-proof valve port, the clamping mechanism releases the clamping of the cylindrical battery, the driving device releases the clamping of the puncture needle, and the puncture needle falls into the water tank through the through hole with the cylindrical battery to extinguish the fire.

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