A battery pack thermal runaway protection system and method

Abstract

The application belongs to the field of battery safety protection, and discloses a protection system and method for battery pack thermal runaway, which can trigger the gas control unit to cool the battery pack and discharge combustible gas, combustion-supporting gas and other gases under the condition of complete power failure in the vehicle through a pure mechanical protection system. Compared with the setting of the traditional electric control monitoring system, the reliability of the scheme is higher, and by directly taking the cross beam, the longitudinal beam and the frame as the delivery channel of the fire-extinguishing gas, compared with the traditional arrangement of the gas pipeline, the weight is lighter, and the processing difficulty is lower, and the gas pipeline does not need to be positionally stabilized.

Description

Technical Field

[0001] This invention belongs to the field of battery safety protection technology, specifically relating to a battery pack thermal runaway protection system and method. Background Technology

[0002] During charging, discharging, and use, power battery packs are prone to thermal runaway due to internal cell failures or abnormal temperature increases. If temperature changes are not monitored in time and effective suppression measures are not taken, it can quickly lead to safety accidents such as fires and explosions.

[0003] Existing thermal runaway suppression solutions for battery modules mostly rely on electromagnetic valve systems controlled by electrical signals. These systems suffer from issues such as response delays and the risk of circuit failures, and may fail in extreme situations (such as a complete vehicle power outage), indicating insufficient reliability of electrical signal control. Furthermore, after a battery has caught fire, traditional fire extinguishing methods often employ spray extinguishing agents. However, these methods are limited in their effectiveness against thermal runaway within confined spaces like battery packs, failing to effectively dilute and expel flammable gases generated inside the battery pack. Summary of the Invention

[0004] The present invention aims to provide a protection system and method for thermal runaway of battery packs, so as to solve the problem of insufficient reliability of electrical signal control in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a battery pack thermal runaway protection system, comprising... The frame has an internal air passage. A crossbeam and a longitudinal beam are installed on the inner side of the frame. The interior of the crossbeam and the longitudinal beam are connected to the air passage. A first air outlet valve is installed on the side wall of the crossbeam, the side wall of the longitudinal beam, and the inner wall of the frame. A first heat-melting cover is fitted on the first air outlet valve. The gas control unit includes a gas storage cylinder, a pressure reducing assembly, and a thermal activation assembly. The gas storage cylinder is installed on the outer wall of the frame and has an outlet gas nozzle. A second heat-fused cover is provided on the outlet gas nozzle. The pressure reducing assembly is installed in the gas passage, and the outlet gas nozzle is located inside the pressure reducing assembly. The thermal activation assembly includes a heat-conducting plate, a heat-conducting rod, and an activation plate. The heat-conducting plate is installed on the inner wall of the frame, the heat-conducting rod is installed on the side wall of the heat-conducting plate and extends into the pressure reducing assembly, and the activation plate is fixed to the end of the heat-conducting rod. The activation plate abuts against the second heat-fused cover, and the heat-conducting plate is also connected to the cold plate of the battery pack. The puncture component is mounted on the excitation plate.

[0006] The present invention is further configured to include an inner sliding cover, which is slidably fitted to the inner side of the gas storage bottle. A limiting ring is also fixed inside the gas storage bottle. The inner sliding cover can abut against the side of the limiting ring away from the outlet gas nozzle. The inner sliding cover has an inner outlet gas nozzle, and a third hot melt cover is provided on the inner outlet gas nozzle. When the inner sliding cover slides toward the outlet air nozzle, the third hot melt cover can be inserted into the inside of the outlet air nozzle, and the third hot melt cover can abut against the excitation plate.

[0007] The invention is further configured such that: the pressure reducing component includes an isolation chamber and a second exhaust valve, the isolation chamber is embedded in the air passage, the heat-conducting rod passes through the isolation chamber, and there are two second exhaust valves symmetrically arranged about the exhaust nozzle, and the second exhaust valves are fixed to the side wall of the isolation chamber.

[0008] The present invention is further configured such that the melting point of the first hot melt shield is the same as that of the second hot melt shield, and both are lower than the melting point of the third hot melt shield.

[0009] The present invention is further configured such that the limiting ring is located at one-third of the inner volume of the gas storage cylinder.

[0010] The invention is further configured such that: the puncture assembly includes a fixed plate, a movable plate, an air tube, and a spring; the fixed plate is fixed to the heat-conducting rod; the movable plate is fitted and fixed to the air tube; the two ends of the air tube are slidably inserted through the fixed plate and the excitation plate, respectively; and the spring is fitted onto the air tube and located between the fixed plate and the movable plate.

[0011] The invention is further configured such that the puncture assembly also includes a limiting block, which is fixed to the side wall of the heat-conducting rod and can abut against the side of the movable plate away from the gas storage bottle.

[0012] The invention is further configured such that a pressure sensor is also provided inside the airway, and the pressure sensor is located inside the isolation chamber.

[0013] The present invention is further configured such that: the top of the frame has a cover, and a pressure valve is installed on the cover.

[0014] This invention also includes a protection method based on a battery pack thermal runaway protection system: S1. Thermal runaway at point P causes the temperature of the cold plate at the bottom of the battery pack to rise, and the temperature is transferred to the first thermal fusible shield near point P. S2, the temperature of the first hot melt cover near point P reaches the melting point and melts; the temperature of the cold plate is transferred to the second hot melt cover in sequence through the heat-conducting plate, heat-conducting rod, and excitation plate, so that the second hot melt cover is heated, softened and melted, and the piercing component pierces the second hot melt cover when the second hot melt cover softens and melts. S3. The fire extinguishing gas in the gas cylinder located on the side of the inner sliding cover near the outlet nozzle enters the pressure reducing assembly through the outlet nozzle and is then depressurized. The fire extinguishing gas passes through the gas passage and is delivered to the first outlet valve that has been melted by the first heat-fused cover. S4. The extinguishing gas is sprayed out from the first outlet valve to the vicinity of point P. The extinguishing gas is used to cool down point P and expel combustible gas and combustion-supporting gas from the battery pack. S5. When the extinguishing gas on the side of the inner sliding cover near the outlet nozzle is discharged, the inner sliding cover gradually approaches the outlet nozzle under the pressure on the side away from the outlet nozzle until the inner outlet nozzle is located inside the outlet nozzle and the third heat-melting cover abuts against the activation plate. The temperature at points S6 and P continues to rise. Under the heat transfer effect of the excitation plate, the third hot melt cover begins to soften and melt. The puncturing component punctures the third hot melt cover when it softens and melts. At this time, the inner vent opens. S7. The extinguishing gas in the gas cylinder located on the side of the inner sliding cover away from the outlet nozzle enters the pressure reducing assembly through the inner outlet nozzle and is depressurized. The extinguishing gas then passes through the gas passage and is delivered to the first outlet valve that has been melted by the first heat-fused cover. S8. Gas is ejected from the first outlet valve to the vicinity of point P, using the fire extinguishing gas to cool point P and expel combustible and combustion-supporting gases from the battery pack.

[0015] This solution has at least the following beneficial effects: 1. When thermal runaway occurs within the battery pack, the abnormally high temperature will first be transferred to the first thermal runaway shield, which is closest to the thermal runaway point, thus melting the first thermal runaway shield. At this time, the gas duct opens, and the fire extinguishing gas in the pressure reducing assembly can enter the battery pack through the gas duct and the first vent valve. Because the cold plate cannot dissipate the abnormal temperature of the battery pack in a timely and effective manner, the temperature of the cold plate rises synchronously. By connecting the heat-conducting plate to the cold plate of the battery pack, this abnormal temperature can also be transferred to the activation plate through the heat-conducting plate and heat-conducting rod, causing the activation plate to heat and melt the second thermal runaway shield. At this time, the fire extinguishing gas in the gas cylinder enters the battery pack through the outlet nozzle, pressure reducing component, and first outlet valve. The high-pressure fire extinguishing gas cools the battery in the battery pack and removes combustible gases. The release of the fire extinguishing gas in the gas cylinder is activated through mechanical heat transfer. In the pure mechanical activation mode, the gas control unit can be triggered to cool the battery pack and remove combustible and combustible gases even when the power is completely cut off in the vehicle. Compared with the traditional electronic control monitoring system, this solution has higher reliability.

[0016] 2. By setting up the puncture component, when the second heat-sealed cover reaches its melting point and begins to soften and melt, the puncture component can puncture the second heat-sealed cover to accelerate its opening, thereby allowing the extinguishing gas in the gas cylinder to flow out more quickly.

[0017] 3. Directly using the crossbeams, longitudinal beams, and frame as the delivery channels for extinguishing gas results in a lighter weight and easier processing compared to traditional gas pipeline layouts, eliminating the need for stabilizing the gas pipelines.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] Figure 1 This is the front view of the present invention (with a battery pack installed). Figure 2 for Figure 1 Top view of the structure (without battery pack); Figure 3 for Figure 2 Enlarged view of point A in the image; Figure 4 for Figure 3 Enlarged view of point B in the image; Figure 5 for Figure 3 Enlarged view of point C in the image; Figure 6 for Figure 2 Enlarged view of the gas storage cylinder. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments: The reference numerals in the accompanying drawings include: 110. Frame; 111. Air duct; 120. Longitudinal beam; 130. Crossbeam; 210. First vent valve; 220. First heat-sealing shield; 310. Gas cylinder; 320. Outlet gas nozzle; 330. Second heat-sealing cover; 410. Heat-conducting plate; 420. Heat-conducting rod; 430. Excitation plate; 510. Isolation chamber; 520. Second vent valve; 610. Inner sliding cover; 620. Limiting ring; 630. Inner vent; 640. Third heat-sealing cover; 710. Fixed plate; 720. Movable plate; 730. Air tube; 740. Spring; 750. Limiting block.

[0021] Example: As attached Figure 1-6As shown, this invention discloses a battery pack thermal runaway protection system, including a frame 110, a gas control unit, and a puncture assembly. The frame 110 has a bottom plate and a cover plate on its upper and lower sides, respectively. The battery pack is housed between the frame 110, the bottom plate, and the cover plate. The frame 110 has an air passage 111 inside (structural features of the main body structure). A crossbeam 130 and a longitudinal beam 120 are installed on the inner side (positional features) of the frame 110. The interior of the crossbeam 130 and the longitudinal beam 120 are respectively connected to the air passage 111. By utilizing the cavities inside the frame 110, the crossbeam 130, and the longitudinal beam 120 to deliver fire extinguishing gas, the complex piping is avoided, the vehicle weight is reduced, and the internal structure of the frame 110, the crossbeam 130, and the longitudinal beam 120 is simplified.

[0022] First vent valves 210 are installed on the side walls of the crossbeam 130, the side walls of the longitudinal beam 120, and the inner wall of the frame 110. First vent valves 210 are fitted with first fusible covers 220. Through the arrangement of multiple first vent valves 210, the first fusible cover 220 near the thermal runaway point P melts first, opening the gas passage 111. The first fusible cover 220 further from point P remains closed. At this time, the extinguishing gas can be selectively ejected from the first vent valve 210 where the first fusible cover 220 has melted, thereby specifically cooling the thermal runaway point. The first vent valve 210 is a one-way vent valve, allowing the extinguishing gas to freely exit from the frame to one side of the first fusible cover 220.

[0023] The gas control unit includes a gas cylinder 310, a pressure reducing assembly, and a thermal activation assembly. The gas cylinder 310 is installed on the outer wall of the frame 110. The gas cylinder 310 is provided with a protective structure and a buffer structure on its exterior to protect and buffer the gas cylinder 310, so as to prevent external factors such as gravel and vehicle vibration from damaging the stability of the connection between the gas cylinder 310 and the frame 110 structure during vehicle operation. The gas cylinder 310 can store high-pressure carbon dioxide or rare gases with large molecular weight. These gases are non-combustible and non-flammable, making them commonly used fire extinguishing gases. In this design, the gas cylinder 310 is a high-pressure gas cylinder with a volume of 3L, storing 2.3-2.5 kg of liquefied carbon dioxide. The gas cylinder 310 has an outlet nozzle 320, on which a second heat-sealing cover 330 is installed. A pressure-reducing assembly is installed in the gas passage 111 to reduce the pressure of the high-pressure carbon dioxide gas in the gas cylinder 310. The outlet nozzle 320 is located within the pressure-reducing assembly.

[0024] The thermal activation assembly includes a heat-conducting plate 410, a heat-conducting rod 420, and an activation plate 430. The heat-conducting plate 410 is installed on the inner wall of the frame 110, the heat-conducting rod 420 is installed on the side wall of the heat-conducting plate 410 and extends into the pressure-reducing assembly, and the activation plate 430 is fixed to the end of the heat-conducting rod 420. The activation plate 430 abuts against the second hot melt cover 330. The heat-conducting plate 410 is also connected to the cold plate of the battery pack (the cold plate is the core heat dissipation component for thermal management in the battery pack, and its condition can directly reflect the operating temperature of the battery pack. By connecting the heat-conducting plate 410 to the cold plate, the heat-conducting plate 410 can have the same temperature as the cold plate). The heat-conducting plate 410, the heat-conducting rod 420, and the activation plate 430 are all made of materials with the same thermal conductivity, used to conduct heat from outside the frame 110 to the second hot melt cover 330. In this design, materials with higher thermal conductivity are selected, thereby allowing the heat from the cold plate to be transferred to the activation plate 430 more quickly.

[0025] The puncture assembly is installed on the excitation plate 430 and is used to assist the excitation plate 430 in puncturing the second heat-sealed cover 330. When the temperature of the excitation plate 430 reaches the melting point of the second heat-sealed cover 330, the second heat-sealed cover 330 softens and melts due to the heat. At this time, the strength of the second heat-sealed cover 330 decreases, and due to the pressure trend of the gas pressure inside the gas cylinder 310, and with the assistance of the puncture assembly, the second heat-sealed cover 330 is more likely to break open to open the outlet gas nozzle 320.

[0026] It also includes an inner sliding cover 610, which is slidably fitted inside the gas cylinder 310. A limiting ring 620 is also fixed inside the gas cylinder 310. The inner sliding cover 610 can abut against the side of the limiting ring 620 away from the outlet nozzle 320. The inner sliding cover 610 has an inner outlet nozzle 630, and a third hot melt cover 640 is provided on the inner outlet nozzle 630. When the inner sliding cover 610 slides toward the outlet nozzle 320, the third hot melt cover 640 can be inserted into the inner side of the outlet nozzle 320, and the third hot melt cover 640 can abut against the excitation plate 430. The piercing component can assist the excitation plate 430 in piercing the third hot melt cover 640.

[0027] By using the inner sliding cover 610 and the third hot-melt cover 640, the high-pressure carbon dioxide inside the gas storage cylinder 310 can be divided into two chambers. After the second hot-melt cover 330 melts the opening, the carbon dioxide gas on the side of the inner sliding cover 610 near the outlet gas nozzle 320 gradually flows out. At this time, the pressure on the left side of the inner sliding cover 610 decreases. Under the action of the carbon dioxide gas pressure on the side of the inner sliding cover 610 away from the outlet gas nozzle 320, the inner sliding cover 610 gradually slides towards the outlet gas nozzle 320, and the inner outlet gas nozzle 630 gradually inserts into the inside of the outlet gas nozzle 320. The third hot-melt cover 640 abuts against the excitation plate 430. (The remaining unmelted residue of the second hot melt shield 330 may prevent the third hot melt shield 640 from approaching the excitation plate 430. That is, there may be a certain gap between the excitation plate 430 and the third hot melt shield 640. However, under the premise of continuous thermal runaway of the battery pack, the temperature of the excitation plate 430 will not decrease. Under the premise that the excitation plate 430 continues to heat the residue of the second hot melt shield 330, the residue will melt and be squeezed out, so that the third hot melt shield 640 can smoothly come into contact with the excitation plate 430. If the thermal runaway of the battery pack is resolved, it is not necessary to ensure that the excitation plate 430 and the third hot melt shield 640 come into contact.)

[0028] This invention also discloses a protection method based on a battery pack thermal runaway protection system: S1. Let the thermal runaway point be point P. The temperature rise at point P causes the temperature of the cold plate at the bottom of the battery pack to rise, and the temperature at point P is transferred to the first thermal fusible shield 220 near point P through heat transfer. S2. The temperature of the first hot melt cover 220 near point P reaches the melting point and melts. At the same time, the temperature of the cold plate is transferred to the second hot melt cover 330 through the heat-conducting plate 410-heat-conducting rod 420-excitation plate 430, causing the second hot melt cover 330 to soften and melt. The piercing component pierces the second hot melt cover 330 when it softens and melts. S3. The high-pressure carbon dioxide gas in the gas storage cylinder 310 located on the side of the inner sliding cover 610 near the outlet gas nozzle 320 enters the pressure reducing assembly through the outlet gas nozzle 320 and is then depressurized. The carbon dioxide gas then passes through the gas passage 111 and is delivered to the first outlet valve 210 that has been melted by the first hot melt cover 220. S4. Carbon dioxide gas is ejected from the first outlet valve 210 to a point near P. The carbon dioxide gas is used to cool the P point and to expel the combustible gas and combustion-supporting gas from the battery pack. S5. When carbon dioxide gas is discharged from the side of the inner sliding cover 610 near the outlet nozzle 320, the inner sliding cover 610 gradually approaches the outlet nozzle 320 under the pressure of the carbon dioxide gas on the side away from the outlet nozzle 320, until the inner outlet nozzle 630 is located inside the outlet nozzle 320 and the third hot melt cover 640 abuts against the excitation plate 430. S6. After the carbon dioxide gas on the side of the inner sliding cover 610 near the outlet nozzle 320 is completely discharged, the temperature at point P continues to rise. At this time, the temperature of the cold plate, as well as the temperatures of the heat-conducting plate 410, the heat-conducting rod 420, and the excitation plate 430, also continue to rise. The third hot melt cover 640 begins to soften and melt under the heat transfer action of the excitation plate 430. The piercing component pierces the third hot melt cover 640 when it softens and melts. At this time, the inner outlet nozzle 630 opens. S7. The high-pressure carbon dioxide gas in the gas storage cylinder 310 located on the side of the inner sliding cover 610 away from the outlet gas nozzle 320 enters the pressure reducing assembly through the inner outlet gas nozzle 630. After being reduced by the pressure reducing assembly, the carbon dioxide gas is transported through the gas passage 111 to the first outlet valve 210 that has been melted by the first hot melt cover 220. S8. Carbon dioxide gas is ejected from the first outlet valve 210 to a point near P. The carbon dioxide gas is used to cool the point P and to expel combustible gas and combustion-supporting gas from the battery pack.

[0029] In this solution, the pressure reducing assembly includes an isolation chamber 510 and a second exhaust valve 520. The isolation chamber 510 is embedded in the air passage 111, and the heat-conducting rod 420 passes through the isolation chamber 510. There are two second exhaust valves 520 symmetrically arranged about the exhaust nozzle 320, and the second exhaust valves 520 are fixed to the side wall of the isolation chamber 510.

[0030] With an opening in the side wall of the frame 110, the heat-conducting rod 420 is fixed to the isolation chamber 510 and forms an integral part with the isolation chamber 510. During installation, the heat-conducting rod 420 can be inserted through the frame 110 and abut against the heat-conducting plate 410. Then, the isolation chamber 510 is fixed to the frame 110 to ensure stable contact between the heat-conducting rod 420 and the heat-conducting plate 410.

[0031] By integrating the isolation chamber 510, the gas storage cylinder 310, the heat-conducting rod 420, and the excitation plate 430 into a single unit, the structure is modularized, thereby simplifying the disassembly and assembly process. After the carbon dioxide gas on the side of the inner sliding cover 610 near the outlet gas nozzle 320 is completely discharged and the temperature of the battery pack is controlled, the gas storage cylinder 310 needs to be maintained and replaced. The modular design facilitates the subsequent replacement and disassembly of the gas storage cylinder 310.

[0032] In this design, the melting point of the first hot melt shield 220 is the same as that of the second hot melt shield 330, and both are lower than the melting point of the third hot melt shield 640. In this design, the melting points of the first hot melt shield 220 and the second hot melt shield 330 can be selected from hot melt materials with a melting point of 60℃-70℃, while the melting point of the third hot melt shield 640 can be selected from hot melt materials with a melting point of 75℃-85℃. The limiting ring 620 is located at one-third of the inner volume of the gas storage cylinder 310.

[0033] For example, the safe operating temperature of a battery pack is typically 20°C-40°C. However, if the operating temperature exceeds 60°C, it may lead to localized thermal runaway or localized deflagration. Monitoring the battery pack temperature through phased physical means can provide early warning and prevention. For instance, if the battery pack temperature reaches 60°C but does not ignite, it indicates an abnormal operating state. Carbon dioxide gas near the outlet of the inner sliding cover 610 provides early warning and prevention, rapidly cooling the battery pack through the blowing and exhaust of high-pressure carbon dioxide gas. After the warning carbon dioxide gas is exhausted (i.e., after the third thermal fusible cover 640 contacts the activation plate 430), if the battery pack temperature continues to rise, the third thermal fusible cover 640 ruptures, releasing carbon dioxide gas to further control the battery pack temperature and expel combustion-supporting and combustible gases. This phased physical control system provides both early warning and prevention. Compared to releasing all carbon dioxide gas at once, this solution is more accurate, practical, and economical and environmentally friendly.

[0034] Furthermore, by setting the volume ratio on both sides of the inner sliding cover 610, the ratio of carbon dioxide gas used for early warning and carbon dioxide gas used for prevention and control can be controlled. In other words, in the event of thermal runaway of the battery pack with combustion or already in combustion, more carbon dioxide gas is used for prevention and control, which can buy more time for the people inside the vehicle. That is, compared with the carbon dioxide gas used for early warning, the carbon dioxide gas used for prevention and control can provide more escape time.

[0035] In this design, the puncture assembly includes a fixed plate 710, a movable plate 720, an air tube 730, and a spring 740. The fixed plate 710 is fixed to the heat-conducting rod 420, and the movable plate 720 is fitted and fixed to the air tube 730. Both ends of the air tube 730 slide through the fixed plate 710 and the activation plate 430, respectively. The air tube 730 can abut against the second heat-sealing shield 330 or the third heat-sealing shield 640. The spring 740 is fitted onto the air tube 730 and located between the fixed plate 710 and the movable plate 720. The puncture assembly also includes a limiting block 750, which is fixed to the side wall of the heat-conducting rod 420 and can abut against the side of the movable plate 720 away from the gas storage cylinder 310.

[0036] The spring 740 applies pressure to the movable plate 720, causing the air pipe 730 to approach the second hot melt shield 330 or the third hot melt shield 640. After the second hot melt shield 330 or the third hot melt shield 640 is heated and softened and melted, the air pipe 730 can easily pierce the second hot melt shield 330 or the third hot melt shield 640 under the pressure of the spring 740, thereby releasing the carbon dioxide gas in the gas cylinder 310. The air pipe 730 can also serve as a connection for carbon dioxide gas. Furthermore, when the temperature has not reached the melting point, the second hot melt shield 330 or the third hot melt shield 640 has high strength, and the elastic force of the spring 740 is unlikely to pierce the second hot melt shield 330 or the third hot melt shield 640, thus providing stable reliability without the need for electric drive.

[0037] In this design, a pressure sensor is also installed inside the airway 111, and the pressure sensor is located inside the isolation chamber 510.

[0038] S9. When in S3, the pressure sensor detects a sudden increase in pressure and issues a thermal runaway warning to the driver's cab. As carbon dioxide gas is ejected, the pressure of the pressure sensor gradually decreases. When in S7, the pressure sensor pressure increases again, at which point a fire alarm is sent to the driver's cab.

[0039] The alarm is triggered by an auxiliary pressure sensor, allowing the mechanical warning and control device to transmit the information to the vehicle via electronic devices, enabling the driver to monitor the situation directly. Even if the pressure sensor fails, the warning and control effect of the solution will not be affected.

[0040] In this design, a one-way pressure valve is installed on the cover at the top of the frame 110. The pressure valve is used to discharge combustible gas, combustion-supporting gas and high-pressure carbon dioxide gas inside the battery pack to prevent local high pressure from causing an explosion.

[0041] S10. When in S4 or S8, carbon dioxide gas enters the inside of the frame 110 from the gas passage 111, causing the pressure inside the frame 110 to increase. At this time, the gas with lower density and located in the upper layer of the frame 110 is discharged first by the pressure valve under the action of pressure.

[0042] The parts of the device not covered herein are the same as or can be implemented using existing technologies.

[0043] Among them, insert and sliding insert are mating bodies with holes, the cross section of the shaft or rod matches the hole, and the shaft or rod can slide relative to the hole. Threaded insert is a hole with threads, the shaft or rod is threaded, and the shaft or rod is connected to the mating body by screwing. Detachable installation can be by bolt thread connection or bolt and nut connection, etc., depending on what can be actually achieved.

[0044] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific technical solutions or characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A battery pack thermal runaway protection system, characterized in that: include The frame (110) has an air passage (111) inside. A crossbeam (130) and a longitudinal beam (120) are installed on the inner side of the frame (110). The interior of the crossbeam (130) and the longitudinal beam (120) are respectively connected to the air passage (111). A first air outlet valve (210) is installed on the side wall of the crossbeam (130), the side wall of the longitudinal beam (120) and the inner wall of the frame (110). A first heat fusion cover (220) is fitted on the first air outlet valve (210). The gas control unit includes a gas cylinder (310), a pressure reducing assembly, and a thermal activation assembly. The gas cylinder (310) is installed on the outer wall of the frame (110). The gas cylinder (310) has an outlet nozzle (320), and a second heat-sealing cover (330) is provided on the outlet nozzle (320). The pressure reducing assembly is installed in the gas passage (111), and the outlet nozzle (320) is located inside the pressure reducing assembly. The thermal activation assembly includes a heat-conducting plate (4). 10) A heat-conducting rod (420) and an excitation plate (430), wherein the heat-conducting plate (410) is installed on the inner wall of the frame (110), the heat-conducting rod (420) is installed on the side wall of the heat-conducting plate (410) and extends into the pressure-reducing assembly, the excitation plate (430) is fixed to the end of the heat-conducting rod (420), the excitation plate (430) abuts against the second hot melt cover (330), and the heat-conducting plate (410) is also connected to the cold plate of the battery pack; The puncture component is mounted on the excitation plate (430).

2. The battery pack thermal runaway protection system as described in claim 1, characterized in that: It also includes an inner sliding cover (610), which is slidably fitted to the inside of the gas storage cylinder (310). A limiting ring (620) is also fixed inside the gas storage cylinder (310). The inner sliding cover (610) can abut against the side of the limiting ring (620) away from the outlet nozzle (320). The inner sliding cover (610) has an inner outlet nozzle (630), and a third heat-fused cover (640) is provided on the inner outlet nozzle (630). When the inner sliding cover (610) slides toward the outlet air nozzle (320), the third hot melt cover (640) can be inserted into the inner side of the outlet air nozzle (320), and the third hot melt cover (640) can abut against the excitation plate (430).

3. The battery pack thermal runaway protection system as described in claim 2, characterized in that: The pressure reducing assembly includes an isolation chamber (510) and a second exhaust valve (520). The isolation chamber (510) is embedded in the air passage (111), and the heat-conducting rod (420) passes through the isolation chamber (510). There are two second exhaust valves (520) symmetrically arranged about the exhaust nozzle (320), and the second exhaust valves (520) are fixed to the side wall of the isolation chamber (510).

4. The battery pack thermal runaway protection system as described in claim 2, characterized in that: The melting point of the first hot melt shield (220) is the same as that of the second hot melt shield (330), and both are lower than the melting point of the third hot melt shield (640).

5. A battery pack thermal runaway protection system as described in claim 2, characterized in that: The limiting ring (620) is located at one-third of the inner volume of the gas storage cylinder (310).

6. A battery pack thermal runaway protection system as described in claim 2, characterized in that: The puncture assembly includes a fixed plate (710), a movable plate (720), an air tube (730), and a spring (740). The fixed plate (710) is fixed to the heat-conducting rod (420), and the movable plate (720) is fitted and fixed to the air tube (730). The two ends of the air tube (730) are slidably inserted through the fixed plate (710) and the excitation plate (430), respectively. The spring (740) is fitted on the air tube (730) and is located between the fixed plate (710) and the movable plate (720).

7. A battery pack thermal runaway protection system as described in claim 6, characterized in that: The puncture assembly also includes a limiting block (750), which is fixed to the side wall of the heat-conducting rod (420) and can abut against the side of the movable plate (720) away from the gas storage bottle (310).

8. A battery pack thermal runaway protection system as described in claim 2, characterized in that: A pressure sensor is also provided inside the airway (111), and the pressure sensor is located inside the isolation chamber (510).

9. A battery pack thermal runaway protection system as described in claim 2, characterized in that: The top of the frame (110) has a cover on which a pressure valve is installed.

10. A protection method based on a battery pack thermal runaway protection system according to any one of claims 2-9, characterized in that: S1. Thermal runaway at point P causes the temperature of the cold plate at the bottom of the battery pack to rise, and the temperature is transferred to the first thermal fusible shield (220) near point P. S2, the temperature of the first hot melt shield (220) near point P reaches the melting point and melts; the temperature of the cold plate is transferred to the second hot melt shield (330) through the heat-conducting plate (410), the heat-conducting rod (420), the excitation plate (430) in sequence, so that the second hot melt shield (330) softens and melts when heated, and the piercing component pierces the second hot melt shield (330) when the second hot melt shield (330) softens and melts; S3. The fire extinguishing gas in the gas cylinder (310) located on the side of the inner sliding cover (610) near the outlet gas nozzle (320) enters the pressure reducing assembly through the outlet gas nozzle (320) and is then depressurized. The fire extinguishing gas then passes through the gas passage (111) and is delivered to the first outlet valve (210) melted by the first heat-melting cover (220). S4. The extinguishing gas is sprayed from the first outlet valve (210) to the vicinity of point P. The extinguishing gas is used to cool down point P and to expel combustible gas and combustion-supporting gas from the battery pack. S5. When the extinguishing gas is discharged from the side of the inner sliding cover (610) near the outlet nozzle (320), the inner sliding cover (610) gradually approaches the outlet nozzle (320) under the pressure push on the side away from the outlet nozzle (320) until the inner outlet nozzle (630) is located inside the outlet nozzle (320) and the third heat-melting cover (640) abuts against the activation plate (430); The temperature at points S6 and P continues to rise. Under the heat transfer effect of the excitation plate (430), the third hot melt cover (640) begins to soften and melt. The puncturing component punctures the third hot melt cover (640) when it softens and melts. At this time, the inner air outlet (630) opens. S7. The fire extinguishing gas in the gas cylinder (310) located on the side of the inner sliding cover (610) away from the outlet gas nozzle (320) enters the pressure reducing assembly through the inner outlet gas nozzle (630) and is then depressurized. The fire extinguishing gas then passes through the gas passage (111) and is delivered to the first outlet valve (210) melted by the first heat-melting cover (220). S8. The extinguishing gas is sprayed from the first outlet valve (210) to the vicinity of point P. The extinguishing gas is used to cool down point P and to discharge combustible gas and combustion-supporting gas from the battery pack.

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