Electric freight vehicle power battery safety explosion-proof early warning device

Abstract

This invention provides a safety explosion-proof early warning device for power batteries in electric freight vehicles, belonging to the field of battery safety technology. It includes an explosion-proof housing with symmetrically distributed first mounting brackets on both sides of the top of the housing. The housing is fixedly connected to the power battery via these brackets. A second mounting bracket is symmetrically installed in the middle of the housing's interior, and compressed nitrogen tanks are evenly distributed between the brackets. By providing independent explosion-proof housings above each power supply module, this invention ensures each module has a dedicated puncture relief channel and a fire extinguishing medium delivery channel. If a module experiences thermal runaway, the triggering component in its corresponding housing can act independently and respond rapidly without requiring cross-module communication and global judgment through the battery management system. This effectively shortens the response path from the occurrence of an anomaly to the execution of protective actions, improving the timeliness of initial thermal runaway response.

Description

Technical Field

[0001] This invention relates to the field of battery safety technology, and in particular to a safety explosion-proof early warning device for power batteries in electric freight vehicles. Background Technology

[0002] The safety protection of power batteries in electric freight vehicles is an important research direction in the current new energy vehicle field. At present, the mainstream protection solution is based on the battery management system. By placing various sensors inside or on the surface of the battery pack, the system collects operating parameters such as battery voltage, current, temperature and internal air pressure in real time. When the monitored values ​​reach the preset threshold, the battery management system issues a warning signal and performs protective actions such as cutting off the high-voltage circuit.

[0003] The aforementioned early warning schemes for electric vehicles have been applied to some models and have indeed improved the operational safety of power batteries to a certain extent. However, there is still room for further improvement. For example, Chinese invention patent CN121688171A proposes a battery management system, a battery early warning method, and related equipment. This invention patent achieves thermal runaway early warning by having a cell parameter acquisition module and a gas sensor work together. The triggering of its early warning and protection functions is highly dependent on the integrity and reliability of the sensor sampling circuit, communication circuit, and electromagnetic execution circuit. However, in real life, electric freight vehicles are subjected to harsh conditions such as vibration, bumps, and alternating high and low temperatures for a long time. It is difficult to completely avoid situations such as aging of circuits and loosening of connectors. Once the circuit is damaged, the corresponding functions are at risk of failure. Moreover, when the power battery experiences thermal runaway, a large amount of high-temperature and high-pressure gas will be generated inside the battery pack in a very short time. It is necessary to quickly vent the gas through a pressure relief channel. However, the signal acquisition, transmission, and execution in existing electronic early warning schemes require a certain response delay, which is difficult to meet the immediate need for rapid pressure relief in the early stage of thermal runaway. Therefore, this application provides a safety explosion-proof early warning device for electric freight vehicle power batteries to meet the requirements. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a safety explosion-proof early warning device for the power battery of electric freight vehicles to solve the problems in the prior art where the early warning function is highly dependent on the integrity of the electronic circuit, the circuit is easily damaged under the harsh operating conditions of freight vehicles, resulting in functional failure, and the electronic signal response is delayed, making it difficult to meet the immediate need for rapid pressure relief in the early stage of thermal runaway.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: An explosion-proof warning device for the power battery of an electric freight vehicle includes an explosion-proof housing. Symmetrically distributed first mounting brackets are located on both sides of the top of the explosion-proof housing, and the housing is fixedly connected to the power battery via these brackets. A second fixing bracket is symmetrically installed in the middle of the housing's interior, with evenly distributed compressed nitrogen tanks nested between the brackets. Evenly distributed puncture tubes are fixedly connected to both sides of the housing's interior, with the bottom of each tube extending to the bottom of the housing. A retractable and sliding puncture needle is fitted inside each tube. A connecting tube is fixedly connected to the top of each tube, and a delivery tube is fixedly connected to the top of the tube. The first fixing... Dry powder is stored between the first and second fixed frames, and the end of the delivery tube is inserted into the bottom of the dry powder. A triggering component is provided below the compressed nitrogen tank. The triggering component is used to release the compressed nitrogen in the compressed nitrogen tank. The triggering component includes a triggering tube fixedly connected to the bottom of the compressed nitrogen tank. An ejection mechanism is provided between the puncture tube and the puncture needle rod. The ejection mechanism is used to push the puncture needle rod out from inside the puncture tube. The ejection mechanism includes a piston plate fixedly connected to the top of the puncture needle rod. A spring is fixedly connected between the piston plate and the puncture tube. The inside of the puncture needle rod has a communicating cavity that communicates with the delivery tube, and the outside of the puncture needle rod has evenly distributed dry powder output channels that communicate with the communicating cavity.

[0006] Optionally, the bottom end of the puncture needle rod extends below the bottom end of the puncture tube, and the bottom of the explosion-proof box is fixedly connected with protective strips symmetrically distributed on both sides of the puncture tube. The length of the bottom end of the puncture needle rod extending from the puncture tube is less than the height of the protective strip.

[0007] Optionally, a uniformly distributed bracket is fixedly connected to the side of the second mounting bracket near the middle of the explosion-proof box. The shape of the bracket is adapted to the end shape of the compressed nitrogen tank, and the compressed nitrogen tank is placed on the bracket.

[0008] Optionally, the top of the trigger tube is connected to the compressed nitrogen tank, a sealing membrane is fixedly connected to the end of the trigger tube near the compressed nitrogen tank, and a memory metal strip located below the sealing membrane is fixedly connected to the inner wall of the trigger tube.

[0009] Optionally, a nitrogen outlet is provided at the bottom of the trigger tube, a trigger pin rod corresponding to the middle position of the sealed membrane is fixedly connected to the top of the memory metal strip, and the end of the memory metal strip extends to the outside of the trigger tube.

[0010] Optionally, a third mounting bracket is fixedly connected to the external side of the trigger tube furthest from the center of the explosion-proof box. A drive motor is fixedly installed in the third mounting bracket, and the drive motor is electrically connected to the vehicle's battery temperature monitoring system.

[0011] Optionally, a transmission rod is fixedly connected to the drive shaft of the drive motor, and the transmission rod is fixedly connected to the end of the memory metal strip extending to the outside of the trigger tube. A uniformly distributed bearing support frame is fixedly connected to the bottom of the inner wall of the explosion-proof box, and the bearing support frame and the transmission rod are rotatably connected by bearings.

[0012] Optionally, a pipe support frame for reinforcing the delivery pipe is fixedly connected in the connecting pipe, and the pipe support frame has evenly distributed through openings.

[0013] Optionally, the piston disc is fixedly connected to a uniformly distributed limiting plate, and the inner wall of the puncture tube is fixedly connected to a limiting ring that mates with the limiting plate. A separation slit is provided between adjacent limiting plates, and the cross-sections of the limiting plate and the limiting ring are interlocked in an L-shape.

[0014] Optionally, a pressure relief port is provided on the outside of the needle tip of the puncture needle rod, and the dry powder output channel is located above the pressure relief port. The dry powder output channel is not provided at the position corresponding to the pressure relief port inside the puncture needle rod, and a rubber ring corresponding to the bottom outlet position of the dry powder output channel is sleeved on the outside of the puncture needle rod.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: In the above solution, by setting up independent explosion-proof boxes above each power supply module, each module has a dedicated puncture relief channel and fire extinguishing medium delivery channel. Once a module experiences thermal runaway, the triggering component in its corresponding box can act independently and respond quickly without going through cross-module communication and global judgment of the battery management system. This effectively shortens the response path from the occurrence of the anomaly to the execution of the protective action and improves the timeliness of handling the initial stage of thermal runaway.

[0016] By designing a dual-mode triggering component consisting of a drive motor and a shape memory metal strip, the drive motor is electrically connected to the vehicle battery temperature monitoring system to achieve electronic triggering, while the shape memory metal strip deforms at high temperatures to achieve physical triggering. Even if the electric freight vehicle is subjected to harsh conditions such as long-term vibration, bumps, and alternating high and low temperatures, and there are situations such as aging of the circuit, loosening of connectors, or damage to the electronic control circuit due to high temperature, the physical triggering method can still independently complete the triggering action. This effectively improves the stability and reliability of the warning device under extreme conditions and solves the technical problem that the warning function in the prior art completely depends on the integrity of the electronic circuit.

[0017] By creating a thermal sensing area at the bottom of the explosion-proof enclosure and installing a memory metal strip and a trigger pin rod in the trigger tube, when the electrical control circuit fails to achieve electrical triggering due to aging or high temperature damage, the continuous high temperature is conducted through the thermal sensing area to the memory metal strip, causing it to deform and drive the trigger pin rod to pierce the sealing membrane and release compressed nitrogen gas. Although this mechanical triggering method has a slightly longer response time than electrical triggering, as a protective structure, it ensures that the explosion-proof warning function can be stably realized under any working condition, making up for the lack of a physical redundancy mechanism independent of the electronic system in the existing solution.

[0018] By linking the release of compressed nitrogen with the ejection of the puncture needle and the pushing of dry powder, the released compressed nitrogen pushes the piston disc to compress the spring and drives the puncture needle to quickly eject and pierce the battery pack casing, achieving millisecond-level rapid depressurization to meet the immediate need for rapid venting in the early stages of thermal runaway. On the other hand, it pushes dry powder through the delivery pipe and the connecting cavity inside the puncture needle. After the puncture needle completes depressurization, it is sprayed out from the dry powder output channel, acting on the thermal runaway area of ​​the battery to isolate oxygen and prevent open flames. This achieves the sequential execution of depressurization and fire extinguishing functions, further enhancing the safety protection performance of the explosion-proof early warning device.

[0019] By setting a pressure relief port and a rubber ring on the outside of the puncture needle rod, and with the interlocking structure of the limiting plate and the limiting ring, the puncture needle rod is initially retracted into the puncture tube and protected by the protective strip, maintaining a preset distance from the battery pack shell to accumulate acceleration impact force. After triggering, the limiting plate and the limiting ring separate and release the limiting force. The spring release elasticity, together with the nitrogen pressure, pushes the puncture needle rod to perform the puncture action, ensuring that the puncture needle rod can stably puncture the shell of the battery pack thermal runaway area. After puncture, the pressure relief port forms a channel connecting the inside and outside of the battery pack to guide the high temperature and high pressure gas to be discharged. At the same time, the rubber ring remains in the puncture tube to unblock the dry powder output channel, and the dry powder is smoothly sprayed out, realizing the automatic switching and precise coordination of puncture pressure relief and dry powder spraying in terms of timing.

[0020] By setting a protective strip at the bottom of the first mounting bracket with a height greater than the extension length of the puncture needle, a preset distance is maintained between the explosion-proof box and the battery pack shell. This not only protects the bottom of the puncture needle to avoid collision damage during transportation and installation, but also provides space for the puncture needle to extend, so that the puncture needle has a greater impact force when it contacts the battery pack shell to stably puncture the shell for pressure relief. Attached Figure Description

[0021] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate embodiments of the invention and, together with the specification, further serve to explain the principles of the invention and enable those skilled in the art to practice and use the invention.

[0022] Figure 1A first-person view structural diagram of a safety explosion-proof early warning device for the power battery of an electric freight vehicle. Figure 2 A second-view structural diagram of a safety explosion-proof early warning device for the power battery of an electric freight vehicle. Figure 3 A schematic diagram of the internal structure of the explosion-proof warning device for the power battery of an electric freight vehicle. Figure 4 This is a schematic diagram of the structure for the second mounting bracket and the compressed nitrogen tank. Figure 5 for Figure 4 Enlarged structural diagram at point A in the middle; Figure 6 for Figure 4 Enlarged structural diagram at point B; Figure 7 This is a schematic diagram of the three-dimensional structure of a compressed nitrogen tank; Figure 8 This is a schematic diagram of the cross-sectional structure of the trigger tube; Figure 9 This is a schematic diagram of the three-dimensional structure of the puncture tube; Figure 10 This is a schematic diagram of the cross-sectional structure of the puncture tube; Figure 11 A schematic diagram of the three-dimensional structure of the puncture needle shaft; Figure 12 This is a schematic diagram of the cross-sectional structure of the puncture needle shaft; Figure 13 This is a schematic diagram of the three-dimensional structure of the limiting plate and the limiting ring.

[0023] Figure label: 1. Explosion-proof housing; 2. First mounting bracket; 3. Protective strip; 4. Puncture tube; 5. Puncture needle rod; 6. Thermal sensing area; 7. First fixing bracket; 8. Second fixing bracket; 9. Compressed nitrogen tank; 10. Delivery pipe; 11. Bracket; 12. Trigger tube; 13. Third fixing bracket; 14. Drive motor; 15. Transmission rod; 16. Nitrogen outlet; 17. Shape memory metal strip; 18. Bearing support frame; 19. Sealing membrane; 20. Trigger needle rod; 21. Connecting pipe; 22. Pipe support frame; 23. Piston disc; 24. Spring; 25. Limiting plate; 26. Limiting ring; 27. Rubber ring; 28. Dry powder output channel; 29. ​​Pressure relief port; 30. Connecting cavity; 31. Separation seam.

[0024] As shown in the figure, specific structures and devices are marked in the figure to clearly illustrate the structure of the embodiments of the present invention. However, this is only for illustrative purposes and is not intended to limit the present invention to this specific structure, device and environment. Those skilled in the art can adjust or modify these devices and environments according to specific needs. Detailed Implementation

[0025] The explosion-proof warning device for the power battery of electric freight vehicles provided by the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should also be noted that, to make the embodiments more detailed, the following embodiments are the best and preferred embodiments, and those skilled in the art can use other alternative methods to implement some known technologies; moreover, the accompanying drawings are only for more specific description of the embodiments and are not intended to specifically limit the present invention.

[0026] It should be noted that the use of terms such as "an embodiment," "an embodiment," "an exemplary embodiment," and "some embodiments" in the specification indicates that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments (whether explicitly described or not) should be within the knowledge of those skilled in the art.

[0027] Generally, terms can be understood at least partly from their use in context. For example, depending at least partly on the context, the term "one or more" as used herein can be used to describe any feature, structure, or characteristic in a singular sense, or a combination of features, structures, or characteristics in a plural sense. Additionally, the term "based on" can be understood not necessarily to convey an exclusive set of factors, but rather, alternatively, depending at least partly on the context, to allow for the presence of other factors that are not necessarily explicitly described.

[0028] It is understood that the meanings of “on”, “above”, and “above” in this invention should be interpreted in the broadest manner, such that “on” not only means “directly on” something, but also includes the meaning of being “on” something with an intervening feature or layer, and that “above” or “above” not only means “on” something, but also includes the meaning of being “on” something without an intervening feature or layer.

[0029] Furthermore, spatially related terms such as “below,” “under,” “lower,” “above,” and “upper” are used herein for convenience to describe the relationship of one element or feature to one or more other elements or features, as illustrated in the accompanying drawings. Spatially related terms are intended to cover different orientations in the use or operation of the device other than those depicted in the accompanying drawings. The device may be oriented in other ways, and the spatially related descriptive terms used herein can be interpreted similarly.

[0030] like Figures 1 to 13 As shown, an embodiment of the present invention provides a safety explosion-proof warning device for the power battery of an electric freight vehicle, including an explosion-proof box 1. First mounting brackets 2 are symmetrically distributed on both sides of the top of the explosion-proof box 1, and the explosion-proof box 1 is fixedly connected to the power battery via the first mounting brackets 2. Second fixing brackets 8 are symmetrically installed in the middle of the interior of the explosion-proof box 1, and compressed nitrogen tanks 9 are uniformly distributed between the second fixing brackets 8. Puncture tubes 4 are uniformly distributed and fixedly connected to both sides of the interior of the explosion-proof box 1. The bottom end of the puncture tube 4 extends to the bottom of the explosion-proof box 1, and a retractable and slidable puncture needle rod 5 is sleeved inside the puncture tube 4. A [missing information - likely a device name] is fixedly connected to the top of the puncture tube 4. The connecting tube 21 and the top end of the puncture tube 4 are fixedly connected to the delivery tube 10. Dry powder is stored between the first fixed frame 7 and the second fixed frame 8 inside the explosion-proof box 1. The end of the delivery tube 10 is inserted into the bottom position of the dry powder. A triggering component is provided below the compressed nitrogen tank 9. The triggering component is used to release the compressed nitrogen in the compressed nitrogen tank 9. An ejection mechanism is provided between the puncture tube 4 and the puncture needle rod 5. The ejection mechanism is used to push the puncture needle rod 5 out from the inside of the puncture tube 4. The inside of the puncture needle rod 5 is provided with a connecting cavity 30 that communicates with the delivery tube 10. The outside of the puncture needle rod 5 is provided with evenly distributed dry powder output channels 28 that communicate with the connecting cavity 30.

[0031] The explosion-proof warning device is mounted above the power battery via the first mounting bracket 2. Each power supply module on the power battery corresponds to one explosion-proof warning device. The triggering component in the device is electrically connected to the vehicle's battery temperature monitoring system. Once the power battery experiences thermal runaway, the monitoring system detects the abnormality and controls the electronic triggering structure in the triggering component to operate, thus activating the entire device. If the electronic control circuit is damaged due to the battery's thermal runaway, the physical structure in the triggering component will deform due to the temperature rise, causing the triggering component to perform its triggering action. This allows the entire triggering component to be triggered by both electronic control and physical mechanisms. Even if the electric freight vehicle is subjected to harsh conditions such as long-term vibration, bumps, and alternating high and low temperatures, resulting in aging wiring or loose connectors, the corresponding functions of the explosion-proof warning device will not fail. After the triggering component operates, the compressed nitrogen stored in the compressed nitrogen tank 9 is released. After the compressed nitrogen is released, it serves two purposes inside the explosion-proof housing 1. First, the released nitrogen pressure pushes the puncture needle rod 5 to slide inside the puncture tube 4. After relative sliding between the puncture needle rod 5 and the puncture tube 4, the ejection mechanism moves simultaneously. Combined with the rapidly rising air pressure inside the explosion-proof housing 1, the puncture needle rod 5 is quickly ejected from inside the puncture tube 4 and punctures the power battery area where thermal runaway has occurred. This rapidly releases the high-temperature and high-pressure gas inside the battery pack, achieving rapid venting and reducing the danger of battery thermal runaway. Second, the released compressed nitrogen is also used to push the dry powder stored between the first fixing frame 7 and the second fixing frame 8. After the puncture needle rod 5 completes the puncture action, the dry powder is sprayed out through the delivery pipe 10 and the puncture needle rod 5, acting on the thermal runaway area of ​​the battery. This provides a timely response after battery thermal runaway, preventing open flames and causing greater danger, further enhancing the safety and explosion-proof performance of the entire explosion-proof warning device.

[0032] In this embodiment, as Figures 1 to 4As shown, the bottom end of the puncture needle rod 5 extends below the bottom end of the puncture tube 4. Protective strips 3, symmetrically distributed on both sides of the puncture tube 4, are fixedly connected to the bottom of the explosion-proof housing 1. The length of the bottom end of the puncture needle rod 5 extending from the puncture tube 4 is less than the height of the protective strip 3. Evenly distributed brackets 11 are fixedly connected to the side of the second fixing frame 8 near the middle of the explosion-proof housing 1. The shape of the brackets 11 matches the end shape of the compressed nitrogen tank 9. The compressed nitrogen tank 9 is placed on the brackets 11. The protective strips 3 are used to separate the bottom of the explosion-proof housing 1 from the battery pack and to protect the puncture needle rod 5 extending from the bottom end of the puncture tube 4, ensuring that the bottom end of the puncture needle rod 5 is flush with the battery pack. There is a certain gap between the outer shells, so that when the triggering component and the ejection mechanism work together, the puncture needle rod 5 has a certain acceleration distance when it is ejected. This results in the puncture needle rod 5 having a greater impact force when it contacts the battery pack outer shell, allowing it to puncture the battery pack outer shell more stably for pressure relief. The bracket 11 on the second fixing frame 8 is used to assist in the positioning of the compressed nitrogen tank 9. The second fixing frame 8 provides support and fixation for the compressed nitrogen tank 9, and leaves a certain gap between the bottom of the compressed nitrogen tank 9 and the bottom of the inner wall of the explosion-proof box 1, so as to facilitate the setting of the triggering component and make more reasonable use of the space inside the explosion-proof box 1.

[0033] In this embodiment, as Figures 2 to 8As shown, the triggering assembly includes a trigger tube 12 fixedly connected to the bottom of a compressed nitrogen tank 9. The top of the trigger tube 12 is connected to the compressed nitrogen tank 9. A sealing membrane 19 is fixedly connected to one end of the trigger tube 12 near the compressed nitrogen tank 9. A shape memory metal strip 17 located below the sealing membrane 19 is fixedly connected to the inner wall of the trigger tube 12. A nitrogen outlet 16 is opened at the bottom of the trigger tube 12, which forms a channel for the trigger tube 12 to connect to the inside of the explosion-proof enclosure 1. When compressed nitrogen in the compressed nitrogen tank 9 is released, it can enter the explosion-proof enclosure 1 through the nitrogen outlet 16 at the bottom of the trigger tube 12. A trigger pin rod 20 corresponding to the middle position of the sealing membrane 19 is fixedly connected to the top of the shape memory metal strip 17, and the end of the shape memory metal strip 17 extends to the outside of the trigger tube 12. A third trigger tube 12 farthest from the middle of the explosion-proof enclosure 1 is fixedly connected to the outside. A drive motor 14 is fixedly installed in the third fixed bracket 13. The drive motor 14 is electrically connected to the vehicle's battery temperature monitoring system. A transmission rod 15 is fixedly connected to the drive shaft of the drive motor 14. The transmission rod 15 is fixedly connected to the end of the memory metal strip 17 extending to the outside of the trigger tube 12. Evenly distributed bearing support frames 18 are fixedly connected to the bottom of the inner wall of the explosion-proof box 1. The bearing support frames 18 and the transmission rod 15 are rotatably connected by bearings. The setting of the bearing support frames 18 can provide auxiliary support for the transmission rod 15. With the cooperation of the bearings, the rotation of the transmission rod 15 is not affected. A heat sensing area 6 corresponding to the position of the trigger component is opened at the bottom of the explosion-proof box 1. The opening of the heat sensing area 6 makes the structure at the bottom of the explosion-proof box 1 thinner in the area where the heat sensing area 6 is located, which can better conduct the external temperature to the position of the trigger component.

[0034] The triggering component has two operating modes. In electronically controlled triggering mode, it primarily relies on the vehicle's battery temperature monitoring system. Upon detecting an abnormal battery pack temperature, it electronically controls the drive motor 14. The drive motor 14, through its drive shaft, rotates the transmission rod 15, causing the shape memory metal strip 17, fixedly connected to the transmission rod 15, to be traction-deformed. This deformation causes the trigger pin 20 to approach the sealing membrane 19 until it punctures the membrane, releasing the compressed nitrogen from the compressed nitrogen tank 9. This then triggers the synchronous operation of other structures within the explosion-proof housing 1. However, in electronically controlled mode, due to aging... When the device is damaged by chemical reactions, high temperatures, or other factors and cannot be electrically triggered, the continuous high temperature will be conducted through the heat-sensing area 6 at the bottom of the explosion-proof housing 1 to the shape memory metal strip 17. Once the shape memory metal strip 17 reaches its deformation temperature due to the high temperature, it will deform, which will also cause the trigger pin rod 20 to move and puncture the sealing membrane 19. Although this mechanical triggering method has a longer response time than the electronic triggering method, it effectively improves the stability of the entire triggering component. When the electronic triggering method cannot be implemented due to various circumstances, it can serve as a protective structure for the triggering component, ensuring that the explosion-proof warning function of the triggering component can be stably realized.

[0035] In this embodiment, as Figures 9 to 13As shown, the ejection mechanism includes a piston disc 23 fixedly connected to the top of the puncture needle rod 5, a spring 24 fixedly connected between the piston disc 23 and the puncture tube 4, a pipe support frame 22 for reinforcing the delivery tube 10 fixedly connected in the connecting tube 21, and a uniformly distributed through opening on the pipe support frame 22. A uniformly distributed limiting plate 25 is fixedly connected to the top of the piston disc 23, and a limiting ring 26 that cooperates with the limiting plate 25 is fixedly connected to the inner wall of the puncture tube 4. A separation slit 31 is opened between adjacent limiting plates 25, and the cross-sections of the limiting plate 25 and the limiting ring 26 are interlocked in an L-shape. A pressure relief port 29 is provided on the outside of the needle tip of the puncture needle rod 5. The dry powder output channel 28 is located above the pressure relief port 29. The dry powder output channel 28 is not provided inside the puncture needle rod 5 at the position corresponding to the pressure relief port 29. A rubber ring 27 is fitted on the outside of the puncture needle rod 5, corresponding to the bottom outlet position of the dry powder output channel 28. When the trigger component works and releases the nitrogen in the compressed nitrogen tank 9, the gas pressure inside the explosion-proof box 1 rises rapidly. The released nitrogen passes through the top of the connecting pipe 21. The through opening on the pipe support frame 22 is fed into the puncture tube 4, pushing the piston disc 23 inside the puncture tube 4 to slide, thereby causing the puncture needle rod 5 to be pushed out from inside the puncture tube 4. On the other hand, it pushes the dry powder stored between the first fixing frame 7 and the second fixing frame 8 into the delivery pipe 10. Through the channel formed by the delivery pipe 10 and the puncture needle rod 5, the dry powder is sprayed out in time after the puncture needle rod 5 completes the puncture and depressurization of the battery pack, isolating the oxygen in the thermal runaway area of ​​the battery pack and preventing the spread of open flames. In its initial state, the puncture needle rod 5 is retracted into the puncture tube 4, with only its bottom end extending beyond the outside of the puncture tube 4 and protected by the protective strip 3, maintaining a certain distance from the battery pack casing. At this time, the limiting plate 25 and the limiting ring 26 on the piston disc 23 are interlocked, and the spring 24 is in a compressed state. When nitrogen gas is forced into the interior of the puncture tube 4, pushing the piston disc 23 downward, the downward movement of the piston disc 23 will cause the limiting plate 25 and the limiting ring 26 to separate, releasing the limitation on the piston disc 23. Subsequently, the elasticity accumulated in the spring 24 is released, and together with the pressure of nitrogen on the piston disc 23, the two work together to push the piston disc 23 to drive the puncture needle rod 5 to perform a puncture action, ensuring that the puncture needle rod 5 can successfully puncture the outer shell of the battery pack thermal runaway area to perform a pressure relief operation. The released nitrogen gas will also push the dry powder from the delivery pipe 10 through into the connecting cavity 30 inside the puncture needle rod 5, and finally spray it out through the dry powder output channel 28 connected to the connecting cavity 30, acting on the outside of the battery pack to prevent the generation of open flames.

[0036] The pressure relief port 29 allows the puncture needle 5 to pierce the battery pack casing, creating a channel between the battery pack casing and the outside environment to guide the discharge of high-temperature, high-pressure gas. This prevents the puncture needle 5 from sealing the puncture hole, thus preventing pressure relief. The rubber ring 27 is used to seal the dry powder output channel 28. Before the puncture needle 5 completes the piercing operation, the end of the dry powder output channel 28 is sealed by the rubber ring 27, preventing the dry powder from being ejected. After the puncture needle 5 extends from the puncture tube 4 and completes the piercing operation, the rubber ring... 27 is left inside the puncture tube 4 and cannot extend with the puncture needle rod 5. The dry powder output channel 28 on the puncture needle rod 5 leaks out, releasing the sealed state and allowing the dry powder to be sprayed out through the dry powder output channel 28 to act on the battery pack. The dry powder output channel 28 is not set at the position corresponding to the pressure relief port 29 inside the puncture needle rod 5 to avoid structural interference between the dry powder output channel 28 and the pressure relief port 29, and also to prevent the high temperature and high pressure gas generated during the pressure relief process from rushing into the puncture needle rod 5 through the dry powder output channel 28, affecting the spraying effect of the dry powder.

[0037] This invention encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of this invention. To provide the public with a thorough understanding of this invention, specific details are described in detail in the following preferred embodiments; however, those skilled in the art will fully understand the invention even without these details. Furthermore, to avoid unnecessary misunderstanding of the essence of this invention, well-known methods, processes, procedures, components, and circuits are not described in detail.

[0038] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A safety explosion-proof early warning device for the power battery of an electric freight vehicle, characterized in that, The explosion-proof box includes a first mounting bracket symmetrically distributed on both sides of the top of the explosion-proof box, and the explosion-proof box is fixedly connected to the power battery above the first mounting bracket. A second fixing bracket is symmetrically installed in the middle of the interior of the explosion-proof box, and compressed nitrogen tanks are evenly distributed between the second fixing brackets. The explosion-proof box has two sides with evenly distributed puncture tubes fixedly connected to it. The bottom of the puncture tubes extends to the bottom of the explosion-proof box. The puncture tubes are fitted with telescopic and sliding puncture needle rods. The top of the puncture tubes is fixedly connected to a connecting tube. The top of the puncture tubes is fixedly connected to a delivery tube. Dry powder is stored between the first and second fixed frames inside the explosion-proof box. The end of the delivery tube is inserted into the bottom of the dry powder. A triggering component is provided below the compressed nitrogen tank. The triggering component is used to release the compressed nitrogen in the compressed nitrogen tank. The triggering component includes a triggering pipe fixedly connected to the bottom of the compressed nitrogen tank. An ejection mechanism is provided between the puncture tube and the puncture needle rod. The ejection mechanism is used to push the puncture needle rod out from inside the puncture tube. The ejection mechanism includes a piston plate fixedly connected to the top of the puncture needle rod, and a spring is fixedly connected between the piston plate and the puncture tube. The puncture needle shaft has an internal cavity that connects to the delivery tube, and the puncture needle shaft has uniformly distributed dry powder output channels that connect to the internal cavity.

2. The electric freight vehicle power battery safety explosion-proof early warning device according to claim 1, characterized in that, The bottom end of the puncture needle extends to below the bottom end of the puncture tube. The bottom of the explosion-proof box is fixedly connected with protective strips symmetrically distributed on both sides of the puncture tube. The length of the bottom end of the puncture needle extending from the puncture tube is less than the height of the protective strip.

3. The electric freight vehicle power battery safety explosion-proof early warning device according to claim 1, characterized in that, On the second mounting bracket, a uniformly distributed bracket is fixedly connected to the side near the middle of the explosion-proof box. The shape of the bracket is adapted to the end shape of the compressed nitrogen tank, and the compressed nitrogen tank is placed on the bracket.

4. The electric freight vehicle power battery safety explosion-proof early warning device according to claim 1, characterized in that, The top of the trigger tube is connected to the compressed nitrogen tank. A sealing membrane is fixedly connected to the end of the trigger tube near the compressed nitrogen tank, and a shape memory metal strip located below the sealing membrane is fixedly connected to the inner wall of the trigger tube.

5. The electric freight vehicle power battery safety explosion-proof early warning device according to claim 4, characterized in that, The bottom of the trigger tube has a nitrogen outlet, and the top of the memory metal strip is fixedly connected to a trigger pin rod corresponding to the middle position of the sealed membrane, and the end of the memory metal strip extends to the outside of the trigger tube.

6. The electric freight vehicle power battery safety explosion-proof early warning device according to claim 5, characterized in that, A third mounting bracket is fixedly connected to the external side of the trigger tube furthest from the center of the explosion-proof box. A drive motor is fixedly installed in the third mounting bracket, and the drive motor is electrically connected to the vehicle's battery temperature monitoring system.

7. The electric freight vehicle power battery safety explosion-proof early warning device according to claim 6, characterized in that, A transmission rod is fixedly connected to the drive shaft of the drive motor. The transmission rod is fixedly connected to the end of the memory metal strip that extends to the outside of the trigger tube. Evenly distributed bearing support frames are fixedly connected to the bottom of the inner wall of the explosion-proof box. The bearing support frames and the transmission rod are rotatably connected by bearings.

8. The explosion-proof early warning device for the power battery of electric freight vehicles according to claim 1, characterized in that, A pipe support frame for reinforcing the delivery pipe is fixedly connected to the connecting pipe, and the pipe support frame has evenly distributed through openings.

9. The electric freight vehicle power battery safety explosion-proof early warning device according to claim 8, characterized in that, The piston disc is fixedly connected to a uniformly distributed limiting plate, and the inner wall of the puncture tube is fixedly connected to a limiting ring that mates with the limiting plate. A separation slit is provided between adjacent limiting plates, and the cross-sections of the limiting plate and the limiting ring are interlocked in an L shape.

10. The electric freight vehicle power battery safety explosion-proof early warning device according to claim 9, characterized in that, The needle tip of the puncture needle shaft has a pressure relief port on the outside. The dry powder output channel is located above the pressure relief port. The dry powder output channel is not located inside the puncture needle shaft at the position corresponding to the pressure relief port. The outside of the puncture needle shaft is fitted with a rubber ring corresponding to the bottom outlet position of the dry powder output channel.

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