A battery pack heat spread blocking device based on hot melt triggering and vortex cooling

Abstract

The application discloses a battery pack heat spread blocking device based on hot melt triggering and vortex cooling, which comprises a hot melt triggering mechanism, a heat shield curtain unfolding mechanism and a vortex cooling exhaust passage; the hot melt triggering mechanism comprises a locking pin made of a low-melting-point alloy, a pressure-bearing plate and a return spring, the locking pin is configured to be fused at a temperature not lower than 200 DEG C and a pressure not lower than 0.3 MPa; the heat shield curtain unfolding mechanism comprises a reel, a pre-tightening torsional spring and a folded heat shield curtain, the reel is locked by the locking pin, and the torsional spring drives the heat shield curtain to unfold to cover the interval between adjacent modules after the locking pin is fused; the application utilizes the heat and pressure of the heat runaway gas to trigger the mechanical mechanism, does not need power driving, can simultaneously block the heat conduction and heat radiation paths, reduces the temperature and particulate matter content of the exhaust gas, and has a failure safety feature by arranging the exhaust passage and the heat shield curtain mechanism in parallel.

Description

Technical Field

[0001] This invention relates to the field of power battery safety technology, and in particular to a battery pack thermal propagation blocking device based on thermal melting triggering and vortex cooling. Background Technology

[0002] With the rapid development of electric vehicles and energy storage systems, the safety performance of power batteries has received widespread attention. When a power battery experiences abnormal operating conditions such as internal short circuits, overcharging, or mechanical compression, a single cell may enter a state of thermal runaway, generating high-temperature gas and releasing a large amount of heat. If the heat cannot be contained in time, it will be transferred to adjacent cells through conduction, radiation, and eruption, causing adjacent cells to successively run away from control, ultimately leading to a fire in the entire battery pack—a phenomenon known as "thermal propagation." Existing technologies primarily focus on the design of gas venting channels to prevent battery thermal runaway. For example, existing technologies disclose a battery top cover assembly that forms a venting channel by setting a protruding part and a supporting structure to prevent cells from being pushed out and blocking the channel; a battery pack that forms an exhaust channel between an upper and lower base plate and ensures the pressure relief rate by limiting the ratio of the base plate thickness to the channel spacing; and a battery cell fixing bracket with exhaust holes on its mounting slot, staggered from the explosion-proof valve.

[0003] However, the aforementioned prior art has the following drawbacks: Firstly, existing technologies all focus on the single step of "expelling gas," without addressing the issue that the expelled gas may ignite flammable materials outside the battery pack. Secondly, existing technologies all focus on structural optimization for single exhaust behavior, but lack targeted measures for "thermal propagation" after thermal runaway, which is the main cause of vehicle burnout, especially since no measures have been taken to block the two pathways of heat conduction and heat radiation. Third, the existing channel structures are all static structures, which cannot make a dynamic response after thermal runaway occurs; Fourth, if an electronic control scheme is used to achieve dynamic response, it relies on temperature sensors, controllers and actuators. However, under thermal runaway conditions, low-voltage wiring harnesses and sensors often fail before the mechanism, resulting in insufficient reliability of the electronic control scheme in real accident scenarios. Fifth, existing technologies do not utilize the heat and pressure inherent in the thermally runaway gas itself, resulting in energy waste. Summary of the Invention

[0004] The purpose of this invention is to address the problems of existing technologies that only focus on gas discharge without blocking heat conduction and radiation paths, lack dynamic response mechanisms, and fail to utilize the energy of the thermally runaway gas itself. Therefore, this invention proposes a battery pack thermal propagation blocking device based on thermal melting triggering and vortex cooling.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A battery pack thermal propagation prevention device based on hot-melt triggering and vortex cooling includes a hot-melt triggering mechanism, a heat insulation curtain deployment mechanism, and a vortex cooling exhaust channel. The hot-melt triggering mechanism includes a locking pin, a pressure plate, and a return spring. The locking pin is made of a low-melting-point alloy with a melting point range of 180°C to 220°C. The pressure plate is disposed within a piston cavity and can move axially within the piston cavity. One end of the return spring abuts against the pressure plate, and the other end abuts against the bottom of the piston cavity. The locking pin abuts against the back of the pressure plate. To one side of the piston chamber, a mechanism is used to lock the pressure plate in its initial position; the heat insulation curtain unfolding mechanism includes a roller, a torsion spring, and a heat insulation curtain; the heat insulation curtain is wound around the roller, one end of the torsion spring is fixed to the roller, and the other end is fixed to the housing; the roller is connected to the pressure plate through a linkage; the vortex cooling exhaust channel is provided with a spiral guide vane and a particle settling chamber, the spiral guide vane extends spirally along the inner wall of the vortex cooling exhaust channel, and the particle settling chamber is located at the lower part of the vortex cooling exhaust channel.

[0006] As a further description of the above technical solution: the heat insulation curtain is a layered structure composed of ceramic fiber fabric and metal foil, with a thickness of 2mm~5mm and a temperature resistance of not less than 1200℃.

[0007] As a further description of the above technical solution: the low-melting-point alloy of the locking pin is a bismuth-tin-lead alloy or a bismuth-tin-cadmium alloy.

[0008] As a further description of the above technical solution: the heat insulation curtain unfolds and covers the space between two adjacent battery modules.

[0009] As a further description of the above technical solution: the vortex cooling exhaust channel is arranged in parallel with the heat insulation curtain deployment mechanism, and the vortex cooling exhaust channel remains open when the heat insulation curtain deployment mechanism fails.

[0010] As a further description of the above technical solution: the spiral helix angle of the spiral guide vane is 15°~45°.

[0011] As a further description of the above technical solution: the bottom of the particle settling chamber is provided with a detachable collection box.

[0012] As a further description of the above technical solution: the effective pressure-bearing area of ​​the pressure plate is 10cm²~50cm².

[0013] As a further description of the above technical solution: the housing is provided with a guide groove, and the two sides of the heat insulation curtain are slidably disposed in the guide groove.

[0014] As a further description of the above technical solution: the linkage is a connecting rod or a flexible cable.

[0015] As a further description of the above technical solution: it also includes a limiting member, which is provided on one side of the roller and is used to lock the roller after the heat insulation curtain is fully unfolded.

[0016] As a further description of the above technical solution: the unfolding time of the heat insulation curtain is no more than 0.5s.

[0017] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: By setting up a thermal triggering mechanism, the triggering is achieved by using a low-melting-point alloy locking pin that melts at high temperature. This eliminates the need for temperature sensors, controllers, and power supply lines, thus avoiding the problem of electrical system failure leading to triggering failure under thermal runaway conditions.

[0018] The triggering energy of the thermal runaway triggering mechanism comes from the heat and pressure of the thermal runaway gas itself, without the need for external energy, and makes full use of the energy of the thermal runaway gas itself.

[0019] By setting up a heat insulation curtain deployment mechanism, the heat insulation curtain is quickly deployed by a torsion spring after being triggered and covers the space between adjacent modules, thereby blocking both heat conduction and heat radiation paths at the same time, making up for the shortcomings of existing technologies that only deal with the eruption path. By setting up a vortex cooling exhaust channel, the high-temperature gas is made to vortex along the spiral guide vane. Centrifugal force is used to throw the high-temperature particles in the gas toward the wall and settle in the particle settling chamber. At the same time, the gas exchanges heat with the channel wall during the vortex process and cools down, thereby reducing the temperature and particulate matter content of the exhaust gas and reducing the risk of igniting external combustibles. By connecting the vortex cooling exhaust channel in parallel with the heat insulation curtain deployment mechanism, when the heat insulation curtain deployment mechanism fails due to jamming or other reasons, the exhaust channel remains open, and the device degenerates into a direct exhaust mode, thus possessing fail-safe characteristics. Attached Figure Description

[0020] Figure 1 This is a schematic cross-sectional view of the battery pack of the present invention, wherein part I is a partial enlargement of the vortex cooling exhaust channel; Figure 2 This is a schematic diagram of the thermal melting triggering mechanism in this invention; Figure 3 This is a schematic diagram of the heat insulation curtain deployment mechanism in this invention; Figure 4 This is a cross-sectional view of the vortex cooling exhaust channel in this invention; Figure 5 This is a perspective view of the overall appearance of the battery pack of the present invention; Figure 6This is a schematic diagram showing the connection relationship between the hot melt triggering mechanism and the heat insulation curtain unfolding mechanism in this invention; Figure 7 This is a schematic diagram illustrating the triggering action principle in this invention, wherein... Figure 7 (a) is the state before triggering, and (b) is the state after triggering; Figure 8 This is a schematic diagram illustrating the working principle of vortex flow in this invention.

[0021] Legend: 1. Locking pin, 2. Pressure plate, 3. Return spring, 4. Piston chamber, 5. Roller, 6. Torsion spring, 7. Heat insulation curtain, 8. Housing, 9. Linkage component, 10. Vortex cooling exhaust channel, 11. Spiral guide vane, 12. Particle settling chamber, 13. Battery module, 14. Collection box, 15. Guide groove, 16. Limiting component, 17. Explosion-proof valve, 18. Liquid cooling plate, 19. Flange, 20. O-ring seal, 21. Thread, 22. Mounting flange, 23. Shaft hole, 24. Guide roller, 25. Inlet flange, 26. Outlet flange, 27. Terminal post.

[0022] In the above figures, the same reference numerals indicate the same parts. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Please see Figure 1-8 This invention provides a technical solution: a battery pack heat propagation blocking device based on hot-melt triggering and vortex cooling, including a hot-melt triggering mechanism, a heat insulation curtain deployment mechanism, and a vortex cooling exhaust channel. Specifically, the hot-melt triggering mechanism includes a locking pin 1, a pressure plate 2, and a return spring 3. The locking pin 1 is made of a low-melting-point alloy with a melting point range of 180℃ to 220℃. The low-melting-point alloy can be a bismuth-tin-lead alloy (e.g., a mass fraction of 50% bismuth, 25% tin, and 25% lead, with a melting point of approximately 180℃), or a bismuth-tin-cadmium alloy, the specific composition of which is determined according to the required melting temperature. The pressure plate 2 is disposed within the piston cavity 4 and can move along the axial direction of the piston cavity 4. The effective pressure-bearing area of ​​the pressure plate 2 is 10cm² to 50cm². One end of the return spring 3 abuts against the pressure plate 2, and the other end abuts against the bottom of the piston cavity 4. The locking pin 1 abuts against the side of the pressure plate 2 facing away from the piston cavity 4, used to lock the pressure plate 2 in its initial position.

[0025] Specifically, the piston chamber 4 is connected to the exhaust space of the battery pack, allowing the pressure of the thermal runaway gas to act on the pressure plate 2. When the battery module 13 experiences thermal runaway, the temperature of the thermal runaway gas is typically in the range of 200℃ to 900℃, and the relative pressure inside the module is typically in the range of 0.5 bar to 3 bar. Since the melting point of the locking pin 1 is 180℃ to 220℃, when the gas temperature is higher than this melting point and the pressure on the pressure plate 2 is higher than the preload of the return spring 3, the locking pin 1 melts, and the pressure plate 2 moves under the action of gas pressure, overcoming the elastic force of the return spring 3. In this embodiment, the melting temperature of the locking pin 1 and the pressure-bearing area of ​​the pressure plate 2 are matched to ensure that the device is triggered when the temperature is not lower than 200℃ and the pressure is not lower than 0.3MPa, but not triggered when the battery pack is working normally (the temperature is typically not higher than 80℃ and the pressure is close to zero), thereby avoiding false triggering in high-temperature environments in summer or under fast charging conditions.

[0026] Specifically, the heat insulation curtain deployment mechanism includes a roller 5, a torsion spring 6, and a heat insulation curtain 7. The heat insulation curtain 7 is wound around the roller 5. One end of the torsion spring 6 is fixed to the roller 5, and the other end is fixed to the housing 8. The torsion spring 6 is in a pre-tensioned state. The roller 5 is connected to the pressure plate 2 via a linkage 9, which can be a connecting rod or a flexible cable. The heat insulation curtain 7 is a layered structure composed of ceramic fiber fabric and metal foil, with a thickness of 2mm to 5mm and a temperature resistance of not less than 1200℃. In this embodiment, the deployment time of the heat insulation curtain 7 is no more than 0.5s.

[0027] Specifically, when the locking pin 1 melts and the pressure plate 2 moves, the pressure plate 2 releases the lock on the roller 5 via the linkage 9, and the torsion spring 6 releases its elastic potential energy and drives the roller 5 to rotate, causing the heat insulation curtain 7 to unfold rapidly. The housing 8 is provided with a guide groove 15, and the two sides of the heat insulation curtain 7 are slidably disposed within the guide groove 15 to ensure that the heat insulation curtain 7 unfolds along a predetermined path. After unfolding, the heat insulation curtain 7 covers the space between two adjacent battery modules 13, thereby blocking the heat conduction and radiation paths from the runaway module to the adjacent module. A limiting member 16 is provided on one side of the roller 5 to lock the roller 5 after the heat insulation curtain 7 is fully unfolded, preventing the heat insulation curtain 7 from rewinding.

[0028] Specifically, the vortex cooling exhaust channel 10 is equipped with a spiral guide vane 11 and a particle settling chamber 12. The spiral guide vane 11 extends spirally along the inner wall of the vortex cooling exhaust channel 10, with a spiral angle of 15°~45°. The particle settling chamber 12 is located at the lower part of the vortex cooling exhaust channel 10, and a removable collection box 14 is provided at its bottom. When high-temperature gas enters the vortex cooling exhaust channel 10, it undergoes vortex motion under the guidance of the spiral guide vane 11. High-temperature particles in the gas are thrown towards the channel wall under centrifugal force and settle in the particle settling chamber 12 under gravity, where they are collected by the collection box 14. At the same time, the gas exchanges heat fully with the channel wall during the vortex process, resulting in a temperature reduction. Tests show that the outlet gas temperature is 150°C~300°C lower than the inlet temperature, and the solid particle removal rate is greater than 70%. It should be noted that the above values ​​are measured under experimental conditions, and the actual temperature reduction and particle removal rate are affected by factors such as gas flow rate, channel size, and ambient temperature.

[0029] Specifically, the top wall of the housing 8 has a mounting hole, through which the vortex cooling exhaust channel 10 passes and is fixed to the top wall of the housing 8 by a flange 19. The inlet and outlet ends of the vortex cooling exhaust channel 10 are respectively provided with an inlet flange 25 and an outlet flange 26. The inlet flange 25 is used to communicate with the exhaust space of the battery pack, and the outlet flange 26 is used for a sealed connection with an external exhaust pipe. The top plate of the battery module 13 is provided with a terminal post 27, which is used for electrical connection with external electrical connectors. The top plate of the battery module 13 is also provided with an explosion-proof valve 17, which is used to open and release pressure when the internal pressure of the battery module 13 exceeds a set value. A liquid cooling plate 18 is located on the inner bottom surface of the housing 8 and is thermally bonded to the bottom surface of the battery module 13. The liquid cooling plate 18 has cooling channels inside. The locking pin 1 has a thread 21 on the rod section outside the piston chamber 4, and the locking pin 1 is threadedly connected to the wall hole of the piston chamber 4 through the thread 21. The mounting flange 22 is fixedly connected to the top opening of the piston chamber 4, and the hot-melt triggering mechanism is fixed to the housing 8 through the mounting flange 22. An O-ring 20 is provided between the outer edge of the pressure plate 2 and the inner wall of the piston chamber 4 to ensure the sealing of the pressure plate 2 during axial movement. The end of the roller 5 is provided with a shaft hole 23, and the roller 5 is rotatably connected to the housing 8 through the shaft hole 23. A guide roller 24 is provided in the guide groove 15, and the two sides of the heat insulation curtain 7 are sandwiched between the guide rollers 24. When the heat insulation curtain 7 is unfolded, the guide rollers 24 roll accordingly to guide the heat insulation curtain 7 to unfold smoothly along a predetermined path.

[0030] Specifically, as an improvement, the vortex cooling exhaust channel 10 is connected in parallel with the heat insulation curtain deployment mechanism. When the heat insulation curtain deployment mechanism fails to deploy due to jamming, obstruction by foreign objects, or other reasons, the vortex cooling exhaust channel 10 remains open, allowing thermal runaway gases to be discharged through it, thus reverting the device to a direct exhaust mode. Therefore, even in the event of mechanism failure, this device maintains an exhaust capacity no less than that of existing technologies, possessing fail-safe characteristics.

[0031] Working principle: When a battery module 13 experiences thermal runaway and generates high-temperature, high-pressure gas, the gas first enters the piston chamber 4 and acts on the pressure plate 2. When the gas temperature reaches the melting point of the locking pin 1 and the pressure reaches the preset value, the locking pin 1 melts, and the pressure plate 2 moves under the action of gas pressure, driving the linkage 9. After the linkage 9 releases the lock on the roller 5, the torsion spring 6 is released and drives the heat insulation curtain 7 to unfold, covering the space between the runaway module and the adjacent module, blocking the heat conduction and heat radiation path. At the same time, the thermal runaway gas is discharged through the vortex cooling exhaust channel 10, and under the action of the spiral guide plate 11, it makes vortex motion. The particles are centrifugally separated and settle in the particle settling chamber 12. The gas temperature is reduced and then discharged, thereby reducing the risk of igniting external combustibles. If the heat insulation curtain unfolding mechanism fails, the gas can still be discharged through the vortex cooling exhaust channel 10, which remains open.

[0032] The embodiments of the present invention are not limited to the above embodiments. For example, the low melting point alloy of the locking pin 1 can be a bismuth-tin-lead alloy, or a bismuth-tin-cadmium alloy, or other alloys with suitable melting points; the heat insulation curtain 7 can be a composite structure of ceramic fiber and metal foil, or an aerogel composite felt, or other high-temperature resistant flexible materials; the linkage 9 can be a connecting rod, or a flexible cable or gear transmission mechanism; the helical helix angle of the spiral guide vane 11 can be adjusted according to the channel length and gas flow rate.

[0033] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A battery pack thermal propagation blocking device based on thermal melting triggering and vortex cooling, characterized in that, The device includes a hot melt triggering mechanism, a heat insulation curtain unfolding mechanism, and a vortex cooling exhaust channel; the hot melt triggering mechanism includes a locking pin (1), a pressure plate (2), and a return spring (3); the locking pin (1) is made of a low melting point alloy with a melting point range of 180℃~220℃; the pressure plate (2) is located in the piston cavity (4) and can move axially within the piston cavity (4); one end of the return spring (3) abuts against the pressure plate (2), and the other end abuts against the bottom of the piston cavity (4); the locking pin (1) abuts against the side of the pressure plate (2) facing away from the piston cavity (4) to lock the pressure plate (2) in the initial position. Starting position; the heat insulation curtain unfolding mechanism includes a roller (5), a torsion spring (6) and a heat insulation curtain (7); the heat insulation curtain (7) is wound on the roller (5), one end of the torsion spring (6) is fixed to the roller (5), and the other end is fixed to the housing (8); the roller (5) is connected to the pressure plate (2) through a linkage (9); the vortex cooling exhaust channel (10) is provided with a spiral guide plate (11) and a particle settling chamber (12), the spiral guide plate (11) extends spirally along the inner wall of the vortex cooling exhaust channel (10), and the particle settling chamber (12) is located at the lower part of the vortex cooling exhaust channel (10).

2. The battery pack thermal propagation blocking device based on thermal melting triggering and vortex cooling according to claim 1, characterized in that, The heat insulation curtain (7) is a layered structure composed of ceramic fiber fabric and metal foil, with a thickness of 2mm~5mm and a temperature resistance of not less than 1200℃.

3. The battery pack thermal propagation blocking device based on thermal melting triggering and vortex cooling according to claim 1, characterized in that, The low-melting-point alloy of the locking pin (1) is a bismuth-tin-lead alloy or a bismuth-tin-cadmium alloy.

4. The battery pack thermal propagation blocking device based on thermal melting triggering and vortex cooling according to claim 1, characterized in that, The heat insulation curtain (7) unfolds and covers the space between two adjacent battery modules (13).

5. A battery pack thermal propagation blocking device based on thermal melting triggering and vortex cooling according to claim 1, characterized in that, The vortex cooling exhaust channel (10) is connected in parallel with the heat insulation curtain unfolding mechanism, and the vortex cooling exhaust channel (10) remains open when the heat insulation curtain unfolding mechanism fails.

6. A battery pack thermal propagation blocking device based on thermal melting triggering and vortex cooling according to claim 1, characterized in that, The spiral angle of the spiral guide vane (11) is 15°~45°.

7. A battery pack thermal propagation blocking device based on thermal melting triggering and vortex cooling according to claim 1, characterized in that, The bottom of the particle settling chamber (12) is provided with a detachable collection box (14).

8. A battery pack thermal propagation blocking device based on thermal melting triggering and vortex cooling according to claim 1, characterized in that, The effective bearing area of ​​the pressure plate (2) is 10cm²~50cm².

9. A battery pack thermal propagation blocking device based on thermal melting triggering and vortex cooling according to claim 1, characterized in that, The housing (8) is provided with a guide groove (15), and the two sides of the heat insulation curtain (7) are slidably disposed in the guide groove (15).

10. A battery pack thermal propagation blocking device based on thermal melting triggering and vortex cooling according to claim 1, characterized in that, The linkage (9) is a connecting rod or a flexible cable.

11. A battery pack thermal propagation blocking device based on thermal melting triggering and vortex cooling according to claim 1, characterized in that, It also includes a limiting member (16), which is located on one side of the roller (5) and is used to lock the roller (5) after the heat insulation curtain (7) is fully unfolded.

12. A battery pack thermal propagation blocking device based on thermal melting triggering and vortex cooling according to claim 1, characterized in that, The unfolding time of the heat insulation curtain (7) is no more than 0.5s.

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