Pressure relief limiting mechanism for explosion-proof sheet of power battery

Abstract

The invention provides a pressure relief limiting mechanism for an anti-explosion piece of a power battery, which is characterized in that a limiting groove is formed in the side wall of each pressure relief ejector rod, one end of each limiting cross rod is inserted into the corresponding limiting groove, the other end of each limiting cross rod is slidably mounted in an insulating convex piece, and a push spring is jointly mounted between each limiting cross rod and the insulating convex piece; a thermal bimetallic strip is arranged on one side of each limiting cross rod, a hinge rod is arranged between each thermal bimetallic strip and the corresponding limiting cross rod, the middle of each hinge rod is hinged to the corresponding insulating protruding piece, the free end of each thermal bimetallic strip makes contact with one end of the corresponding hinge rod, and a limiting block is installed at the other end of each hinge rod. Each limiting cross rod is provided with a limiting opening, and the limiting blocks are inserted into the corresponding limiting openings. Linkage of pressure relief and fire extinguishing is achieved, on one hand, the pressure relief ejector rod is locked, and on the other hand, the fire extinguishing mechanism is started to spray a dry powder fire extinguishing agent.

Description

Technical Field

[0001] This invention relates to the field of power battery technology, and in particular to a pressure relief and limiting mechanism for a power battery explosion-proof plate. Background Technology

[0002] The top cover of a power battery is an important component of a lithium-ion battery. Currently, the top cover structure of a power battery mainly includes a cover plate, terminals, lower insulating components, upper insulating components, and sealing rings. To ensure the safety of the power battery, a pressure relief port is opened on the cover plate, and an explosion-proof diaphragm is welded at the pressure relief port. When the power battery is overcharged or experiences internal thermal runaway, the internal air pressure increases, and the explosion-proof diaphragm increases the safety of the power battery to a certain extent.

[0003] The main problem with the existing top cover structure is that the explosion-proof sheet is squeezed and ruptured by the internal air pressure of the power battery. However, the gap created by the rupture of the explosion-proof sheet is relatively small, which makes it impossible for the air pressure inside the power battery to be released quickly, resulting in an explosion. Moreover, if a fire occurs inside, the flames can easily burst out during the depressurization process and spread to other nearby power battery cells, causing damage to a large number of power battery cells.

[0004] Therefore, there is a need for a power battery top cover structure that can solve the above problems and a power battery that uses this structure. Summary of the Invention

[0005] This invention proposes a pressure relief and limiting mechanism for a power battery explosion-proof plate, which realizes the linkage between pressure relief and fire extinguishing. On the one hand, it locks the pressure relief top rod, and on the other hand, it activates the fire extinguishing mechanism to spray dry powder fire extinguishing agent.

[0006] One technical solution of the present invention is implemented as follows: The power battery explosion-proof pressure relief limiting mechanism includes a horizontally arranged limiting crossbar. Each of the pressure relief top rods has a limiting groove on its side wall. One end of each limiting crossbar is inserted into the corresponding limiting groove. The other end of each limiting crossbar is slidably installed in the insulating protrusion. A push spring is installed between the limiting crossbar and the insulating protrusion. A bimetallic strip is provided on one side of each limiting crossbar. A hinge rod is provided between each bimetallic strip and the limiting crossbar. The middle part of the hinge rod is hinged to the insulating protrusion. The free end of each bimetallic strip is in contact with one end of the corresponding hinge rod. A limiting block is installed on the other end of each hinge rod. Each limiting crossbar has a limiting opening, and the limiting block is inserted into the corresponding limiting opening.

[0007] As a preferred technical solution, a heat insulation box is provided on one side of the fixed end of the thermal bimetallic strip, and a heating element is fixed inside the heat insulation box. The fixed end of the thermal bimetallic strip extends into the corresponding heat insulation box, and the end of the thermal bimetallic strip extending into the heat insulation box contacts the heating element. Ceramic temperature sensors and ceramic pressure sensors are fixedly installed on both sides of the insulating protrusion, and each of the ceramic temperature sensors and ceramic pressure sensors is connected to the corresponding heating element.

[0008] By adopting the above technical solution, the beneficial effects of the present invention are as follows: Since the limiting mechanism includes a limiting crossbar, a push spring, a hot bimetallic strip, a hinge rod, and a limiting block, the setting of the limiting mechanism realizes the linkage action between the pressure relief device and the fire extinguishing mechanism. It mainly plays two roles: one is to lock the pressure relief top rod, and the other is to activate the fire extinguishing mechanism to spray dry powder extinguishing agent.

[0009] Because the fixed end of the bimetallic strip extends into a heat insulation box, which contains a heating element, and an insulating protrusion with a ceramic temperature sensor and a ceramic pressure sensor, the ceramic temperature sensor monitors the internal temperature of the battery cell in real time, and the ceramic pressure sensor monitors the internal pressure of the battery cell in real time. When the temperature detected by the ceramic temperature sensor reaches the preset explosion temperature, or the pressure detected by the ceramic pressure sensor reaches the preset explosion pressure, the heating element heats the bimetallic strip, causing it to bend downwards and push the hinge rod. The movement causes the limiting block on the hinge rod to move upward and gradually disengage from the limiting crossbar. Freed from the limiting block's restraint, the limiting crossbar slides under the force of the push spring. One end of the limiting crossbar disengages from the pressure relief rod, allowing the pressure relief rod to move upward quickly and push open the explosion-proof disc. Simultaneously, the other end of the limiting crossbar pushes the piston in the fire extinguishing mechanism to slide within the piston chamber. The air pressure inside the piston chamber increases, and this increased pressure is used to pressurize the dry powder storage chamber through the vent pipe. The dry powder extinguishing agent is then sprayed out through the dry powder nozzle, using the dry powder extinguishing agent to perform flame-retardant treatment on the inside of the power battery cells. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a schematic diagram of the structure of the top cover of the power battery; Figure 2 for Figure 1 Enlarged view of the structure at point A in the middle; Figure 3 This is a structural schematic diagram of the insulating protrusion and the pressure relief device. Figure 4 for Figure 3 Enlarged view of the structure of the present invention at point B; Figure 5 This is a schematic diagram of the pressure relief device under pressure relief conditions in this invention.

[0012] The components are as follows: 1. Cover plate; 2. Lower insulating component; 3. Positive electrode assembly; 4. Negative electrode assembly; 5. Pressure relief port; 6. Explosion-proof sheet; 7. Insulating protrusion; 8. Through hole; 9. Annular groove; 10. Pressure relief push rod; 11. Lifting spring; 12. Limiting crossbar; 13. Limiting groove; 14. Push spring; 15. Thermostatic bimetallic strip; 16. Hinge rod; 17. Limiting block; 18. Limiting opening; 19. Piston chamber; 20. Dry powder storage chamber; 21. Dry powder nozzle; 22. Piston; 23. Vent pipe; 24. Discharge hole; 25. Guide groove; 26. Protective top plate; 27. Electrode post; 28. Sealing ring; 29. ​​Upper insulating component; 30. Heat insulation box; 31. Heating element; 32. Ceramic temperature sensor; 33. Ceramic pressure sensor. Detailed Implementation

[0013] 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.

[0014] like Figure 4 and Figure 5 As shown, the pressure relief limiting mechanism of the power battery explosion-proof sheet includes a horizontally arranged limiting crossbar 12, and a limiting groove 13 is provided on the side wall of the pressure relief top rod 10. One end of the limiting crossbar 12 is inserted into the corresponding limiting groove 13, and the other end of the limiting crossbar 12 is slidably installed in the insulating protrusion 7. A push spring 14 is installed between the limiting crossbar 12 and the insulating protrusion 7. In this embodiment, the push spring 14 is a compression spring.

[0015] Each side of the limiting crossbar 12 is provided with a thermal bimetallic strip 15. In this embodiment, the thermal bimetallic strip 15 is made of copper and iron sheets combined together. Since the thermal expansion coefficient of copper is greater than that of iron, the thermal bimetallic strip 15 will bend towards the side where the iron sheet is located under high temperature. A hinge rod 16 is provided between the thermal bimetallic strip 15 and the limiting crossbar 12. The middle part of the hinge rod 16 is hinged to the insulating protrusion 7. The free end of the thermal bimetallic strip 15 is in contact with one end of the corresponding hinge rod 16. A limiting block 17 is installed at the other end of the hinge rod 16. A limiting opening 18 is provided on the limiting crossbar 12. The limiting block 17 is inserted into the corresponding limiting opening 18. In this embodiment, the setting of the limiting mechanism realizes the linkage action of the pressure relief device and the fire extinguishing mechanism, which mainly plays two roles: one is to lock the pressure relief top rod 10, and the other is to start the fire extinguishing mechanism to spray dry powder extinguishing agent.

[0016] Furthermore, a heat insulation box 30 is provided on one side of the fixed end of the bimetallic strip 15, and a heating element 31 is fixed inside the heat insulation box 30. The fixed end of the bimetallic strip 15 extends into the corresponding heat insulation box 30, and the end of the bimetallic strip 15 extending into the heat insulation box 30 contacts the heating element 31. Ceramic temperature sensors 32 and ceramic pressure sensors 33 are fixedly installed on both sides of the insulating protrusion 7. The ceramic temperature sensors 32 and ceramic pressure sensors 33 are connected to the corresponding heating elements 31. The ceramic temperature sensors 32 and ceramic pressure sensors 33 monitor the temperature and air pressure inside the power battery cell in real time. Whether the ceramic temperature sensor 32 detects that the temperature has reached the preset temperature or the ceramic pressure sensor 33 detects that the pressure has reached the preset pressure, the heating element 31 will be activated to heat the bimetallic strip 15. After the bimetallic strip 15 reaches a certain temperature, it bends, unlocks the pressure relief device, and activates the fire extinguishing mechanism.

[0017] like Figure 1-Figure 5 As shown, the power battery top cover structure includes a cover plate 1, an insulating component 2 fixed below the cover plate 1, a positive electrode assembly 3 and a negative electrode assembly 4 respectively provided at both ends of the cover plate 1, a pressure relief port 5 provided in the middle of the cover plate 1, an explosion-proof sheet 6 welded and fixed inside the pressure relief port 5, a downward protruding insulating protrusion 7 provided directly below the pressure relief port 5, the insulating protrusion 7 is fixed on the lower insulating component 2, a pair of pressure relief devices for breaking the explosion-proof sheet 6 are provided on the insulating protrusion 7, a pair of fire extinguishing mechanisms for preventing internal flames from escaping are also provided inside the insulating protrusion 7, and several through holes 8 are provided through the bottom of the insulating protrusion 7.

[0018] like Figure 3-Figure 5As shown, each pressure relief device includes a pressure relief rod 10, each pressure relief rod 10 is slidably mounted vertically inside the insulating protrusion 7, and a lifting spring 11 is installed between each pressure relief rod 10 and the insulating protrusion 7. Each pressure relief rod 10 is connected to a limiting mechanism for limiting the pressure relief rod 10. In this embodiment, the lifting spring 11 is a compression spring.

[0019] like Figure 3-Figure 5 As shown, both the upper and lower surfaces of the explosion-proof sheet 6 are provided with annular grooves 9. The positions and shapes of the two grooves 9 are exactly the same, and the positions of the grooves 9 correspond to the positions of the pressure relief rods 10. In this embodiment, the arrangement of the annular grooves 9 on both sides of the explosion-proof sheet 6 reduces the structural strength of the explosion-proof sheet 6, making it easier for the pressure relief rods 10 to break through the explosion-proof sheet 6, forming a larger pressure relief opening and accelerating the speed of pressure relief inside the power battery cell.

[0020] like Figure 4 and Figure 5 As shown, each fire extinguishing mechanism includes a piston chamber 19, a dry powder storage chamber 20, and a dry powder nozzle 21 disposed within an insulating protrusion 7. Each piston chamber 19 is coaxially arranged with a limiting crossbar 12. A piston 22 is slidably installed in each piston chamber 19. One end of each limiting crossbar 12 near the piston chamber 19 extends into the piston chamber 19. One end of each limiting crossbar 12 extending into the piston chamber 19 is fixedly connected to the piston 22. Each dry powder storage chamber 20 is connected to the corresponding piston chamber 19 through a vent pipe 23. Each dry powder storage chamber 20 has several discharge holes 24 on its cavity wall. Each dry powder nozzle 21 has several arc-shaped guide grooves 25 on its peripheral wall. The inlet end of each guide groove 25 corresponds to a discharge hole 24.

[0021] The internal pressure of the power battery cell increases due to the rise in temperature. The bimetallic strip 15 bends under the increased temperature, pushing the hinge rod 16 and causing it to rotate. This causes the limiting block 17 to move upwards and disengage from the limiting opening 18, unlocking the limiting crossbar 12. After unlocking, the limiting crossbar 12 slides inwards under the force of the pushing spring 14, unlocking the pressure relief rod 10. The unlocked pressure relief rod 10 then moves upwards under the force of the lifting spring 11, puncturing the explosion-proof sheet 6. This allows the internal air pressure to escape through the opening on the explosion-proof plate 6. Simultaneously, as the limiting crossbar 12 moves, it drives the piston 22 to slide within the piston chamber 19, increasing the air pressure inside the piston chamber 19. At the same time, the piston chamber 19 pressurizes the dry powder storage chamber 20 through the vent pipe 23, using this pressure to force the dry powder extinguishing agent out of the dry powder storage chamber 20 and spray it into the power battery cells through the discharge hole 24 and the dry powder nozzle 21. This provides flame-retardant treatment to the inside of the power battery cells, preventing internal flames from escaping and damaging other power battery cells during the pressure relief process. Furthermore, each pressure relief port 5 is topped with a protective top plate 26, which in this embodiment protects the explosion-proof plate 6.

[0022] like Figure 1 and Figure 2 As shown, both the positive electrode assembly 3 and the negative electrode assembly 4 include an electrode post 27 fixed on the cover plate 1. A sealing ring 28 is provided between each electrode post 27 and the cover plate 1. An upper insulating member 29 is provided between each electrode post 27 and the upper surface of the cover plate 1. A lower insulating member 2 is provided between the electrode post 27 and the lower surface of the cover plate 1.

[0023] In summary, the power battery explosion-proof pressure relief limiting mechanism of the present invention realizes the linkage action between the pressure relief device and the fire extinguishing mechanism, and mainly plays two roles: on the one hand, it locks the pressure relief top rod, and on the other hand, it activates the fire extinguishing mechanism to spray dry powder fire extinguishing agent.

[0024] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A pressure relief and limiting mechanism for a power battery explosion-proof sheet, characterized in that, It includes a horizontally set limiting crossbar, and each of the pressure relief top rods has a limiting groove on its side wall. One end of each limiting crossbar is inserted into the corresponding limiting groove, and the other end of each limiting crossbar is slidably installed in the insulating protrusion. A push spring is installed between each limiting crossbar and the insulating protrusion. A bimetallic strip is provided on one side of each limiting crossbar. A hinge rod is provided between each bimetallic strip and the limiting crossbar. The middle part of the hinge rod is hinged to the insulating protrusion. The free end of each bimetallic strip is in contact with one end of the corresponding hinge rod. A limiting block is installed on the other end of each hinge rod. Each limiting crossbar has a limiting opening, and the limiting block is inserted into the corresponding limiting opening.

2. The power battery explosion-proof pressure relief and limiting mechanism according to claim 1, characterized in that, A heat insulation box is provided on one side of the fixed end of the bimetallic strip. A heating element is fixed inside the heat insulation box. The fixed end of the bimetallic strip extends into the corresponding heat insulation box. The end of the bimetallic strip extending into the heat insulation box is in contact with the heating element. Ceramic temperature sensors and ceramic pressure sensors are fixedly installed on both sides of the insulating protrusion. The ceramic temperature sensors and ceramic pressure sensors are connected to the corresponding heating elements.

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