Power battery top cover structure and power battery using the same

Abstract

The present invention proposes a power battery top cover structure and a power battery using the structure, relating to the technical field of power batteries, including a cover plate, a lower insulating member, a positive electrode assembly and a negative electrode assembly. A pressure relief port is provided in the middle of the cover plate, an explosion-proof plate is welded and fixed in the pressure relief port, an insulating protrusion is provided directly below the pressure relief port, a pair of pressure relief devices and a pair of fire extinguishing mechanisms are provided on the insulating protrusion, a plurality of through holes are penetrated by the bottom of the insulating protrusion, an annular groove is provided on the upper and lower surfaces of the explosion-proof plate, each pressure relief device includes a pressure relief push rod, a lifting spring is commonly installed between each pressure relief push rod and the insulating protrusion, and each pressure relief push rod is connected to a limiting mechanism. The present invention realizes the rapid release of internal air pressure of the power battery, solves the problem of explosion caused by too slow release of internal air pressure, and at the same time adds a fire extinguishing mechanism to avoid the situation where internal flames escape and cause fire in nearby power battery cells.

Description

Technical Field

[0001] The present invention relates to the technical field of power batteries, and in particular to a power battery top cover structure and a power battery using the same. Background Art

[0002] The power battery top cover is an important component of the lithium-ion battery. At present, the top cover structure of the power battery mainly includes the cover plate, the pole, the lower insulating member, the upper insulating member, and the sealing ring. In order to ensure the safety of the power battery, a pressure relief vent will be opened on the cover plate, and an explosion-proof plate will be welded at the pressure relief vent. When the power battery is in special circumstances such as overcharging or internal thermal runaway, the internal air pressure increases. The setting of the explosion-proof plate 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 plate is squeezed and ruptured by the internal air pressure of the power battery, but the gap created by the rupture of the explosion-proof plate is relatively small, resulting in the air pressure inside the power battery not being quickly discharged, causing an explosion; and if a fire occurs inside, the flames can easily spread during the pressure release 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 using the structure. Summary of the Invention

[0005] The present invention proposes a power battery top cover structure and a power battery using the structure, which realizes the rapid release of internal air pressure in the power battery, solves the problem of explosion caused by slow release of internal air pressure, and adds a fire extinguishing mechanism to avoid the situation where internal flames escape and cause fire in nearby power battery cells.

[0006] A technical solution of the present invention is achieved as follows:

[0007] The power battery top cover structure includes a cover plate, a lower insulating member is fixed below the cover plate, a positive electrode assembly and a negative electrode assembly are respectively provided at both ends of the cover plate, a pressure relief port is provided in the middle of the cover plate, an explosion-proof disk is welded and fixed in the pressure relief port, a downwardly protruding insulating protrusion is provided directly below the pressure relief port, the insulating protrusion is fixed to the lower insulating member, a pair of pressure relief devices for rupturing the explosion-proof disk are provided on the insulating protrusion, a pair of fire extinguishing mechanisms for preventing internal flames from escaping are also provided in the insulating protrusion, and a plurality of through holes are penetrated at the bottom of the insulating protrusion;

[0008] Each of the pressure relief devices includes a pressure relief push rod, each of the pressure relief push rods is vertically slidably installed in the insulating protrusion, a lifting spring is commonly installed between each of the pressure relief push rods and the insulating protrusion, and each of the pressure relief push rods is connected to a limiting mechanism for limiting the pressure relief push rod.

[0009] As a preferred technical solution, each of the limiting mechanisms includes a horizontally arranged limiting cross bar, a limiting groove is provided on the side wall of each of the pressure relief push rods, one end of each of the limiting cross bars is inserted into the corresponding limiting groove, and the other end of each of the limiting cross bars is slidably installed in the insulating protrusion, and a push spring is commonly installed between each of the limiting cross bars and the insulating protrusion;

[0010] A thermal bimetallic strip is provided on one side of each of the limiting cross bars, a hinged rod is provided between each of the thermal bimetallic strips and the limiting cross bar, the middle part of each of the hinged rods is hinged to the insulating protrusion, the free end of each of the thermal bimetallic strips is in contact with one end of the corresponding hinged rod, a limiting block is installed on the other end of each of the hinged rods, a limiting opening is provided on each of the limiting cross bars, and each of the limiting blocks is inserted into the corresponding limiting opening.

[0011] As a preferred technical solution, a thermal insulation box is provided on one side of the fixed end of each thermal bimetallic strip, a heating element is fixed in each thermal insulation box, the fixed end of each thermal bimetallic strip extends into the corresponding thermal insulation box, and one end of each thermal bimetallic strip extending into the thermal insulation box is in contact with the heating element. Ceramic temperature sensors and ceramic pressure sensors are fixedly installed on both side walls of the insulating protrusion, and each ceramic temperature sensor and ceramic pressure sensor is connected to the corresponding heating element.

[0012] As a preferred technical solution, an annular groove is provided on both the upper and lower surfaces of the explosion-proof disk. The positions and shapes of the two annular grooves are exactly the same, and the positions of the annular grooves correspond to the positions of the pressure relief push rods.

[0013] As a preferred technical solution, each of the fire extinguishing mechanisms includes a piston cavity, a dry powder storage cavity and a dry powder nozzle arranged in the insulating protrusion, each of the piston cavity is coaxially arranged with the limiting cross bar, a piston is slidably installed in each of the piston cavity, one end of each of the limiting cross bars close to the piston cavity extends into the piston cavity, and one end of each of the limiting cross bars extending into the piston cavity is fixedly connected to the piston, each of the dry powder storage cavity is connected to the corresponding piston cavity through a ventilation pipe, and a plurality of discharge holes are provided on the cavity wall of each of the dry powder storage cavity, and a plurality of arc-shaped material guide grooves are provided on the peripheral wall of each of the dry powder nozzles, and the feeding end of each of the material guide grooves corresponds to a discharge hole.

[0014] As a preferred technical solution, a protective top sheet is provided on the top of each pressure relief port.

[0015] As a preferred technical solution, the positive electrode assembly and the negative electrode assembly each include a pole fixed on the cover plate, a sealing ring is commonly provided between each pole and the cover plate, an upper insulating member is provided between each pole and the upper surface of the cover plate, and the lower insulating member is provided between the pole and the lower surface of the cover plate.

[0016] Another technical solution of the present invention is achieved as follows:

[0017] A power battery using the power battery top cover structure includes the power battery top cover structure.

[0018] By adopting the above technical solution, the beneficial effects of the present invention are:

[0019] Since the power battery top cover structure includes a cover plate, a lower insulating member, an explosion-proof plate, an insulating protrusion and a pressure relief device, in the present invention, the pressure relief device is used to push open the explosion-proof plate, thereby increasing the opening area for pressure relief, so that the internal air pressure can be quickly and timely discharged from the openings at both ends of the explosion-proof plate, thereby solving the problem of explosion caused by slow air pressure release.

[0020] Since a fire extinguishing mechanism is also provided in the insulating protrusion, in the present invention, the fire extinguishing mechanism is used to spray a dry powder fire extinguishing agent below the pressure relief port to perform a flame retardant operation on the interior of the power battery cell, thereby avoiding the situation where the power battery catches fire during the pressure relief process. Moreover, even if there is a flame inside, it can effectively extinguish the fire, thereby preventing the internal flame from escaping through the pressure relief port and affecting nearby power battery cells.

[0021] Since an annular groove is provided on both the upper and lower surfaces of the explosion-proof disk, in the present invention, the annular grooves on both sides form a circle of weak structural positions on the explosion-proof disk, so that the pressure relief push rod in the pressure relief device can easily push out a larger opening on the explosion-proof disk, thereby effectively increasing the area of the pressure relief opening of the power battery cell, so that the air pressure inside the power battery cell can be released from the opening in a timely and rapid manner.

[0022] Since the limiting mechanisms include a limiting cross bar, a push spring, a thermal bimetallic strip, a hinged rod and a limiting block, in the present invention, 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. On the one hand, it locks the pressure relief top rod, and on the other hand, it starts the fire extinguishing mechanism to spray the dry powder fire extinguishing agent.

[0023] Since the fixed end of the thermal bimetallic strip extends into an insulation box, a heating element is provided in the insulation box, and a ceramic temperature sensor and a ceramic pressure sensor are provided on the insulating protrusion. In the present invention, the ceramic temperature sensor monitors the temperature inside the power battery cell in real time, and the ceramic pressure sensor is used to monitor the air pressure inside the power battery cell in real time. When the temperature monitored by the ceramic temperature sensor reaches the preset explosion temperature, or the air pressure monitored by the ceramic pressure sensor reaches the preset explosion pressure, the heating element heats the hot plug metal sheet, causing it to bend downward due to the heat and press the hinge rod. The cam is pushed upward, driving the limit block on the hinged rod to move upward and gradually separate from the limit cross bar. The limit cross bar that has lost the restriction of the limit block slides under the elastic force of the push spring, and one end of the limit cross bar separates from the pressure relief push rod, so that the pressure relief push rod can quickly move upward and push open the explosion-proof disk. At the same time, the other end of the limit cross bar pushes the piston in the fire extinguishing mechanism to slide in the piston cavity. The air pressure in the piston cavity increases, and the increased air pressure inflates and pressurizes the dry powder storage cavity through the vent pipe. The dry powder fire extinguishing agent will be sprayed out through the dry powder nozzle, and the dry powder fire extinguishing agent is used to perform flame retardant treatment on the inside of the power battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 It is a structural schematic diagram of the present invention;

[0026] Figure 2 for Figure 1 A magnified view of the structure at point A;

[0027] Figure 3 Schematic diagram of the structure of the insulating protrusion and the pressure relief device in the present invention;

[0028] Figure 4 for Figure 3 A magnified view of the structure at B in the middle;

[0029] Figure 5 It is a structural schematic diagram of the pressure relief device in the pressure relief state of the present invention.

[0030] Among them: 1. Cover plate; 2. Lower insulating part; 3. Positive electrode assembly; 4. Negative electrode assembly; 5. Pressure relief port; 6. Explosion-proof disk; 7. Insulating protrusion; 8. Through hole; 9. Ring groove; 10. Pressure relief ejector pin; 11. Lifting spring; 12. Limiting cross bar; 13. Limiting groove; 14. Push spring; 15. Thermal bimetallic strip; 16. Articulated 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. Material guide trough; 26. Protective top plate; 27. Pole; 28. Sealing ring; 29. Upper insulating part; 30. Insulation box; 31. Heating element; 32. Ceramic temperature sensor; 33. Ceramic pressure sensor. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0032] Example 1

[0033] like Figure 1-Figure 5 As shown in common, the power battery top cover structure includes a cover plate 1, a lower insulating member 2 is fixed under the cover plate 1, a positive electrode assembly 3 and a negative electrode assembly 4 are respectively provided at both ends of the cover plate 1, a pressure relief port 5 is provided in the middle of the cover plate 1, an explosion-proof plate 6 is welded and fixed in the pressure relief port 5, and a downwardly protruding insulating protrusion 7 is provided directly below the pressure relief port 5. The insulating protrusion 7 is fixed on the lower insulating member 2, and a pair of pressure relief devices for bursting the explosion-proof plate 6 are provided on the insulating protrusion 7. A pair of fire extinguishing mechanisms for preventing internal flames from escaping are also provided in the insulating protrusion 7. A number of through holes 8 are provided through the bottom of the insulating protrusion 7.

[0034] like Figure 3-Figure 5As shown in common, each pressure relief device includes a pressure relief push rod 10, each pressure relief push rod 10 is vertically slidably installed in the insulating protrusion 7, and a lifting spring 11 is installed between each pressure relief push rod 10 and the insulating protrusion 7. Each pressure relief push rod 10 is connected to a limiting mechanism for limiting the pressure relief push rod 10. In this embodiment, the lifting spring 11 is a compression spring.

[0035] like Figure 4 and Figure 5 As shown in common, each limiting mechanism includes a horizontally arranged limiting cross bar 12, and a limiting groove 13 is provided on the side wall of each pressure relief top rod 10. One end of each limiting cross bar 12 is inserted into the corresponding limiting groove 13, and the other end of each limiting cross bar 12 is slidably installed in the insulating protrusion 7. A push spring 14 is commonly installed between each limiting cross bar 12 and the insulating protrusion 7. In this embodiment, the push spring 14 adopts a compression spring.

[0036] Among them, a thermal bimetallic strip 15 is provided on one side of each limiting cross bar 12. In this embodiment, the thermal bimetallic strip 15 is made of a composite copper sheet and an iron sheet. Since the thermal expansion coefficient of copper is greater than that of iron, the thermal bimetallic strip 15 will bend toward the side where the iron sheet is located under high temperature; a hinged rod 16 is provided between each thermal bimetallic strip 15 and the limiting cross bar 12, and the middle part of each hinged rod 16 is hinged to the insulating protrusion 7. The free end of each thermal bimetallic strip 15 contacts one end of the corresponding hinged rod 16, and a limit block 17 is installed at the other end of each hinged rod 16. Each limiting cross bar 12 is provided with a limit opening 18, and each limit block 17 is inserted into the corresponding limit opening 18. In this embodiment, the setting of the limit mechanism realizes the linkage action of the pressure relief device and the fire extinguishing mechanism, which mainly plays two roles. On the one hand, it locks the pressure relief top rod 10, and on the other hand, it activates the fire extinguishing mechanism to spray the dry powder fire extinguishing agent.

[0037] Moreover, a heat insulation box 30 is provided on one side of the fixed end of each thermal bimetallic strip 15, and a heating element 31 is fixed in each heat insulation box 30. The fixed end of each thermal bimetallic strip 15 extends into the corresponding heat insulation box 30, and one end of each thermal 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 side walls of the insulating protrusion 7. Each of the ceramic temperature sensor 32 and the ceramic pressure sensor 33 is connected to the corresponding heating element 31. In this embodiment, the ceramic temperature sensor 32 and the ceramic pressure sensor 33 monitor the temperature and air pressure inside the power battery cell in real time. Regardless of whether the ceramic temperature sensor 32 detects that the temperature reaches the preset temperature or the ceramic pressure sensor 33 detects that the pressure reaches the preset pressure, the heating element 31 will be started to heat the thermal bimetallic strip 15. After the thermal bimetallic strip 15 reaches a certain temperature, it will bend, the pressure relief device will be unlocked, and the fire extinguishing mechanism will be started.

[0038] like Figure 3-Figure 5 As shown in common, an annular groove 9 is provided on the upper and lower surfaces of the explosion-proof disc 6. The positions and shapes of the two annular grooves 9 are exactly the same. The positions of the annular grooves 9 correspond to the positions of the pressure relief push rods 10. In this embodiment, the provision of the annular grooves 9 on both sides of the explosion-proof disc 6 reduces the structural strength of the explosion-proof disc 6, making it easier for the pressure relief push rods 10 to break the explosion-proof disc 6, forming a larger pressure relief opening, and accelerating the speed of pressure relief inside the power battery cell.

[0039] like Figure 4 and Figure 5 As shown in common, each fire extinguishing mechanism includes a piston cavity 19, a dry powder storage cavity 20 and a dry powder nozzle 21 arranged in the insulating protrusion 7, each piston cavity 19 is coaxially arranged with the limiting cross bar 12, and a piston 22 is slidably installed in each piston cavity 19, and one end of each limiting cross bar 12 close to the piston cavity 19 extends into the piston cavity 19, and one end of each limiting cross bar 12 extending into the piston cavity 19 is fixedly connected to the piston 22, and each dry powder storage cavity 20 is connected to the corresponding piston cavity 19 through a vent pipe 23, and a plurality of discharge holes 24 are provided on the cavity wall of each dry powder storage cavity 20, and a plurality of arc-shaped guide grooves 25 are provided on the peripheral wall of each dry powder nozzle 21, and the feeding end of each guide groove 25 corresponds to a discharge hole 24.

[0040] In the present invention, the air pressure inside the power battery cell increases due to the increase in temperature. The thermal bimetallic strip 15 bends under the action of the temperature increase. The bent thermal bimetallic strip 15 pushes the hinge rod 16, causing the hinge rod 16 to rotate, driving the limit block 17 to move upward and disengage from the limit opening 18, thereby unlocking the limit cross bar 12. The unlocked limit cross bar 12 slides inward under the elastic force of the push spring 14, thereby unlocking the pressure relief push rod 10. The unlocked pressure relief push rod 10 moves upward under the elastic force of the lifting spring 11, and the explosion-proof disk 6 is lifted by the pressure relief push rod 10. The explosion-proof plate 6 is broken, and the internal air pressure is released through the opening on the explosion-proof plate 6; at the same time, the limiting cross bar 12 will drive the piston 22 to slide in the piston cavity 19 during the movement, so that the air pressure in the piston cavity 19 increases, and at the same time, the piston cavity 19 is inflated and pressurized into the dry powder storage cavity 20 through the vent pipe 23, and the dry powder fire extinguishing agent is squeezed out of the dry powder storage cavity 20 by pressure, and sprayed into the power battery cell through the discharge hole 24 and the dry powder nozzle 21, so as to perform flame retardant treatment on the interior of the power battery cell, thereby avoiding the situation that the internal flames escape and cause damage to other power battery cells during the pressure relief process.

[0041] In addition, a protective top sheet 26 is provided on the top of each pressure relief port 5 . In this embodiment, the protective top sheet 26 serves to protect the explosion-proof disk 6 .

[0042] like Figure 1 and Figure 2 As shown together, the positive electrode assembly 3 and the negative electrode assembly 4 both include a pole 27 fixed on the cover plate 1, a sealing ring 28 is provided between each pole 27 and the cover plate 1, an upper insulating member 29 is provided between each pole 27 and the upper surface of the cover plate 1, and a lower insulating member 2 is provided between the pole 27 and the lower surface of the cover plate 1.

[0043] Example 2

[0044] A power battery using the power battery top cover structure includes the power battery top cover structure.

[0045] In summary, the power battery top cover structure proposed in the present invention and the power battery using the same achieve rapid release of internal air pressure in the power battery, solving the problem of explosion caused by slow release of internal air pressure. At the same time, a fire extinguishing mechanism is added to avoid the situation where internal flames escape and cause fires in nearby power battery cells.

[0046] 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 in the scope of protection of the present invention.

Claims

1. A power battery top cover structure, comprising a cover plate, with a lower insulating member fixed below the cover plate, characterized in that: A positive electrode assembly and a negative electrode assembly are respectively provided at both ends of the cover plate, a pressure relief port is provided in the middle of the cover plate, an explosion-proof disk is welded and fixed in the pressure relief port, a downwardly protruding insulating protrusion is provided directly below the pressure relief port, the insulating protrusion is fixed to the lower insulating member, a pair of pressure relief devices for rupturing the explosion-proof disk are provided on the insulating protrusion, a pair of fire extinguishing mechanisms for preventing internal flames from escaping are also provided in the insulating protrusion, and a plurality of through holes are penetrated at the bottom of the insulating protrusion; Each of the pressure relief devices includes a pressure relief push rod, each of the pressure relief push rods is vertically slidably installed in the insulating protrusion, a lifting spring is commonly installed between each of the pressure relief push rods and the insulating protrusion, and each of the pressure relief push rods is connected to a limiting mechanism for limiting the pressure relief push rod; Each of the limiting mechanisms includes a horizontally arranged limiting cross bar, a limiting groove is provided on the side wall of each of the pressure relief push rods, one end of each of the limiting cross bars is inserted into the corresponding limiting groove, and the other end of each of the limiting cross bars is slidably installed in the insulating protrusion, and a push spring is commonly installed between each of the limiting cross bars and the insulating protrusion; A thermal bimetallic strip is provided on one side of each of the limiting cross bars, a hinged rod is provided between each of the thermal bimetallic strips and the limiting cross bar, the middle part of each of the hinged rods is hinged to the insulating protrusion, the free end of each of the thermal bimetallic strips is in contact with one end of the corresponding hinged rod, a limiting block is installed on the other end of each of the hinged rods, a limiting opening is provided on each of the limiting cross bars, and each of the limiting blocks is inserted into the corresponding limiting opening.

2. The power battery top cover structure according to claim 1, characterized in that: A thermal insulation box is provided on one side of the fixed end of each thermal bimetallic strip, and a heating element is fixed in each thermal insulation box. The fixed end of each thermal bimetallic strip extends into the corresponding thermal insulation box, and one end of each thermal bimetallic strip extending into the thermal insulation box contacts the heating element. Ceramic temperature sensors and ceramic pressure sensors are fixedly installed on both side walls of the insulating protrusion, and each ceramic temperature sensor and ceramic pressure sensor is connected to the corresponding heating element.

3. The power battery top cover structure according to claim 2, characterized in that: An annular groove is provided on both the upper and lower surfaces of the explosion-proof disk. The positions and shapes of the two annular grooves are exactly the same, and the positions of the annular grooves correspond to the positions of the pressure relief ejector rods.

4. The power battery top cover structure according to claim 3, characterized in that: Each of the fire extinguishing mechanisms includes a piston cavity, a dry powder storage cavity and a dry powder nozzle arranged in the insulating protrusion. Each of the piston cavity is coaxially arranged with the limiting cross bar. A piston is slidably installed in each of the piston cavity. The end of each limiting cross bar close to the piston cavity extends into the piston cavity. The end of each limiting cross bar extending into the piston cavity is fixedly connected to the piston. Each of the dry powder storage cavity is connected to the corresponding piston cavity through a ventilation pipe. A number of discharge holes are provided on the cavity wall of each dry powder storage cavity. A number of arc-shaped material guide grooves are provided on the peripheral wall of each dry powder nozzle. The feeding end of each material guide groove corresponds to a discharge hole.

5. The power battery top cover structure according to claim 4, characterized in that: A protective top sheet is provided on the top of each pressure relief port.

6. The power battery top cover structure according to claim 5, characterized in that: The positive electrode assembly and the negative electrode assembly each include a pole fixed on the cover plate, a sealing ring is commonly provided between each pole and the cover plate, an upper insulating member is provided between each pole and the upper surface of the cover plate, and the lower insulating member is provided between the pole and the lower surface of the cover plate.

7. Power battery, characterized in that: It comprises the power battery top cover structure according to any one of claims 1 to 6.

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