Explosion-proof valve and battery pack

Abstract

The explosion-proof valve comprises a valve body, a guide rod, a first sealing ring, a spring and a waterproof breathable film, the valve body is provided with a first cavity channel extending inwards from the side wall and a second cavity channel extending inwards from the bottom face, the first cavity channel is communicated with the second cavity channel, and a limiting step is arranged in front of the communication position of the first cavity channel; the guide rod is movably arranged in the first cavity channel, and a first sealing ring is arranged on the guide rod; the spring is arranged in the first cavity channel and is used for applying a backward loading force to the guide rod; the waterproof breathable film is arranged below the second cavity channel; in the natural state, the guide rod tightly abuts against the first sealing ring on the limiting step to form sealing, and when the air pressure in the target shell is larger than the loading force of the spring, the guide rod moves forwards to enable the first sealing ring to be separated from the limiting step for pressure relief. The explosion-proof valve can effectively meet the requirements of water resistance, ventilation and reliable pressure relief at the same time, and ensures the performance and safety of the battery in various environments.

Description

Technical Field

[0001] The present invention relates to the technical field of battery manufacturing, and in particular to an explosion-proof valve and a battery pack. Background Art

[0002] During the use of power batteries, when abnormal conditions such as short circuit, overcharge, and over-discharge occur, a large amount of gas will be generated due to the reaction inside the battery, causing the pressure inside the battery to increase sharply, causing the battery shell to deform or even explode. For this reason, an explosion-proof valve is usually installed on the battery shell. When the pressure inside the battery increases to a certain pressure value, the explosion-proof valve opens to discharge the gas inside the battery to relieve the pressure.

[0003] The existing explosion-proof valves generally cannot be restored to their original state after the pressure relief action, resulting in functional failure and frequent replacement, which has disadvantages such as high cost and inconvenience in use. In addition, the existing explosion-proof valves are difficult to effectively meet the requirements of waterproof, breathable and reliable pressure relief at the same time, affecting the performance and safety of the battery in various environments. Summary of the invention

[0004] The object of the present invention is to provide an explosion-proof valve which can effectively meet the requirements of waterproofness, air permeability and reliable pressure relief at the same time, and ensure the performance and safety of the battery in various environments.

[0005] The purpose of the present invention is achieved by the following technical solutions: An explosion-proof valve, installed on a target housing, comprises: The valve body has a first cavity extending inward from the side wall and a second cavity extending inward from the bottom surface, wherein the first and second cavities are connected, and a limiting step is provided in front of the connecting point of the first cavity; A guide rod is movably disposed in the first cavity, and a first sealing ring is disposed on the guide rod; A spring, disposed in the first cavity, and used for applying a backward loading force to the guide rod; A waterproof and breathable membrane, arranged below the second cavity; In a natural state, the guide rod presses the first sealing ring against the limit step to form a seal. When the air pressure in the target housing is greater than the loading force of the spring, the guide rod moves forward to separate the first sealing ring from the limit step to release pressure.

[0006] In the above scheme, the explosion-proof valve can effectively meet the requirements of waterproof, breathable and reliable pressure relief at the same time, ensuring the performance and safety of the battery in various environments. In addition, the waterproof and breathable membrane is arranged away from the guide rod, which not only simplifies the structural design, but also avoids accidental damage to the waterproof and breathable membrane during valve stem installation or use, thereby improving the reliability of the explosion-proof valve function.

[0007] In some embodiments, the first cavity is disposed transversely, and the second cavity is disposed obliquely, and the two are connected to form a "7"-shaped airflow channel.

[0008] In the above scheme, the guide rod is installed horizontally in the first cavity and the second cavity is tilted to shorten the distance from the bottom surface to the top surface of the valve body 1. While meeting the functional requirements, the volume of the valve body is greatly reduced, which plays a role in saving space.

[0009] In some embodiments, the limiting step includes an inclined mating surface, and the angle between the mating surface and the horizontal plane is 110°-130°.

[0010] In the above scheme, if the included angle is less than 110°, the contact area between the mating surface and the first sealing ring is small, and it is difficult to maintain a good sealing state. If the included angle is greater than 130°, the limiting effect of the mating surface on the first sealing ring decreases, causing it to cross the limiting step and cause the sealing to be completed. When the included angle between the mating surface and the horizontal plane is 110°-130°, the sealing effect formed by the first sealing ring and the mating surface is better.

[0011] In some embodiments, the rear portion of the guide rod is provided with a first and a second spaced-apart convex ring portion; the spring is located at the front side of the first convex ring portion, and the first sealing ring is located between the first and the second convex ring portions.

[0012] In the above solution, the first and second convex ring parts are provided to facilitate the installation and positioning of the spring and the first sealing ring.

[0013] In some embodiments, the first and second convex ring parts are respectively slidably disposed in the first and second cavity sections of the first cavity channel, and air guide grooves are respectively disposed on the outer periphery of the first and second convex ring parts.

[0014] In the above scheme, either the first or second convex ring portion can slightly guide the movement of the guide rod, thereby improving the stability of the pressure relief switch, and by providing an air guide groove, ensuring that the air flow path is unobstructed.

[0015] In some embodiments, a hollow rivet column is disposed at the front end of the first cavity, and the rivet column is used to fix the spring and assist the movement of the guide rod.

[0016] In some embodiments, a plurality of elastic membrane petals are evenly distributed around the inner side of the rivet column; in a natural state, each of the elastic membrane petals is closed but an air-permeable gap is left between adjacent ones, and when the air pressure in the target shell is greater than the loading force of the spring, the guide rod moves forward to force each of the elastic membrane petals to open, thereby forming a breathable air channel.

[0017] In the above scheme, the elastic membrane flap can usually prevent large-sized debris from entering the first cavity, ensuring the normal use of the valve function, and can adaptively control the flow rate according to the gas flow rate during pressure relief to achieve the function of rapid exhaust and pressure relief.

[0018] In some embodiments, the front end of the guide rod is hollowed out, or the front end of the guide rod is provided with an air guide hole extending to the middle of the rod shaft.

[0019] In the above scheme, the hollow design or the air guide hole design at the front end of the guide rod can guide more gas to flow from the first cavity to the outside of the elastic membrane petal, further enhancing the exhaust and pressure relief function.

[0020] In some embodiments, a second sealing ring is provided between the valve body and the target housing, and the second sealing ring is located at the outer periphery of the waterproof breathable membrane.

[0021] In the above solution, the second sealing ring is used to improve the sealing between the valve body and the target housing to prevent external water vapor from invading the interior of the target housing and affecting its service life.

[0022] In some embodiments, a welding structure is further provided on the bottom surface of the valve body; the welding structure includes a boss provided on the outer edge of the bottom surface of the valve body, and a conical protrusion provided on the lower end of the boss.

[0023] In the above solution, the welding structure can increase the contact area of ​​welding and make the force on the weld more uniform, thereby improving the welding quality and strength.

[0024] In some embodiments, the explosion-proof valve is configured as follows: the pressure relief range is 0.1MPa to 0.2MPa, and the explosion relief range is 0.3MPa to 0.8MPa.

[0025] The present invention also provides a battery pack, comprising the above-mentioned explosion-proof valve.

[0026] Compared with the prior art, the beneficial effects of the present invention include at least: 1. It can effectively meet the requirements of waterproof, breathable and reliable pressure relief at the same time, ensuring the performance and safety of the battery in various environments.

[0027] 2. Placing the waterproof breathable membrane away from the guide rod not only simplifies the structural design, but also avoids accidental damage to the waterproof breathable membrane during valve stem installation or use, thereby improving the reliability of the explosion-proof valve function.

[0028] 3. The "7" type flow channel design not only meets the functional requirements, but also greatly reduces the volume of the valve body, thus saving space.

[0029] 4. The double convex ring design on the guide rod can not only strengthen the fixation of the first sealing ring, but also play a guiding role and improve the stability of movement.

[0030] 5. The elastic diaphragm can prevent large-sized debris from entering the first cavity, ensuring the normal use of the valve. It can also adaptively control the flow rate according to the gas flow rate during pressure relief to achieve the function of rapid exhaust and pressure relief. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a three-dimensional structural schematic diagram of the explosion-proof valve of the present invention.

[0032] Figure 2 It is a schematic diagram of the cross-sectional structure of an explosion-proof valve.

[0033] Figure 3 It is a schematic diagram of the structure inside the valve body.

[0034] Figure 4 It is a structural diagram of the guide rod.

[0035] Figure 5 It is a schematic diagram of the distribution of elastic membrane petals in the rivet column.

[0036] Figure 6 It is a schematic diagram of the coordination between the guide rod and the elastic membrane petal.

[0037] Figure 7 It is a schematic structural diagram of the battery pack of the present invention.

[0038] In the figure: 1. valve body; 11. first cavity; 111. first cavity section; 112. second cavity section; 12. second cavity; 13. limit step; 131. mating surface; 2. guide rod; 21. first convex ring portion; 22. second convex ring portion; 23. air guide hole; 3. first sealing ring; 4. spring; 5. waterproof breathable membrane; 6. air guide groove; 7. rivet column; 8. elastic membrane petal; 9. second sealing ring; 10. welding structure; 101. boss; 102. conical protrusion. DETAILED DESCRIPTION

[0039] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to make the present invention more comprehensive and complete and to fully convey the concepts of example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their repeated description will be omitted.

[0040] The words expressing positions and directions described in the present invention are all explained with reference to the accompanying drawings as examples, but they can be changed as needed, and all such changes are included in the protection scope of the present invention.

[0041] See also Figures 1 to 4 As shown, the present invention discloses an explosion-proof valve, which is installed on a target housing and includes a valve body 1, a guide rod 2, a first sealing ring 3, a spring 4 and a waterproof breathable membrane 5.

[0042] The valve body 1 is generally cylindrical in structure and can be fixed to a target housing, such as a battery housing, by welding (see Figure 7 The valve body 1 has a first cavity 11 extending inward from the side wall and a second cavity 12 extending inward from the bottom surface (see Figure 3 ), and the first and second cavities 11, 12 are connected, so that an on-off controllable airflow channel is formed between the target shell and the external atmosphere.

[0043] In addition, the first cavity 11 is provided with a limiting step 13 in front of the connecting portion, which is used to cooperate with the first sealing ring 3 to achieve sealing (see Figure 2 In the present application, the limiting step 13 can be formed by connecting a first cavity section 111 and a second cavity section 112 of different calibers, wherein the first cavity section 111 is also used to install the main body of the spring 4 and the guide rod 2, and the second cavity section 112 is used to connect the second cavity 12.

[0044] The guide rod 2 is movably arranged in the first cavity 11, for example, it can move forward and backward along the length direction of the first cavity 11, and a first sealing ring 3 is arranged on the guide rod 2. The first sealing ring 3 moves synchronously with the guide rod 2, and can form a seal with the limiting step 13 after being squeezed, thereby cutting off the first cavity 11 to prevent external moisture or impurities from invading and affecting or damaging the components in the target shell.

[0045] The spring 4 is also arranged in the first cavity 11, one end of which is fixed and the other end is connected to the guide rod 2. In the present application, a hollow rivet column 7 can be arranged at the front end of the first cavity 11, and a first convex ring portion 21 can be arranged at the rear of the guide rod 2, and the spring 4 can be installed between the rivet column 7 and the first convex ring portion 21. Note that the elasticity needs to be designed to be in a compressed state, so that it can apply a backward loading force (elastic force) to the guide rod 2, thereby squeezing the first sealing ring 3 onto the limiting step 13.

[0046] The waterproof breathable membrane 5 is arranged below the second cavity 12. For example, the waterproof breathable membrane 5 can be welded to the bottom surface of the valve body 1 and cover the air port of the second cavity 12, thereby preventing external moisture from entering the interior of the target shell, but does not affect the release of gas inside the target shell to the outside.

[0047] It is worth mentioning that the present application arranges the waterproof breathable membrane 5 away from the guide rod 2, which not only simplifies the structural design, but also avoids accidental damage to the waterproof breathable membrane 5 during valve stem installation or use, thereby improving the reliability of the explosion-proof valve function.

[0048] Still see Figure 2 As shown, the principle of the explosion-proof valve is as follows: In the natural state, the guide rod 2 relies on the loading force generated by the compression of the spring 4 to press the first sealing ring 3 against the limiting step 13 to form a seal. A small amount of gas generated in the target shell can also enter the air flow channel through the waterproof breathable membrane 5 and be discharged to the external atmosphere, thereby maintaining the balance of the pressure difference between the inside and outside of the target shell, thereby improving its own service life and safety.

[0049] Specifically, when the air pressure in the target housing is abnormal, that is, the air pressure rises sharply and is greater than the loading force of the spring 4, the gas can penetrate the waterproof breathable membrane 5 into the airflow channel, and further compress the spring 4, the guide rod 2 moves forward to separate the first sealing ring 3 from the limit step 13, and the explosion-proof valve automatically releases pressure to ensure the safety of the target housing. Exemplarily, the explosion-proof valve is configured as follows: the pressure relief range is 0.1MPa~0.2MPa, and the explosion relief range is 0.3MPa~0.8MPa. For example, in the explosion-proof valve of the present application, when the internal air pressure of the target housing reaches 0.15MPa, the guide rod 2 can be away from the first sealing ring 3 for pressure relief, and reset and automatically close when the pressure is relieved to less than 0.1MPa. During the pressure relief process, if the air pressure in the target housing continues to rise to 0.5MPa, the explosion-proof valve can trigger the explosion relief function, as described below.

[0050] In the above-mentioned explosion-proof valve, the valve body 1 can be made of PBT material, which makes the valve body 1 have high rigidity, hardness and good processing performance, which is conducive to the molding of the first and second cavities 11 and 12, while ensuring the heat resistance and thermal stability of the valve body 1 to meet the working conditions. The guide rod 2 and the spring 4 are both made of stainless steel, wherein the length, elastic coefficient and compression amount of the spring 4 can be designed according to the specific demand scenario. The first sealing ring 3 is preferably made of high-temperature resistant fluororubber material to adapt to the electrolyte working condition sealing. The waterproof and breathable membrane 5 can be made of polytetrafluoroethylene, which is resistant to high temperature and corrosion, and has good waterproof and breathable properties.

[0051] See also Figure 2 and Figure 3 As shown, in some embodiments, the first cavity 11 is arranged horizontally, and the second cavity 12 is arranged obliquely, and the two are connected to form a "7"-shaped airflow channel. Compared with the "T"-shaped airflow channel of the existing explosion-proof valve, the present application shortens the distance from the bottom surface to the top surface of the valve body 1 by installing the guide rod 2 horizontally in the first cavity 11 and tilting the second cavity 12. While meeting the functional requirements, the volume of the valve body 1 is greatly reduced, which plays a role in saving space.

[0052] Or Figure 3As shown, in some embodiments, the limiting step 13 includes an inclined mating surface 131, which can better contact with the first sealing ring 3 to form a seal. Among them, the angle between the mating surface 131 and the horizontal plane is 110°-130°. If the angle is less than 110°, the contact area between the mating surface 131 and the first sealing ring 3 is small, and it is difficult to maintain a good sealing state. If the angle is greater than 130°, the limiting effect of the mating surface 131 on the first sealing ring 3 decreases, so that it may cross the limiting step 13 to achieve sealing. In the present application, the angle between the mating surface 131 and the horizontal plane is preferably 115°-125°, for example, it can be 120°.

[0053] The first protruding ring portion 21 of the guide rod 2 is used not only to abut against the spring 4, but also to abut against the first sealing ring 3 on the other side, that is, the rear side. However, during the pressure relief process, the forward movement of the guide rod 2 may cause the first sealing ring 3 to deviate or fall off, thereby affecting the sealing effect. Figure 4 As shown, in some embodiments, a second convex ring portion 22 is further provided at the rear of the guide rod 2. The second convex ring portion 22 is spaced apart and distributed behind the first convex ring portion 21. The two together form a groove-shaped structure for installing the first sealing ring 3 and enabling the first sealing ring 3 to move, thereby improving the reliability of the seal.

[0054] Furthermore, the first and second convex ring parts 21 and 22 are respectively slidably disposed in the first and second cavity sections 111 and 112 of the first cavity 11, and either of the first and second convex ring parts 21 and 22 can slightly guide the movement of the guide rod 2, thereby improving the stability of the pressure relief switch. In addition, the first and second convex ring parts 21 and 22 are each provided with an air guide groove 6 on their outer periphery, which satisfies the guiding function while ensuring that the air flow channel is unobstructed.

[0055] In some embodiments, the rivet post 7 can be fixed to the front end of the first cavity 11 by hot riveting, which is more conducive to the combination and fixation of the rivet post 7 and the valve body 1, and the front side of the rivet post 7 is a plane to facilitate the hot riveting operation. In addition, the rivet post 7 is also used to assist the movement of the guide rod 2 to ensure that the guide rod 2 can move normally.

[0056] See also Figure 5 and Figure 6 As shown, a plurality of elastic membrane petals 8 are evenly distributed in the circumferential direction on the inner side of the rivet column 7. The elastic membrane petals 8 are roughly fan-shaped, and the number can be 2-6, preferably 4.

[0057] In the natural state, each elastic membrane flap 8 is closed but there is a ventilated gap between adjacent ones. It can be understood that the closed elastic membrane flap 8 can basically cover the first cavity 11, thereby preventing large-sized debris from entering and hindering the extension and contraction of the spring 4 or the movement of the guide rod 2, ensuring the normal use of the valve function, and the design of the reserved ventilated gap can meet the ventilating requirements of the explosion-proof valve, so that the gas in the target shell can be released without hindrance.

[0058] When the air pressure in the target housing is greater than the loading force of the spring 4, that is, when the pressure is released, due to the high air pressure in the air passage, the guide rod 2 moves forward to force each elastic membrane petal 8 to open, thereby forming a permeable air passage. The opening and closing of the elastic membrane petal 8 is controlled by the guide rod 2, and the size of the permeable air passage can be adaptively controlled according to the gas flow rate. Specifically, the greater the air pressure, the greater the distance the guide rod 2 moves forward, and the larger the opening of the elastic membrane petal 8 is, so as to achieve the function of rapid exhaust and pressure relief, and vice versa, it is reduced, which will not be elaborated here.

[0059] Furthermore, if Figure 4 As shown, the front end of the guide rod 2 is hollowed out (not shown), or the front end of the guide rod 2 is provided with an air guide hole 23 extending to the middle of the rod body. Both of the above methods can guide more gas from the first cavity 11 to the outside of the elastic membrane 8, further enhancing the exhaust and pressure relief function.

[0060] See also Figure 1 and Figure 2 As shown, in some embodiments, a second sealing ring 9 is provided between the valve body 1 and the target housing. The second sealing ring 9 can also be made of high temperature resistant fluororubber material. It is located on the periphery of the waterproof breathable membrane 5 to improve the sealing between the valve body 1 and the target housing and prevent external water vapor from invading the interior of the target housing and affecting its service life. In the present application, the bottom surface of the valve body 1 is also provided with a groove structure, and the second sealing ring 9 is installed in the groove. By welding the valve body 1 and the target housing, the second sealing ring 9 can be compressed to form a seal.

[0061] like Figure 2 As shown, in some embodiments, the bottom surface of the valve body 1 is further provided with a welding structure 10. Specifically, the welding structure 10 includes a boss 101 provided at the outer edge of the bottom surface of the valve body 1, and a conical protrusion 102 provided at the lower end of the boss 101. In the present application, the bosses 101 are distributed at intervals in the circumferential direction, and can be fixed to the target shell by ultrasonic welding with the help of the conical protrusion 102 at the lower end thereof (as a welding line) (see Figure 7 ). Under normal conditions, the gas generated in the target shell is vented and depressurized through the flow channel in the valve body 1. When the internal air pressure is abnormal (for example, the pressure rises to 0.5MPa at a very fast speed), the air flow channel alone cannot ensure safety. At this time, the huge pressure can break the welding position between the boss 101 and the target shell, causing the gas in the target shell to be quickly discharged to the outside atmosphere, avoiding the risk of explosion and playing the role of explosion relief.

[0062] The present invention also discloses a battery pack (not shown), comprising the above-mentioned explosion-proof valve, wherein the valve body 1 of the explosion-proof valve is welded to the battery shell of the battery pack, and the second cavity 12 is kept connected to the interior of the battery shell, thereby improving the safety and reliability of the battery pack.

[0063] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, substitute and modify the above embodiments within the scope of the invention without departing from the principles and purpose of the present invention. All such changes should fall within the scope of protection of the claims of the present invention.

Claims

1. An explosion-proof valve, installed on a target housing, characterized in that: include: A valve body (1) having a first cavity (11) extending inwardly from a side wall and a second cavity (12) extending inwardly from a bottom surface, wherein the first and second cavities (12) are connected, and a limiting step (13) is provided in front of the connecting point of the first cavity (11); A guide rod (2) is movably arranged in the first cavity (11), and a first sealing ring (3) is arranged on the guide rod (2); A spring (4) is arranged in the first cavity (11), and the spring (4) is used to apply a backward loading force to the guide rod (2); A waterproof and breathable membrane (5) arranged below the second cavity (12); In a natural state, the guide rod (2) presses the first sealing ring (3) against the limiting step (13) to form a seal, and when the air pressure in the target housing is greater than the loading force of the spring (4), the guide rod (2) moves forward to separate the first sealing ring (3) from the limiting step (13) to release pressure.

2. The explosion-proof valve according to claim 1, characterized in that: The first cavity (11) is arranged horizontally, and the second cavity (12) is arranged obliquely, and the two are connected to form a "7"-shaped air flow channel.

3. The explosion-proof valve according to claim 1, characterized in that: The limiting step (13) comprises an inclined matching surface (131), and the angle between the matching surface (131) and the horizontal plane is 110°-130°.

4. The explosion-proof valve according to claim 1, characterized in that: The rear portion of the guide rod (2) is provided with first and second convex ring portions (21, 22) spaced apart from each other; The spring (4) is located at the front side of the first convex ring portion (21), and the first sealing ring (3) is located between the first and second convex ring portions (21, 22).

5. The explosion-proof valve according to claim 4, characterized in that: The first and second convex ring parts (21, 22) are respectively slidably arranged in the first and second cavity sections (111, 112) of the first cavity channel (11).

6. The explosion-proof valve according to claim 1, characterized in that: A hollow rivet column (7) is provided at the front end of the first cavity (11), and the rivet column (7) is used to fix the spring (4) and assist the movement of the guide rod (2).

7. The explosion-proof valve according to claim 6, characterized in that: A plurality of elastic membrane petals (8) are evenly distributed in the circumferential direction on the inner side of the rivet post (7); In a natural state, each of the elastic membrane petals (8) is closed but an air permeable gap is left between adjacent ones. When the air pressure in the target housing is greater than the loading force of the spring (4), the guide rod (2) moves forward to force each of the elastic membrane petals (8) to open, thereby forming a air permeable air channel.

8. The explosion-proof valve according to claim 7, characterized in that: The front end of the guide rod (2) is hollowed out, or the front end of the guide rod (2) is provided with an air guide hole (23) extending to the middle of the rod body.

9. The explosion-proof valve according to claim 1, characterized in that: A second sealing ring (9) is provided between the valve body (1) and the target housing, and the second sealing ring (9) is located on the outer periphery of the waterproof and breathable membrane (5).

10. The explosion-proof valve according to claim 1, characterized in that: The bottom surface of the valve body (1) is also provided with a welding structure (10); The welding structure (10) comprises a boss (101) arranged on the outer edge of the bottom surface of the valve body (1), and a conical protrusion (102) arranged at the lower end of the boss (101).

11. The explosion-proof valve according to claim 1, characterized in that: The explosion-proof valve is configured as follows: the pressure relief range is 0.1MPa to 0.2MPa, and the explosion relief range is 0.3MPa to 0.8MPa.

12. A battery pack, characterized in that: Comprising an explosion-proof valve as described in any one of claims 1-11.

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