Explosion-proof valve and battery box

Abstract

The utility model discloses a kind of explosion-proof valve and battery box, it is related to valve body technical field, wherein, explosion-proof valve includes valve main body, movable frame and gas-permeable membrane, valve main body is used to be fixed in the lateral wall of battery box, valve main body is formed with mounting hole, the circumferential of mounting hole is equipped with vent, movable frame is movably arranged in mounting hole, gas-permeable membrane is arranged in movable frame and cover is arranged in vent;In the technical scheme provided by the utility model, gas-permeable membrane has microporous structure, microporous structure only allows gas molecules to pass through, but does not allow liquid molecules or other dust to pass through, so as to realize the balance of gas inside and outside box body.When the gas pressure in box body is greater than critical value, movable frame will be pushed to drive gas-permeable membrane and vent to separate, high-pressure gas and electrolyte in the inside of box body are relieved from vent, so as to guarantee the safe use of battery.

Description

Technical Field

[0001] This utility model relates to the field of valve body technology, and in particular to an explosion-proof valve and a battery box. Background Technology

[0002] A battery explosion-proof valve is a safety pressure relief device integrated into the housing of a battery cell or battery module. It is usually made of metal or composite materials and has a grooved valve plate or elastic diaphragm inside. When the internal gas pressure rises sharply to a set threshold (such as 3-5 kPa) due to thermal runaway or short circuit, the valve plate breaks instantly or the diaphragm flips over to form a directional relief channel, which quickly discharges high-temperature and high-pressure gas and electrolyte vapor, preventing the housing from exploding and suppressing the spread of flames. Afterwards, it remains open to avoid secondary pressurization, thereby limiting thermal runaway to a single battery cell or a local module.

[0003] In related technologies, explosion-proof valves are disposable products that become permanently ineffective after a single use, and they cannot balance the air pressure inside and outside the enclosure when not in an explosion-proof state. Utility Model Content

[0004] The main purpose of this invention is to propose an explosion-proof valve and a battery box, which aims to provide an explosion-proof valve that can balance the air pressure inside and outside the battery box under normal use.

[0005] To achieve the above objectives, the explosion-proof valve proposed in this utility model includes:

[0006] A valve body for fixing to the side wall of the battery box, the valve body having a mounting hole and a vent hole circumferentially provided in the mounting hole;

[0007] The movable frame is movably inserted through the mounting hole;

[0008] A breathable membrane is provided on the movable frame and covers the explosion vent.

[0009] In one embodiment, the movable frame includes a cover plate and a guide rod. The cover plate is disposed on the guide rod, the guide rod is movably disposed in the mounting hole, the cover plate covers the explosion vent, and the breathable membrane is disposed on the side of the cover plate facing away from the explosion vent.

[0010] In one embodiment, the valve body has an annular stepped surface, and the cover plate can abut against or detach from the annular stepped surface;

[0011] The annular stepped surface is provided with a groove, and the explosion-proof valve also includes a first sealing ring. The first sealing ring has a top surface and a bottom surface that are disposed opposite to each other. The top surface contacts the cover plate, and the bottom surface contacts the annular stepped surface. Both the top surface and the bottom surface are provided with annular grooves.

[0012] In one embodiment, the guide rod has an annular protrusion at one end away from the cover plate, and the explosion-proof valve further includes a return spring, which is sleeved on the guide rod, and the two ends of the return spring abut against the valve body and the annular protrusion, respectively.

[0013] In one embodiment, the explosion-proof valve further includes a moisture-proof cap, which is disposed on the side of the valve body facing away from the breathable membrane. The moisture-proof cap and the valve body enclose a sealing cavity, and the return spring is located inside the sealing cavity.

[0014] In one embodiment, the waterproof cap is made of nylon.

[0015] In one embodiment, the cover plate is provided with a connecting post facing the guide rod, and the cover plate is threadedly connected to the guide rod through the connecting post;

[0016] At least a portion of the structure of the connecting post is located inside the guide rod.

[0017] In one embodiment, the breathable membrane is an expanded polytetrafluoroethylene membrane.

[0018] In one embodiment, a second sealing ring is provided on the side of the valve body facing away from the breathable membrane.

[0019] This utility model also proposes a battery box, including the explosion-proof valve as described above.

[0020] This utility model proposes an explosion-proof valve and a battery box. The explosion-proof valve includes a valve body, a movable frame, and a breathable membrane. The valve body is fixed to the side wall of the battery box. The valve body has mounting holes. The movable frame is movably mounted on the valve body through the mounting holes and can move relative to the valve body. The breathable membrane is located on the movable frame and can move with it. The breathable membrane has a microporous structure that allows only gas molecules to pass through, but not liquid molecules or other dust particles, thereby achieving a balance between the gas inside and outside the box. When the gas pressure inside the box exceeds a critical value, the movable frame is pushed to detach the breathable membrane from the explosion vent. The high-pressure gas and electrolyte inside the box are then released through the explosion vent, thus ensuring the safety of battery use. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model 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 this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of an embodiment of the explosion-proof valve provided by this utility model;

[0023] Figure 2 for Figure 1 Explosion diagram of an explosion-proof valve;

[0024] Figure 3 This is a cross-sectional view of the explosion-proof valve in the closed state.

[0025] Figure 4 This is a cross-sectional view of the explosion-proof valve in the open position.

[0026] Explanation of icon numbers:

[0027] 100. Explosion-proof valve; 1. Valve body; 11. Annular stepped surface; 111. Groove; 12. Fixing structure; 1a. Mounting hole; 1b. Fixing threaded hole; 1c. Pressure relief channel; 2. Movable frame; 21. Cover plate; 211. First plate; 212. Second plate; 213. Third plate; 213a. Exhaust groove; 214. Connecting column; 214a. Second channel; 22. Guide rod; 221. Annular protrusion; 22a. First channel; 23. Return spring; 3. Breathable membrane; 4. Moisture-proof cap; 5. First sealing ring; 6. Second sealing ring.

[0028] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0029] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0030] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0031] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0032] The battery explosion-proof valve 100 is a safety pressure relief device integrated into the housing of a battery cell or battery module. It is usually made of metal or composite materials and has a grooved valve plate or elastic diaphragm inside. When the internal gas pressure rises sharply to a set threshold (such as 3-5 kPa) due to thermal runaway or short circuit, the valve plate breaks instantly or the diaphragm flips over to form a directional relief channel, which quickly discharges high-temperature and high-pressure gas and electrolyte vapor, prevents the housing from exploding and suppresses the spread of flames. Afterwards, it remains open to avoid secondary pressurization, thereby limiting thermal runaway to a single battery cell or a local module.

[0033] In related technologies, although the explosion-proof valve 100 can provide pressure relief protection in the instant of thermal runaway, it has two major drawbacks: First, the valve plate or diaphragm is designed for single burst, and it will be permanently damaged after the action, requiring the entire module to be returned to the factory for replacement, resulting in extremely high maintenance costs; Second, the valve body lacks micro-pressure balancing function, and the pressure difference caused by daily temperature differences or altitude changes cannot be mitigated. Over a long period of time, the pressure inside the box will be much higher than that outside, which may lead to deformation or explosion.

[0034] To address the aforementioned problems, this utility model proposes an explosion-proof valve 100, which aims to provide an explosion-proof valve 100 that can balance the air pressure inside and outside the battery box under normal use conditions. Figures 1 to 4 This is a schematic diagram of an embodiment of the explosion-proof valve 100 of this utility model.

[0035] Please refer to Figure 1 This utility model proposes an explosion-proof valve 100, including a valve body 1, a movable frame 2, and a breathable membrane 3. The valve body 1 is used to fix to the side wall of the battery box. The valve body 1 has a mounting hole 1a. The mounting hole 1a is provided with an explosion vent in the circumference. The movable frame 2 is movably inserted through the mounting hole 1a. The breathable membrane 3 is provided on the movable frame 2 and covers the explosion vent.

[0036] This utility model proposes an explosion-proof valve 100 and a battery box. The explosion-proof valve 100 includes a valve body 1, a movable frame 2, and a breathable membrane 3. The explosion-proof valve 100 is fixed to the side wall of the battery box via the valve body 1. The valve body 1 has a mounting hole 1a. The movable frame 2 is movably mounted on the valve body 1 through the mounting hole 1a and can move relative to the valve body 1. The breathable membrane 3 is located on the movable frame 2 and can move with the movable frame 2. The breathable membrane 3 has a microporous structure that allows only gas molecules to pass through, but not liquid molecules or other dust particles, thereby achieving a balance between the gas inside and outside the box. When the gas pressure inside the box exceeds a critical value, the movable frame 2 is pushed to cause the breathable membrane 3 to detach from the explosion vent. The high-pressure gas and electrolyte inside the box are then released through the explosion vent, thus ensuring the safety of battery use.

[0037] The explosion-proof valve 100 proposed in this application has a closed state and an open state. When the pressure inside the battery box does not exceed the pressure threshold set by the valve body, the explosion-proof valve 100 is in the closed state. In the closed state, the explosion-proof valve 100 can still communicate with the outside gas. Specifically, the guide rod 22 is located inside the battery box. The guide rod 22 has a hollow structure and is provided with a first channel 22a communicating with the inside of the box. The other end of the guide rod 22 is connected to the connecting post 214 of the cover plate 21. The connecting post 214 is provided with a second channel 214a. The end of the second channel 214a away from the first channel 22a is connected to the vent membrane 3. The vent membrane 3 is provided on the third plate 213. The third plate 213 is provided with multiple exhaust grooves 213a on the side facing away from the second channel 214a. For details, please refer to further description. Figure 2 When the air pressure inside the chamber is too high but does not reach the pressure threshold, the gas can be discharged from the exhaust groove 213a through the first channel 22a, the second channel 214a, and then through the breathable membrane 3, thereby achieving pressure balance with the outside.

[0038] In one embodiment of this application, the breathable membrane 3 adopts a three-dimensional microfiber network structure of expanded polytetrafluoroethylene (ePTFE) membrane, with a pore size distribution of 0.1–1.0 μm, which is 2–3 orders of magnitude larger than gas molecules (approximately 0.3 nm), but 1–2 orders of magnitude smaller than liquid water droplets (>1000 μm) and typical dust particles (>10 μm). Due to the "size sieving" effect, when a micro-pressure difference of ±3–5 kPa is generated inside the chamber due to temperature difference or altitude change, gas molecules can diffuse freely along the micropores to achieve bidirectional isobaric equilibrium, while water, electrolyte droplets, and dust are blocked because surface tension cannot wet the hydrophobic membrane surface, achieving IP67 waterproof and breathable rating. The ePTFE microfiber has low internal surface energy and a droplet contact angle >160°, further preventing capillary penetration. At the same time, the membrane material is heat resistant to 260°C and electrolyte corrosion resistant, maintaining a certain amount of air permeability for a long time, ensuring that the explosion-proof valve 100 continuously balances the internal and external pressures without failure when closed.

[0039] The breathable membrane 3 releases daily air pressure fluctuations within the range of ±3–5kPa in real time through a bidirectional micro-pressure differential conduction mechanism, preventing the enclosure from fatigue and deformation due to repeated expansion and collapse caused by the "breathing effect". At the same time, it prevents external water and dust from entering, reducing the internal temperature rise rate by more than 20% and lowering the long-term operating temperature of components by 5–8℃. This extends the lifespan of the battery cells and electronic components by about 30% and reduces the maintenance frequency of the sealing strips by more than 50%.

[0040] To achieve pressure relief of the battery box, the movable frame 2 includes a cover plate 21 and a guide rod 22. For details, please refer to further documentation. Figure 3 A cover plate 21 is mounted on a guide rod 22, which is movably mounted in a mounting hole 1a. The cover plate 21 covers the explosion vent, and a breathable membrane 3 is located on the side of the cover plate 21 facing away from the explosion vent. Correspondingly, the valve body 1 has an annular stepped surface 11. The cover plate 21 can abut against or detach from the annular stepped surface 11. When the battery is in normal operating condition, the cover plate 21 of the movable frame 2 abuts against the annular stepped surface 11 of the valve body 1, thereby achieving a seal. When the internal pressure of the battery is too high and pressure relief is required, the internal high-pressure gas pushes the cover plate 21 upward, disengaging it from the annular stepped surface 11, thereby forming a pressure relief channel 1c between the cover plate 21 and the valve body 1. Figure 4 As shown, the gas flow rate of the pressure relief channel 1c per unit time is much greater than that of the gas flow rate of the breathable membrane 3, and the internal high-pressure gas is depressurized through the pressure relief channel 1c.

[0041] Furthermore, the annular stepped surface 11 is provided with a groove 111, and the explosion-proof valve 100 also includes a first sealing ring 5. The first sealing ring 5 has a top surface and a bottom surface that are arranged opposite to each other. The top surface contacts the cover plate 21, and the bottom surface contacts the annular stepped surface 11. Both the top surface and the bottom surface are provided with annular grooves. The groove 111 and the first sealing ring 5 with double annular grooves form a "double labyrinth + elastic rebound" seal between the cover plate 21 and the annular stepped surface 11: the groove 111 provides a compression margin, and the double annular grooves generate two independent sealing lines, which improves the dustproof, waterproof, and salt spray resistance to IP67 / IP68; it still maintains its elasticity under thermal cycling at -40℃ to 125℃, which not only prevents short circuits or corrosion caused by daily water vapor and dust infiltration, but also ensures that zero leakage can be restored instantly after depressurization, reducing seal failure and maintenance frequency.

[0042] The explosion-proof valve 100 proposed in this application can be used multiple times. Specifically, the end of the guide rod 22 away from the cover plate 21 is provided with an annular protrusion 221. The explosion-proof valve 100 also includes a return spring 23, which is sleeved on the guide rod 22, and the two ends of the return spring 23 abut against the valve body 1 and the annular protrusion 221 respectively. The return spring 23 is pre-compressed around the guide rod 22, with its two ends abutting against the valve body 1 and the annular protrusion 221, respectively, forming a constant rebound force. When the gas pressure inside the chamber is lower than the set threshold, this rebound force presses the movable frame 2 against the annular step surface 11, making the cover plate 21 fit tightly against the first sealing ring 5, and the valve remains closed with zero leakage. Once the internal gas pressure exceeds the threshold, the gas thrust overcomes the spring preload, the guide rod 22 slides outward along the mounting hole 1a, and the cover plate 21 opens to release pressure. After the pressure release is completed, the gas pressure drops sharply, the spring immediately releases its stored energy, pushes the annular protrusion 221 in the opposite direction, and makes the guide rod 22 quickly return to its original position. The cover plate 21 then presses the sealing ring again, completing a repeatable "compression-depression-rebound" cycle without any external power or manual intervention.

[0043] The reset spring 23 integrates the opening threshold, sealing rebound, and repeatable action into the same guide rod 22: the spring preload precisely sets the pressure relief point, which avoids accidental opening and ensures timely explosion relief; after pressure relief, it can automatically reset without replacing parts, achieving a lifetime maintenance-free cycle and reducing operation and maintenance costs; at the same time, the spring is enclosed in the valve body, which is dustproof and moistureproof, so that the explosion-proof valve 100 has both the reliability of a disposable explosion valve and the economy of a resettable valve.

[0044] To extend the service life of the explosion-proof valve 100, the explosion-proof valve 100 also includes a moisture-proof cap 4. The moisture-proof cap 4 is located on the side of the valve body 1 facing away from the breathable membrane 3. The moisture-proof cap 4 and the valve body 1 enclose a sealed cavity. The return spring 23 is located inside the sealed cavity. The moisture-proof cap 4 encapsulates the return spring 23, guide rod 22 and other metal parts in a dry sealed cavity that is completely isolated from the electrolyte. This not only blocks the erosion of corrosive gases and droplets, but also prevents jamming and spring force attenuation caused by salt spray and moisture, so that the spring maintains a constant preload, significantly reducing operation and maintenance costs and improving system reliability.

[0045] The moisture-proof cap 4 is made of nylon material. The nylon moisture-proof cap 4 is lightweight, resistant to electrolyte corrosion and self-lubricating. It will not increase the weight of the valve body and can resist acid and alkali corrosion for a long time to avoid embrittlement. Its smooth inner wall and elastic modulus can effectively absorb vibration and prevent dust or crystal particles from getting stuck in the spring gap, ensuring that the reset action is always smooth and the pressure relief threshold is stable.

[0046] In one embodiment of this application, the cover plate 21 is composed of a first plate 211, a second plate 212 and a third plate 213 stacked together. The third plate 213 is the plate closest to the valve body 1. The third plate 213 is provided with a connecting post 214 facing the guide rod 22. The cover plate 21 is threadedly connected to the guide rod 22 through the connecting post 214. At least part of the structure of the connecting post 214 is located inside the guide rod 22, so as to facilitate the disassembly and assembly of the guide rod 22 and the cover plate 21, and to facilitate the maintenance and replacement of the vent membrane 3 or the return spring 23.

[0047] In one embodiment of this application, a fixing structure 12 is provided on the outer periphery of the valve body 1. For details, please refer to further details. Figure 2 The fixed structure is hexagonal, which can be matched with positioning fixtures to facilitate the installation of the explosion-proof valve 100.

[0048] This utility model also proposes a battery box, which includes the aforementioned explosion-proof valve 100. The explosion-proof valve 100 is installed at the explosion vent position on the side wall of the battery box and is connected to the box body through a fixing threaded hole 1b. The bottom surface of the valve body 1 abuts against the side wall of the battery box. To prevent external gas, liquid, or dust from entering the box body through the gap between the valve body 1 and the side wall of the battery box, a second sealing ring 6 is provided on the side of the valve body 1 facing away from the breathable membrane 3. For details, please refer to further description. Figure 3 By setting a second sealing ring 6, it can be ensured that when the explosion-proof valve 100 comes into contact with the enclosure, the second sealing ring 6 can seal the gap between the two, preventing moisture and dust from entering the enclosure. The specific structure of the explosion-proof valve 100 is as described in the above embodiments. Since this battery box adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described in detail here.

[0049] The above description is merely an exemplary embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural transformations made based on the technical concept of the present utility model and the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. An explosion-proof valve, characterized in that, include: A valve body for fixing to the side wall of the battery box, the valve body having a mounting hole and a vent hole circumferentially provided in the mounting hole; The movable frame is movably inserted through the mounting hole; A breathable membrane is provided on the movable frame and covers the explosion vent.

2. The explosion-proof valve as described in claim 1, characterized in that, The movable frame includes a cover plate and a guide rod. The cover plate is disposed on the guide rod, the guide rod is movably disposed in the mounting hole, the cover plate covers the explosion vent, and the breathable membrane is disposed on the side of the cover plate facing away from the explosion vent.

3. The explosion-proof valve as described in claim 2, characterized in that, The valve body has an annular stepped surface, and the cover plate can abut against or detach from the annular stepped surface. The annular stepped surface is provided with a groove, and the explosion-proof valve also includes a first sealing ring. The first sealing ring has a top surface and a bottom surface that are disposed opposite to each other. The top surface contacts the cover plate, and the bottom surface contacts the annular stepped surface. Both the top surface and the bottom surface are provided with annular grooves.

4. The explosion-proof valve as described in claim 2, characterized in that, The guide rod has an annular protrusion at one end away from the cover plate. The explosion-proof valve also includes a return spring, which is sleeved on the guide rod, and the two ends of the return spring abut against the valve body and the annular protrusion, respectively.

5. The explosion-proof valve as described in claim 4, characterized in that, The explosion-proof valve also includes a moisture-proof cap, which is located on the side of the valve body facing away from the breathable membrane. The moisture-proof cap and the valve body enclose a sealed cavity, and the return spring is located inside the sealed cavity.

6. The explosion-proof valve as described in claim 5, characterized in that, The waterproof cap is made of nylon.

7. The explosion-proof valve as described in claim 2, characterized in that, The cover plate is provided with a connecting post facing the guide rod, and the cover plate is threadedly connected to the guide rod through the connecting post; At least a portion of the structure of the connecting post is located inside the guide rod.

8. The explosion-proof valve as described in any one of claims 1 to 7, characterized in that, The breathable membrane is an expanded polytetrafluoroethylene membrane.

9. The explosion-proof valve as described in any one of claims 1 to 7, characterized in that, The valve body is provided with a second sealing ring on the side facing away from the breathable membrane.

10. A battery box, characterized in that, Includes the explosion-proof valve as described in any one of claims 1 to 9.

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