Multi-stage pressure relief explosion-proof valve

Abstract

The present invention relates to the technical field of explosion-proof valves, and in particular to a multi-stage pressure relief explosion-proof valve, comprising a valve body and an explosion-proof membrane arranged in the valve body, wherein the explosion-proof membrane is provided with multiple layers and the gas flux gradually increases from the air inlet end of the valve body to the pressure relief port end, wherein the circulation of gas through the explosion-proof membrane and the external environment is the first stage of pressure relief, when the gas pressure exceeds the pressure that the explosion-proof membrane can withstand, the explosion-proof membrane ruptures in sequence to form multi-stage pressure relief, when the gas pressure reaches the opening pressure of the valve body, the pressure relief port of the valve body opens to form the last stage of pressure relief, the provision of the multi-layer explosion-proof membrane not only reduces the opening pressure of the explosion-proof valve, but also improves the overall sealing of the valve, thereby broadening the scope of application.

Description

Technical Field

[0001] The present invention relates to the technical field of explosion-proof valves, and in particular to a multi-stage pressure relief explosion-proof valve. Background Art

[0002] Large electric battery packs, the core of new energy vehicles, aircraft, and yachts, require critical operational stability and fault tolerance for unexpected situations. To ensure stability and fault tolerance, large battery packs must meet basic requirements such as breathability and waterproofing. They must also be able to respond quickly to abnormal outages such as short circuits, overcharges, and over-discharges, thereby suppressing and delaying further damage. To address these various types of outages, a common practice is to install explosion-proof valves on the battery packs to accommodate these conditions.

[0003] In the existing technology, spring valves are mostly used to deal with this type of loss of control. Currently, this type of explosion-proof valve has only two pressure relief opening levels: primary pressure relief achieved through a breathable membrane and secondary pressure relief achieved by opening the valve core. However, this type of explosion-proof valve requires pre-determining the opening pressure of the explosion-proof valve based on the application scenario of the battery pack. If the opening pressure is set too high, the explosion-proof valve will have difficulty opening when the battery pack loses control and will not play its original protective role. If the opening pressure is set too low, the overall sealing of the valve will be insufficient, resulting in water leakage. Therefore, the applicability of this explosion-proof valve is relatively narrow and can only be used on battery packs in the same environment, which increases the production cost of the explosion-proof valve. Summary of the Invention

[0004] The purpose of the present invention is to provide a multi-stage pressure relief explosion-proof valve that can achieve multi-stage pressure relief while realizing waterproof and breathable functions. During use, there is no need to worry about the redesign cost and replacement cost caused by changes in the air pressure at the product output end, thereby improving applicability.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] 14. The multi-stage pressure relief explosion-proof valve according to claim 13, wherein the valve body comprises a shell, a piston and a shell cover, and the shell is provided with an air inlet and a pressure relief port; the piston is located in the shell, and the side of the piston facing the pressure relief port is concave to form a pressure relief groove, and the pressure relief groove is connected to the air inlet, and the piston has a first state and a second state. When the piston is in the first state, it can close the pressure relief port. When the preset pressure is reached, the piston is converted to the second state and can open the pressure relief port; the shell cover is provided at the notch of the pressure relief groove, and a pressure relief hole is provided between the shell cover and the piston; the explosion-proof membrane is provided with multiple layers, and the multiple layers of the explosion-proof membrane are fixed in the pressure relief groove and the air flux increases successively from the side close to the air inlet to the side close to the pressure relief port, and the preset pressure at which the piston is converted to the second state is greater than the pressure at which the explosion-proof membrane ruptures.

[0007] Optionally, a sealing step is provided inside one end of the housing where the pressure relief port is provided, and the piston can abut against or disengage from the sealing step to close or open the pressure relief port.

[0008] Optionally, the valve body further includes a piston rod and an elastic member, the piston rod being connected to the side of the piston facing away from the pressure relief groove, the elastic member being configured to provide a force to the piston to close the pressure relief port, a first air vent being axially penetrated through the piston rod, and the first air vent being connected to the pressure relief groove.

[0009] Optionally, the valve body further comprises a bottom sleeve, the bottom sleeve being fixedly connected to one end of the shell where the air inlet is opened, the end of the bottom sleeve away from the shell being closed, an air vent being provided at the connection between the shell and the bottom sleeve, the piston rod and the elastic member being both provided inside the bottom sleeve, and one end of the piston rod passing through the bottom sleeve and connected to the piston.

[0010] Optionally, a connecting ring is provided at one end of the shell where the air inlet is opened, the connecting ring is connected to the inner wall of the shell through a connecting rod, and the bottom sleeve is connected to the connecting ring.

[0011] Optionally, the valve body further includes a pressure relief plate, which is arranged between the explosion-proof membrane and the shell cover, and a third groove is circumferentially provided on the pressure relief plate.

[0012] Optionally, a second groove is provided on the end surface of the piston where the pressure relief groove is provided, and the second groove and the shell cover are combined to form the pressure relief hole.

[0013] Optionally, a limiting protrusion is provided on both sides of the notch of the third groove, and the limiting protrusion can be inserted into the second groove to limit the pressure relief plate.

[0014] Optionally, a pressure ring is further included, which is pressed against the explosion-proof membrane and has an interference fit with the piston.

[0015] Optionally, a plurality of pressure steps are arranged around the pressure relief groove, and the pressure ring can press the explosion-proof membrane against the pressure steps in sequence.

[0016] The beneficial effects of the present invention are as follows: by setting explosion-proof membranes with different air fluxes, the present invention can rupture automatically step by step under different pressures, thereby realizing a multi-stage pressure relief opening function, solving the contradiction between too low opening pressure and insufficient sealing, and expanding the scope of application. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the three-dimensional structure of a multi-stage pressure relief explosion-proof valve proposed in an embodiment of the present invention from one angle;

[0018] Figure 2 This is a schematic diagram of the three-dimensional structure of the multi-stage pressure relief explosion-proof valve proposed in an embodiment of the present invention from another angle;

[0019] Figure 3 is a cross-sectional view of a multi-stage pressure relief explosion-proof valve proposed in an embodiment of the present invention;

[0020] Figure 4 Schematic diagram of the explosion structure of the multi-stage pressure relief explosion-proof valve proposed in an embodiment of the present invention;

[0021] Figure 5 Schematic diagram of the structure of the pressure relief plate proposed in an embodiment of the present invention.

[0022] In the figure: 1. Shell; 1a. First annular groove; 1b. Sealing step; 1c. Connecting ring; 1c1. First groove; 1d. Connecting rod; 1e. Second annular groove; 2. Piston; 2a. Second vent hole; 2b. Pressure relief groove; 2c. Second groove; 2d. Pressing step; 3. Explosion-proof membrane; 4. Shell cover; 5. Bottom sleeve; 6. Piston rod; 6a. First vent hole; 7. Elastic member; 8. Second sealing ring; 9. First sealing ring; 10. Pressing ring; 11. Pressure relief plate; 11a. Third groove; 11b. Limiting protrusion. DETAILED DESCRIPTION

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0024] In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0025] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0026] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., referring to positions or locations, are based on the positions or locations shown in the accompanying drawings and are intended solely for ease of description and simplified operation. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meaning.

[0027] Current explosion-proof valves are primarily used in products requiring pressure relief, such as battery packs. They consist of a valve body, a valve core, and an explosion-proof membrane. The membrane is a breathable membrane. Because the pore size of the membrane is much larger than the gas molecules in the air, yet much smaller than the particle size of particles like water and dust, it effectively achieves both waterproofing and breathability. It also achieves dynamic internal and external pressure balance through internal and external gas exchange, effectively achieving primary pressure relief. When the pressure at the product's output is excessive, the internal pressure opens the valve core, allowing the interior to connect directly to the outside world, thereby achieving secondary pressure relief. Clearly, this type of explosion-proof valve has extremely stringent requirements for the opening pressure setting, resulting in a limited scope of application.

[0028] For this purpose, refer to Figure 1-5As shown, this embodiment proposes a multi-stage pressure relief explosion-proof valve, including a valve body, an explosion-proof membrane 3 arranged in the valve body, the valve body including a shell 1, a piston 2 and a shell cover 4, the shell 1 is provided with an air inlet and a pressure relief port, the air inlet is connected to the pressure output end of the product, the piston 2 is located in the shell 1 and has a first state and a second state, when the piston 2 is in the first state, it can close the pressure relief port, when the preset pressure is reached, the piston 2 is converted to the second state, and can open the pressure relief port; the side of the piston 2 facing the pressure relief port is concave to form a pressure relief groove 2b, the pressure relief groove 2b is connected to the air inlet, the explosion-proof membrane 3 adopts a self-rupturing breathable membrane, the multi-layer explosion-proof membrane 3 is fixed in the pressure relief groove 2b, and the air flux increases successively from the side close to the air inlet to the side close to the pressure relief port. It can be understood that the preset pressure for opening the piston 2 is greater than the pressure at which the explosion-proof membrane 3 ruptures, the shell cover 4 is provided at the notch of the pressure relief groove 2b to protect the explosion-proof membrane 3, and a pressure relief hole is provided between the shell cover 4 and the piston 2. For example, a second groove 2c communicating with the pressure relief groove 2b is provided on the end surface of the piston 2 , and the second groove 2c cooperates with the shell cover 4 to form a pressure relief hole. In specific implementation, the shell 1 can be glued to the end surface of the piston 2 .

[0029] A self-rupturing breathable membrane is one that automatically expands and ruptures when exposed to additional air pressure. The multi-stage pressure relief explosion-proof valve in this embodiment utilizes multiple layers of self-rupturing membranes with varying airflow rates. This membrane adapts to the varying output pressures of connected products, rupturing at varying predetermined pressures to provide pressure relief. Because the membrane is arranged in stages, it reduces the minimum opening pressure while improving the overall sealing performance of the valve, broadening its scope of application.

[0030] Taking the three-layer explosion-proof membrane 3 as an example, the above-mentioned multi-stage pressure relief explosion-proof valve has a total of five levels of pressure relief channels. When the product is operating normally, the first-stage pressure relief channel is opened, and the gas can achieve dynamic internal and external pressure balance through the pressure relief groove 2b and the pressure relief hole; when the product is slightly thermally runaway, the multi-stage pressure relief explosion-proof valve is subjected to less pressure. According to the pressure size, it can trigger the self-rupture of the three-layer explosion-proof membrane 3 in turn, serving as the second to fourth levels of pressure relief respectively. When the product is rapidly out of control, the air pressure increases sharply, the piston 2 is pushed open, the pressure relief port is opened, the fifth-stage pressure relief channel is opened, and the gas is discharged directly from the pressure relief port.

[0031] Specifically, a sealing step 1b is provided inside one end of the housing 1 where the pressure relief port is provided. When the piston 2 abuts against the sealing step 1b, the pressure relief port is closed. When the piston 2 is separated from the sealing step 1b, the pressure relief port is opened. In order to ensure the sealing between the piston 2 and the housing 1, the valve body also includes a piston rod 6 and an elastic member 7. The piston rod 6 is connected to the side of the piston 2 facing away from the pressure relief groove 2b, and can be specifically screwed. The elastic member 7 is configured to provide the piston 2 with a force to close the pressure relief port. A first air vent 6a is provided axially through the piston rod 6. The first air vent 6a is connected to the pressure relief groove 2b through the second air vent 2a. Gas can enter the pressure relief groove 2b through the first air vent 6a and the second air vent 2a. When the air pressure in the product exceeds the elastic pressure of the elastic member 7, the gas can push the piston 2 to open the pressure relief port. Exemplarily, the elastic member 7 is a compression spring, which is sleeved on the piston rod 6, with one end fixed relative to the piston rod 6 and the other end fixed relative to the housing 1. The compression spring can also provide constraints on the piston 2 when the piston 2 disengages from the sealing step 1b, thereby preventing the piston 2 from popping out of the housing 1 due to excessive air pressure and causing damage to the external environment. The compression spring can specifically be a compression spring with an elastic coefficient k between 0.1-20N / mm.

[0032] In addition, the valve body includes a bottom sleeve 5, which is fixedly connected to the end of the housing 1 where the air inlet is opened. The end of the bottom sleeve 5 away from the housing 1 is closed. A vent is provided at the connection between the housing 1 and the bottom sleeve 5, allowing gas to enter the interior of the bottom sleeve 5 through the vent. The piston rod 6 and the elastic member 7 are both disposed within the bottom sleeve 5, with one end of the piston rod 6 extending through the bottom sleeve 5 to connect with the piston 2. Because the piston rod 6 and the elastic member 7 are both located within the bottom sleeve 5, the bottom sleeve 5 can effectively prevent the accumulation of combustion ejecta, preventing them from adhering to the elastic member 7 and affecting its compression stroke, thereby preventing the opening effect and exhaust pressure relief efficiency.

[0033] Specifically, a connecting ring 1c is provided at one end of the air inlet of the housing 1. This connecting ring 1c is connected to the inner wall of the housing 1 via a connecting rod 1d. The bottom sleeve 5 is connected to the connecting ring 1c by an interference fit or rivet connection. The piston rod 6 passes through the connecting ring 1c and is threadedly connected to the piston 2. A first groove 1c1 is provided along the outer circumference of the connecting ring 1c along its axial direction. The first groove 1c1 cooperates with the bottom sleeve 5 to form an air vent. For example, multiple first grooves 1c1 are provided, so that multiple air vents are evenly distributed along the circumference of the connecting ring 1c. Multiple connecting rods 1d are also provided, spaced apart around the connecting ring 1c.

[0034] refer to Figure 3-4As shown, in order to fix the explosion-proof membrane 3 in the pressure relief groove 2b, the multi-stage pressure relief explosion-proof valve in this embodiment also includes a pressure ring 10. Each layer of the explosion-proof membrane 3 is pressed and fixed by a pressure ring 10. The pressure ring 10 presses against the explosion-proof membrane 3 and has an interference fit with the piston 2. Due to the characteristics of the material of the explosion-proof membrane 3 itself, it is difficult for the explosion-proof membrane 3 to stick to the pressure ring 10. In order to prevent the explosion-proof membrane 3 from detaching from the pressure ring 10 when the air pressure is too high, multiple levels of pressure steps 2d are arranged around the pressure relief groove 2b. The number of pressure steps 2d is the same as the number of layers of the explosion-proof membrane 3. The pressure ring 10 can press the explosion-proof membrane 3 against the pressure steps 2d in sequence to increase the contact area and improve the friction. Specifically, the piston 2 is set to a truncated cone shape, and its radius gradually increases from the end close to the piston rod 6 to the end away from the piston rod 6. The pressure ring 10 is set to a circular ring shape, and its inner diameter and outer diameter gradually increase from the end close to the piston rod 6 to the end away from the piston rod 6. After assembly, the pressure ring 10 can form a stepped structure. The explosion-proof membrane 3 is set to a circle, and its area also increases step by step from the end close to the piston rod 6 to the end away from the piston rod 6.

[0035] refer to Figure 3-5 As shown, the valve body further includes a pressure relief plate 11, which is disposed between the pressure ring 10 and the housing cover 4, away from the piston 2. Specifically, the pressure relief plate 11 is circumferentially provided with a plurality of third grooves 11a for ventilation. To prevent the pressure relief plate 11 from rotating, a limiting protrusion 11b is provided on either side of at least one of the third grooves 11a. The limiting protrusion 11b can be snapped into the second groove 2c and abutted against the groove wall of the second groove 2c, thereby limiting the position of the pressure relief plate 11.

[0036] To ensure a tight seal between piston 2 and housing 1, a first annular groove 1a is defined on the stepped surface within housing 1, within which a first sealing ring 9 is positioned. Similarly, a second annular groove 1e is defined on the inlet end face of housing 1, within which a second sealing ring 8 is positioned. This second sealing ring 8 is used to seal the multi-stage pressure relief and explosion-proof valve of this embodiment with the product. Furthermore, a mounting seat is provided on the outer periphery of the housing, with a through-hole provided for threaded connection to the product.

[0037] When the multi-stage pressure relief explosion-proof valve in this embodiment is applied to a battery pack, the explosion-proof membrane 3 can be a self-rupturing membrane with an air flux of 1.5-4.5KPa, 4.5-7.5KPa, or 7.5-10.5KPa, respectively, according to its specific use environment.

[0038] This embodiment also provides a method for preparing an explosion-proof valve, which is used to prepare the above-mentioned multi-stage pressure relief explosion-proof valve. Taking the multi-stage pressure relief explosion-proof valve with three layers of explosion-proof membranes 3 as an example, the method specifically includes the following steps:

[0039] S1. Use stainless steel materials to process and manufacture various structures for assembling the valve body according to the required size and structure. The valve body includes a bottom sleeve 5, a piston rod 6, an elastic member 7, a housing 1, a piston 2, a pressure ring 10, a pressure relief plate 11 and a housing cover 4. Apply rust-proof liquid to prevent rust.

[0040] S2, use 20-200 mesh shot blasting to frost the shell cover 4 and piston 2;

[0041] S3, manufacturing explosion-proof membranes 3 with different air permeabilities according to the sizes of the pressure ring 10 and the pressure relief groove 2b in the piston 2;

[0042] S4, using nitrile rubber to make the first sealing ring 9 and the second sealing ring 8;

[0043] S5. Assemble the valve body, install the explosion-proof membrane 3 and the pressure ring 10 in the pressure relief groove 2b in ascending order, then install the pressure relief plate 11 and the shell cover 4. The shell cover 4 is bonded to the end face of the piston 2 with epoxy AB adhesive;

[0044] S6. Test the assembled valve as a whole, including air tightness test (if gas can only flow out from the second air vent, it proves good air tightness), water pressure test (at 0-50KPa, no water leakage for 1-50 minutes proves good waterproofness), opening pressure test (level 1: open at normal pressure; level 2-4: open between 0.1-20N; level 5: open greater than 20N), pressure relief flow test (level 1 pressure relief: less than 0.1L / min; level 2-4 pressure relief: 0.1-30L / min; level 5 pressure relief >30L / min), etc.

[0045] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. A person skilled in the art would be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A multi-stage pressure relief explosion-proof valve, comprising a valve body and an explosion-proof membrane (3), characterized in that: The valve body comprises: A housing (1), wherein the housing (1) is provided with an air inlet and a pressure relief port; A piston (2) is located in the housing (1); a side of the piston (2) facing the pressure relief port is inwardly concave to form a pressure relief groove (2b); the pressure relief groove (2b) is communicated with the air inlet; the piston (2) has a first state and a second state; when the piston (2) is in the first state, the pressure relief port is closed; when a preset pressure is reached, the piston (2) switches to the second state and is able to open the pressure relief port; A shell cover (4) is arranged at the notch of the pressure relief groove (2b), and a pressure relief hole is provided between the shell cover (4) and the piston (2); The explosion-proof membrane (3) is provided with multiple layers, and the multiple layers of the explosion-proof membrane (3) are fixed in the pressure relief groove (2b) and the air flux increases successively from the side close to the air inlet to the side close to the pressure relief port. The preset pressure at which the piston (2) is converted to the second state is greater than the pressure at which the explosion-proof membrane (3) ruptures.

2. The multi-stage pressure relief explosion-proof valve according to claim 1, characterized in that: A sealing step (1b) is provided inside one end of the pressure relief port on the housing (1), and the piston (2) can abut against or disengage from the sealing step (1b) to close or open the pressure relief port.

3. The multi-stage pressure relief explosion-proof valve according to claim 1 or 2, characterized in that: The valve body further comprises a piston rod (6) and an elastic member (7), wherein the piston rod (6) is connected to the side of the piston (2) facing away from the pressure relief groove (2b), and the elastic member (7) is configured to provide the piston (2) with a force for closing the pressure relief port, and a first air vent (6a) is provided in the piston rod (6) along the axial direction, and the first air vent (6a) is communicated with the pressure relief groove (2b).

4. The multi-stage pressure relief explosion-proof valve according to claim 3, characterized in that: The valve body further comprises a bottom sleeve (5), the bottom sleeve (5) being fixedly connected to one end of the shell (1) where the air inlet is opened, the end of the bottom sleeve (5) away from the shell (1) being closed, an air vent being provided at the connection between the shell (1) and the bottom sleeve (5), the piston rod (6) and the elastic member (7) being both provided inside the bottom sleeve (5), and one end of the piston rod (6) passing through the bottom sleeve (5) to be connected to the piston (2).

5. The multi-stage pressure relief explosion-proof valve according to claim 4, characterized in that: A connecting ring (1c) is provided at one end of the air inlet of the shell (1), the connecting ring (1c) is connected to the inner wall of the shell (1) via a connecting rod (1d), and the bottom sleeve (5) is connected to the connecting ring (1c).

6. The multi-stage pressure relief explosion-proof valve according to claim 1, characterized in that: The valve body further comprises a pressure relief plate (11), wherein the pressure relief plate (11) is arranged between the explosion-proof membrane (3) and the shell cover (4), and a third groove (11a) is circumferentially provided on the pressure relief plate (11).

7. The multi-stage pressure relief explosion-proof valve according to claim 6, characterized in that: A second groove (2c) is provided on the end surface of the piston (2) where the pressure relief groove (2b) is provided. The second groove (2c) and the shell cover (4) are combined to form the pressure relief hole.

8. The multi-stage pressure relief explosion-proof valve according to claim 7, characterized in that: A limiting protrusion (11b) is provided on both sides of the notch of the third groove (11a), and the limiting protrusion (11b) can be inserted into the second groove (2c) to limit the pressure relief plate (11).

9. The multi-stage pressure relief explosion-proof valve according to claim 1, characterized in that: It also includes a pressure ring (10), which is pressed against the explosion-proof membrane (3) and has an interference fit with the piston (2).

10. The multi-stage pressure relief explosion-proof valve according to claim 9, characterized in that: Multiple pressure-releasing steps (2d) are arranged around the pressure relief groove (2b), and the pressure ring (10) can press the explosion-proof membrane (3) against the pressure-releasing steps (2d) in sequence.

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