Explosion-proof valves and battery packs

Abstract

This invention relates to the field of battery technology and discloses an explosion-proof valve and a battery pack. The explosion-proof valve includes a base, a valve cover, a valve body, and an elastic element. When the explosion-proof valve is not open, the valve body is stably in a closed position under the thrust of the elastic element. When the valve body is subjected to a thrust from the base toward the valve cover, the guide element slides from one first recess to another under the guidance of the guide channel formed between the guide unit and the limiting unit, causing the valve body to switch from the closed position to the open position, thus opening the explosion-proof valve. The switching process of the valve body position is automatically achieved by the guiding effect of the guide channel on the guide element, resulting in a high degree of automation. Furthermore, after the valve body switches to the open position, it can also quickly and effectively discharge foreign matter such as leaked electrolyte from the battery pack, realizing the integration of the leakage hole and the explosion-proof valve into one unit, timely discharge of high-temperature and high-pressure gases and leaked electrolyte, and improving the safety of the battery pack.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to explosion-proof valves and battery packs. Background Technology

[0002] Battery packs are core components of electric vehicles and energy storage systems. They contain multiple battery cells, and as batteries age or operate in harsh environments, cell damage can occur, leading to electrolyte leakage, thermal runaway, and other abnormal situations. This not only damages other cells that are not experiencing problems but can also negatively impact the safety and performance of the entire battery pack. Therefore, addressing cell thermal runaway and rapidly draining leaked electrolyte from the battery pack casing is crucial. Traditional battery packs typically include explosion-proof valves and leakage ports. The explosion-proof valves usually release high-temperature, high-pressure gases to handle cell thermal runaway, while the leakage ports drain leaked electrolyte to resolve the leakage problem.

[0003] However, explosion-proof valves are typically spring-loaded or pin-type valves, which are complex in structure and usually require multiple steps or auxiliary tools to switch between open and closed states, making their operation mechanism quite complicated. Leakage ports also typically require manual disassembly using tools. This complex and inefficient process prevents the timely release of high-temperature, high-pressure gases and leaked electrolyte generated by thermal runaway. In the event of thermal runaway or leakage, time is of the essence. Failure to promptly open the explosion-proof valve and leakage port for pressure relief and electrolyte drainage could lead to damage to more battery cells or even more dangerous situations such as battery pack explosions. Summary of the Invention

[0004] In view of this, the present invention provides an explosion-proof valve and a battery pack to solve the problem that the battery pack cannot discharge high-temperature and high-pressure gases and leaked electrolyte in a timely manner.

[0005] In a first aspect, the present invention provides an explosion-proof valve, comprising: a base having a first through hole, a guide unit disposed on one side of the base, the guide unit being corrugated and having at least two first recesses; a valve cover covering the base and located outside the guide unit, the valve cover having a vent hole, and a limiting unit disposed on the inner side of the valve cover opposite to the guide unit, the limiting unit being corrugated and offset from the guide unit, the limiting unit and the guide unit forming a guide channel; and a valve body disposed between the base and the valve cover, the valve body having a second through hole. The valve body has a through position where the second through hole communicates with the first through hole, and a closed position where the second through hole corresponds to a solid portion on the base. A guide member is provided on the valve body, and the guide member is located in the guide channel. When the valve body is subjected to a thrust from the base toward the valve cover, the guide member is adapted to move from one of the first recesses to another under the guidance of the guide channel, so as to drive the valve body to switch between the closed position and the through position. An elastic member abuts between the valve body and the valve cover to provide a thrust toward the base to the valve body.

[0006] Beneficial effects: By setting the valve body and valve cover on one side of the base, and abutting the valve body and valve cover with an elastic element, the valve body is pressed onto the base by the thrust of the valve cover and the elastic element. By setting a corrugated guide unit on the base, the guide unit has an undulating shape, with the first recess lower than the first protrusion. When the explosion-proof valve is not open, the valve body is stably in the closed position under the thrust of the elastic element. When the valve body is subjected to a thrust from the base toward the valve cover, under the guidance of the guide channel formed between the guide unit and the limiting unit, the guide element slides out from one of the first recesses, passes around the first protrusion, and then slides to the adjacent first recess, thereby driving the valve body to switch from the closed position to the open position, so that the second through hole and the first through hole are connected, and the battery pack is inside. The gas is discharged to the outside of the battery pack through the first through hole, the second through hole, and the vent on the valve cover, thereby depressurizing the battery pack. The switching process of the valve body position is automatically achieved by the guiding effect of the guide channel on the guide component, without manual intervention, and has a high degree of automation. After the valve body switches to the conduction position, under the thrust of the elastic component, the valve body always stays in the conduction position. Therefore, the electrolyte and other foreign objects leaking from the battery cells can be quickly and effectively discharged from the battery pack without manual operation, reducing potential risks and improving maintenance efficiency. The leakage hole and the explosion-proof valve are integrated into one unit, which can efficiently, quickly and reliably discharge the high-temperature and high-pressure gas and electrolyte leaking from the battery cells caused by thermal runaway, which is beneficial to improving the safety and maintainability of the battery pack.

[0007] In one optional embodiment, the guiding unit includes an inclined first guiding surface and a first limiting surface, the inclination direction of the first guiding surface and the first limiting surface being opposite, and the number of both the first guiding surface and the first limiting surface being at least two, with the first limiting surface and the first guiding surface being alternately connected in sequence; the limiting unit includes an inclined second guiding surface and a second limiting surface, the inclination direction of the second guiding surface and the second limiting surface being opposite, and the number of both the second guiding surface and the second limiting surface being at least two, with the second limiting surface and the second guiding surface being alternately connected in sequence; the length of the first guiding surface is greater than the length of the first limiting surface, the length of the second guiding surface is greater than the length of the second limiting surface, and the inclination direction of the second guiding surface is opposite to the inclination direction of the first guiding surface.

[0008] Beneficial effects: By setting the guide unit to include at least two first guide surfaces and at least two first limiting surfaces, and the corrugated guide unit correspondingly having at least two first recesses and at least one first protrusion, the guide component can be switched from one first recess to another first recess via a first protrusion, thereby realizing the switching of the valve body from the closed position to the open position. Since the length of the first guide surface is greater than the length of the first limiting surface, and the length of the second guide surface is greater than the length of the second limiting surface, the tilt angle of the first limiting surface is greater than the tilt angle of the first guide surface, and the tilt angle of the second limiting surface is greater than the tilt angle of the second guide surface. The projection of the second guide surface on the guide unit covers the most convex point of a set of first protrusions and the most concave point of the first recess, and the projection of the first guide surface on the limiting unit covers the most convex point of a set of second protrusions and the most concave point of the second recess, ensuring the switching of the valve body position, which is conducive to ensuring the smooth opening of the explosion-proof valve and improving the safety of the battery pack.

[0009] In one optional embodiment, the surface contours of both the guide unit and the limiting unit are smoothly transitioned curves, the guide member is cylindrical, and the axis of the cylinder is perpendicular to the axis of the valve body.

[0010] Beneficial effects: By setting the surface contours of both the guide unit and the limiting unit to be smoothly transitioning curves, that is, the surfaces of the recessed and raised parts are curved, and the guide component is set to be cylindrical, with the circumferential surface of the cylinder contacting the surface of the guide unit and / or the limiting unit, it is convenient for the guide component to move smoothly along the curve, improving the smoothness and stability of the guide component movement process, thereby ensuring that the valve body can switch smoothly between the closed position and the open position.

[0011] In one optional embodiment, the projection of the guide unit on the base is annular; the base has a first mounting hole located at the center of the annular area enclosed by the guide unit; the valve body includes a main body and a mounting part fixedly connected, the cross-sectional area of ​​the main body is larger than the cross-sectional area of ​​the mounting part, the mounting part is slidably inserted in the first mounting hole, the main body is located within the annular area enclosed by the base, the second through hole is opened on the main body, and the guide protrudes from the outer peripheral surface of the main body.

[0012] Beneficial effects: By opening a first mounting hole at the center of the guide unit on the base, the mounting part of the valve body can be movably inserted into the first mounting hole. The valve body can move relative to the base along the axis of the first mounting hole, and the first mounting hole limits the mounting part radially along the first mounting hole. The valve body is always located within the annular area enclosed by the guide unit. During the movement of the guide member along the guide unit, the valve body rotates around the axis of the first mounting hole. Multiple first recesses on the guide unit are arranged circumferentially around the first mounting hole. The guide member can switch between multiple first recesses sequentially as the valve body rotates around the axis of the first mounting hole, repeating the cycle, so as to realize the repeated use of the explosion-proof valve for opening and closing.

[0013] In one optional embodiment, there are four first guide surfaces and four first limiting surfaces, two first through holes, and two first through holes symmetrically arranged on both sides of the first mounting hole. There are also two second through holes symmetrically arranged on both sides of the first mounting hole.

[0014] Beneficial effects: The guide component switches sequentially on the four recesses, which can realize the continuous switching of the valve body in the closed position, the open position, the closed position, and the open position, enabling the explosion-proof valve to be used in multiple cycles, and with a high degree of automation.

[0015] In one optional embodiment, the second through hole is a waist-shaped hole, and the first through hole and the second through hole have the same shape and the same size.

[0016] Beneficial effects: By setting the second through hole as an oblong hole, the space on the main body can be better utilized, ensuring sufficient exhaust passage to the maximum extent. At the same time, space can be reserved for the arrangement of elastic elements and the first sealing ring. The layout is compact, which helps to reduce the overall volume of the valve body and thus reduce weight.

[0017] In one optional embodiment, the waist-shaped hole is part of a ring concentrically arranged with the main body, the radius of the outer circle corresponding to the ring is r1, the radius of the inner circle corresponding to the ring is r2, and the central angle corresponding to the waist-shaped hole is α, satisfying: Where α≤60°, and Q is the gas generation rate of the battery pack.

[0018] Beneficial effects: By defining the relationship between the parameters of the waist-shaped orifice and the gas production rate of the battery pack through calculation formulas, the size parameters of the first and second through holes can be obtained based on the gas production of the battery pack. This allows for the selection of the appropriate explosion-proof valve specifications for the actual project. The obtained size parameters are highly reliable, ensuring that when the first and second through holes are connected, a channel of sufficient size can be formed to discharge the gas trapped in the battery pack, thereby improving the safety of the battery pack.

[0019] In one optional embodiment, the explosion-proof valve further includes: a vent hole, the vent hole penetrating the main body and the mounting part, and a breathable membrane corresponding to the vent hole is attached to the side of the valve body facing the valve cover. The breathable membrane is a one-way membrane, which is suitable for discharging the gas on the side of the vent hole away from the valve cover to the side of the vent hole close to the valve cover.

[0020] Beneficial effects: The breathable membrane is a one-way membrane used to seal the ventilation holes. When the air pressure inside the battery pack is slightly higher, it allows the gas inside the battery pack to flow out to the outside of the battery pack through the breathable membrane, thereby ensuring the air pressure balance inside and outside the battery pack. However, the breathable membrane can block the gas outside the battery pack from entering the battery pack, preventing external gas from damaging the inside of the battery pack.

[0021] In one optional embodiment, the explosion-proof valve further includes: a first sealing ring and a second sealing ring, the first sealing ring being disposed between the valve body and the base, and the second sealing ring being adapted to be disposed on the side of the explosion-proof valve facing the battery pack housing; and / or, the explosion-proof valve further includes: a mounting surface, the mounting surface extending outward from at least a portion of the circumferential surface of the base, or the mounting surface extending outward from at least a portion of the circumferential surface of the valve cover, the mounting surface being adapted to connect with the battery pack housing.

[0022] Beneficial effects: The first sealing ring ensures a tight seal between the valve body and the base when they abut against each other, while the second sealing ring ensures a tight seal between the explosion-proof valve and the battery pack housing, thus improving the valve's sealing performance. The mounting surface facilitates installation of the explosion-proof valve onto the battery pack housing, enhancing the seal between the valve and the housing. Furthermore, by placing the mounting surface on the valve cover, the explosion-proof valve can be installed inside the battery pack housing, reducing its footprint on the external space of the battery pack and preventing damage from the external environment, thereby improving the battery pack's safety.

[0023] Secondly, the present invention also provides a battery pack, comprising: a housing having a vent hole; a plurality of battery cells disposed inside the housing; and the aforementioned explosion-proof valve corresponding to and connected to the vent hole on the outside or inside of the housing. Since the battery pack includes the explosion-proof valve and has the same effect as the explosion-proof valve, it will not be described further here. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of an explosion-proof valve according to an embodiment of the present invention;

[0026] Figure 2 for Figure 1 An exploded view of the explosion-proof valve is shown below;

[0027] Figure 3 for Figure 1 The front view of the explosion-proof valve is shown below;

[0028] Figure 4 for Figure 3 The diagram shows the internal structure of the explosion-proof valve hidden behind the side wall of the valve cover.

[0029] Figure 5 This is a schematic diagram of the explosion-proof valve in the closed state according to an embodiment of the present invention;

[0030] Figure 6 This is a schematic diagram of the explosion-proof valve in the open state according to an embodiment of the present invention;

[0031] Figure 7 This is a schematic diagram of the structure of a base according to an embodiment of the present invention;

[0032] Figure 8 for Figure 7 The front view of the base shown;

[0033] Figure 9 for Figure 7 A top view of the base shown;

[0034] Figure 10 This is a schematic diagram of the structure of a valve body according to an embodiment of the present invention;

[0035] Figure 11 for Figure 10 The top view of the valve body shown;

[0036] Figure 12 for Figure 10 The front view of the valve body is shown below;

[0037] Figure 13 This is a schematic diagram of the structure of a valve cover according to an embodiment of the present invention;

[0038] Figure 14 for Figure 13 The front view of the valve cover is shown;

[0039] Figure 15 for Figure 14 A cross-sectional view along the AA direction;

[0040] Figure 16 for Figure 13 The top view of the valve cover shown;

[0041] Figure 17 for Figure 13 The valve cover shown is a bottom view;

[0042] Figure 18 This is a schematic diagram of the structure of another explosion-proof valve according to an embodiment of the present invention.

[0043] Explanation of reference numerals in the attached figures:

[0044] 1. Base; 101. First through hole; 102. First mounting hole; 103. First groove; 104. Mounting surface; 105. Second mounting hole; 110. Guide unit; 111. First guide surface; 112. First limiting surface; 2. Valve cover; 201. Vent hole; 202. Second groove; 210. Limiting unit; 211. Second guide surface; 212. Second limiting surface; 3. Valve body; 310. Main body; 311. Second through hole; 312. Guide component; 320. Mounting part; 301. Vent hole; 302. Mounting groove; 4. Elastic component; 5. Vent membrane; 6. First sealing ring; 7. Second sealing ring. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] Spring-loaded and pin-type explosion-proof valves in related technologies have the following disadvantages:

[0047] Complex Structure: Spring-loaded and pin-type explosion-proof valves typically consist of multiple parts, including springs, valve covers, guide shafts, diaphragms, glands, and valve bodies. This complex structure increases manufacturing costs and may lead to more potential failure points. Operational Complexity: The operating mechanisms of spring-loaded and pin-type explosion-proof valves are relatively complex, usually requiring numerous steps or tools to switch between open and closed states, increasing operational complexity and difficulty. Poor Durability: Components such as springs and valves in spring-loaded and pin-type explosion-proof valves are susceptible to wear and corrosion, leading to performance degradation or failure, affecting long-term stability and durability. Susceptibility to External Factors: The springs or pins in spring-loaded and pin-type explosion-proof valves are easily affected by external temperature, pressure, and other factors, potentially causing the valve to malfunction under extreme conditions, thus affecting the safety performance of the battery pack. Inability to Remove Foreign Objects: The design of spring-loaded and pin-type explosion-proof valves typically allows only unidirectional venting, failing to effectively remove foreign objects blocking the valve. This may cause the valve to fail, consequently affecting the safety performance of the entire battery pack.

[0048] The following is combined with Figures 1 to 18 The following describes embodiments of the present invention.

[0049] According to an embodiment of the present invention, an explosion-proof valve is provided, comprising: a base 1, a valve cover 2, a valve body 3, and an elastic element 4. The base 1 has a first through hole 101, and a guide unit 110 is provided on one side of the base 1. The guide unit 110 is corrugated and has at least two first recesses. The valve cover 2 is disposed on the base 1 and located outside the guide unit 110. The valve cover 2 has a vent hole 201, and a limiting unit 210 is provided on the inner side of the valve cover 2, opposite to the guide unit 110. The limiting unit 210 is corrugated and offset from the guide unit 110, forming a guide channel between the limiting unit 210 and the guide unit 110. The valve body 3 is disposed between the base 1 and the valve cover 2, and a second through hole 3 is provided on the valve body 3. 11. The valve body 3 has a conducting position where the second through hole 311 communicates with the first through hole 101, and a closing position where the second through hole 311 corresponds to the solid part on the base 1. A guide member 312 is provided on the valve body 3. The guide member 312 is located in the guide channel. When the valve body 3 is subjected to a thrust from the base 1 toward the valve cover 2, the guide member 312 is adapted to move from one first recess to another under the guidance of the guide channel, so as to drive the valve body 3 to switch between the closing position and the conducting position. The elastic member 4 abuts between the valve body 3 and the valve cover 2 to provide a thrust toward the base 1 to the valve body 3. The first recess is formed by the guide unit 110 being recessed from the side away from the surface of the base 1 toward the surface of the base 1.

[0050] It should be noted that the explosion-proof valve is installed on the battery pack housing, and the explosion-proof valve corresponds to the vent hole on the housing. When the explosion-proof valve is not open, the explosion-proof valve closes the vent hole. When the explosion-proof valve is open, the explosion-proof valve connects the inside and outside of the housing, and discharges the high-pressure gas in the battery pack through the explosion-proof valve to prevent the battery pack from exploding.

[0051] In this embodiment, the guide unit 110 is corrugated and has a first recess and a first protrusion arranged alternately. When the guide member 312 is located in the first recess, the valve body 3 is in a closed position or a closed position. The first recess and the first protrusion are not in the same plane parallel to the surface of the base 1. The guide unit 110 has an undulating shape, and the first recess is lower than the first protrusion, that is, the distance from the surface of the first recess to the surface of the base 1 is smaller. The limiting unit 210 is corrugated and has a second recess and a second protrusion. Since the limiting unit 210 and the guide unit 110 are misaligned, the first recess and the second protrusion are opposite to each other, and the first protrusion and the second recess are opposite to each other. The guide channel formed between the limiting unit 210 and the guide unit 110 also has an undulating shape. The guide channel provides guidance for the movement of the guide member 312. The guide unit 110 protrudes from the surface of the base 1. The first recess refers to the part of the guide unit 110 that is recessed in the direction close to the surface of the base 1, and the first protrusion refers to the part of the guide unit 110 that is protruding in the direction away from the surface of the base 1. The limiting unit 210 protrudes from the surface of the valve cover 2 on the side opposite to the base 1. The second recess refers to the part of the limiting unit 210 that is recessed in the direction close to the surface of the valve cover 2, and the second protrusion refers to the part of the limiting unit 210 that is protruding in the direction away from the surface of the valve cover 2.

[0052] When the explosion-proof valve is in the closed state, under the thrust of the elastic element 4, the guide 312 on the valve body 3 is pushed to a first recessed part at a low position, and the valve body 3 abuts against the base 1. The valve body 3 is in a closed position corresponding to the second through hole 311 and the solid part on the base 1. When the gas pressure inside the battery pack is high due to thermal runaway or other reasons, the gas passes through the first through hole 101 on the base 1 and applies a thrust toward the valve cover 2 to the solid part on the valve body 3. The valve body 3 moves away from the base 1 (i.e., closer to the valve cover 2), and the guide 312 moves away from the first recessed part until it contacts the limiting unit 210 on the valve cover 2. The limiting unit 210 restricts the guide 312 from disengaging from the explosion-proof valve, and at the same time, the corrugated surface of the limiting unit 210 provides a guide 312 with The guiding and limiting unit 210 and the guiding unit 110 are staggered, with the first recess and the second protrusion facing each other. Under the thrust of the gas inside the battery pack of the valve body 3, the guide member 312 moves towards the valve cover 2. Then, it slides along the corrugated surface of the limiting unit 210, passing sequentially through the second recess and the second protrusion. This gives the guide member 312 a tendency to move towards the first recess on the base 1. Combined with the thrust of the elastic member 4, the guide member 312 slides along the guiding channel to another first recess, thereby switching the valve body 3 to the conducting position and the explosion-proof valve to the open state. The gas inside the battery pack is discharged through the exhaust channel formed by the first through hole 101 and the second through hole 311, and then through the vent hole 201 on the valve cover 2. Here, "high position" refers to the position with a larger distance from the surface of the base 1, and "low position" refers to the position with a smaller distance from the surface of the base 1.

[0053] The explosion-proof valve of this embodiment uses a valve body 3 and a valve cover 2 on one side of the base 1, with an elastic member 4 abutting between the valve body 3 and the valve cover 2. The valve body 3 is pressed onto the base 1 by the thrust of the valve cover 2 and the elastic member 4. A corrugated guide unit 110 is provided on the base 1, with the guide unit 110 having an undulating shape and the first recess being lower than the first protrusion. When the explosion-proof valve is not open, the valve body 3 is stably in the closed position under the thrust of the elastic member 4. When the valve body 3 is subjected to a thrust from the base 1 toward the valve cover 2, the guide member 312 slides out from one of the first recesses, passes around the first protrusion, and then slides to another adjacent first recess under the guidance of the guide channel formed between the guide unit 110 and the limiting unit 210. This drives the valve body 3 to switch from the closed position to the open position, allowing the second through hole 311 to open. The first through hole 101 is connected to the battery pack, and the gas inside the battery pack is discharged to the outside of the battery pack through the first through hole 101, the second through hole 311 and the vent hole 201 on the valve cover 2, thereby depressurizing the battery pack. The switching process of the valve body 3 position is automatically realized by the guiding effect of the guide channel on the guide member 312, without manual intervention, and the degree of automation is high. After the valve body 3 switches to the connected position, under the thrust of the elastic member 4, the valve body 3 is always in the connected position. Therefore, without manual operation, the electrolyte and other foreign objects leaking from the battery cells can be quickly and effectively discharged through the explosion-proof valve, reducing potential risks and improving maintenance efficiency. The leakage hole and the explosion-proof valve are integrated into one unit, which can efficiently, quickly and reliably discharge the high-temperature and high-pressure gas and electrolyte leaking from the battery cells caused by thermal runaway, which is beneficial to improving the safety and maintainability of the battery pack.

[0054] It should be noted that conventional spring-loaded explosion-proof valves rely on a spring to push the valve cover out for venting. In actual use, foreign objects may obstruct the valve cover, preventing it from opening. However, in this embodiment, the valve cover 2 is fixedly connected to the base 1, and the valve cover 2 remains fixed relative to the base 1. The opening channel is inside the explosion-proof valve, which avoids the valve failing to open due to foreign objects, thus ensuring higher reliability. Furthermore, compared to traditional spring-loaded explosion-proof valves, this embodiment requires fewer components, is simpler to install, and saves costs.

[0055] Specifically, there are at least two first recesses and at least one guide portion, with one guide portion disposed between the two first recesses; when the guide 312 is located in one of the first recesses, the second through hole 311 corresponds to the solid portion on the base 1; when the guide 312 is located in another first recess adjacent to the first recess, the second through hole 311 communicates with the first through hole 101.

[0056] In one embodiment, the valve body 3 has a mounting groove 302 on the side facing the valve cover 2, and the elastic element 4 is installed in the mounting groove 302. The mounting groove 302 limits the elastic element 4, improves the stability of the elastic element 4, and ensures the smooth opening of the explosion-proof valve.

[0057] Preferably, the elastic element 4 is a spring, which has good elasticity, mature technology, and low cost.

[0058] Preferably, the guide unit 110 is integrally formed with the base 1, and the limiting unit 210 is integrally formed with the valve cover 2.

[0059] In one embodiment, the guide unit 110 includes an inclined first guide surface 111 and a first limiting surface 112, the inclination directions of the first guide surface 111 and the first limiting surface 112 are opposite, and the number of the first guide surface 111 and the first limiting surface 112 is at least two, and the first limiting surface 112 and the first guide surface 111 are connected alternately in sequence; the limiting unit 210 includes an inclined second guide surface 211 and a second limiting surface 212, the inclination directions of the second guide surface 211 and the second limiting surface 212 are opposite, and the number of the second guide surface 211 and the second limiting surface 212 is at least two, and the second limiting surface 212 and the second guide surface 211 are connected alternately in sequence. The tilt setting refers to the tilt relative to the plane of the base 1 surface; the first limiting surface 112 and the first guiding surface 111 of the guide unit 110 are alternately connected to form a corrugated shape, a first recess is formed at the corner of the corrugated shape near the base 1, and a first protrusion is formed at the corner of the corrugated shape away from the base 1; the second limiting surface 212 and the second guiding surface 211 of the limiting unit 210 are alternately connected to form a corrugated shape, a second recess is formed at the corner of the corrugated shape near the valve cover 2, and a second protrusion is formed at the corner of the corrugated shape away from the valve cover 2; the number of second guiding surfaces 211 is equal to the number of first guiding surfaces 111 and corresponds one-to-one, and the number of second limiting surfaces 212 is equal to the number of first limiting surfaces 112 and corresponds one-to-one. By setting the guide unit 110 to include at least two first guide surfaces 111 and at least two first limiting surfaces 112, the corrugated guide unit 110 has at least two first recesses and at least one first protrusion, which can satisfy the requirement that the guide member 312 can switch from one first recess to another first recess via the first protrusion, thereby realizing the valve body 3 switching from the closed position to the open position.

[0060] It should be noted that when there are two of each of the first guide surface 111 and the first limiting surface 112, the sequential alternation of the first limiting surface 112 and the first guide surface 111 refers to the sequential connection of the first limiting surface 112, the first guide surface 111, the first limiting surface 112, and the first guide surface 111, forming a "W" shape. The two corners at the bottom of the "W" shape are the first recessed portion, and the corner at the top of the "W" shape is the first protruding portion. When there are more than two of each of the first guide surface 111 and the first limiting surface 112, the sequential connection of the first limiting surface 112, the first guide surface 111, and the first limiting surface 112 is still formed by connecting the first limiting surface 112, the first limiting surface 111, and the first limiting surface 112 in sequence. The guide surfaces 111 are connected in an alternating manner to form multiple interconnected "V" shapes. The bottom tip of each "V" shape is the first recess, and the connection point between the open end of one "V" shape and another "V" shape forms the first protrusion. The guide unit 110 can have multiple first recesses and multiple first protrusions, thereby enabling the guide member 312 to switch sequentially on multiple first recesses. This facilitates the sequential switching of the valve body 3 between closed position, open position, closed position, open position, etc., allowing for multiple cycles of use of the explosion-proof valve with a high degree of automation. The arrangement of the second guide surface 211 and the second limiting surface 212 on the limiting unit 210 is similar to that of the guide unit 110, and will not be described again here.

[0061] In this embodiment, the length of the first guide surface 111 is greater than the length of the first limiting surface 112, and the length of the second guide surface 211 is greater than the length of the second limiting surface 212. The inclination direction of the second guide surface 211 is opposite to the inclination direction of the first guide surface 111. It should be noted that the inclination direction refers to the direction of inclination relative to the plane on which the surface of the base 1 is located; the length of the guide surface refers to the extension distance of the guide surface along the direction from the protrusion to the recess; the length of the limiting surface refers to the extension distance of the limiting surface along the direction from the recess to the protrusion. Here, the guide surface refers to the first guide surface or the second guide surface, and the limiting surface refers to the first limiting surface or the second limiting surface.

[0062] Further integration Figure 4As shown, since the length of the first guide surface 111 is greater than the length of the first limiting surface 112, and the length of the second guide surface 211 is greater than the length of the second limiting surface 212, the tilt angle of the first limiting surface 112 is greater than the tilt angle of the first guide surface 111, and the tilt angle of the second limiting surface 212 is greater than the tilt angle of the second guide surface 211. The projection of the second guide surface 211 on the guide unit 110 covers the most convex point of a set of first protrusions and the most concave point of the first recess, and the projection of the first guide surface 111 on the limiting unit 210 covers the most convex point of a set of second protrusions and the most concave point of the second recess. When the valve body 3 is pushed away from the base 1 by the gas inside the battery pack, the guide member 312 moves from the first recess towards the valve cover 2 until it contacts the second guide surface 211. Then it slides along the second guide surface 211, causing the valve body 3 to rotate along its axis. At the same time, the valve body 3 continues to move towards the valve cover 2 until the guide member 312 moves to the deepest point of the second recess. Under the action of motion inertia and the pushing force of the elastic member 4, the guide member 312 bypasses the second recess and moves along the second limiting surface 212, causing the valve body 3 to rotate along its axis and move towards the base 1 along the axis. After the guide member 312 slides out of the second limiting surface 212, it falls into the range of the first guide surface 111 and contacts the first guide surface 111. The guide member 312 slides along the first guide surface 111, causing the valve body 3 to rotate along its axis and move towards the base 1 along the axis until the guide member 312 slides to the lowest point of the first recess. By setting the inclination direction of the first guide surface 111 to be opposite to that of the first limiting surface 112, and the inclination direction of the second guide surface 211 to be opposite to that of the second limiting surface 212, the first limiting surface 112 and the second guide surface 211 are inclined in the same direction, and the second limiting surface 212 and the first guide surface 111 are inclined in the same direction. This ensures that the component movement of the guide member 312 along the plane parallel to the surface of the base 1 always has a tendency to rotate in the same direction, so as to ensure the switching of the valve body 3's working position, which is conducive to ensuring the smooth opening of the explosion-proof valve and improving the safety of the battery pack.

[0063] Furthermore, by setting the length of the first guide surface 111 to be greater than the length of the first limiting surface 112, the tilt angle of the first limiting surface 112 is greater than the tilt angle of the first guide surface 111. The first guide surface 111 with a smaller tilt angle can provide a certain buffering effect for the guide member 312, improving the stability of the guide member 312 when it reaches the first recess. At the same time, the first limiting surface 112 with a larger tilt angle can block the guide member 312 that slides down from the first guide surface 111, so that the guide member 312 stays in the first recess, ensuring that the working position of the valve body 3 is in a stable state after one switch, and preventing the guide member 312 from sliding further to the next first recess, thus causing the valve body 3 to switch its working position twice in a row.

[0064] Specifically, the guide unit 110 rotates counterclockwise, and the limiting unit 210 rotates clockwise.

[0065] It is understood that, as an alternative implementation, the length of the first guide surface 111 and the length of the first limiting surface 112 can also be equal. In this case, the deepest point of the first recess is directly opposite the most convex point of the second protrusion, and the most convex point of the first protrusion is directly opposite the deepest point of the second recess. The guide unit 110 and the limiting unit 210 have the same shape. The guide channel formed between the guide unit 110 and the limiting unit 210 has the same corrugated shape as the guide unit 110, which allows the guide member 312 to pass through and can also achieve the guiding function.

[0066] In one embodiment, the surface contours of both the guide unit 110 and the limiting unit 210 are smoothly transitioning curves, and the guide member 312 is cylindrical, with the axis of the cylinder perpendicular to the axis of the valve body 3. By setting the surface contours of both the guide unit 110 and the limiting unit 210 to be smoothly transitioning curves, i.e., the surfaces of the recessed and protruding parts are curved, and the guide member 312 is cylindrical with its circumferential surface in contact with the surfaces of the guide unit 110 and / or the limiting unit 210, the guide member 312 can move smoothly along the cylinder, improving the smoothness and stability of the movement process, thereby ensuring that the valve body 3 can smoothly switch between the closed position and the open position.

[0067] In other embodiments, the surface contours of the guide unit 110 and the limiting unit 210 may not be smooth transitions, but rather be polygonal, which can also achieve the guiding effect on the guide member 312.

[0068] In one embodiment, the projection of the guide unit 110 onto the base 1 is annular; the base 1 has a first mounting hole 102 located at the center of the annulus formed by the guide unit 110; the valve body 3 includes a main body portion 310 and a mounting portion 320 fixedly connected, the cross-sectional area of ​​the main body portion 310 is larger than the cross-sectional area of ​​the mounting portion 320, the mounting portion 320 is slidably inserted into the first mounting hole 102, the main body portion 310 is located within the annular area enclosed by the base 1, a second through hole 311 is formed on the main body portion 310, and a guide member 312 protrudes from the outer peripheral surface of the main body portion 310. Here, the cross-sectional area refers to the cross-sectional area on a plane perpendicular to the axis of the valve body 3; the first mounting hole 102 is a circular hole; the projection of the guide unit 110 onto the base 1 is annular; the mounting portion 320 is cylindrical, and the main body portion 310 is cylindrical; the guide member 312 protruding from the outer peripheral surface of the main body portion 310 overlaps the surface of the guide unit 110 on the side away from the base 1.

[0069] By opening a first mounting hole 102 at the center of the guide unit 110 on the base 1, the mounting part 320 of the valve body 3 is movably inserted into the first mounting hole 102. The valve body 3 can then move relative to the base 1 along the axis of the first mounting hole 102, and the first mounting hole 102 radially limits the mounting part 320. The valve body 3 is always located within the annular area enclosed by the guide unit 110. During the movement of the guide member 312 along the guide unit 110, the valve body 3 rotates around the axis of the first mounting hole 102. Multiple first mounting holes 102 on the guide unit 110... A recessed portion is arranged circumferentially around the first mounting hole 102. The guide member 312 can rotate with the valve body 3 around the axis of the first mounting hole 102 and switch between multiple first recessed portions in sequence, repeating cyclically. This enables the explosion-proof valve to be repeatedly opened and closed. The valve body 3 has good stability and accuracy during movement, which helps to ensure smooth communication between the second through hole 311 and the first through hole 101 when the valve body 3 is in the open position, ensuring the exhaust effect of the explosion-proof valve. It also ensures that the second through hole 311 is blocked when the valve body 3 is in the closed position, ensuring the airtightness of the explosion-proof valve.

[0070] Specifically, the guide unit 110 has multiple first guide surfaces 111, and the number of first limiting surfaces 111 is equal to the number of first guide surfaces 111. The first limiting surfaces 112 and the first guide surfaces 111 alternate in sequence and are connected end to end to form a ring-shaped guide unit. Correspondingly, the limiting unit 210 is also ring-shaped and is set in a similar manner to the guide unit 110, which will not be described in detail here.

[0071] In other embodiments, the projection of the guide unit 110 on the base 1 can also be an unclosed ring. As long as the guide unit 110 has at least two first recesses and a first protrusion located between the two first recesses, the valve body 3 can be switched from the closed position to the open position, thereby opening the explosion-proof valve and fulfilling the functions of venting and discharging leaked electrolyte and other foreign matter from the explosion-proof valve.

[0072] In one embodiment, there are four first guide surfaces 111 and four first limiting surfaces 112. Correspondingly, there are four second guide surfaces 211 and four second limiting surfaces 212. There are two first through holes 101, which are symmetrically arranged on both sides of the first mounting hole 102. There are also two second through holes 311, which are symmetrically arranged on both sides of the first mounting hole 102. It should be noted that the two first through holes 101 are symmetrically arranged on both sides of the first mounting hole 102, meaning that the two first through holes 101 are symmetrical about the radial direction of the first mounting hole 102. The two second through holes 311 correspond one-to-one with the two first through holes 101. When the valve body 3 is in the open position, each second through hole 311 corresponds to one first through hole 101, and the second through hole 311 and the first through hole 101 are connected. However, when the valve body 3 is in the closed position, the second through holes 311 and the first through holes 101 are misaligned, and they are not connected. By setting four first guide surfaces 111 and four first limiting surfaces 112, four recesses are formed on the guide unit 110. The central angle between the line connecting two adjacent recesses is 90°. That is, the valve body 3 can switch positions by rotating 90° around the axis of the valve body 3 under the drive of the guide member 312. At the same time, by setting two first through holes 101 on the base 1, the central angle between the two symmetrically arranged first through holes 101 is 180°. Correspondingly, the central angle between the two second through holes 311 is also 180°. After the valve body 3 rotates 180° around the axis, the second through holes 311 coincide with the one when it is not rotated. Therefore, the guide member 312 switches sequentially on the four recesses, which can realize the continuous switching of the valve body 3 between the closed position, the open position, the closed position, and the open position, realizing the multiple cycles of the explosion-proof valve and achieving a high degree of automation.

[0073] Further integration Figure 4 As shown, under normal battery pack conditions, the elastic element 4 is slightly compressed, and the valve body 3 is in a closed position. The elastic element 4 acts to press the valve body 3, ensuring that the explosion-proof valve is in a closed state. When the battery experiences thermal runaway, the high-pressure gas inside the battery pack pushes the valve body 3 away from the base 1. At this time, the elastic element 4 is further compressed, and the guide element 312 on the valve body 3 moves along the shape trajectory of the limiting unit 210 on the valve cover 2 (the direction of movement of the guide element 312 is as follows). Figure 4As indicated by the middle arrow, the valve body 3 rotates counterclockwise around its axis. After the valve body 3 rotates 90°, the second through hole 311 on the valve body 3 coincides with the first through hole 101 on the base 1. The high-pressure gas in the battery pack is discharged through the channel formed by the connection between the first through hole 101 and the second through hole 311, and then discharged through the vent hole 201 on the valve cover 2. After the high-pressure gas is discharged, the elastic element 4 rebounds. At this time, the valve body 3 and the base 1 are pressed together, but the first through hole 101 and the second through hole 311 are still in a conductive state, that is, the explosion-proof valve is still in the open state. At this time, if there is electrolyte, foreign matter or other liquid in the battery pack, it can be discharged from the explosion-proof valve, further improving the safety of the battery and facilitating the subsequent disassembly and inspection process.

[0074] It should be noted that conventional pin-type explosion-proof valves are disposable products and must be scrapped after use or accidental opening. However, the explosion-proof valve in this embodiment can still be used after opening. While conventional spring-loaded explosion-proof valves are reusable, after thermal runaway, due to the lack of high-pressure gas within the battery pack, the spring-loaded valve returns to the closed state. At this point, foreign objects and electrolyte within the battery pack cannot be discharged, making subsequent disassembly and troubleshooting difficult. The explosion-proof valve in this embodiment can remain open after thermal runaway, facilitating the discharge of foreign objects. Furthermore, during troubleshooting, the valve can be returned to the closed state by inflating. Therefore, the explosion-proof valve in this embodiment combines the advantages of both pin-type and spring-loaded explosion-proof valves.

[0075] In one embodiment, the second through hole 311 is an oblong hole, and the first through hole 101 has the same shape and size as the second through hole 311. The main body 310 of the valve body 3 is cylindrical. By setting the second through hole 311 to be an oblong hole, the space on the main body 310 can be better utilized, ensuring sufficient exhaust passage to the maximum extent. At the same time, space can be reserved for the elastic element 4 and the first sealing ring 6. The layout is compact, which helps to reduce the overall volume of the valve body 3, thereby reducing the weight.

[0076] In one embodiment, the oblong hole is part of a ring concentrically arranged with the main body 310, the radius of the outer circle corresponding to the ring is r1, the radius of the inner circle corresponding to the ring is r2, and the central angle corresponding to the oblong hole is α, satisfying: Where α≤60°, and Q is the gas generation rate of the battery pack. By defining the relationship between the parameters of the oblong orifice and the gas generation rate of the battery pack through the calculation formula, the size parameters of the first and second through holes can be obtained based on the gas generation of the battery pack. This allows for the selection of the appropriate explosion-proof valve specifications for the actual project. The obtained size parameters are highly reliable, ensuring that when the first through hole 101 and the second through hole 311 are connected, a channel of sufficient size can be formed to discharge the gas trapped in the battery pack, thereby improving the safety of the battery pack.

[0077] It should be noted that the phenomenon of thermal runaway in lithium batteries is complex and variable. The selection of explosion-proof valves also needs to take into account the material of the enclosure itself, the operating conditions of the battery pack, etc., and should be combined with simulation analysis and test data.

[0078] Lithium-ion battery thermal runaway and thermal propagation is a complex failure phenomenon caused by multiple factors. In-depth research into the mechanism of thermal runaway and the phenomenon of cell explosion is a very tedious engineering task. This embodiment, for the convenience of quantitative calculation, is based on the following assumptions:

[0079] 1) A battery pack contains several cells. The gas production rate of a single cell is defined as q, with the unit being (L / s). The value of q is generally determined through cell testing.

[0080] 2) The number of cells that fail to control is defined as n, in units of (cells). The value of n is generally determined based on the thermal runaway requirements during the project design phase.

[0081] 3) The total gas production rate of the entire battery pack is defined as Q, then Q = nq, unit (L / s);

[0082] 4) A circular through-hole with a diameter of 10mm (area 78.5mm²) 2 The exhaust rate is 6 L / s (at a pressure of 24 kPa);

[0083] Therefore, the required through-hole area for thermal runaway can be calculated as: S0 = Q ÷ 6 × 78.5 = 13.1Q (mm²) 2 ).

[0084] In this embodiment, the valve body 3 has two second through holes 311, and the base 1 has two first through holes 101. Both the first through holes 101 and the second through holes 311 are oblong holes. After the exhaust channel of the explosion-proof valve is opened, the cross-sectional area of ​​the exhaust channel is the total area of ​​the two oblong holes.

[0085]

[0086] To ensure that the two second through holes 311 can meet the venting requirements, S1 > S0 must be satisfied. That is, the relationship between the size parameters of the oblong hole and the total gas production rate of the battery pack must satisfy:

[0087]

[0088] Right now:

[0089]

[0090] At the same time, the following conditions must be met: r1>r2 and α≤60°. If there is no solution, the number of explosion-proof valves can be increased.

[0091] The waist-shaped hole is part of a ring concentrically arranged with the main body 310. The outline of the waist-shaped hole includes an inner arc, an outer arc, and two semicircles connecting the ends of the inner and outer arcs. The radius of the circle corresponding to the inner arc is r2, the radius of the circle corresponding to the outer arc is r1, and the radius of the semicircle is r3 = (r1-r2) / 2. The angle between the center of the two semicircles and the line connecting the circles corresponding to the inner and outer arcs is the central angle α corresponding to the waist-shaped hole. If α > 60°, the circumferential dimension of the waist-shaped hole is too large. When the valve body 3 switches to the closed position, the second through hole 311 may partially communicate with the first through hole 101. The second through hole 311 cannot be completely closed, the explosion-proof valve cannot be sealed, and the explosion-proof valve is unqualified.

[0092] The calculation formulas relating various parameters of the oblong orifice to the gas generation rate of the battery pack were experimentally verified.

[0093] The implementation plan selects a certain specification of blade battery cell. Based on the test results of this specification, the gas production rate q of a single battery cell is 16.25 L / s. According to the customer requirement that the number of thermal runaway cells should not exceed one, the total gas production rate Q of the entire package is 16.25 L / s. The parameters of the oblong orifice are: α = 60°, r1 = 18 mm, r2 = 12 mm. Substituting the above parameters of the oblong orifice into the formula... The calculated value is 18.71 L / s, which is greater than 16.25 L / s, meaning it is greater than Q, thus satisfying the formula. The explosion-proof valve, manufactured using these parameters, was installed on a battery pack containing blade cells of the aforementioned specifications for thermal runaway testing. When thermal runaway occurred within the battery pack's cells, the explosion-proof valve was able to promptly release the high-pressure gas from the battery pack. The test passed, indicating that when the parameters of the oblong orifice satisfy the formula... At the same time, the explosion-proof valve has a channel of sufficient size to discharge the gas trapped in the battery pack, ensuring the safety of the battery pack.

[0094] In one embodiment, the explosion-proof valve further includes a vent 301, which penetrates the main body 310 and the mounting portion 320. A breathable membrane 5 corresponding to the vent 301 is attached to the side of the valve body 3 facing the valve cover 2. The breathable membrane 5 is a one-way membrane, suitable for guiding gas from the side of the vent 301 away from the valve cover 2 to the side of the vent 301 close to the valve cover 2. The breathable membrane 5 is a one-way membrane used to seal the vent 301. When the internal pressure of the battery pack is slightly high, it allows gas inside the battery pack to flow out through the breathable membrane 5 to the outside of the battery pack. The breathable membrane 5 can prevent external gas from entering the battery pack, preventing damage to the battery pack's interior from external gas. Under normal operating conditions, the battery cells will heat up during use, or factors such as entering high-altitude areas or changes in external temperature will cause slight fluctuations in the internal pressure of the battery pack. At this time, the battery pack can exchange air with the external environment through the breathable membrane 5 of the explosion-proof valve, thereby ensuring the balance of internal and external pressure of the battery pack.

[0095] In one embodiment, the explosion-proof valve further includes a first sealing ring 6 and a second sealing ring 7. The first sealing ring 6 is disposed between the valve body 3 and the base 1, and the second sealing ring 7 is adapted to be disposed on the side of the explosion-proof valve facing the battery pack housing. The first sealing ring 6 ensures the sealing between the valve body 3 and the base 1 when they abut against each other, and the second sealing ring 7 ensures the sealing between the explosion-proof valve and the battery pack housing, thereby improving the sealing performance of the explosion-proof valve.

[0096] Specifically, a first groove 103 is formed on the side of the base 1 facing the main body portion 310 of the valve body 3. The first groove 103 is adapted to fit the first sealing ring 6 to install the first sealing ring 6. The elastic member 4 applies a pushing force toward the base 1 to the main body portion 310 to press the first sealing ring 6. Preferably, the first groove 103 is located between the first through hole 101 and the first mounting hole 102.

[0097] In one embodiment, the explosion-proof valve further includes a mounting surface 104, which extends outward from at least a portion of the circumferential surface of the base 1, and is adapted to connect with the battery pack housing. By providing the mounting surface 104, it is easier to install the explosion-proof valve onto the battery pack housing, improving the sealing between the explosion-proof valve and the housing. By placing the mounting surface 104 on the base 1, it facilitates communication between the first through hole 101 on the base 1 and the vent hole on the housing, further improving the sealing between the base 1 and the housing.

[0098] Specifically, the explosion-proof valve is installed on the outside of the battery pack housing, and a second mounting hole 105 is constructed on the mounting surface 104 for bolts to be inserted for fixing; a third groove (not shown in the figure) adapted to the second sealing ring 7 is constructed on the side of the base 1 away from the valve cover 2 for installing the second sealing ring 7.

[0099] In other embodiments, the mounting surface 104 extends outward from at least a portion of the circumferential surface of the valve cover 2. Correspondingly, a second groove 202 is formed on the surface of the valve cover 2 away from the base 1 to install the second sealing ring 7. By providing the mounting surface 104 on the valve cover 2, the explosion-proof valve can be installed inside the battery pack housing via the mounting surface 104, thereby reducing the space occupied by the external environment of the battery pack and preventing damage to the explosion-proof valve from the external environment, thus improving the safety of the battery pack.

[0100] In one embodiment, the base 1 and valve cover 2 are both made of plastic, and the valve body 3 is made of aluminum.

[0101] In this embodiment, the explosion-proof valve has a simple structure, requires no manual operation during opening, has a high degree of automation, is easy to maintain, and has a low cost. The explosion-proof valve also functions as a leakage hole, allowing it to remain open after high-pressure gas is discharged, facilitating the removal of foreign objects from the battery pack. Refilling the battery pack with gas then helps it return to a closed state. The explosion-proof valve is reusable, combining the advantages of both pin-type and spring-loaded explosion-proof valves. The valve opening and closing process does not require moving the valve cover 2; it is achieved solely through the relative movement of the valve body 3 and the base 1, avoiding the problem of the valve failing to open properly under special circumstances. The dimensions of the first through-hole 101 and the second through-hole 311 of the explosion-proof valve are determined based on the gas production of the battery cell. Parametric design allows for the selection of the appropriate explosion-proof valve specifications for the actual project, promoting product standardization and platform design, and improving production efficiency and product quality. The explosion-proof valve can be placed either outside or inside the battery pack housing, making the battery pack design more compact and reducing the space occupied on the external parts of the battery pack.

[0102] According to an embodiment of the present invention, another aspect provides a battery pack, comprising: a housing, a plurality of battery cells, and the aforementioned explosion-proof valve. The housing is provided with a vent; the plurality of battery cells are disposed inside the housing; the explosion-proof valve corresponds to the vent and is connected to the outside or inside of the housing.

[0103] Preferably, the explosion-proof valve is located on the battery pack housing near the bottom, which not only ensures the venting effect but also helps to improve the discharge of electrolyte.

[0104] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. An explosion-proof valve, characterized in that, include: The base has a first through hole, and a guide unit is provided on one side of the base. The guide unit is corrugated and has at least two first recesses. A valve cover is provided on the base and located outside the guide unit. The valve cover has a vent hole. The inner side of the valve cover has a limiting unit that is opposite to the guide unit. The limiting unit is corrugated and offset from the guide unit. A guide channel is formed between the limiting unit and the guide unit. A valve body is disposed between the base and the valve cover. The valve body has a second through hole and a through position where the second through hole communicates with the first through hole, and a closed position where the second through hole corresponds to a solid part on the base. A guide member is provided on the valve body and is located in the guide channel. When the valve body is subjected to a thrust from the base toward the valve cover, the guide member is adapted to move from one of the first recesses to another under the guidance of the guide channel, so as to drive the valve body to switch between the closed position and the through position. An elastic element abuts between the valve body and the valve cover to provide a thrust toward the base to the valve body.

2. The explosion-proof valve according to claim 1, characterized in that, The guiding unit includes an inclined first guiding surface and a first limiting surface, the first guiding surface and the first limiting surface having opposite inclination directions, and there are at least two of each of the first guiding surface and the first limiting surface, which are alternately connected in sequence; the limiting unit includes an inclined second guiding surface and a second limiting surface, the second guiding surface and the second limiting surface having opposite inclination directions, and there are at least two of each of the second guiding surface and the second limiting surface, which are alternately connected in sequence; The length of the first guide surface is greater than the length of the first limiting surface, the length of the second guide surface is greater than the length of the second limiting surface, and the tilt direction of the second guide surface is opposite to the tilt direction of the first guide surface.

3. The explosion-proof valve according to claim 2, characterized in that, The surface contours of both the guide unit and the limiting unit are smoothly transitioned curves, and the guide member is cylindrical with its axis perpendicular to the axis of the valve body.

4. The explosion-proof valve according to claim 2, characterized in that, The projection of the guide unit on the base is annular; the base is provided with a first mounting hole, which is located at the center of the annulus formed by the guide unit. The valve body includes a main body and a mounting part that are fixedly connected. The cross-sectional area of ​​the main body is larger than that of the mounting part. The mounting part is slidably inserted in the first mounting hole. The main body is located in the annular area enclosed by the base. The second through hole is opened on the main body. The guide protrudes from the outer peripheral surface of the main body.

5. The explosion-proof valve according to claim 4, characterized in that, The number of the first guide surface and the first limiting surface are both four, the number of the first through holes is two, the two first through holes are symmetrically arranged on both sides of the first mounting hole, and the number of the second through holes is two, which are also symmetrically arranged on both sides of the first mounting hole.

6. The explosion-proof valve according to claim 5, characterized in that, The second through hole is a waist-shaped hole, and the first through hole and the second through hole have the same shape and the same size.

7. The explosion-proof valve according to claim 6, characterized in that, The waist-shaped hole is part of a ring concentrically arranged with the main body. The radius of the outer circle corresponding to the ring is r1, the radius of the inner circle corresponding to the ring is r2, and the central angle corresponding to the waist-shaped hole is α, satisfying: Where α≤60°, and Q is the gas generation rate of the battery pack.

8. The explosion-proof valve according to claim 4, characterized in that, The explosion-proof valve further includes a vent hole that penetrates the main body and the mounting part. A breathable membrane corresponding to the vent hole is attached to the side of the valve body facing the valve cover. The breathable membrane is a one-way membrane, which is suitable for discharging gas from the side of the vent hole away from the valve cover to the side of the vent hole close to the valve cover.

9. The explosion-proof valve according to any one of claims 1 to 8, characterized in that, The explosion-proof valve further includes: a first sealing ring and a second sealing ring, wherein the first sealing ring is disposed between the valve body and the base, and the second sealing ring is adapted to be disposed on the side of the explosion-proof valve facing the battery pack housing; And / or, the explosion-proof valve further includes: a mounting surface extending outward from at least a portion of the circumferential surface of the base, or the mounting surface extending outward from at least a portion of the circumferential surface of the valve cover, the mounting surface being adapted to connect with the housing of the battery pack.

10. A battery pack, characterized in that, include: A housing, wherein an exhaust port is provided on the housing; Several battery cells are disposed inside the housing; The explosion-proof valve according to any one of claims 1 to 9 corresponds to the vent hole and is connected to the outside or inside of the housing.

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