Pressure relief valve and pressure relief method for fire prevention and control of lithium battery boxes

Abstract

The present invention discloses a pressure relief valve and a pressure relief method for fire prevention and control of a lithium battery box, and relates to the technical field of battery box accessories, including a shell, the shell having an exhaust channel, one end of the exhaust channel is connected to the lithium battery box; a valve core, the valve core includes a rotating shaft rotatably mounted on the shell and a plurality of sealing plates annularly distributed on the outside of the rotating shaft, and when the corresponding sealing plate is flipped and perpendicular to the exhaust channel, the exhaust channel is sealed; a limiting mechanism, the limiting mechanism is arranged on one side of the shell, and is used to limit the circumferential freedom of the valve core; a trigger mechanism, the trigger mechanism is used to release the circumferential limitation of the valve core by the limiting mechanism when the temperature in the lithium battery box reaches an upper limit pre-threshold. While discharging the high-temperature and high-pressure gas in the lithium battery box, the present invention can also emit a warning sound through the warning mechanism to remind surrounding staff to eliminate hidden dangers or let other personnel evacuate, thereby improving safety performance.

Description

Technical Field

[0001] The present invention relates to the technical field of battery box accessories, and in particular to a pressure relief valve and a pressure relief method thereof for fire prevention and control of a lithium battery box. Background Art

[0002] Lithium battery boxes are special containers for storing and transporting lithium batteries. They usually have certain safety features, such as fire prevention, explosion prevention, temperature control, etc., to ensure the safe use and storage of lithium batteries. In the manufacturing process of lithium-ion batteries, the installation of a pressure relief valve is essential. When a battery is short-circuited or overcharged during use, a large amount of heat may be generated inside the battery, causing the internal pressure to rise, forming high-temperature and high-pressure gas, which may cause spontaneous combustion (during thermal runaway, the internal temperature of the battery can reach 1000°C or higher, and in some cases, the flame temperature during thermal runaway can reach 1500°C). The design of the pressure relief valve needs to ensure that it can respond quickly when the pressure reaches a certain threshold, discharge the high-temperature and high-pressure gas, and release the pressure to protect the safety of the battery and the user.

[0003] The existing pressure relief valve of the lithium battery box does not have the function of alerting the surrounding staff when releasing pressure, and cannot enable the surrounding staff to react immediately or stay away from the lithium battery box, which poses certain safety hazards. In addition, the pressure relief valve of the lithium battery box is generally invalid or cannot be reset by itself after the pressure is released, and needs to be installed again or reset manually, which is more cumbersome. Summary of the invention

[0004] The purpose of the present invention is to provide a pressure relief valve and a pressure relief method for fire prevention and control of a lithium battery box, which solves the problem that the pressure relief valve of the lithium battery box does not have the function of alerting surrounding staff when releasing pressure, and cannot enable surrounding staff to react in the first time or stay away from the lithium battery box, which poses certain safety hazards.

[0005] The present invention solves the above technical problems through the following technical solutions, which include:

[0006] A housing, wherein the housing has an exhaust passage, one end of which is connected to the lithium battery box;

[0007] The valve core includes a rotating shaft rotatably mounted on the housing and a plurality of sealing plates annularly distributed on the outer side of the rotating shaft, and when the corresponding sealing plates are turned over and perpendicular to the exhaust channel, the exhaust channel is sealed;

[0008] A limiting mechanism, which is arranged on one side of the housing and is used to limit the circumferential freedom of the valve core;

[0009] A trigger mechanism, which is used to release the circumferential limitation of the valve core by the limiting mechanism when the temperature in the lithium battery box reaches an upper limit pre-threshold value, so that the high-temperature and high-pressure gas in the lithium battery box is ejected through the exhaust channel and drives the valve core to rotate;

[0010] The warning mechanism is arranged on the other side of the shell and is used to issue a warning sound when the valve core rotates.

[0011] Preferably, the limiting mechanism comprises a first round block fixed to the end of the rotating shaft and a limiting member fixed to the outside of the shell, the outer surface of the first round block is provided with a guide groove group, and the limiting member is used to limit the circumferential angle of the first round block;

[0012] The guide groove group includes an annular groove, and the lower side of the annular groove is connected to a plurality of annularly distributed vertical grooves, and the plurality of vertical grooves correspond one to one with a plurality of sealing plates. The connection between the vertical groove and the annular groove is open to form a tapered portion between two adjacent vertical grooves.

[0013] Preferably, the limiting member comprises a bracket fixed to the outer side of the housing, a moving block is vertically slidably arranged on one side of the bracket through a slide rail and slider structure, a first spring is installed between the bracket and the moving block, the first spring applies a force to the moving block to move toward one side of the vertical groove, a roller is rotatably installed on the side of the moving block, and the roller is located in the guide groove group;

[0014] The force of the first spring drives the roller to move toward one side of the vertical groove, and the roller squeezes the first round block to rotate it until the roller moves into the corresponding vertical groove, thereby limiting the circumferential rotation of the valve core and sealing the exhaust channel through the corresponding sealing plate.

[0015] Preferably, the trigger mechanism includes a mounting piece fixed to the inner wall of the lithium battery box, a liquid crystal elastic pull rope is fixed on the mounting piece, a steel wire rope is fixed to one end of the liquid crystal elastic pull rope away from the mounting piece through a connecting piece, the end of the steel wire rope away from the liquid crystal elastic pull rope extends to connect with the upper end of the moving block, and the turning point of the steel wire rope during its passage is transitioned through a guide wheel. When the temperature in the lithium battery box reaches the upper limit pre-threshold value, the force generated by the contraction and deformation of the liquid crystal elastic pull rope causes the roller to move to the annular groove, thereby releasing the circumferential restriction of the valve core;

[0016] The mounting member comprises a fixing cylinder fixed to the inner wall of the lithium battery box, the end of the liquid crystal elastic pull rope passes through the inner hole of the fixing cylinder, and the outer side of the fixing cylinder is threadedly connected with a first bolt for tightening the liquid crystal elastic pull rope;

[0017] The connecting piece includes a fixing sleeve, the ends of the liquid crystal elastic pull rope and the steel wire rope are respectively inserted into two inner holes of the fixing sleeve, and the outer side of the fixing sleeve is threadedly connected with a second bolt and a third bolt which respectively tighten the liquid crystal elastic pull rope and the steel wire rope.

[0018] Preferably, there are multiple trigger mechanisms, and the multiple trigger mechanisms are located at multiple positions on the inner wall of the lithium battery box.

[0019] Preferably, the warning mechanism includes a second round block fixed to the end of the rotating shaft and a mounting bracket fixed to the outside of the shell, a plurality of top grooves are opened at the end of the second round block, the bottom of the top groove has a pit portion and an inclined portion, and the inclined portion is located on one side of the pit portion; a knocking piece and a bell are installed on the mounting bracket, one end of the knocking piece extends into the top groove, and when the second round block rotates with the valve core, the knocking piece will be pushed back and forth to knock the bell, and the vibration of the bell will produce a sound wave warning.

[0020] Preferably, the knocking member includes a sliding rod slidably mounted on a mounting frame, a retaining ring is fixed on the sliding rod, a second spring sleeved on the sliding rod is arranged between the retaining ring and the mounting frame, the second spring applies a force to the sliding rod to displace toward the second round block, a ball bearing is embedded in the side of the sliding rod close to the second round block, a knocking head is axially slidably mounted on the other end of the sliding rod, and a third spring is installed between the knocking head and the sliding rod.

[0021] Preferably, a sealing member is provided at the outer edge of the sealing plate, and the sealing member comprises a liquid crystal elastic strip wrapped around the outer edge of the sealing plate, and the outer side of the liquid crystal elastic strip is wrapped with a soft strip.

[0022] Preferably, the shell includes an arc-shaped portion and a straight pipe portion tangentially connected to the arc-shaped portion, an exhaust channel is formed in the straight pipe portion, and a mounting portion is fixed to an air inlet end of the exhaust channel.

[0023] The present invention also proposes a pressure relief method of a pressure relief valve for fire prevention and control of a lithium battery box as described above, comprising the following steps:

[0024] Step 1: Release the circumferential restriction of the valve core: When the temperature in the lithium battery box rises to the upper limit pre-threshold value, the force generated by the contraction of the length of the liquid crystal elastic pull rope will pull the roller into the annular groove, so that the shaft can rotate freely and compress the first spring;

[0025] Step 2: Gas discharge: The gas in the lithium battery box is ejected through the exhaust channel, and drives the valve core to rotate;

[0026] Step 3: Issue a warning: The second round block rotates synchronously with the valve core, and the second round block pushes the reciprocating striking piece to strike the bell, and the bell issues a warning sound;

[0027] Step 4: Seal the exhaust channel: When the temperature in the lithium battery box drops to the lower pre-threshold value, the liquid crystal elastic rope returns to its original length, and the roller slides into the vertical groove due to the force of the first spring to prevent the valve core from rotating, so that the corresponding sealing plate seals the exhaust channel.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] 1. While discharging the high-temperature and high-pressure gas in the lithium battery box, the present invention can also emit a warning sound through the warning mechanism to remind surrounding staff to eliminate hidden dangers or let other personnel evacuate, thereby improving safety performance;

[0030] 2. In the present invention, through the cooperation between the limiting mechanism and the valve core, when the temperature in the lithium battery box returns to normal, the valve core can be reset automatically without manual reset by personnel, and the exhaust channel can be sealed automatically, and the rotation of the valve core can also be limited;

[0031] 3. In the present invention, a sealing member is arranged at the outer edge of the sealing plate. When the temperature in the lithium battery box of the sealing member increases, the liquid crystal elastic strip of the sealing member will shrink when subjected to high temperature, and will drive the soft strip to shrink toward one side of the sealing plate, thereby avoiding the contact between the soft strip and the inner wall of the shell, so that the sealing plate can rotate smoothly. When the temperature in the lithium battery box drops to normal temperature, the liquid crystal elastic strip will expand, driving the soft strip to expand outward, so that the soft strip is in close contact with the inner wall of the shell, thereby ensuring the sealing performance;

[0032] 4. The present invention does not require the use of electrical components, which can avoid the risk of electrical component failure and improve the stability of the equipment;

[0033] 5. The present invention changes the structure of the traditional pressure relief valve. Compared with the traditional pressure relief valve, the exhaust passage is wider, the exhaust is faster, and the safety hazard is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0035] Figure 2 for Figure 1 A schematic diagram of the three-dimensional structure of the middle shell;

[0036] Figure 3 It is a schematic diagram of the structure of the sealing plate inside the shell;

[0037] Figure 4 for Figure 2 Schematic diagram of the three-dimensional structure of the limiting mechanism;

[0038] Figure 5 for Figure 2 Schematic diagram of the three-dimensional structure of the warning mechanism;

[0039] Figure 6 for Figure 5 A schematic diagram of the structure of the middle striking member;

[0040] Figure 7 is a schematic diagram of a top-view cross-sectional structure of a shell;

[0041] Figure 8 for Figure 1 Schematic diagram of the structure of the trigger mechanism.

[0042] The numbers in the figure represent:

[0043] 11-arc-shaped portion; 12-straight tube portion; 13-mounting portion; 2-limiting mechanism; 21-first round block; 211-vertical groove; 212-conical portion; 213-annular groove; 22-bracket; 23-moving block; 24-roller; 25-slide rail slider structure; 26-first spring; 3-warning mechanism; 31-second round block; 311-inclined portion; 312-pit portion; 32-mounting frame; 33-bell; 3 4- striking piece; 341- sliding rod; 342- striking head; 343- third spring; 344- retaining ring; 345- second spring; 346- ball bearing; 41- rotating shaft; 42- sealing plate; 43- sealing piece; 5- trigger mechanism; 51- fixing cylinder; 52- first bolt; 53- liquid crystal elastic pull rope; 54- fixing sleeve; 55- second bolt; 56- third bolt; 57- steel wire rope; 58- guide wheel. DETAILED DESCRIPTION

[0044] The above and other technical features and advantages of the present invention are described in more detail below in conjunction with the accompanying drawings.

[0045] This embodiment provides a technical solution: a pressure relief valve for fire prevention and control of a lithium battery box, such as Figure 1 and Figure 2 As shown, it includes a housing, a valve core, a limiting mechanism 2, a triggering mechanism 5 and a warning mechanism 3.

[0046] like Figure 1 and Figure 2 As shown, the shell includes an arc portion 11 and a straight tube portion 12 tangentially connected to the arc portion 11, an exhaust channel is formed in the straight tube portion 12, and a mounting portion 13 is fixed to the air inlet end of the exhaust channel, and the mounting portion 13 is used to fix to the side wall of the lithium battery box, that is, an exhaust hole is opened on the side wall of the lithium battery box, and one end of the exhaust channel is connected to the exhaust hole of the lithium battery box to discharge the high-temperature and high-pressure gas in the lithium battery box. It should be noted that the high-temperature and high-pressure gas in this embodiment refers to the gas in the lithium battery box when the batteries in the lithium battery box generate a lot of heat, thereby causing the internal pressure to rise, and the gas has a certain temperature and pressure.

[0047] like Figure 2 , Figure 3 and Figure 7 As shown, the valve core includes a rotating shaft 41 rotatably mounted on the shell and a plurality of sealing plates 42 annularly distributed on the outside of the rotating shaft 41, and when the corresponding sealing plate 42 is flipped to be perpendicular to the exhaust channel, the exhaust channel can be blocked to achieve sealed exhaust channel, thereby preventing external air or debris from entering the lithium battery box. When the high-temperature and high-pressure gas in the lithium battery box is discharged through the exhaust channel, the rotating shaft 41 is driven to rotate under the action of the plurality of sealing plates 42.

[0048] like Figure 3 As shown, a sealing member 43 is provided at the outer edge of the sealing plate 42. The sealing member 43 includes a liquid crystal elastic strip coated on the outer edge of the sealing plate 42. The outer side of the liquid crystal elastic strip is coated with a soft strip. The soft strip is made of sponge, rubber or other soft materials. The liquid crystal elastic strip will shrink in a high temperature environment (the temperature is above 120℃-170℃), which will drive the soft strip to shrink to one side of the sealing plate 42, thereby avoiding the contact between the soft strip and the inner wall of the shell, so that the sealing plate 42 rotates smoothly. When the temperature in the lithium battery box drops to normal temperature, the liquid crystal elastic strip will expand, driving the soft strip to expand outward, so that the soft strip is in close contact with the inner wall of the shell, thereby ensuring the sealing.

[0049] The liquid crystal elastic strip and the liquid crystal elastic rope 53 are both made of liquid crystal elastomer material. Liquid crystal elastomer (LCEs) is a special polymer material that combines the ordered molecular arrangement characteristics of liquid crystal and the flexibility of elastomer. This material has an ordered structure of liquid crystal phase at the molecular level, and exhibits the reversible deformation ability of elastomer at the macro level. Liquid crystal elastomer exhibits a negative thermal expansion coefficient, that is, as the temperature increases, the volume decreases.

[0050] like Figures 2 to 4 As shown, the limiting mechanism 2 is arranged on one side of the shell, and is used to limit the circumferential freedom of the valve core (that is, whether it can rotate with the rotating shaft 41). When the normal working temperature in the lithium battery box is reached, the valve core can be limited by the limiting mechanism 2 to fix the valve core. When the temperature in the lithium battery box rises, the valve core is in a rotatable state.

[0051] like Figure 4 As shown, the limiting mechanism 2 includes a first round block 21 fixed to the end of the rotating shaft 41 and a limiting member fixed to the outside of the shell. The outer surface of the first round block 21 is provided with a guide groove group, and the limiting member is used to limit the circumferential angle of the first round block 21.

[0052] like Figure 4As shown, the guide groove group includes an annular groove 213, and the lower side of the annular groove 213 is connected to a plurality of annularly distributed vertical grooves 211, the number of the plurality of vertical grooves 211 is consistent with the number of the plurality of sealing plates 42, and the two correspond one to one, the width of the vertical groove 211 is adapted to the diameter of the roller 24, and the connection between the vertical groove 211 and the annular groove 213 is an open setting to form a tapered portion 212 between two adjacent vertical grooves 211.

[0053] like Figure 2 and Figure 4 As shown, the limiting member includes a bracket 22 fixed to the outside of the shell, and a moving block 23 is vertically slidably arranged on one side of the bracket 22 through a slide rail slider structure 25. A first spring 26 is installed between the bracket 22 and the moving block 23. The first spring 26 applies a force to the moving block 23 to move toward one side of the vertical groove 211. A roller 24 is rotatably installed on the side of the moving block 23, and the roller 24 is located in the guide groove group.

[0054] The force of the first spring 26 will drive the roller 24 to move toward one side of the vertical groove 211. When the roller 24 moves downward from the annular groove 213, when the roller 24 corresponds to one of the vertical grooves 211, the roller 24 directly enters the vertical groove 211. If the roller 24 is staggered from the vertical groove 211, the roller 24 will first contact the tapered portion 212. Since the two sides of the tapered portion 212 are inclined, under the action of the roller 24, the roller 24 will cause the first round block 21 to rotate until the roller 24 moves to the corresponding vertical groove 211. At this time, the corresponding sealing plate 42 will block the exhaust channel to achieve sealing of the exhaust channel and limit the circumferential rotation of the valve core.

[0055] like Figure 2 and Figure 4 As shown, the trigger mechanism 5 is used to release the circumferential limitation of the valve core by the limiting mechanism 2 when the temperature in the lithium battery box reaches the upper limit pre-threshold value, so that the high-temperature and high-pressure gas in the lithium battery box is ejected through the exhaust channel and drives the valve core to rotate; the trigger mechanism 5 includes a mounting member fixed to the inner wall of the lithium battery box, a liquid crystal elastic pull rope 53 is fixed on the mounting member, and a steel wire rope 57 is fixed to the end of the liquid crystal elastic pull rope 53 away from the mounting member through a connecting member, and the end of the steel wire rope 57 away from the liquid crystal elastic pull rope 53 extends to be connected to the upper end of the moving block 23, and the steel wire rope 57 transitions through the turning point in the process of passing through the guide wheel 58. The specific number and position of the guide wheel 58 need to be set according to actual needs to ensure that the steel wire rope 57 can smoothly and labor-savingly pull the moving block 23 to move.

[0056] When the temperature in the lithium battery box reaches the upper limit pre-threshold value, the liquid crystal elastic pull rope 53 will shrink and deform due to the influence of the high temperature, and the length of the liquid crystal elastic pull rope 53 will be shortened. The moving block 23 and the roller 24 will be displaced by pulling the steel wire rope 57, so that the roller 24 moves to the annular groove 213. The roller 24 will not block the rotation of the first round block 21, that is, the circumferential restriction of the valve core is released, so that it can rotate freely.

[0057] like Figure 8 As shown, the mounting part includes a fixing cylinder 51 fixed to the inner wall of the lithium battery box, the outer diameter of the liquid crystal elastic rope 53 is adapted to the inner hole diameter of the fixing cylinder 51, the end of the liquid crystal elastic rope 53 passes through the inner hole of the fixing cylinder 51, and the outer side of the fixing cylinder 51 is threadedly connected with a first bolt 52 that tightens the liquid crystal elastic rope 53 to fix the liquid crystal elastic rope 53. When installing the liquid crystal elastic rope 53, the length of the liquid crystal elastic rope 53 can be adjusted by pulling the liquid crystal elastic rope 53 as needed, which brings convenience to the installation. It should be noted that: when the temperature felt by the liquid crystal elastic rope 53 reaches the upper limit pre-threshold value, the tension brought by the contraction of the liquid crystal elastic rope 53 is greater than the pressure of the compression deformation of the first spring 26, and at this time, the roller 24 is displaced into the annular groove 213.

[0058] like Figure 8 As shown, the connecting piece includes a fixing sleeve 54, which has two inner holes. The ends of the liquid crystal elastic pull rope 53 and the steel wire rope 57 are respectively inserted into the two inner holes of the fixing sleeve 54, and the outer side of the fixing sleeve 54 is threadedly connected with a second bolt 55 and a third bolt 56 that respectively tighten the liquid crystal elastic pull rope 53 and the steel wire rope 57, so as to fix the liquid crystal elastic pull rope 53 and the steel wire rope 57.

[0059] In other embodiments, there can be multiple trigger mechanisms 5, and the multiple trigger mechanisms 5 are respectively arranged at multiple positions on the inner wall of the lithium battery box, for example, on the four inner walls of the lithium battery box. When overheating occurs in different positions of the lithium battery box, the roller 24 can be pulled to move, thereby improving the sensitivity of the pressure relief valve triggering.

[0060] like Figure 2 and Figure 5As shown, the warning mechanism 3 is arranged on the other side of the shell, and is used to emit a warning sound when the valve core rotates, so as to remind the surrounding personnel to eliminate hidden dangers or stay away from danger. The warning mechanism 3 includes a second round block 31 fixed to the end of the rotating shaft 41 and a mounting frame 32 fixed to the outside of the shell, the mounting frame 32 has two horizontal plates, and a plurality of top grooves are opened at the end of the second round block 31, and the number of top grooves is set according to needs. The plane shape of the top groove is an arc structure, and the bottom of the top groove has a pit portion 312 and an inclined portion 311, and the inclined portion 311 is located on one side of the pit portion 312; a knocking piece 34 and a bell 33 are installed on the mounting frame 32, and one end of the knocking piece 34 extends into the top groove, and when the second round block 31 rotates, the knocking piece 34 will move from the pit portion 312 to the inclined portion 311, that is, the knocking piece 34 can be moved to one side of the bell 33, and finally contact the bell 33 to achieve a knock.

[0061] When the second round block 31 rotates with the valve core, the knocking member 34 will be reciprocated and knock the bell 33 under the action of multiple top grooves, and the bell 33 vibrates to generate sound wave warning. The principle is similar to that of the school bell used in schools, which generates louder sound waves through vibration.

[0062] like Figure 5 and Figure 6 As shown, the knocking member 34 includes a sliding rod 341 slidably mounted on the mounting frame 32, a retaining ring 344 is fixed on the sliding rod 341, and a second spring 345 is arranged between the retaining ring 344 and the mounting frame 32, and the second spring 345 gives the sliding rod 341 a force to move toward the side of the second round block 31, and a ball 346 is embedded and rolled on the side of the sliding rod 341 close to the second round block 31, and the ball 346 can reduce the friction between the sliding rod 341 and the second round block 31, and the other end of the sliding rod 341 is axially slidably mounted with a knocking head 342. Specifically: an installation inner hole is opened at the end of the sliding rod 341, and the end of the knocking head 342 has a plug-in portion that is plugged and slidably arranged in the installation inner hole, and a third spring 343 is installed between the knocking head 342 and the sliding rod 341. In this embodiment, the two ends of the third spring 343 are respectively mounted on the bottom of the installation inner hole and the end of the plug-in portion of the knocking head 342.

[0063] The setting of the third spring 343 can create a certain buffer zone between the knocking head 342 and the sliding rod 341, and the total length of the two can be contracted. When the ball 346 contacts the end plane of the second round block 31, the knocking head 342 contacts the bell 33 again, and the third spring 343 can be compressed, which can avoid the knocking piece 34 and the bell 33 from being stuck together, thereby ensuring the normal operation of the smooth equipment.

[0064] This embodiment also provides a technical solution: a pressure relief method of a pressure relief valve as described above for fire prevention and control of a lithium battery box, comprising the following steps:

[0065] Step 1: Release the circumferential restriction of the valve core: When the temperature in the lithium battery box rises to the upper limit pre-threshold value, the force generated by the contraction of the length of the liquid crystal elastic pull rope 53 will pull the roller 24 into the annular groove 213, so that the shaft 41 can rotate freely and compress the first spring 26;

[0066] Step 2: Gas discharge: The gas in the lithium battery box is ejected through the exhaust channel, and drives the valve core to rotate;

[0067] Step 3, issuing a warning: the second round block 31 rotates synchronously with the valve core, and the second round block 31 pushes the reciprocating knocking member 34 to knock the bell 33, and the bell 33 issues a warning sound, that is, the effect of exhausting the air while warning the surrounding personnel is achieved;

[0068] Step 4, seal the exhaust channel: when the temperature in the lithium battery box drops to the lower limit pre-threshold, the liquid crystal elastic pull rope 53 returns to its original length, and the roller 24 slides into the vertical groove 211 due to the force of the first spring 26 to prevent the valve core from rotating, so that the corresponding sealing plate 42 seals the exhaust channel.

[0069] The above are only preferred embodiments of the present invention, which are only illustrative and not restrictive. Those skilled in the art understand that many changes, modifications, and even equivalences may be made to the present invention within the spirit and scope defined by the claims, but all of them will fall within the scope of protection of the present invention.

Claims

1. A pressure relief valve for fire prevention and control of lithium battery boxes, characterized in that: include: A housing, wherein the housing has an exhaust passage, one end of which is connected to the lithium battery box; A valve core, the valve core comprising a rotating shaft (41) rotatably mounted on the housing and a plurality of sealing plates (42) annularly distributed outside the rotating shaft (41), and when the sealing plates (42) are turned over to be perpendicular to the exhaust channel, the exhaust channel is sealed; A limiting mechanism (2), the limiting mechanism (2) being arranged on one side of the housing and being used to limit the circumferential freedom of the valve core; the limiting mechanism (2) comprising a first round block (21) fixed to the end of the rotating shaft (41) and a limiting member fixed to the outside of the housing, the outer surface of the first round block (21) being provided with a guide groove group, the limiting member being used to limit the circumferential angle of the first round block (21); The guide groove group comprises an annular groove (213), the lower side of the annular groove (213) is connected to a plurality of annularly distributed vertical grooves (211), and the plurality of vertical grooves (211) correspond to the plurality of sealing plates (42) one by one, and the connection between the vertical grooves (211) and the annular groove (213) is open-type, so as to form a tapered portion (212) between two adjacent vertical grooves (211); A trigger mechanism (5), the trigger mechanism (5) being used to release the circumferential restriction of the valve core by the restriction mechanism (2) when the temperature in the lithium battery box reaches an upper limit pre-threshold value, so that the high-temperature and high-pressure gas in the lithium battery box is ejected through the exhaust channel and the valve core is driven to rotate; A warning mechanism (3) is arranged on the other side of the housing and is used to emit a warning sound when the valve core rotates.

2. The pressure relief valve for fire prevention and control of a lithium battery box according to claim 1, characterized in that: The limiting member comprises a bracket (22) fixed to the outer side of the housing, a moving block (23) is vertically slidably arranged on one side of the bracket (22) via a slide rail and slider structure (25), a first spring (26) is installed between the bracket (22) and the moving block (23), the first spring (26) applies a force to the moving block (23) to move toward one side of the vertical groove (211), a roller (24) is rotatably installed on the side of the moving block (23), and the roller (24) is located in the guide groove group; The force of the first spring (26) drives the roller (24) to move toward one side of the vertical groove (211), and the roller (24) squeezes the first round block (21) to rotate it until the roller (24) moves into the corresponding vertical groove (211), thereby limiting the circumferential rotation of the valve core and sealing the exhaust channel through the corresponding sealing plate (42).

3. The pressure relief valve for fire prevention and control of a lithium battery box according to claim 2, characterized in that: The trigger mechanism (5) comprises a mounting member fixed to the inner wall of the lithium battery box, a liquid crystal elastic pull rope (53) being fixed to the mounting member, a steel wire rope (57) being fixed to one end of the liquid crystal elastic pull rope (53) away from the mounting member via a connecting member, the end of the steel wire rope (57) away from the liquid crystal elastic pull rope (53) extending to be connected to the upper end of the moving block (23), and the turning point during the passage of the steel wire rope (57) is transitioned through a guide wheel (58), when the temperature in the lithium battery box reaches an upper limit pre-threshold value, the force generated by the contraction and deformation of the liquid crystal elastic pull rope (53) causes the roller (24) to move to the annular groove (213), thereby releasing the circumferential restriction of the valve core; The mounting member comprises a fixing cylinder (51) fixed to the inner wall of the lithium battery box, the end of the liquid crystal elastic pull rope (53) passes through the inner hole of the fixing cylinder (51), and the outer side of the fixing cylinder (51) is threadedly connected to a first bolt (52) for tightening the liquid crystal elastic pull rope (53); The connecting member comprises a fixing sleeve (54), the ends of the liquid crystal elastic pull rope (53) and the steel wire rope (57) are respectively inserted into two inner holes of the fixing sleeve (54), and the outer side of the fixing sleeve (54) is threadedly connected with a second bolt (55) and a third bolt (56) for respectively tightening the liquid crystal elastic pull rope (53) and the steel wire rope (57).

4. The pressure relief valve for fire prevention and control of a lithium battery box according to claim 1 or 3, characterized in that: The number of the trigger mechanisms (5) is plural, and the plurality of trigger mechanisms (5) are respectively located at multiple positions on the inner wall of the lithium battery box.

5. The pressure relief valve for fire prevention and control of a lithium battery box according to claim 1, characterized in that: The warning mechanism (3) comprises a second round block (31) fixed to the end of the rotating shaft (41) and a mounting frame (32) fixed to the outside of the housing, the end of the second round block (31) is provided with a plurality of top grooves, the bottom of the top grooves comprises a concave portion (312) and an inclined portion (311), and the inclined portion (311) is located on one side of the concave portion (312); a knocking piece (34) and a bell (33) are mounted on the mounting frame (32), one end of the knocking piece (34) extends into the top groove, and when the second round block (31) rotates with the valve core, the knocking piece (34) is reciprocally pushed to knock the bell (33), and the bell (33) vibrates to generate a sound wave warning.

6. The pressure relief valve for fire prevention and control of a lithium battery box according to claim 5, characterized in that: The knocking member (34) comprises a slide bar (341) slidably mounted on a mounting frame (32); a retaining ring (344) is fixed on the slide bar (341); a second spring (345) sleeved on the slide bar (341) is arranged between the retaining ring (344) and the mounting frame (32); the second spring (345) exerts a force on the slide bar (341) to displace toward one side of the second round block (31); a ball (346) is embedded and rollingly mounted on one side of the slide bar (341) close to the second round block (31); a knocking head (342) is axially slidably mounted on the other end of the slide bar (341); and a third spring (343) is installed between the knocking head (342) and the slide bar (341).

7. The pressure relief valve for fire prevention and control of a lithium battery box according to claim 1, characterized in that: The outer edge of the sealing plate (42) is provided with a sealing member (43), and the sealing member (43) comprises a liquid crystal elastic strip wrapped around the outer edge of the sealing plate (42), and the outer side of the liquid crystal elastic strip is wrapped with a soft strip.

8. The pressure relief valve for fire prevention and control of a lithium battery box according to claim 1, characterized in that: The shell comprises an arc-shaped portion (11) and a straight pipe portion (12) tangentially connected to the arc-shaped portion (11); an exhaust channel is formed in the straight pipe portion (12); and a mounting portion (13) is fixed to the air inlet end of the exhaust channel.

9. A pressure relief method for a pressure relief valve used for fire prevention and control of a lithium battery box according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: Release the circumferential restriction of the valve core: When the temperature in the lithium battery box rises to the upper limit pre-threshold value, the force generated by the length contraction of the liquid crystal elastic pull rope (53) will pull the roller (24) into the annular groove (213), so that the rotating shaft (41) can rotate freely and compress the first spring (26); Step 2: Gas discharge: The gas in the lithium battery box is ejected through the exhaust channel, and drives the valve core to rotate; Step 3: issuing a warning: the second round block (31) rotates synchronously with the valve core, and the second round block (31) pushes the reciprocating knocking member (34) to knock the bell (33), and the bell (33) issues a warning sound; Step 4: Sealing the exhaust passage: When the temperature in the lithium battery box drops to the lower pre-threshold value, the liquid crystal elastic pull rope (53) returns to its original length, and the roller (24) slides into the vertical groove (211) due to the force of the first spring (26), thereby preventing the valve core from rotating, and allowing the corresponding sealing plate (42) to seal the exhaust passage.

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