Anti-explosion valve, cover plate assembly and battery

Abstract

The utility model discloses an anti-explosion valve, a cover plate assembly and a battery. Belongs to the technical field of batteries, the anti-explosion valve is used for the battery, the battery comprises a cover plate, the anti-explosion valve is suitable for being installed at an anti-explosion hole of the cover plate, the anti-explosion valve comprises a valve body and an elastic piece, the valve body comprises an upper core body, a blasting core and a lower core body, the blasting core is connected between the upper core body and the lower core body, and the elastic piece is arranged in the axial direction of the anti-explosion hole. One end of the elastic piece is pressed against the lower flange of the lower core body, the other end of the elastic piece is suitable for pressing against the inner wall of the cover plate, the elastic force of the elastic piece can enable the upper flange of the upper core body to be propped against the outer wall of the cover plate, so that the battery is sealed, and the explosion core of the valve body can be snapped when a high-pressure reaction occurs in the battery; the explosion-proof valve is arranged in the battery, so that the explosion-proof valve is completely opened, the pressure in the battery is quickly released, the safety of the battery is improved, in addition, whether helium exists in the battery or not can be detected through micro-opening of the explosion-proof valve before secondary helium detection is carried out on the battery, and the accuracy of secondary helium detection can be effectively improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to an explosion-proof valve, a cover plate assembly and a battery. Background Art

[0002] In the related art, when performing a secondary helium test on a battery, helium can be filled inside the battery, and then the sealing performance of the battery can be judged by detecting whether the battery has leaked helium. If it is detected that the battery has not leaked helium, the sealing performance of the battery is qualified, otherwise it is unqualified. During the actual test, if the battery has a large leak due to poor sealing, the helium inside the battery may have completely leaked through the leak before the secondary helium test. As a result, no helium leakage will be detected during the secondary helium test, and the battery's sealing performance will be judged to be qualified. In this case, the secondary helium test will be mistakenly judged to be qualified, but the battery still has a leakage problem. Utility Model Content

[0003] The present invention aims to solve at least one of the above-mentioned technical problems in the prior art to a certain extent. To this end, the present invention proposes an explosion-proof valve that is conducive to improving the accuracy of secondary helium detection.

[0004] The utility model also provides a cover plate assembly with the explosion-proof valve.

[0005] The utility model also provides a battery with the cover plate assembly.

[0006] According to the explosion-proof valve of the embodiment of the present invention, the explosion-proof valve is used for a battery, and the battery includes a cover plate, and the explosion-proof valve is suitable for being installed at the explosion-proof hole of the cover plate, and the explosion-proof valve includes: a valve body and an elastic member, and the valve body includes: an upper core body, an explosion core and a lower core body, the cross-sectional areas of the upper core body and the lower core body are both larger than the cross-sectional area of ​​the explosion core, and the upper core body is suitable for passing through the explosion-proof hole and fitting with the gap of the explosion-proof hole, the upper core body has an upper flange, and the lower core body has a lower flange, in the axial direction of the explosion-proof hole, the explosion core is connected between the upper core body and the lower core body, and the upper flange and the lower flange are arranged opposite to each other on both sides of the cover plate; in the axial direction of the explosion-proof hole, one end of the elastic member presses against the lower flange, and the other end of the elastic member is suitable for pressing against the inner wall of the cover plate.

[0007] According to the explosion-proof valve of the embodiment of the present invention, the elastic force of its elastic member can cause the upper flange of the valve body to abut against the outer wall of the cover plate, thereby achieving sealing of the battery. In addition, the explosion core of the valve body can be broken when a high-pressure reaction occurs inside the battery, so that the explosion-proof valve is fully opened to quickly release the pressure inside the battery, which is beneficial to improving the safety of the battery. In addition, before the battery undergoes a secondary helium test, the slight opening of the explosion-proof valve can be used to detect whether there is helium inside the battery, which can effectively improve the accuracy of the secondary helium test.

[0008] According to some embodiments of the present invention, the explosion-proof valve further comprises: a sealing ring, wherein in the axial direction of the explosion-proof hole, the sealing ring clamp is adapted to be clamped between the upper flange and the outer wall of the cover plate.

[0009] According to some embodiments of the present invention, the explosion-proof valve further includes: a protective ring, which is clamped between the upper core body and the explosion-proof hole in the radial direction of the explosion-proof hole; an air guide groove is formed on the outer wall of the upper core body, and the air guide groove and the protective ring together define an air guide channel connected to the interior of the battery.

[0010] According to some embodiments of the present invention, there are multiple air guide grooves, and the multiple air guide grooves and the protective ring together define multiple air guide channels.

[0011] According to some embodiments of the present invention, the total flow area of ​​the plurality of air guide channels is S1, which satisfies the relationship: 1.6×10 -14 m 2 ≤S1≤2.0×10 -14 m 2 .

[0012] According to some embodiments of the present invention, the upper flange and the lower flange are both annular flanges.

[0013] According to some embodiments of the present invention, the cross-sectional area of ​​the explosive core is S2, which satisfies the relationship: 3×10 - 14 m 2 ≤S2≤5×10 -14 m 2 .

[0014] According to some embodiments of the present invention, the valve body is a machined aluminum part.

[0015] According to another embodiment of the present invention, a cover plate assembly includes a cover plate and the above-mentioned explosion-proof valve.

[0016] According to the cover plate assembly of the embodiment of the present invention, the elastic force of its elastic member can cause the upper flange of the valve body to abut against the outer wall of the cover plate, thereby achieving sealing of the battery. In addition, the explosion core of the valve body can be broken when a high-pressure reaction occurs inside the battery, so that the explosion-proof valve is fully opened to quickly release the pressure inside the battery, which is beneficial to improving the safety of the battery. In addition, before the battery undergoes a secondary helium test, the slight opening of the explosion-proof valve can be used to detect whether there is helium inside the battery, which can effectively improve the accuracy of the secondary helium test.

[0017] A battery according to another embodiment of the present invention includes the above-mentioned cover plate assembly.

[0018] In the battery according to the embodiment of the present invention, the elastic force of the elastic member can cause the upper flange of the valve body to abut against the outer wall of the cover plate, thereby achieving sealing of the battery. In addition, the explosion core of the valve body can be broken when a high-pressure reaction occurs inside the battery, so that the explosion-proof valve is fully opened to quickly release the pressure inside the battery, which is beneficial to improving the safety of the battery. In addition, before the battery undergoes a secondary helium test, the slight opening of the explosion-proof valve can be used to detect whether there is helium inside the battery, which can effectively improve the accuracy of the secondary helium test.

[0019] Additional aspects and advantages of the present invention will be given in part in the following description and will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of an explosion-proof valve, a cover plate and a lower plastic according to an embodiment of the present utility model;

[0021] Figure 2 is a cross-sectional view of a valve body according to an embodiment of the present utility model;

[0022] Figure 3 is a three-dimensional diagram of a valve body according to an embodiment of the present utility model;

[0023] Figure 4 It is a cross-sectional view of a cover plate assembly according to an embodiment of the present utility model.

[0024] Reference numerals:

[0025] Valve body 1; upper core 11; upper flange 111; air guide groove 112; explosion core 12; lower core 13; lower flange 131; communication space 14;

[0026] Elastic member 2; sealing ring 3; protective ring 4;

[0027] Explosion-proof valve 10; cover plate 20; injection hole 201; outer wall 202; inner wall 203; collecting column 30; pole 40; lower plastic 50;

[0028] Cover plate assembly 100 . DETAILED DESCRIPTION

[0029] The following describes in detail embodiments of the present invention, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0030] In the description of the present invention, it should be understood that the terms "upper", "lower", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0031] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of this utility model, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0032] In this utility model, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or mutual communication; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. For those skilled in the art, the specific meanings of the above terms in this utility model can be understood according to the specific circumstances.

[0033] The following combination Figure 1-Figure 4 The explosion-proof valve 10 , the cover plate assembly 100 and the battery according to the embodiment of the present invention are described in detail.

[0034] Reference Figure 1-Figure 3As shown, according to the explosion-proof valve 10 of the embodiment of the present invention, the explosion-proof valve 10 is used for a battery, the battery includes a cover plate 20, the explosion-proof valve 10 is suitable for installation at the explosion-proof hole of the cover plate 20, the explosion-proof valve 10 includes: a valve body 1 and an elastic member 2, the valve body 1 includes: an upper core 11, an explosion core 12 and a lower core 13, the cross-sectional area of ​​the upper core 11 and the lower core 13 are both larger than the cross-sectional area of ​​the explosion core 12, the upper core 11 is suitable for passing through the explosion-proof hole and matching the gap of the explosion-proof hole, the upper core 11 has an upper flange 1 11. The lower core 13 has a lower flange 131. In the axial direction of the explosion-proof hole, the explosion core 12 is connected between the upper core 11 and the lower core 13, and the upper flange 111 and the lower flange 131 are arranged opposite to each other on both sides of the cover plate 20. In the axial direction of the explosion-proof hole, one end of the elastic member 2 presses against the lower flange 131, and the other end of the elastic member 2 is suitable for pressing against the inner wall 203 of the cover plate 20, so that the upper flange 111 presses against the outer wall 202 of the cover plate 20 to achieve sealing, which can prevent leakage inside the battery.

[0035] It can be understood that the upper core 11 is suitable for being inserted into the explosion-proof hole, and the cross-sectional areas of the upper core 11 and the lower core 13 are both larger than the cross-sectional area of ​​the explosion core 12, and the explosion core 12 is connected between the upper core 11 and the lower core 13. A connecting space 14 connected to the interior of the battery can be formed between the upper core 11 and the lower core 13. The gas inside the battery can enter the connecting space 14 and apply upward pressure to the upper core 11. When the battery is in normal use, the internal air pressure of the battery is lower than the external air pressure of the battery. The downward force applied by the external air pressure of the battery on the upper core 11 is greater than the upward force applied by the internal air pressure of the battery on the upper core 11, and the elastic member 2 can apply a downward elastic force to the lower core 13. Under the action of the air pressure difference between the inside and outside of the battery and the elastic force of the elastic member 2, the upper flange 111 can be tightly abutted against the outer wall 202 of the cover plate 20 to form a sealing structure to prevent battery leakage.

[0036] In addition, since the internal air pressure of the battery can exert an upward force on the upper core 11 and the elastic member 2 between the inner wall 203 of the cover plate 20 and the lower flange 131 can exert a downward elastic force on the lower core 13, the explosion core 12 located between the upper core 11 and the lower core 13 is in a tensile state. When a high-pressure reaction occurs inside the battery, the pressure exerted by the gas inside the battery on the upper core 11 increases, and the tension on the explosion core 12 also increases accordingly. When the tension on the explosion core 12 exceeds the maximum bearing capacity of the explosion core 12, the explosion core 12 is broken, and the upper core 11 is pushed out of the explosion-proof hole by the high-pressure gas inside the battery. The explosion-proof valve 10 is fully opened to quickly release the pressure inside the battery to avoid major accidents caused by untimely battery pressure relief, thereby helping to improve the safety of the battery.

[0037] It should be noted that before performing a secondary helium test on the battery, it is necessary to first extract negative pressure from the inside of the battery and fill the battery with helium to achieve secondary helium return of the battery. After the helium filling is completed, the air pressure inside the battery is still lower than the air pressure outside the battery. Under the action of the air pressure difference between the inside and outside of the battery and the elastic force of the elastic member 2, the upper flange 11 can be tightly abutted against the outer wall 202 of the cover plate 20. The battery can be left to stand for a period of time, and then negative pressure can be extracted separately from the upper surface of the upper core 11, and the air pressure on the upper surface of the upper core 11 can be made lower than the air pressure inside the battery. Since the upper core 11 is fitted with the gap between the explosion-proof hole, the force exerted by the air pressure inside the battery on the upper core 11 can push the valve body 1 as a whole to move upward, so that the upper flange 1 11 is separated from the outer wall 202 of the cover plate 20, realizing the micro-motion opening of the explosion-proof valve 10. The gas inside the battery can flow to the outside of the battery through the gap between the upper core 11 and the explosion-proof hole. The helium detection device can detect whether the gas flowing from the inside of the battery to the outside of the battery contains helium. If helium is detected, there is helium inside the battery, and a secondary helium test of the battery can be performed to further detect the sealing of the battery. If no helium is detected, the sealing performance of the battery is poor, there may be a leak, and the helium in the battery has completely leaked. This embodiment detects whether there is helium in the battery by micro-motion opening the explosion-proof valve 10 before the secondary helium test of the battery, which can effectively improve the accuracy of the secondary helium test and avoid the secondary helium test from being misjudged as qualified. Among them, the elastic member 2 can be a compression spring, the helium detection device can be a helium detection mass spectrometer, and the outer wall 202 of the cover plate 20 can be Figure 1 The upper end wall of the middle cover plate 20 and the inner wall 203 of the cover plate 20 can be Figure 1 The lower end wall of the middle cover plate 20.

[0038] According to the explosion-proof valve 10 of the embodiment of the present invention, the elastic force of its elastic member 2 can make the upper flange 111 of the valve body 1 abut against the outer wall 202 of the cover plate 20, thereby achieving sealing of the battery. In addition, the explosion core 12 of the valve body 1 can be broken when a high-pressure reaction occurs inside the battery, so that the explosion-proof valve 10 is fully opened to quickly release the pressure inside the battery, which is beneficial to improving the safety of the battery. In addition, before the battery undergoes a secondary helium test, the slight opening of the explosion-proof valve 10 can be used to detect whether there is helium inside the battery, which can effectively improve the accuracy of the secondary helium test.

[0039] In some embodiments of the present invention, referring to Figure 1 As shown, the explosion-proof valve 10 also includes: a sealing ring 3, in the axial direction of the explosion-proof hole (ie Figure 1The sealing ring 3 is adapted to be clamped between the upper flange 111 and the outer wall 202 of the cover plate 20, and the sealing ring 3 can fill the gap between the upper flange 111 and the outer wall 202 of the cover plate 20. Under the action of the air pressure difference between the inside and outside of the battery and the elastic force of the elastic member 2, the upper flange 111 of the valve body 1 and the outer wall 202 of the cover plate 20 can be tightly abutted through the sealing ring 3 to ensure the sealing of the battery and prevent the gas in the battery from leaking to the outside through the gap between the upper flange 111 and the outer wall 202 of the cover plate 20.

[0040] In some embodiments of the present invention, referring to Figure 1 As shown, the explosion-proof valve 10 also includes: a protective ring 4, which is clamped between the upper core body 11 and the explosion-proof hole in the radial direction of the explosion-proof hole. An air guide groove 112 is formed on the outer wall of the upper core body 11. The air guide groove 112 and the protective ring 4 together define an air guide channel connected to the interior of the battery. When the explosion-proof valve 10 is slightly opened, the gas inside the battery can flow to the outside of the battery through the air guide channel, thereby realizing sampling of the gas inside the battery.

[0041] Reference Figure 1 As shown, the protective ring 4 is sleeved on the outer wall of the upper core 11. The protective ring 4 can guide the upper core 11 so that the upper core 11 moves along the axial direction of the protective ring 4 and prevents the upper core 11 from axially deflecting, which is conducive to the stable movement of the upper core 11. The protective ring 4 can also prevent the upper core 11 from contacting the inner wall of the explosion-proof hole. When the explosion-proof valve 10 is slightly opened, the upper core 11 and the inner wall of the explosion-proof hole are prevented from rubbing against each other, thereby reducing the wear of the upper core 11 and improving the service life of the valve body 1. The material of the protective ring 4 can be fluororubber, which has good high temperature resistance and corrosion resistance, which is conducive to improving the service life of the protective ring 4.

[0042] In some embodiments of the present invention, referring to Figure 2 and Figure 3 As shown, there are multiple air guide grooves 112, which together with the protective ring 4 define multiple air guide channels. It is understandable that the cross-sectional area of ​​each air guide groove 112 can be set to be smaller, so as to avoid the structural strength of the valve body 1 being affected by setting a large flow area for a single air guide groove 112, thereby improving the durability of the valve body 1 and thus improving the service life of the explosion-proof valve 10. The air guide grooves 112 can be configured as semicircular grooves for ease of processing and manufacturing.

[0043] In some embodiments of the present invention, the total flow area of ​​the plurality of air guide channels is S1, which satisfies the relationship: 1.6×10 -14 m 2 ≤S1≤2.0×10 -14 m 2, for example, S1 can be 1.6×10 -14 m 2 , 1.8×10 -14 m 2 , 2.0×10 -14 m 2 When the explosion-proof valve 10 is slightly opened, the helium detection device can accurately detect whether the gas flowing from the inside of the battery to the outside of the battery contains helium, and avoid excessive leakage of gas from the inside of the battery to the outside of the battery, which facilitates the normal implementation of the secondary helium detection. The total flow area of ​​the multiple gas guide channels is the sum of the cross-sectional areas of the multiple gas guide grooves 112.

[0044] It is understandable that when S1<1.6×10 -14 m 2 When the explosion-proof valve 10 is slightly opened, the total flow area of ​​the multiple gas guide channels is small. When the explosion-proof valve 10 is slightly opened, the amount of gas inside the battery flowing to the outside of the battery through the multiple gas guide channels is small, which easily leads to the situation where the amount of helium is small and the amount of helium is less than the detection limit of the helium detection device. It is difficult for the helium detection device to accurately detect whether there is helium inside the battery. When S1>2.0×10 -14 m 2 When the total flow area of ​​the multiple gas guide channels is large, the amount of gas inside the battery flowing to the outside of the battery through the multiple gas guide channels is large, the gas inside the battery leaks quickly, the detectable operation time is short, the detection is difficult, and before the secondary helium test is performed, it is easy to cause the amount of helium inside the battery to be small, making it difficult to perform the secondary helium test. In this embodiment, S1 is 1.6×10 -14 m 2 ~2.0×10 -14 m 2 The total flow area of ​​the multiple gas guide channels is moderate. When the explosion-proof valve 10 is slightly opened, the amount of gas flowing to the outside of the battery through the gas guide channels is moderate, so that the helium detection mass spectrometer can accurately detect whether there is helium inside the battery. At the same time, a large amount of gas flowing from the inside of the battery to the outside of the battery can be avoided, so as to ensure the amount of helium inside the battery and facilitate the normal implementation of the secondary helium detection.

[0045] It should be noted that when the battery undergoes a secondary helium test, the battery filled with helium needs to be placed in a sealed box. Whether the sealing performance of the battery is qualified is determined by detecting whether there is helium leakage in the sealed box. If it is detected that there is no helium leakage in the battery, the sealing performance of the battery is qualified, otherwise it is unqualified. In this embodiment, before the battery undergoes a secondary helium test, the explosion-proof valve 10 is slightly opened to sample the gas inside the battery to detect whether there is helium inside the battery. If there is helium, a secondary helium test can be performed. If there is no helium, the sealing performance of the battery is poor and no secondary helium test is required. By controlling the total flow area of ​​the multiple gas guide channels to 1.6×10 -14 m2 ~2.0×10 -14 m 2 Within the range, the gas inside the battery can be sampled while avoiding a large amount of gas flowing from the inside of the battery to the outside of the battery, so as to ensure the amount of helium inside the battery and facilitate the normal implementation of the secondary helium inspection.

[0046] In some embodiments of the present invention, referring to Figure 3 As shown, the upper flange 111 and the lower flange 131 are both annular flanges, which facilitates the processing and manufacturing of the upper flange 111 and the lower flange 131 .

[0047] In other embodiments of the present invention, the upper flange 111 and the lower flange 131 can be triangular, quadrilateral or other deformable shapes. The shapes of the upper flange 111 and the lower flange 131 are not limited to those described in this embodiment and can be set according to actual conditions.

[0048] In some embodiments of the present invention, referring to Figure 1 As shown, the explosion-proof hole can be a countersunk hole that can accommodate at least part of the upper flange 111, the sealing ring 3 and the protective ring 4 to prevent the upper flange 111 from protruding from the outer surface of the cover plate 20, which is beneficial to reducing the risk of the upper flange 111 being hit.

[0049] In some embodiments of the present invention, the cross-sectional area of ​​the explosive core 12 is S2, which satisfies the relationship: 3×10 -14 m 2 ≤S2≤5×10 -14 m 2 , for example, S2 can be 3×10 -14 m 2 , 4×10 -14 m 2 , 5×10 -14 m 2 , which can ensure the normal use of the battery while improving the safety of the battery.

[0050] It is understandable that when S2<3×10 -14 m 2 When S2>5×10 -14 m 2 When the cross-sectional area of ​​the explosion core 12 is large, the structural strength of the explosion core 12 is too high, and a high-voltage reaction may occur inside the battery, and the explosion core 12 may be difficult to be broken, making it difficult to quickly release the pressure inside the battery, and the battery safety is poor. In this embodiment, S2 is 3×10 -14 m 2 ~5×10-14 m 2 Within the range, the cross-sectional area of ​​the explosion core 12 is moderate, and the structural strength of the explosion core 12 is moderate, so that the tensile strength of the explosion core 12 can be about 100 MPa, which can ensure the normal use of the battery while improving the safety of the battery.

[0051] In some embodiments of the present invention, the valve body 1 is a machined aluminum part, which is beneficial to ensuring the processing accuracy of the valve body 1, thereby facilitating accurate control of the fully opening pressure of the explosion-proof valve 10.

[0052] It is understandable that machining has high precision and good reliability, which can make the machining precision of the explosion core 12 reach 1μm. The tensile strength of the explosion core 12 can be basically considered to be the same between the raw materials of the explosion core 12 of the same batch, and the full opening pressure of the explosion-proof valve 10 can be controlled to a precision range of -3.922kPa to 3.931kPa. For example, the preset full opening pressure of the explosion-proof valve 10 can be 1MPa. The valve body 1 is made by machining. Due to the machining error, the lower limit of the full opening pressure of the explosion-proof valve 10 is 0.997MPa and the upper limit is 1.003MPa. In addition, the tensile strength of aluminum material is relatively low, so when a high-pressure reaction occurs inside the battery, it is easy for the explosion core 12 made of aluminum to be pulled and exploded, thereby opening the explosion-proof valve 10.

[0053] According to the explosion-proof valve 10 of the embodiment of the present invention, the upper core body 11 is penetrated by the explosion-proof hole and matched with the gap of the explosion-proof hole. The explosion-proof valve 10 can be repeatedly opened and closed by micro-movement, and the gas inside the battery can be sampled, which solves the problem that some batteries with leaks cannot be detected during the secondary helium inspection process, thereby helping to improve the accuracy of the secondary helium inspection. The valve body 1 is manufactured by mechanical processing, which can replace the traditional laser etching solution. The high precision and good reliability of mechanical processing are utilized to achieve precise control of the fully opening pressure of the explosion-proof valve 10. The limited sampling of the gas inside the battery by multiple air guide grooves 112 can avoid affecting the internal gas pressure and components of the battery.

[0054] In some embodiments of the present invention, before the secondary helium test of the battery, the explosion-proof valve 10 can be partially pumped with negative pressure using a device. Assuming that the lower surface area of ​​the explosion-proof valve 10 is S3, the upper surface area of ​​the explosion-proof valve 10 is S4, the negative pressure inside the battery is the absolute pressure P1, the atmospheric pressure outside the battery is P2, and the tensile strength σ of the explosion core 12 is b About 100Mpa,

[0055] The fully opening pressure P3 of the explosion-proof valve 10 is approximately 0.9 MPa to 1.1 MPa, satisfying the following equation 1:

[0056] P3(S3-S2)-P2S4=S2σ b ,

[0057] Simplifying the equation, we can get the following equation 2:

[0058]

[0059] The cross-sectional area of ​​the explosive core 12 can be calculated according to the above-mentioned relational formula 2.

[0060] During the secondary helium test, the outside of the explosion-proof valve 10 is vacuumed. When the absolute pressure outside the battery reaches P4, the explosion-proof valve 10 opens slightly. P4 satisfies the following equation 3:

[0061]

[0062] Wherein, k is the stiffness coefficient of the elastic member 2, and x is the compression amount of the elastic member 2, which is generally 0.05mm to 0.25mm. After opening, the helium inside the battery can leak to the outside of the battery through the multiple gas guide grooves 112. The specific leakage amount is determined by factors such as the diameter of the gas guide groove 112, the pressure difference between the inside and outside of the explosion-proof valve 10, and the opening time of the explosion-proof valve 10. Under normal circumstances, the minimum detectable leak rate Q0 of the helium detection mass spectrometer is 10 -11 Pa·m 3 / s, when the normal production temperature T is 298K, the absolute air pressure inside the battery is about P1, the absolute air pressure outside the battery is P4, the air guide groove 112 is semicircular, and the free volume inside the battery is about v1.

[0063] According to the ideal gas state equation, the number of moles of helium n satisfies the following relationship:

[0064]

[0065] Where R is a constant.

[0066] Secondly, according to the gas density formula, the density ρ of helium satisfies the following relationship 5:

[0067]

[0068] Where M is the molar mass of helium, which is generally 4.003 g / mol.

[0069] Finally, the helium leakage rate Q is calculated according to the leakage flow formula:

[0070]

[0071] Where C is the leakage coefficient, S5 is the total theoretical area of ​​the multiple air guide grooves 112, ΔP is the pressure difference between the inside and outside of the battery, ΔP = P4 - P1. Substituting the minimum detectable leak rate Q0 into the above formula, the total theoretical area of ​​the multiple air guide grooves 112 can be obtained. The total theoretical area of ​​the multiple air guide grooves 112 can be multiplied by a coefficient of 1.5 to 2 to obtain the total cross-sectional area of ​​the multiple air guide grooves 112. In this embodiment, the total cross-sectional area of ​​the multiple air guide grooves 112 is 1.8×10 -14 m 2 .

[0072] According to another embodiment of the present invention, a cover plate assembly 100 includes a cover plate 20 and the explosion-proof valve 10 of the above embodiment.

[0073] According to the cover plate assembly 100 of the embodiment of the present invention, the elastic force of its elastic member 2 can make the upper flange 111 of the valve body 1 abut against the outer wall 202 of the cover plate 20, thereby achieving sealing of the battery, and the explosion core 12 of the valve body 1 can be broken when a high-pressure reaction occurs inside the battery, so that the explosion-proof valve 10 is fully opened to quickly release the pressure inside the battery, which is beneficial to improving the safety of the battery. In addition, before the secondary helium test is performed on the battery, the slight opening of the explosion-proof valve 10 can be used to detect whether there is helium inside the battery, which can effectively improve the accuracy of the secondary helium test.

[0074] In some embodiments of the present invention, referring to Figure 4 As shown, the cover plate 20 is provided with an injection hole 201, through which electrolyte can be added to the battery. The cover plate assembly 100 also includes multiple current collecting posts 30, multiple poles 40, and a lower plastic 50 connected to the cover plate 20. The lower plastic 50 can isolate the multiple current collecting posts 30 to prevent short circuits. The current collecting posts 30 are suitable for electrical connection with the poles 40, which can serve as the connection point between the battery and the external circuit. The current collecting posts 30 are suitable for collecting the current inside the battery and transmitting it to the external circuit through the poles 40. The lower plastic 50 can be crimped to the cover plate 20 through the current collecting posts 30.

[0075] A battery according to another embodiment of the present invention includes the cover plate assembly 100 of the above embodiment.

[0076] In the battery according to the embodiment of the present invention, the elastic force of the elastic member 2 can cause the upper flange 111 of the valve body 1 to abut against the outer wall 202 of the cover plate 20, thereby achieving sealing of the battery. In addition, the explosion core 12 of the valve body 1 can be broken when a high-pressure reaction occurs inside the battery, so that the explosion-proof valve 10 is fully opened to quickly release the pressure inside the battery, which is beneficial to improving the safety of the battery. In addition, before the secondary helium test of the battery, the slight opening of the explosion-proof valve 10 can be used to detect whether there is helium inside the battery, which can effectively improve the accuracy of the secondary helium test.

[0077] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

[0078] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are illustrative and cannot be understood as limitations on the present invention. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. An explosion-proof valve, characterized in that: The explosion-proof valve is used for a battery, the battery comprises a cover plate (20), the explosion-proof valve is suitable for being installed at an explosion-proof hole of the cover plate (20), and the explosion-proof valve comprises: A valve body (1), the valve body (1) comprising: an upper core (11), an explosion core (12) and a lower core (13); the cross-sectional areas of the upper core (11) and the lower core (13) are both larger than the cross-sectional area of ​​the explosion core (12); the upper core (11) is suitable for being passed through the explosion-proof hole and being gap-matched with the explosion-proof hole; the upper core (11) has an upper flange (111); the lower core (13) has a lower flange (131); in the axial direction of the explosion-proof hole, the explosion core (12) is connected between the upper core (11) and the lower core (13); and the upper flange (111) and the lower flange (131) are arranged opposite to each other on both sides of the cover plate (20); An elastic member (2), in the axial direction of the explosion-proof hole, one end of the elastic member (2) presses against the lower flange (131), and the other end of the elastic member (2) is suitable for pressing against the inner wall (203) of the cover plate (20).

2. The explosion-proof valve according to claim 1, characterized in that: The explosion-proof valve further comprises: a sealing ring (3); in the axial direction of the explosion-proof hole, the sealing ring (3) is adapted to be clamped between the upper flange (111) and the outer wall (202) of the cover plate (20).

3. The explosion-proof valve according to claim 1, characterized in that: The explosion-proof valve further comprises: a protection ring (4), which is sandwiched between the upper core (11) and the explosion-proof hole in the radial direction of the explosion-proof hole; An air guide groove (112) is formed on the outer side wall of the upper core (11), and the air guide groove (112) and the protective ring (4) together define an air guide channel communicating with the interior of the battery.

4. The explosion-proof valve according to claim 3, characterized in that: There are multiple air guide grooves (112), and the multiple air guide grooves (112) and the protection ring (4) together define multiple air guide channels.

5. The explosion-proof valve according to claim 4, characterized in that: The total flow area of ​​the plurality of air guide channels is S1, which satisfies the relationship: 1.6×10 -14 m 2 ≤S1≤2.0×10 -14 m 2 .

6. The explosion-proof valve according to claim 1, characterized in that: The upper flange (111) and the lower flange (131) are both annular flanges.

7. The explosion-proof valve according to claim 1, characterized in that: The cross-sectional area of ​​the explosive core (12) is S2, which satisfies the relationship: 3×10 -14 m 2 ≤S2≤5×10 -14 m 2 .

8. The explosion-proof valve according to any one of claims 1 to 7, characterized in that: The valve body (1) is a machined aluminum part.

9. A cover plate assembly, characterized in that: include: A cover plate (20) and an explosion-proof valve according to any one of claims 1 to 8.

10. A battery, characterized in that: Comprising the cover plate assembly according to claim 9.

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