An explosion-proof valve, a battery and an electric device

Abstract

The application discloses an explosion-proof valve, a battery and an electric device. The explosion-proof valve comprises a valve body provided with a notch, wherein the valve body comprises a connecting part connected to both ends of the notch; the tensile strength of the valve body is sigma b ; the residual thickness at the notch is t; the burst value of the valve body is P; the pressure relief coefficient of the valve body is k; the distance between the connecting part and the end of the notch away from the connecting part is a force arm, and the force arm is D; k=t / P, wherein 0.8<=k<=1.3. When k is greater than or equal to 0.8 and less than or equal to 1.3, the burst value of the explosion-proof valve can remain stable for a long time, the degree of decrease of the burst value of the valve body caused by the release of the internal residual stress of the explosion-proof valve is reduced, and the explosion-proof valve can be normally used.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of batteries, in particular to an explosion-proof valve, a battery and an electric device. BACKGROUND

[0002] The explosion-proof valve is a commonly used structure in batteries, and is used to timely open the valve to release pressure when thermal runaway occurs in the battery cell, reduce the risk of explosion, and ensure the safety of the battery system. When designing the burst value of the explosion-proof valve, it needs to meet the requirements that the valve cannot be opened during the entire life cycle of the battery cell under normal use, and the valve can be opened to release pressure before the shell cover bursts when the battery cell is in thermal runaway. The explosion-proof valve is an important component for ensuring the safety of the battery.

[0003] However, it is found in actual use that the burst value of the explosion-proof valve on the cover plate of some battery cells meets the requirements in the initial state, but the burst value of the explosion-proof valve of this part decreases after a period of time, such as 3 months or half a year, even if the cover plate does not bear the pressure in the battery cell.

[0004] The main reason for the above-mentioned situation is that there is residual stress in the explosion-proof valve during the stamping process. Annealing treatment is needed after stamping to eliminate the residual stress in the sheet. Due to incomplete annealing of the cover plate, the strength of the cover plate does not reach a stable value, and the residual stress in the explosion-proof valve sheet remains from the stamping process. The residual stress is slowly released over time, resulting in a decrease in the tensile strength of the explosion-proof valve, so that the burst value of the explosion-proof valve does not meet the specification requirements. SUMMARY

[0005] Therefore, the present application provides an explosion-proof valve, a battery and an electric device, which solve the technical problem that the residual stress in the explosion-proof valve sheet remains from the stamping process is slowly released over time, resulting in a decrease in the tensile strength of the explosion-proof valve, so that the burst value of the explosion-proof valve does not meet the specification requirements.

[0006] To achieve the above-mentioned purpose, the first aspect of the present application provides an explosion-proof valve, which adopts the following technical scheme:

[0007] The explosion-proof valve comprises:

[0008] The valve body is provided with a notch; the valve body comprises a connecting portion connected to both ends of the notch;

[0009] The tensile strength of the valve body is σ b ; the residual thickness at the notch is t; the burst value of the valve body is P; and the pressure release coefficient of the valve body is k;

[0010] The distance between the connecting portion and the end of the notch away from the connecting portion is a force arm, and the force arm is D; k= wherein 0.8≤k≤1.3.

[0011] Optionally, the valve body further comprises a body part and a rim part, the rim part is arranged around the body part, the score is arranged between the body part and the rim part; the thickness of the connecting part is e, the thickness of the body part is w, t

[0012] Optionally, 0.3w

[0013] Optionally, the shear strength of the valve body is τ, 0.5σ b ≤τ≤0.6σ b , 1.3≤ ≤2.6.

[0014] Optionally, 0.9≤k≤1.2.

[0015] Optionally, the score is in a square ring shape, the connecting part is in a strip shape, the vertical distance between the connecting part and the end of the score away from the connecting part is the force arm, or the score is in an oval ring shape, the connecting part is in an arc shape, the maximum vertical distance between the tangent line of the connecting part and the end of the score away from the connecting part is the force arm, or the score is in a rounded rectangular ring shape, the connecting part is in a strip shape, the vertical distance between the connecting part and the end of the score away from the connecting part is the force arm, or the score is in an irregular shape, the maximum vertical distance between the tangent line of the connecting part and the end of the score away from the connecting part is the force arm.

[0016] Optionally, the burst value of the valve body is P, 0.5Mpa≤P≤2Mpa, the score residual thickness t of the explosion-proof valve is 0.03mm≤t≤0.3mm, the force arm D of the explosion-proof valve is 4mm≤D≤44mm.

[0017] Optionally, the valve body is further provided with a groove, the score is arranged on the bottom wall of the groove, the rim part is arranged around the body part to define the groove, and the thickness of the rim part is greater than the thickness of the body part.

[0018] In a second aspect, the present application provides an explosion-proof valve, which adopts the following technical scheme:

[0019] A battery comprising the shell and the above-mentioned explosion-proof valve, and the explosion-proof valve is arranged on the shell.

[0020] In a third aspect, the present application provides an electric device, which adopts the following technical scheme:

[0021] An electric device comprising the above-mentioned explosion-proof valve, and / or the above-mentioned battery.

[0022] Compared with the prior art, the present application has the following beneficial effects: the valve body is provided with a notch, and after being stressed, the connecting part can serve as a fulcrum to push the valve body, so that the valve body bursts to play a pressure relief effect; the conventional detection method is to detect the burst value to determine whether the valve body can be normally used, but due to the existence of residual stress, this detection method does not have accuracy; based on this, the burst value of the valve body is derived as P= , and then this relationship is changed into: the pressure relief coefficient k= , based on this relationship, by controlling the mutual ratio of the notch residual thickness t, the tensile strength, the burst value P of the valve body, and the force arm D, the pressure relief coefficient k is kept in the range of greater than or equal to 0.8 and less than or equal to 1.3, so that the burst value of the explosion-proof valve remains stable for a long time, reduces the degree of the burst value of the valve body caused by the release of the internal residual stress of the explosion-proof valve, thereby avoiding the explosion-proof valve from being opened during the normal use of the battery cell, and ensuring that the explosion-proof valve can still be normally and safely used under the condition of long time span. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0024] Figure 1 The structure schematic diagram of the first valve body of the explosion-proof valve provided by the embodiments of the present application;

[0025] Figure 2 The sectional view of A-A direction in Figure 1

[0026] Figure 3 The structure schematic diagram of the second valve body of the explosion-proof valve provided by the embodiments of the present application;

[0027] Figure 4 The structure schematic diagram of the third valve body of the explosion-proof valve provided by the embodiments of the present application;

[0028] Figure 5 The structure schematic diagram of the fourth valve body of the explosion-proof valve provided by the embodiments of the present application;

[0029] Figure 6 The structure schematic diagram of the fifth valve body of the explosion-proof valve provided by the embodiments of the present application;

[0030] Figure 7 The structure schematic diagram of another form of the fifth valve body of the explosion-proof valve provided by the embodiments of the present application; ​

[0031] Figure 8 A structural schematic diagram of a battery provided for an embodiment of the present application is shown in FIG. 1.

[0032] Figure 9 A structural schematic diagram of a cover plate and a valve body provided for an embodiment of the present application is shown in FIG. 2.

[0033] Reference signs:

[0034] 100, valve body; 101, body portion; 102, edge portion; 110, groove; 120, score; 200, connecting portion; 300, cover plate; 310, opening. DETAILED DESCRIPTION

[0035] In order to make the inventive objectives, characteristics and advantages of the present application more obvious and easy to understand, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the embodiments described below are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application.

[0036] The technical solutions of the present application will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0037] In the description of the present application, it should be understood that the terms "upper", "lower", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be understood as limiting the present application.

[0038] In the production and manufacturing process of the explosion-proof valve, it usually needs to go through stamping, annealing and other processing steps. The role of the stamping step is to make the explosion-proof valve have different appearance profiles, and at the same time, to obtain the indentation by stamping to meet the pressure opening function of the explosion-proof valve, while the annealing step is used to change the metallographic structure inside the explosion-proof valve, to reduce the residual stress inside, to stabilize the size of the structure and to reduce the tendency of structure deformation and cracking.

[0039] However, in the annealing process, the product usually undergoes specific steps such as heating, holding and cooling at a suitable speed. At this time, if the annealing is not complete, the tensile strength of the explosion-proof valve will decrease, the explosion-proof value of the explosion-proof valve will not meet the specification requirements, and there is a possibility of producing fine cracks, which will cause hidden troubles to the safety of the battery in use. On the other hand, if the annealing temperature is not properly controlled, there will also be residual stress, which will cause softening phenomenon during annealing, resulting in unstable size of the explosion-proof valve, resulting in large explosion-proof value range of the cover plate 300 in the same batch, and the notch residual thickness t under the same explosion-proof value is large, which requires a large material thickness, resulting in material waste.

[0040] From the above description, it can be seen that there are many factors that cause residual stress in the structure of the explosion-proof valve, including but not limited to annealing temperature, annealing time, etc. However, the current detection method for detecting whether the explosion-proof valve is working normally mainly detects the size of the explosion-proof value, but this detection method has certain limitations, such as being unable to ensure the stability of the explosion-proof valve in a long time span, which will cause hidden troubles to the safety of use, and therefore it is necessary to further optimize the long-time stable use performance of the explosion-proof valve.

[0041] The following refers to Figures 1 to 9 The explosion-proof valve, the battery and the electric equipment according to the present application are described.

[0042] Referring to Figure 1 and Figure 2 , according to the first aspect of the embodiments of the present application, an explosion-proof valve is provided, which comprises a valve body 100, and a notch 120 is formed on the valve body 100. At the same time, the valve body 100 is also provided with a connecting portion 200, and the notch 120 and the connecting portion 200 are usually recessed and formed on the outer surface of the valve body 100 by etching. The connecting portion 200 is connected to both ends of the notch 120, and at this time the connecting portion 200 and the notch 120 form a closed loop structure. The notch 120 is equivalent to reducing the overall thickness of the valve body 100, so that it is easy to open when subjected to the pressure inside the battery, and during the opening process, the connecting portion 200 acts as a fulcrum. When subjected to pressure, the valve body 100 can be lifted towards the outside along the extension direction of the notch 120, thereby realizing the opening and pressure relief function and reducing the risk of battery explosion.

[0043] On this basis, in order to reflect the stability of the explosion-proof valve in long-term use from multiple aspects, a pressure relief coefficient is selected, and the pressure relief coefficient is defined as K, which satisfies the following relationship formula at this time:

[0044] P= , after conversion, k= ;

[0045] In this embodiment, the value range of K is controlled between 0.8≤k≤1.3, which is equivalent to:

[0046] 0.8≤ ≤1.3;

[0047] In the above parameters, the pressure relief coefficient of the valve body 100 is k, the burst value of the valve body 100 is P, the unit is MPa, the residual thickness of the notch 120 is t, the unit is mm, the tensile strength of the valve body 100 is σ b , the unit is MPa; the pressure relief coefficient of the valve body 100 is k, it can be understood that, as shown in Figure 1 , the distance between the connecting part 200 and the end of the notch 120 away from the connecting part 200 is the force arm, the force arm is the vertical distance from the action line of the force to the rotating shaft, it can be understood that the force arm takes the connecting part 200 as the starting point, and the farthest end away from the connecting part 200 as the terminal point, and this terminal part is also the weak point of the valve body 100, the pressure will first tear the valve body 100 from this position, and then drive the valve body 100 to open entirely, on this basis, the force arm is defined as D, the unit is mm.

[0048] It can be understood that the above parameters have the following relationship: under the condition that other parameters remain unchanged, the first case is that the notch residual thickness t increases, which will improve the shear performance of the notch 120, thereby increasing the burst value P; the second case is that the tensile strength σ b increases, which will also improve the shear performance of the material, thereby increasing the burst value P; the third case is that when the force arm D increases, it means that the pressure required to drive the valve body 100 to deform becomes smaller, thereby reducing the burst value P.

[0049] At this point, based on the above relationship, on the one hand, by setting the notch 120 and the connecting part 200 on the valve body 100, the valve body 100 can be opened under pressure, and under the action of the fulcrum of the connecting part 200, the valve body 100 can be sequentially opened from the notch 120 away from the connecting part 200 to the notch close to the connecting part 200, and the opening action is stable and reliable; on the other hand, the above relationship is equivalent to the overall correlation of the burst value P, the notch residual thickness t, the tensile strength σ b of the valve body 100, and the force arm D and other parameters, by limiting the value range of the pressure relief coefficient k, the parameters can achieve a relatively reasonable overall value, thereby finally improving the use stability of the valve body 100 in a long time environment.

[0050] Further, continue to refer to Figure 1 and Figure 2, the valve body 100 further comprises a body part 101 and a rim part 102. The rim part 102 is located outside the body part 101, and the rim part 102 is arranged around the body part 101; at the same time, the notch 120 is arranged between the body part 101 and the rim part 102, and the connecting part 200 is located between the body part 101 and the rim part 102; generally, the notch 120 is integrally connected with the body part 101 and the rim part 102 respectively, and the connecting part 200 is integrally connected with the body part 101 and the rim part 102 respectively, and the integrally connected manner can obtain good connection stability between structures; at this time, the thickness of the connecting part 200 is defined as e, and the thickness of the body part 101 is defined as w, and the thickness e and the thickness w satisfy the following relationship: t Figure 2 The thickness relationship of the notch 120, the connecting part 200 and the body part 101 is consistent with the Z direction, and satisfies the following relationship: t

[0051] Based on the above structure, under the condition of satisfying the above thickness relationship, the shear resistance of the body part 101 is greater than that of the connecting part 200, and the shear resistance of the connecting part 200 is greater than that of the notch 120, so that when the pressure of the explosion-proof valve breaks through the critical value, the notch 120 can be damaged first, the body part 101 can be opened along the notch 120, and then the body part 101 and the rim part 102 are separated; at this time, the connecting part 200 can still maintain the effect of connecting the body part 101 and the rim part 102, thereby playing the role of fulcrum; at the same time, in the process of opening the body part 101, because the thickness of the body part 101 is greater than the thickness of the notch 120 and the connecting part 200, good shear resistance can be obtained, so that the body part 101 is not easy to be damaged during opening, thereby the pressure relief hole on the battery can be opened more completely, the opening action is stable and complete, and the pressure relief action demand can be better met.

[0052] Further, in order to optimize the stability of the explosion-proof valve under long-term conditions, 0.3w

[0053] On the one hand, the notch residual thickness t is equivalent to the difference between the thickness w of the body part 101 and the depth of the notch 120; when the notch residual thickness t is less than or equal to 0.3w, the mutual ratio between the notch 120 and the body part 101 will be too small, and under long-term conditions, the residual stress will cause the shear resistance of the connection between the two to be insufficient, which is easy to cause fracture, so that the body part 101 is opened too early, which affects the strength of the explosion-proof valve, and further affects the stability of the explosion value; when the notch residual thickness t is greater than or equal to 0.7w, because the thickness of the notch 120 part accounts for a large proportion, the body part 101 is not easy to open, which will also affect the stability of the explosion value.

[0054] On the other hand, when the thickness e of the connecting portion 200 is less than or equal to 1.2t, the thickness e of the connecting portion 200 is close to the residual thickness of the notch 120 at this time, resulting in a thin overall thickness of the connecting portion 200, which is prone to breakage under pressure, affecting the fulcrum effect of the connecting portion 200, resulting in weakened support effect of the connecting portion 200 on the body portion 101, and unbalanced stress on the body portion 101, affecting the blasting value; when the thickness e of the connecting portion 200 is greater than 0.9w, the thickness e of the connecting portion 200 is close to the thickness w of the body portion 101, which will result in that the connecting portion 200 cannot well adapt to the opening action of the body portion 101, and it is difficult to deform, affecting its fulcrum function, and it is also possible to cause opening difficulty, resulting in excessive internal pressure of the battery, affecting safety performance.

[0055] Therefore, when 0.3w < t < 0.7w, 1.2t < e < 0.9w, the body portion 101 can obtain a relatively stable blasting value in a long-term state, and at the same time, it is beneficial to the opening of the body portion 101 under appropriate pressure, and the safety performance is guaranteed.

[0056] Further, with reference to Figure 2 In order to optimize the structural stability of the valve body 100, the valve body 100 is further provided with a groove 110, the notch 120 is arranged on the bottom wall of the groove 110, and the edge portion 102 is arranged around the body portion 101 to define the groove 110, and in addition, the thickness of the edge portion 102 is greater than the thickness of the body portion 101.

[0057] At this time, on the one hand, the groove 110 can accommodate the body portion 101 therein, and play a certain protection role; on the other hand, the thickness of the edge portion 102 is set to be greater than the thickness of the body portion 101, so that the edge portion 102 has better shear performance than the body portion 101, and the edge portion 102 is not prone to deformation when the valve body 100 is blasted, so as to facilitate the smooth opening of the body portion 101.

[0058] Based on the above structure, in some embodiments, the value of k can be controlled at 0.8, 0.98, 0.9, 0.95, 1.0, 1.07, 1.11, 1.2 or 1.3, etc. In other embodiments, the value of k can also be controlled in the range between any two of the above-mentioned values, and the range between any two of the above-mentioned values will not be listed here; when the value of k is in the above-mentioned value point or value range, the blasting value can be kept small for a long time.

[0059] Preferably, the range of the value of k is further reduced, wherein 0.9 ≤ k ≤ 1.2. Experiments show that when the range of the value of k is limited to 0.9 to 1.2, the blasting value resists decay better for a long time.

[0060] In one embodiment, the burst value P of the valve body 100 is in the range of 0.5Mpa≤P≤2Mpa. If the burst value of the valve body 100 is less than 0.5Mpa, the valve body 100 is prone to open at a small pressure, causing the valve body 100 to open prematurely. If the burst value of the valve body 100 is greater than 2Mpa, it will increase the difficulty of opening the valve body 100. Therefore, when the burst value P of the valve body 100 is in the above range, the valve body 100 can open in time under a reasonable opening pressure, thereby achieving timely exhaust and avoiding battery explosion.

[0061] For example, the burst value P of the valve body 100 can be 0.5Mpa, 0.6Mpa, 0.7Mpa, 0.8Mpa, 0.882Mpa, 0.887Mpa, 0.892Mpa, 0.894Mpa, 0.9Mpa, 0.903Mpa, 1.0Mpa, 1.1Mpa, 1.2Mpa, 1.3Mpa, 1.4Mpa, 1.5Mpa, 1.596Mpa, 1.6Mpa, 1.605Mpa, 1.7Mpa, 1.8Mpa, 1.9Mpa, 2.0Mpa, etc. It can be understood that the burst value P can also be controlled in the range between any two of the above values.

[0062] In one embodiment, the notch residual thickness t of the explosion-proof valve is in the range of 0.03mm≤t≤0.3mm. If the notch residual thickness t is less than 0.03mm, the connection thickness of the notch 120 will be too small and prone to breakage, resulting in insufficient strength and possible premature opening of the explosion-proof valve. If the thickness of the notch 120 is greater than 0.3mm, the thickness of the notch 120 will be too large, increasing the difficulty of opening the valve body 100, making it difficult for the valve body 100 to open in time, resulting in failure to exhaust in time and increasing the risk of battery explosion. Therefore, when the notch residual thickness t is in the range of 0.03mm to 0.3mm, the valve body 100 can obtain good connection strength and avoid premature opening as much as possible, and the valve body 100 can open in time under suitable pressure, so that the valve body 100 can play its explosion-proof role in time.

[0063] For example, the notch residual thickness t can be 0.03mm, 0.05mm, 0.079mm, 0.1mm, 0.112mm, 0.125mm, 0.131mm, 0.153mm, 0.156mm, 0.2mm, 0.214mm, 0.25mm, 0.3mm, etc. It can be understood that the notch residual thickness t can also be controlled in the range between any two of the above values.

[0064] In one embodiment, the arm D of the explosion-proof valve is in the range of 4mm≤D≤44mm. Wherein, the arm D can affect the pressure required for the valve body 100 to open, and in turn affect the size of the burst value P. Wherein, if the arm D is less than 4mm, the pressure required for the valve body 100 to open will increase, resulting in the valve body 100 not being able to open in time, and the risk of explosion inside the battery increases; when the value of the arm D is greater than 44mm, the burst value P of the arm will decrease, which means that only a small pressure is needed to make the valve body 100 open, which will also cause the valve body 100 to open in advance, affecting normal use; therefore, by controlling the value of the arm D in the range of 4mm≤D≤44mm, the valve body 100 can be guaranteed to have a reasonable burst value P, so that the valve body 100 can open in time under suitable pressure, and the valve body 100 can play its explosion-proof role in time.

[0065] For example, the arm D of the explosion-proof valve can be: 4mm, 5mm, 10mm, 15mm, 15.8mm, 20mm, 20.7mm, 25mm, 30mm, 35mm, 40mm, 44mm, etc. It can be understood that the value of the arm D of the explosion-proof valve can also be controlled in the range between any two of the above-mentioned value points.

[0066] Further, in actual application, due to different design requirements of different types of batteries, the shape and contour of the valve body 100 are also different. Specifically, the shape and contour of the valve body 100 are mainly reflected in the extension contour of the notch 120. At this time, different valve body 100 contours can adapt to the opening requirements of different battery types. In order to define the arm D under different shapes of the notch 120, the following several notch 120 structures are provided in this embodiment as examples, but the shape of the valve body 100 of the present application is not limited to the following several notch 120 contour schemes.

[0067] Specifically, in one embodiment, referring to Figure 3 , the notch 120 is square ring-shaped, and the notch 120 has four sides connected in sequence. At this time, the connecting portion 200 is located on one of the sides of the notch 120, and the connecting portion 200 is strip-shaped. At this time, the side where the connecting portion 200 is located is arranged opposite to the other side, and the vertical distance between the other side and the connecting portion 200 is the farthest, so the vertical distance between the connecting portion 200 and the end of the notch 120 away from the connecting portion 200 is the arm. At this time, when the valve body 100 is subjected to pressure from the inside of the battery, the valve body 100 first opens from the other side of the notch 120 away from the connecting portion 200.

[0068] In another embodiment, referring back to Figure 1, the notch 120 can also be in the shape of an oval ring, in which case the notch 120 has two straight sections parallel to each other and two arc-shaped sections opposite to each other, the arc-shaped sections being located at the ends of the straight sections and connected to the straight sections, in which case the connecting portion 200 can be arranged at the straight sections or in the arc-shaped sections; when the connecting portion 200 is located in the arc-shaped sections of the notch 120, the connecting portion 200 is in the shape of an arc to adapt to the extension profile of the arc-shaped sections, thereby being able to more stably serve as a fulcrum; in this case, the maximum vertical distance between the tangent of the connecting portion 200 and the end of the notch 120 away from the connecting portion 200 is the force arm, based on the above arrangement, when the valve body 100 is subjected to pressure from the inside of the battery, the valve body 100 is opened from the other arc-shaped section of the notch 120 away from the connecting portion 200.

[0069] It can be understood that, with reference to Figure 1 , the connecting portion 200 of the present scheme is located at the straight sections of the oval ring-shaped notch 120, and the size of the force arm D is consistent with the case of the square ring-shaped notch 120 described above, which will not be repeated here.

[0070] Further, with reference to Figure 4 , if the notch 120 is in the shape of a circle, in this case, the profile of the notch 120 can be understood as a further deformation of the oval ring shape, which is equivalent to omitting the straight sections of the notch 120, in which case the connecting portion 200 arranged on the notch 120 is in the shape of an arc, and the size of the force arm D is the diameter of the notch 120.

[0071] In another embodiment, with reference to Figure 5 , the notch 120 is in the shape of a rounded rectangular ring. Specifically, the rounded rectangular ring-shaped notch 120 includes two long sides parallel to each other and two short sides parallel to each other, and the connecting portion 200 can be arranged on the long sides or on the short sides, in which case the connecting portion 200 is in the shape of a strip, and the vertical distance between the connecting portion 200 and the end of the notch 120 away from the connecting portion 200 is the force arm. It can be understood that the force arm is formed in a similar manner to the force arm of the square ring-shaped notch 120 described above, when the connecting portion 200 is located on the long sides of the notch 120, the size of the force arm is the length of the short sides, and when the connecting portion 200 is located on the short sides, the size of the force arm is the length of the long sides, if the valve body 100 is subjected to pressure from the inside of the battery, the valve body 100 will be opened from the other side of the notch 120 away from the connecting portion 200.

[0072] In another embodiment, the notch 120 is in the shape of an irregular figure. Specifically, as Figure 6As shown, the score 120 has a runway profile, at this time, the score 120 includes two opposite flat sections, and also includes two arc-shaped sections at both ends, one of which has a smaller curvature, and the other has a larger curvature, and the arc-shaped section and the flat section are connected to form two flat sections arranged in a figure-eight shape, and a large and small arc-shaped section opposite to the opening 310, and finally form a runway profile.

[0073] At this time, the connecting portion 200 can be arranged on the flat section or the arc-shaped section. Referring to Figure 7 When the connecting portion 200 is located in one of the arc-shaped sections, the maximum vertical distance between the tangent line of the connecting portion 200 and the end of the score 120 away from the connecting portion 200 is the force arm, which is equivalent to the distance between the two arc-shaped sections as the force arm distance.

[0074] When the connecting portion 200 is located in the flat section, referring to Figure 6 At this time, the maximum vertical distance between the tangent line of the connecting portion 200 and the end of the score 120 away from the connecting portion 200 is the force arm, but before that, an extension line tangent to the arc-shaped section near the force arm is needed, and the intersection distance between the tangent line of the connecting portion 200 and the extension line of the arc-shaped section is the force arm distance, which determines the force arm defining method of the irregular pattern.

[0075] In summary, when determining the size of the force arm, the setting position of the connecting portion 200 should be determined first. If the connecting portion 200 is a strip, a vertical line is drawn on the basis of the strip, and the length of the vertical line extended to the other side of the score 120 is the force arm distance. When the connecting portion 200 is an arc-shaped structure, the tangent line of the connecting portion 200 is obtained, and the length of the vertical line of the tangent line extended to the other side of the score 120 is the size of the force arm. When the pattern is irregular, an extension line can be arranged on the other side of the score 120, and the intersection distance between the vertical line of the connecting portion 200 and the extension line is determined to obtain the size of the force arm. Therefore, as long as the size of the force arm of the score 120 can be measured, the relationship in this embodiment can be applied.

[0076] The explosion-proof valve is tested under different parameters, and the test results are shown in Table 1:

[0077]

[0078] Table 1

[0079] It should be explained that the tensile strength σ b in the above table is a relatively ideal value under a predetermined suitable annealing temperature and time, and is not the actual tensile strength of the embodiment. If the actual tensile strength is to be measured, the sample must be destroyed, which will result in the inability to detect the blasting value. It can be understood that the tensile strength σ bThe actual size is usually related to the selected material, and in the same batch or the same type of material, the tensile strength σ b is usually constant, but in different materials, the tensile strength σ b has different values, for example, the material currently used by the explosion-proof valve is usually MFX2, which is a high-formability aluminum material with good mechanical processing performance, and the tensile strength of MFX2 is usually 110 Mpa; In addition, the explosion-proof valve usually tries to use steel materials such as SPCC, which is a "general cold-rolled carbon steel sheet and steel strip" that also has good mechanical properties and can meet the use requirements of the explosion-proof valve, and the tensile strength of SPCC is usually 310 Mpa; At this time, when the burst value P and the force arm D in the relationship are constant, the greater the tensile strength σ b , the better the mechanical properties of the material, and at this time the notch residual thickness t can be made smaller.

[0080] In addition, the initial burst value P is the average burst value of the same batch of explosion-proof valves, not the burst value of the sample tested after standing, and the initial burst value of the sample is considered to be close to the initial average burst value of the same batch.

[0081] At this time, based on the test data in the above table, the following comparisons can be made:

[0082] Example one and example two are compared:

[0083] The force arm is unchanged, the length of the explosion-proof valve is increased, the notch residual thickness t is basically consistent with the burst value, the coefficient k is within the above range, at this time it meets the relationship, and the burst value changes little after a long time of storage. It is explained that under this condition, the area of the explosion-proof valve can be improved by increasing the length of the explosion-proof valve. It can be understood that as long as the size of the force arm is not changed, no matter what structure the profile of the valve body 100 adopts, it can meet the above relationship. The above relationship has excellent universal testing effect and is suitable for valve 100 structures of various profile shapes.

[0084] Example one and example three are compared:

[0085] The force arm is smaller, the length of the explosion-proof valve is unchanged, the notch residual thickness t is also reduced, thereby making the notch residual thickness t correspondingly change, and finally making the burst value P basically consistent, and the coefficient k is also within the reasonable range, and the burst value changes little after a long time of storage.

[0086] Example one and example four are compared:

[0087] The arm and length are unchanged, the notch residual thickness t changes little, and the blasting value is basically consistent. However, the coefficient k of example four is not in the above range of 0.8-1.3, and actually reaches 1.35. The blasting value of the explosion-proof valve in example four decreases obviously after long-term standing, and the reason is that the internal stress is not completely eliminated during the annealing process. Therefore, the internal stress can be quickly known to determine whether the blasting value P of the explosion-proof valve under long-term conditions has stability.

[0088] Example one and example five are compared:

[0089] The arm and length are unchanged, the notch residual thickness t changes little, and the blasting value is basically consistent. However, the coefficient k of example four is not in the above range of 0.8-1.3, and actually reaches 1.35. The blasting value of the explosion-proof valve in example four decreases obviously after long-term standing, and the reason is that the internal stress is not completely eliminated during the annealing process. Therefore, the internal stress can be quickly known to determine whether the blasting value P of the explosion-proof valve under long-term conditions has stability.

[0090] Example one and example six are compared:

[0091] The arm and length are unchanged, the material changes, the tensile strength changes, and correspondingly, the residual thickness and the blasting value also change. The coefficient k is in the above range, and the blasting value changes little after long-term storage. Therefore, it can be known that the relationship of the present embodiment can meet the long-term stability test requirements of different materials.

[0092] Example six and example seven are compared:

[0093] The arm and length are unchanged, the residual thickness changes, and the blasting value is basically consistent. However, the coefficient k of example four is not in the above range of 0.8-1.3, and is 1.36. Its blasting value decreases obviously after long-term standing, and the reason is that the internal stress is not completely eliminated during the annealing process. At this time, the accuracy of the relationship is further verified.

[0094] In summary, in order to achieve the effect of not reducing the long-term burst value of the explosion-proof valve, the parameters in the relationship should be adjusted as a whole. If a single parameter is adjusted greatly, although the problem of rapid reduction of the burst value can be overcome, problems such as uncontrollable size, safety hazards or material waste may occur. Only by adjusting the ratio of each parameter within a reasonable range can the explosion-proof valve be kept stable for a long time, meet the design specification requirements, and reduce safety hazards.

[0095] Alternatively, the relationship of the pressure relief coefficient k can also be controlled and calculated by referring to more different parameters, such as introducing shear strength as a control parameter in another embodiment. Here, for the sake of description, the shear strength of the valve body 100 is defined as τ. It can be understood that the shear strength is generally 50% to 60% of the tensile strength of the material, so we have: 0.5σ b ≤τ≤0.6σ b .

[0096] By substituting this relationship into the above relationship of the pressure relief coefficient k, the final transformation can be obtained as:

[0097] 1.3≤ ≤2.6;

[0098] As can be seen from the above relationship, when using shear strength to test the long-term burst value stability of the explosion-proof valve, only the value of the pressure relief coefficient needs to be controlled in the range of 1.3 to 2.6, which is conducive to the stability of the explosion-proof valve being tested under more different types of parameters and is more convenient to use.

[0099] Exemplarily, The value of k can be 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, etc., or a range between any two of the above parameter values.

[0100] Preferably, based on the above relationship, the numerical range can be further controlled, such as 1.5≤ <2.4. In this range, the burst value of the explosion-proof valve remains relatively stable for a long time, and the burst value does not become smaller due to the release of internal residual stress, thereby avoiding the explosion-proof valve opening during normal use of the battery.

[0101] With reference to Figure 8 and Figure 9 , the battery of the second aspect embodiment of the present application comprises a shell and the explosion-proof valve of the first aspect embodiment described above, and the explosion-proof valve is arranged on the shell.

[0102] Specifically, one side of the shell is provided with an opening 310, and a cover plate 300 is arranged at the opening 310, the cover plate 300 is provided with a pressure relief port, and the valve body 100 of the explosion-proof valve is arranged on the cover plate 300 and covers the pressure relief port.

[0103] In addition, the power equipment of the third aspect of the present application comprises the explosion-proof valve of the first aspect of the present application and / or the battery of the first aspect of the present application. It can be understood that the power equipment includes but is not limited to electric vehicles, energy storage systems, medical devices, unmanned aerial vehicles, model aircraft equipment, and electric tools, etc. The specific form of the power equipment is not limited here.

[0104] It should be noted that in this paper, relational terms such as first and second are used only to distinguish one entity or operation from another, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment.

[0105] Although the embodiments of the present application have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and spirits of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

[0106] The above, the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirits and scopes of the technical solutions of the embodiments of the present application.

Claims

1. An explosion-proof valve, characterized in that, include: The valve body (100) is provided with grooves (120); the valve body (100) includes a connecting part (200) which is connected to both ends of the grooves; The tensile strength of the valve body (100) is σ b The residual thickness at the notch (120) is the notch residual thickness t; the burst value of the valve body (100) is P; the pressure relief coefficient of the valve body (100) is k; The distance between the connecting part (200) and the end of the groove (120) away from the connecting part (200) is the lever arm, and the lever arm is D; k= Where 0.8 ≤ k ≤ 1.3; The burst value of the valve body (100) is P, 0.5 MPa ≤ P ≤ 2 MPa, the residual thickness of the groove of the explosion-proof valve is t, 0.03 mm ≤ t ≤ 0.3 mm, and the lever arm of the explosion-proof valve is D, 4 mm ≤ D ≤ 44 mm.

2. The explosion-proof valve according to claim 1, characterized in that, The valve body (100) further includes a body portion (101) and an edge portion (102), the edge portion (102) being disposed around the body portion (101), and the groove (120) being disposed between the body portion (101) and the edge portion (102); the thickness of the connecting portion (200) is e, the thickness of the body portion (101) is w, and t <e<w。 3. The explosion-proof valve according to claim 2, characterized in that, 0.3w <t<0.7w,1.2t<e<0.9w。 4. The explosion-proof valve according to claim 1, characterized in that, The shear strength of the valve body (100) is τ, 0.5σ. b ≤τ≤0.6σ b , 1.3≤ ≤2.

6.

5. The explosion-proof valve according to any one of claims 1 to 4, characterized in that, 0.9≤k≤1.2。 6. The explosion-proof valve according to claim 1, characterized in that, The engraving is square-ring shaped, the connecting part (200) is strip-shaped, and the vertical distance between the connecting part (200) and the end of the engraving (120) away from the connecting part (200) is the lever arm. Alternatively, the notch (120) may be elliptical, the connecting portion (200) may be arc-shaped, and the maximum vertical distance between the tangent of the connecting portion (200) and the end of the notch (120) away from the connecting portion (200) may be the lever arm. Alternatively, the notch (120) may be a rounded rectangular ring, the connecting portion (200) may be a strip, and the vertical distance between the connecting portion (200) and the end of the notch (120) furthest from the connecting portion (200) may be the lever arm. Alternatively, the notch (120) may be irregular in shape, and the maximum vertical distance between the tangent of the connecting portion (200) and the end of the notch (120) away from the connecting portion (200) may be the lever arm.

7. The explosion-proof valve according to claim 2, characterized in that, The valve body is also provided with a groove (110), the groove (120) is provided on the bottom wall of the groove (110), the edge portion (102) is provided around the body portion (101) to define the groove (110), and the thickness of the edge portion (102) is greater than the thickness of the body portion (101).

8. A battery, characterized in that, The battery includes a housing and an explosion-proof valve as described in any one of claims 1 to 7, the explosion-proof valve being disposed on the housing.

9. Electrical equipment, characterized in that, include: The explosion-proof valve according to any one of claims 1 to 7, and / or the battery according to claim 8.

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