Explosion-proof valve, battery and electric equipment

Abstract

The invention discloses an anti-explosion valve, a battery and electric equipment. Comprising a valve body provided with nicks. The valve body comprises a connecting part, and the connecting part is connected to the two ends of the nick; the tensile strength of the valve body is sigma b; the residual thickness of the nick is the nick residual thickness t; the blasting value of the valve body is P; the pressure relief coefficient of the valve body is k; the distance between the connecting part and one end, far away from the connecting part, of the nick is a force arm, and the force arm is D; k is equal to # imgabs0 #, and k is larger than or equal to 0.8 and smaller than or equal to 1.3. When k is larger than or equal to 0.8 and smaller than or equal to 1.3, the explosion value of the explosion-proof valve can be kept stable in a long time, the degree that the explosion value of the valve body is decreased due to release of internal residual stress of the explosion-proof valve is reduced, and therefore the situation that the explosion-proof valve is opened in the normal use period of a battery cell is avoided, and it is guaranteed that the explosion-proof valve can be used normally.

Description

Technical Field

[0001] The invention relates to the field of batteries, and in particular to an explosion-proof valve, a battery and electrical equipment. Background Art

[0002] Explosion-proof valves are a commonly used structure in batteries. They are used to open and release pressure in time when the battery cell experiences thermal runaway, thereby reducing the risk of explosion and ensuring the safety of the battery system. The explosion value of the explosion-proof valve must be designed to ensure that the valve cannot be opened during the entire life cycle of normal use of the battery cell, but that the valve can be opened to release pressure before the shell cover explodes when the battery cell experiences thermal runaway. The valve is an important component for ensuring battery safety.

[0003] However, in actual use, it was found that the explosion-proof values ​​of the explosion-proof valves on the covers of some battery cells met the requirements in the initial state, but even if the covers of these explosion-proof valves were not subjected to the internal pressure of the battery cells, the explosion values ​​of these explosion-proof valves would decrease over time, such as after 3 months or half a year.

[0004] The main reason for the above situation is that residual stress will be left in the explosion-proof valve during the stamping process. Annealing treatment is required after stamping to eliminate the residual stress in the sheet. Due to incomplete annealing, the strength of the cover plate has not reached a stable value, and residual stress from the stamping process is still left in the explosion-proof valve sheet. The residual stress will be slowly released over time, resulting in a decrease in the tensile strength of the explosion-proof valve, making the explosion value of the explosion-proof valve fail to meet the specification requirements. Summary of the invention

[0005] To this end, the present invention provides an explosion-proof valve, a battery and an electrical device, which solve the technical problem that the residual stress from the stamping process still remains in the explosion-proof valve sheet and is slowly released over time, resulting in a decrease in the tensile strength of the explosion-proof valve, making the explosion value of the explosion-proof valve fail to meet the specification requirements.

[0006] In order to achieve the above-mentioned object, the first aspect of the present invention provides an explosion-proof valve, which adopts the following technical solution:

[0007] Explosion-proof valve, including:

[0008] The valve body is provided with a notch; the valve body includes a connecting portion, and the connecting portion is 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 the notch residual thickness t; the burst value of the valve body is P; the pressure relief 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 the force arm, and the force arm is D; k= , where 0.8≤k≤1.3.

[0011] Optionally, the valve body further comprises a main body and an edge portion, the edge portion is arranged around the main body, and the notch is arranged between the main body and the edge portion; the thickness of the connecting portion is e, the thickness of the main body is w, and the thickness of the t <e<w。

[0012] Optional, 0.3w <t<0.7w,1.2t<e<0.9w。

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

[0014] Optional, 0.9≤k≤1.2.

[0015] Optionally, the notch is in the shape of a square ring, the connecting portion is in the shape of a strip, and the vertical distance between the connecting portion and the end of the notch away from the connecting portion is the lever arm; or, the notch is in the shape of an elliptical ring, the connecting portion is in the shape of an arc, and the maximum vertical distance between the tangent of the connecting portion and the end of the notch away from the connecting portion is the lever arm; or, the notch is in the shape of a rounded rectangular ring, the connecting portion is in the shape of a strip, and the vertical distance between the connecting portion and the end of the notch away from the connecting portion is the lever arm; or, the notch is in the shape of an irregular shape, and the maximum vertical distance between the tangent of the connecting portion and the end of the notch away from the connecting portion is the lever arm.

[0016] Optionally, the bursting value of the valve body is P, 0.5Mpa≤P≤2Mpa, the residual thickness of the notch of the explosion-proof valve is t, 0.03mm≤t≤0.3mm, and 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 notch is provided on the bottom wall of the groove, the edge portion is provided around the main body portion to define and form the groove, and the thickness of the edge portion is greater than the thickness of the main body portion.

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

[0019] The battery comprises the shell and the explosion-proof valve, wherein the explosion-proof valve is arranged on the shell.

[0020] In a third aspect, the present invention provides an electrical device, which adopts the following technical solution:

[0021] Electrical equipment, including the above-mentioned explosion-proof valve, and / or the above-mentioned battery.

[0022] Compared with the prior art, the present invention has the following beneficial effects: the valve body is provided with notches, and after being subjected to force, the connection part can be used as a fulcrum to push the valve body, so that the valve body bursts and has a pressure relief effect; the conventional detection method is to detect the burst value to determine whether the valve body can be used normally, but due to the existence of residual stress, this detection method is not accurate; based on this, the burst value of the valve body is derived to be P= , and then transform this relationship into: Pressure relief coefficient k = Based on this relationship, by controlling the ratio of the notch residual thickness t, tensile strength, the bursting value P of the valve body, and the lever arm D, the pressure relief coefficient k is maintained in the range of greater than or equal to 0.8 and less than or equal to 1.3, so that the bursting value of the explosion-proof valve remains relatively stable for a long time, and the degree to which the bursting value of the valve body becomes smaller due to the release of the internal residual stress of the explosion-proof valve is reduced, thereby avoiding the explosion-proof valve from opening during the normal use of the battery cell, and ensuring that the explosion-proof valve can be used normally and safely under long-term spans. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0024] Figure 1 A schematic structural diagram of a first type of valve body of an explosion-proof valve provided in an embodiment of the present invention;

[0025] Figure 2 for Figure 1 Sectional view along AA direction;

[0026] Figure 3 A schematic structural diagram of a second valve body of an explosion-proof valve provided in an embodiment of the present invention;

[0027] Figure 4 A schematic structural diagram of a third valve body of an explosion-proof valve provided in an embodiment of the present invention;

[0028] Figure 5 A schematic structural diagram of a fourth valve body of an explosion-proof valve provided in an embodiment of the present invention;

[0029] Figure 6 A schematic structural diagram of a fifth valve body of an explosion-proof valve provided in an embodiment of the present invention;

[0030] Figure 7 A schematic structural diagram of another form of the fifth valve body of the explosion-proof valve provided in an embodiment of the present invention;

[0031] Figure 8 A schematic diagram of the structure of a battery provided by an embodiment of the present invention;

[0032] Fig. 9 A schematic structural diagram of a cover plate and a valve body provided in an embodiment of the present invention.

[0033] Reference numerals:

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

[0035] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0037] In the description of the present invention, it is necessary to understand that the orientations or positional relationships indicated by the terms "upper", "lower", "top", "bottom", "inside", "outside", etc. 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.

[0038] During the manufacturing process of explosion-proof valves, stamping, annealing and other processing steps are usually required. The purpose of the stamping step is to give the explosion-proof valve a different appearance profile, and to obtain indentations through 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, reduce residual stress inside, stabilize the size of the structure, and reduce structural deformation and crack tendency.

[0039] However, in the annealing process, the product usually undergoes specific steps such as heating, heat preservation, and cooling at an appropriate speed. At this time, if the annealing is incomplete, the tensile strength of the explosion-proof valve will be reduced, resulting in the explosion value of the explosion-proof valve not meeting the specification requirements, and there may also be small cracks, which will cause hidden dangers to the safety of battery use; on the other hand, if the annealing temperature is not properly controlled, there will be residual stress, which will cause softening during annealing, resulting in unstable size of the explosion-proof valve, resulting in large differences in the explosion value of the same batch of cover plates 300, and the residual thickness t of the notch will be large under the same explosion value, so the required material thickness will be large, resulting in material waste.

[0040] From the above brief description, it can be seen that there are many factors that cause residual stress in the explosion-proof valve structure, including but not limited to annealing temperature, annealing time, etc. At present, when detecting whether the explosion-proof valve is working normally, the main method is to directly detect the size of the explosion-proof value. However, the above detection method has certain limitations. For example, it cannot ensure that the explosion-proof valve remains stable under long-term conditions, posing a hidden danger to safety in use. Therefore, it is necessary to further optimize the long-term stable use performance of the explosion-proof valve.

[0041] Reference below Figures 1 to 9 The explosion-proof valve, battery and electrical equipment according to the present invention are described.

[0042] Reference Figure 1 and Figure 2 According to an embodiment of the present invention, in a first aspect, an explosion-proof valve is provided, including a valve body 100, on which a notch 120 is provided. At the same time, a connecting portion 200 is also provided on the valve body 100, and the notch 120 and the connecting portion 200 are usually formed by etching in a concave manner on the outer surface of the valve body 100, and the connecting portion 200 is connected to both ends of the notch 120. At this time, the connecting portion 200 and the notch 120 form a closed loop structure, and the notch 120 is equivalent to reducing the overall thickness of the valve body 100, thereby making it easy to open when subjected to pressure inside the battery, and in the opening process, the connecting portion 200 acts as a fulcrum, and when subjected to pressure, the valve body 100 can be lifted toward the outside along the extension direction of the notch 120, thereby realizing the opening 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 under long-term use from many aspects, a pressure relief coefficient is selected and defined as K. At this time, the following relationship formula must be satisfied:

[0044] P= , after conversion, we get: k= ;

[0045] In this embodiment, the value range of K is controlled within 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, in MPa, the residual thickness at the notch 120 is the notch residual thickness t, in mm, and the tensile strength of the valve body 100 is σ b , unit MPa; the pressure relief coefficient of the valve body 100 is k. It can be understood that if Figure 1 As shown, the distance between the connecting portion 200 and the end of the notch 120 away from the connecting portion 200 is the lever arm. The lever arm is the vertical distance from the line of action of the force to the rotation axis. It can be understood that the lever arm starts from the connecting portion 200 and ends at the farthest end away from the connecting portion 200. The end point 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 completely. On this basis, the lever arm is defined as D, in 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: the notch residual thickness t increases, which will improve the shear resistance at the notch 120, thereby increasing the burst value P; the second case is: the tensile strength σ b Increase, which will also improve the shear resistance of the material, thereby increasing the bursting value P; the third situation is: 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 bursting value P.

[0049] So far, based on the above relationship, on the one hand, by providing the notch 120 and the connecting portion 200 on the valve body 100, the valve body 100 can be opened when subjected to pressure, and under the action of the fulcrum of the connecting portion 200, the valve body 100 can be opened sequentially from the notch 120 far from the connecting portion 200 to the notch close to the connecting portion 200, and the opening action is smooth and reliable; on the other hand, the above relationship is equivalent to the burst value P, the notch residual thickness t, and the tensile strength σ of the valve body 100. b , and the force arm D and other parameters are integrally associated, and by limiting the value range of the pressure relief coefficient k, each parameter can reach a more reasonable value as a whole, which can ultimately improve the stability of the valve body 100 in long-term environments.

[0050] Further, continue to refer to Figure 1 and Figure 2, the valve body 100 also includes a main body 101 and an edge portion 102. The edge portion 102 is located outside the main body 101, and the edge portion 102 is arranged around the main body 101; at the same time, the notch 120 is arranged between the main body 101 and the edge portion 102, and the connecting portion 200 is located between the main body 101 and the edge portion 102; usually, the notch 120 is integrally connected to the main body 101 and the edge portion 102, respectively, and the connecting portion 200 is integrally connected to the main body 101 and the edge portion 102, respectively, and the integral connection method can achieve good connection stability between the structures; at this time, the thickness of the connecting portion 200 is defined as e, and the thickness of the main body 101 is defined as w, and the thickness e and the thickness w are Figure 2 The thickness of the notch 120, the connecting portion 200 and the main body 101 are consistent in the Z direction, and the thickness relationship between the notch 120, the connecting portion 200 and the main body 101 satisfies the following relationship: <e<w。

[0051] Based on the above structural setting, when the above thickness relationship is satisfied, the shear resistance of the main body 101 is greater than that of the connecting portion 200, and the shear resistance of the connecting portion 200 is greater than that of the notch 120, so that when the pressure breaks through the critical value of the explosion-proof valve, it can first cause damage at the notch 120, and the main body 101 can be opened along the notch 120, thereby separating the main body 101 from the edge portion 102; and at this time, the connecting portion 200 can still maintain the effect of connecting the main body 101 and the edge portion 102, thereby playing a fulcrum role; at the same time, in the process of opening the main body 101, because the thickness of the main body 101 is greater than the thickness of the notch 120 and the connecting portion 200, good shear resistance can be obtained, so that the main body 101 is not easily damaged when opened, and the pressure relief hole on the battery can be opened more completely, and the opening action is smooth and complete, which can better meet the pressure relief action requirements.

[0052] Furthermore, in order to optimize the stability of the explosion-proof valve under long-term conditions, 0.3w <t<0.7w,1.2t<e<0.9w。

[0053] On the one hand, the residual thickness t of the notch is equivalent to the difference between the thickness w of the main body 101 and the depth of the notch 120. When the residual thickness t of the notch is less than or equal to 0.3w, the ratio between the notch 120 and the main body 101 will be too small. Under long-term conditions, the residual stress will cause the shear resistance of the connection between the two to be insufficient, which may easily lead to fracture, causing the main body 101 to open prematurely, affecting the strength of the explosion-proof valve, and further affecting the stability of the bursting value; when the residual thickness t of the notch is greater than or equal to 0.7w, the main body 101 is not easy to open because the thickness of the notch 120 accounts for a large proportion, which will ultimately affect the stability of the bursting value.

[0054] On the other hand, when the thickness e of the connecting portion 200 is less than or equal to 1.2t, at this time, the thickness e of the connecting portion 200 is relatively close to the remaining thickness of the notch 120, resulting in a relatively thin overall thickness of the connecting portion 200, which is easily damaged under the action of pressure, affecting the fulcrum effect of the connecting portion 200, weakening the support effect of the connecting portion 200 on the main body portion 101, causing the main body portion 101 to be unbalanced in force and affecting the bursting value; when the thickness e of the connecting portion 200 is greater than 0.9w, it will cause the thickness e of the connecting portion 200 to be similar to the thickness w of the main body portion 101, which will result in the connecting portion 200 not being able to adapt well to the opening action of the main body portion 101, being difficult to rotate and deform, affecting its fulcrum function, and may also cause difficult opening, resulting in excessive internal pressure of the battery and affecting the safety performance.

[0055] Therefore, when 0.3w < t < 0.7w and 1.2t < e < 0.9w, the main body portion 101 can obtain a relatively stable bursting value in the long term, and at the same time, it is beneficial for the main body portion 101 to open under appropriate pressure to ensure safety performance.

[0056] Further, with continued reference to Figure 2 , 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 provided on the bottom wall of the groove 110, and the edge portion 102 is arranged around the main body portion 101 to define and form the groove 110. In addition, the thickness of the edge portion 102 is greater than the thickness of the main body portion 101.

[0057] At this time, on the one hand, the groove 110 can accommodate the main body portion 101 therein, playing a certain protective role; on the other hand, setting the thickness of the edge portion 102 to be greater than the thickness of the main body portion 101 can enable the edge portion 102 to have better shear resistance than the main body portion 101. When the valve body 100 bursts, the edge portion 102 is not easily deformed, facilitating the smooth opening of the main body portion 101.

[0058] Based on the above structural settings, in some embodiments, the value of k can be controlled at values such as 0.8, 0.98, 0.9, 0.95, 1.0, 1.07, 1.11, 1.2, or 1.3. In some other embodiments, the value of k can also be controlled within the range between any two of the above numerical points. The ranges between any two of these points are not listed one by one here; when the k value is within the above numerical points or numerical ranges, the bursting value can maintain a relatively small extreme difference for a long time.

[0059] Preferably, the value range of k is further reduced, where 0.9 ≤ k ≤ 1.2. Experiments have shown that when the value range of k is further restricted to the interval of 0.9 to 1.2 at this time, the bursting value has a better effect of resisting attenuation in the long term.

[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 will be easily opened under a relatively small pressure, thereby causing the valve body 100 to open in advance. When 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 within the above range, it can be opened in time when subjected to a reasonable opening pressure, thereby achieving timely exhaust and avoiding battery explosion.

[0061] Exemplarily, the bursting 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 bursting value P can also be controlled within the range between any two numerical points mentioned above.

[0062] In one embodiment, the residual thickness t of the notch of the explosion-proof valve is in the range of 0.03mm≤t≤0.3mm. When the residual thickness t of the notch is less than 0.03mm, the connection thickness of the notch 120 will be too small, which is easy to break, resulting in insufficient strength, which may cause the explosion-proof valve to open prematurely; and when the thickness of the notch 120 is greater than 0.3mm, the thickness of the notch 120 will be too large, and the difficulty of opening the valve body 100 will increase, so that the valve body 100 cannot be opened in time, resulting in the inability to exhaust in time, and the risk of battery explosion will increase. Therefore, when the residual thickness of the notch 120 is between 0.03mm and 0.3mm, it can ensure that the valve body 100 obtains good connection strength, avoids premature opening as much as possible, and can also enable the valve body 100 to be opened in time under suitable pressure, so that the valve body 100 can play its explosion-proof role in time.

[0063] Exemplarily, the residual thickness t of the notch 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 value of the residual thickness t of the notch can also be controlled within the range between any two of the above-mentioned numerical points.

[0064] In one embodiment, the value range of the force arm D of the explosion-proof valve is between 4mm≤D≤44mm. Among them, the force arm D can affect the pressure required when the valve body 100 is opened, and then affect the size of the burst value P. Among them, if the force arm D is less than 4mm, the pressure required when the valve body 100 is opened will increase, resulting in the valve body 100 not being able to open in time, and the risk of internal explosion of the battery will increase; and when the value of the force arm D is greater than 44mm, the burst value P of the force arm will be reduced, which is equivalent to only requiring a smaller pressure to open the valve body 100, which will also cause the valve body 100 to open in advance, affecting normal use; based on this, by controlling the value range of the force arm D between 4mm≤D≤44mm, it can be ensured that the valve body 100 obtains a reasonable burst value P, so that the valve body 100 can be opened in time under a suitable pressure, and the valve body 100 can play its explosion-proof role in time.

[0065] Exemplarily, the force 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 force arm D of the explosion-proof valve can also be controlled within the range between any two of the above-mentioned numerical points.

[0066] Furthermore, in actual applications, due to different design requirements for batteries of different models, 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 extended contour of the notch 120. At this time, different contours of the valve body 100 can adapt to the opening requirements of different battery types. In order to facilitate the definition of the force arm D under different types of notch 120 shapes, the following 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 several notch 120 contour schemes described below.

[0067] Specifically, in one embodiment, referring to Figure 3 , the notch 120 is in a square ring shape, and the notch 120 has four sides connected in sequence. At this time, the connection part 200 is located on one of the sides of the notch 120, and the connection part 200 is in a strip shape. At this time, because the side where the connection part 200 is located is opposite to the other side, and the vertical distance between the other side and the connection part 200 is the farthest, the vertical distance between the connection part 200 and the end of the notch 120 away from the connection part 200 is the force 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 connection part 200.

[0068] In another embodiment, review Figure 1, the notch 120 may also be in the shape of an elliptical ring, in which case the notch 120 has two straight sections parallel to each other and two arc sections arranged oppositely, the arc sections are located at the ends of the straight sections and connected to the straight sections, at this time, the connecting portion 200 may be arranged at the straight section or in the middle of the arc section; when the connecting portion 200 is located in the arc section of the notch 120, the connecting portion 200 is in the shape of an arc to adapt to the extended profile of the arc section, so as to be able to act as a fulcrum more stably; at this time, 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 can be taken as the lever arm, based on the above arrangement, when the valve body 100 is subjected to pressure from inside the battery, the valve body 100 opens from the other arc section of the notch 120 away from the connecting portion 200.

[0069] It is understandable that, referring to Figure 1 The connecting portion 200 of the present embodiment is located at the straight section of the elliptical annular notch 120 , and the size of its force arm D is consistent with that of the square annular notch 120 described above, which will not be elaborated here.

[0070] Further, refer to Figure 4 If the notch 120 has a circular contour, the contour of the notch 120 at this time can be understood as a further deformation of the elliptical ring, which is equivalent to omitting the straight section of the notch 120. At this time, the connecting portion 200 arranged on the notch 120 has an arc contour, and the size of the force arm D is the diameter of the notch 120.

[0071] In another embodiment, referring to Figure 5 , the notch 120 is in the shape of a rounded rectangular ring. Specifically, the rounded rectangular ring notch 120 includes two long sides parallel to each other and two short sides parallel to each other. The connecting portion 200 can be arranged on the long side or on the short side. In this 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 lever arm. It can be understood that the lever arm is formed in a similar manner to the lever arm of the square ring notch 120 described above. When the connecting portion 200 is located on the long side of the notch 120, the lever arm is the length of the short side, and when the connecting portion 200 is located on the short side, the lever arm is the length of the long side. If the valve body 100 is subjected to pressure from the inside of the battery, the valve body 100 will open from the other side of the notch 120 away from the connecting portion 200.

[0072] In another embodiment, the notch 120 is in an irregular pattern. Figure 6As shown, the notch 120 has a runway profile, and here the notch 120 includes two relatively straight sections, and also includes arc sections at both ends, one of the arc sections at both ends has a smaller curvature, while the other has a larger curvature. At this time, the arc section is connected to the straight section to form two straight sections arranged in an eight-shaped shape, and two relatively large and small arc sections at the opening 310, finally forming a runway profile.

[0073] At this time, the connecting portion 200 can be arranged in a straight section or in an arc section. Figure 7 When the connecting portion 200 is located in one of the arc segments, 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 lever arm, which is equivalent to the distance between the arc segments at both ends being the lever arm distance.

[0074] When the connecting portion 200 is located in the straight section, refer to Figure 6 At this time, the maximum vertical distance between the tangent line of the connecting portion 200 and the end of the notch 120 away from the connecting portion 200 is the lever arm. However, before this, an extension line tangent to the arc segment close to the lever arm is required, and the intersection distance between the tangent line of the connecting portion 200 and the extension line of the arc segment is the lever arm distance, so as to determine the lever arm definition method of the irregular figure.

[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 in the shape of a strip, a vertical line is drawn on the basis of the strip, and the vertical line is extended to the position on the other side of the notch 120, which is the distance of the force arm; when the connecting portion 200 is an arc structure, the tangent of the connecting portion 200 is obtained, and the length of the vertical line of the tangent extending to the other opposite side of the notch 120 is the size of the force arm. When the pattern is an irregular pattern, an extension line can be set on the other opposite side of the notch 120, and the size of the force arm can be obtained by determining the distance between the intersection of the vertical line of the connecting portion 200 and the extension line. Therefore, no matter what kind of contour the notch 120 adopts, as long as the size of its force arm can be measured, the relationship formula of this embodiment can be applied.

[0076] The explosion-proof valve was tested under different parameter conditions. The test results are shown in Table 1:

[0077]

[0078] Table 1

[0079] It should be explained that the tensile strength σ in the above table b , is a preset ideal value under a suitable annealing temperature and time, and is not the actual tensile strength of the embodiment. If you want to actually measure the tensile strength, you have to destroy the sample to test, which makes it impossible to detect the burst value. It can be understood that the tensile strength σ bThe actual size of is usually related to the selected material. 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 The value of is different. For example, the material currently used for explosion-proof valves is usually MFX2, which is a high-formability aluminum material with good machining performance. The tensile strength of MFX2 is usually 110Mpa. In addition, explosion-proof valves usually try to use steel, such as SPCC. SPCC is a "general cold-rolled carbon steel sheet and steel strip", which also has good mechanical properties and can meet the use requirements of explosion-proof valves. The tensile strength of SPCC is usually 310Mpa. At this time, when the burst value P and the force arm D in the relationship remain unchanged, the tensile strength σ b The larger it is, the better the mechanical properties of the material are, and the residual thickness t of the notch can be made smaller.

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

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

[0082] Compared with Example 2, Example 1 has the following characteristics:

[0083] The force arm remains unchanged, the length of the explosion-proof valve is increased, the residual thickness of the notch 120 is basically consistent with the burst value, the coefficient k is within the above range, and the relationship is met at this time, and the burst value does not change much after long-term storage. It means that under this condition, the area of ​​the explosion-proof valve can be increased 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 contour of the valve body 100 adopts, the above relationship can be satisfied. The above relationship has an excellent general inspection effect and is suitable for valve 100 structures of various contour shapes.

[0084] Compared with Example 3, Example 1 has the following characteristics:

[0085] The lever arm becomes smaller, but the length of the explosion-proof valve does not change. The residual thickness t of the notch is also reduced, which causes the residual thickness t to change accordingly. Ultimately, the bursting value P is basically the same, and the coefficient k is also within a reasonable range. After long-term storage, the bursting value does not change much.

[0086] Compared with Example 4, Example 1 has the following characteristics:

[0087] The force arm and length remain unchanged, the residual thickness t of the notch changes slightly, and the bursting value is basically the same. However, the coefficient k of the fourth embodiment is not within the above range of 0.8 to 1.3, but actually reaches 1.35. The bursting value of the explosion-proof valve in the fourth embodiment decreases significantly after being left still for a long time. The reason is that the internal stress is not completely eliminated during the annealing process. Therefore, the disappearance of the internal stress can be quickly known, so as to judge whether the bursting value P of the explosion-proof valve under long-term conditions is stable.

[0088] Compared with Example 5, Example 1 has the following characteristics:

[0089] The force arm and length remain unchanged, and the residual thickness t of the notch becomes larger, so that the bursting value is basically the same, but the coefficient k of the fourth embodiment is not in the above range of 0.8~1.3, but 0.78. At this time, the bursting value of the explosion-proof valve does not drop significantly after a long period of static, indicating that the problem of the decrease in the bursting value can be solved by increasing the value of the residual thickness t of the notch; however, if only the residual thickness t of the notch is increased, the extreme difference of the explosion-proof valves in the same batch will be large, such as 0.882-0.848=0.034, which means that the annealing temperature is very high, which will lead to other problems, such as softening of the explosion-proof valve and instability of the size of the explosion-proof valve; in addition, if the same bursting value is to be achieved, the residual thickness of the notch 120 must be larger, and the required material thickness will also be larger, which will also lead to material waste. Therefore, if only the residual thickness t of the notch is increased without considering the control of other parameter values, it will ultimately be impossible to obtain a product that meets the design specifications.

[0090] Compared with Example 6, Example 1:

[0091] The arm and length remain unchanged, the material changes lead to changes in tensile strength, and correspondingly, the residual thickness and burst value also change. The coefficient k is within the above range, and the burst value does not change much after long-term storage. It can be seen that the relationship of this embodiment can meet the long-term stability test requirements under different materials.

[0092] Compared with Example 7, Example 6:

[0093] The force arm and length remain unchanged, the residual thickness changes, and the burst value is basically the same. However, the coefficient k of Example 4 is not within the above range of 0.8-1.3, but is 1.36. Its burst value drops significantly after long-term static standing, because the internal stress is not completely eliminated during the annealing process, which further reflects the accuracy of the relationship.

[0094] In summary, in order to achieve the effect of preventing the explosion-proof valve from decreasing in the long term, the parameters in the relationship should be adjusted as a whole. If a single parameter is adjusted significantly, although the problem of the explosion value decreasing too quickly can be overcome, it may cause problems such as uncontrollable size, safety hazards or material waste. Only by adjusting the ratio of each parameter within a reasonable range can the explosion-proof valve remain stable over a long period of time, meet the design specifications and reduce safety hazards.

[0095] Optionally, the relationship of the pressure relief coefficient k can also refer to more different parameters for control and calculation. For example, in another embodiment, the shear strength can also be introduced as its control parameter. Here, for the convenience 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 it can be obtained that: 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 is:

[0097] 1.3≤ ≤2.6;

[0098] It can be seen from the above relationship that when the shear strength is used to test the stability of the explosion value of the explosion-proof valve over a long period of time, it is only necessary to control the value of the pressure relief coefficient within 1.3 to 2.6. This is conducive to testing the stability of the explosion-proof valve under more different types of parameters and is more convenient to use.

[0099] For example, The value of 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 it can be a range between any two of the above parameter values.

[0100] Preferably, based on the above relationship, its value range can be further controlled, such as 1.5< <2.4. Within this range, the explosion value of the explosion-proof valve remains relatively stable for a long time, and the explosion value will not decrease due to the release of internal residual stress, thereby avoiding the explosion-proof valve from opening during normal use of the battery cell.

[0101] Reference Figure 8 and Fig. 9 The battery of the second embodiment of the present invention comprises a shell and an explosion-proof valve of the first embodiment, wherein the explosion-proof valve is arranged on the shell.

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

[0103] In addition, the electrical equipment of the third aspect embodiment of the present invention includes the explosion-proof valve of the first aspect embodiment and / or the battery of the first aspect embodiment. It can be understood that the electrical equipment includes but is not limited to electric vehicles, energy storage systems, medical equipment, drones, model aircraft equipment, and electric tools, and the specific form of the electrical equipment is not limited herein.

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

[0105] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

[0106] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. Explosion-proof valve, characterized in that: include: A valve body (100) is provided with a notch (120); the valve body (100) comprises a connecting portion (200), and the connecting portion (200) is connected to two ends of the notch; 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 portion (200) and an end of the notch (120) away from the connecting portion (200) is a force arm, and the force arm is D; k= , where 0.8≤k≤1.

3.

2. The explosion-proof valve according to claim 1, characterized in that: The valve body (100) further comprises a main body portion (101) and an edge portion (102), wherein the edge portion (102) is arranged around the main body portion (101), and the notch (120) is arranged between the main body portion (101) and the edge portion (102); the thickness of the connecting portion (200) is e, the thickness of the main body portion (101) is w, and the thickness of the connecting portion (200) is 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 notch is in the shape of a square ring, the connecting portion (200) is in the shape of a strip, and the vertical distance between the connecting portion (200) and an end of the notch (120) away from the connecting portion (200) is a force arm. Alternatively, the notch (120) is in the shape of an elliptical ring, the connecting portion (200) is in the shape of an arc, and the maximum vertical distance between a tangent line of the connecting portion (200) and an end of the notch (120) away from the connecting portion (200) is a lever arm, Alternatively, the notch (120) is in the shape of a rounded rectangular ring, the connecting portion (200) is in the shape of a strip, and the vertical distance between the connecting portion (200) and an end of the notch (120) away from the connecting portion (200) is a lever arm, Alternatively, the notch (120) is in an irregular shape, and the maximum vertical distance between a tangent line of the connecting portion (200) and an end of the notch (120) away from the connecting portion (200) is a lever arm.

7. The explosion-proof valve according to claim 1, characterized in that: The explosion value of the valve body (100) is P, 0.5Mpa≤P≤2Mpa, the residual thickness of the notch of the explosion-proof valve is t, 0.03mm≤t≤0.3mm, and the force arm D of the explosion-proof valve is 4mm≤D≤44mm.

8. The explosion-proof valve according to claim 1, characterized in that: The valve body is further provided with a groove (110), the notch (120) is provided on the bottom wall of the groove (110), the edge portion (102) is arranged around the main body portion (101) to define and form the groove (110), and the thickness of the edge portion (102) is greater than the thickness of the main body portion (101).

9. A battery, characterized in that The battery comprises a housing and an explosion-proof valve according to any one of claims 1 to 8, wherein the explosion-proof valve is arranged on the housing.

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

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