Explosion-proof structure and battery

Abstract

The invention discloses an explosion-proof structure and a battery, the explosion-proof structure comprises a cover plate, the cover plate is provided with an explosion-proof groove, the explosion-proof groove comprises a first sub-groove and a second sub-groove, the projections of the first sub-groove and the second sub-groove on one side surface of the cover plate enclose a closed circular ring, and the thickness of the cover plate at the position of the first sub-groove is smaller than the thickness of the cover plate at the position of the second sub-groove. The first sub-groove and the second sub-groove are formed in the cover plate, the thickness of the part, where the first sub-groove is located, of the cover plate is smaller than that of the part, where the second sub-groove is located, of the cover plate, and when the internal pressure of the battery is increased, the first sub-groove in the cover plate is firstly opened, and then the second sub-groove in the cover plate is opened, so that secondary pressure relief of the battery is formed; the purpose of discharging combustible gas and combustion-supporting gas in a time-sharing mode is achieved, the problems that when an existing explosion-proof structure is exploded, the combustible gas, the combustion-supporting gas and substances in the battery interact, the thermal runaway degree is increased, and battery explosion is caused are solved, the reliability of the cover plate is improved, and the explosion-proof effect is guaranteed.

Description

[0001] This application claims the priority of the PCT international application with the application number PCT / CN2023 / 143524 filed with the China National Intellectual Property Administration on December 29, 2023. The entire content of the above application is incorporated herein by reference. Technical Field

[0002] This application belongs to the technical field of batteries, and particularly relates to an explosion-proof structure and a battery. Background Art

[0003] During the use of power batteries, due to short circuits or other reasons, the internal pressure of the battery may increase and exceed the safety value, leading to potential hazards such as explosions. To minimize such hazards, an explosion-proof diaphragm is generally provided on the battery cover plate. The explosion-proof diaphragm gradually deforms as the internal pressure increases until it explodes and opens.

[0004] During the thermal runaway process of the battery, when the battery temperature rises to a certain stage, the internal electrolyte will decompose into combustible gases such as methane. As the battery temperature continues to rise, the battery will also decompose into combustion-supporting gases such as oxygen. When the internal pressure of the battery further increases, the explosion-proof diaphragm bursts. At the moment when the explosion-proof valve bursts, the combustible gas, the combustion-supporting gas, and the battery internal substances interact with each other, intensifying the thermal runaway degree and easily causing the battery to explode. Summary of the Invention

[0005] Embodiments of this application provide an explosion-proof structure and a battery to solve the problem that when the explosion-proof structure in the related art bursts, the interaction between the combustible gas, the combustion-supporting gas, and the battery internal substances intensifies the thermal runaway degree and causes the battery to explode.

[0006] In a first aspect, embodiments of this application provide an explosion-proof structure applied to a battery, including a cover plate. An explosion-proof groove is provided on the cover plate. The explosion-proof groove includes a first sub-groove and a second sub-groove. The projections of the first sub-groove and the second sub-groove on one side of the cover plate enclose a closed ring. The thickness of the cover plate at the position where the first sub-groove is located is less than the thickness of the cover plate at the position where the second sub-groove is located.

[0007] In a second aspect, embodiments of this application also provide a battery, including: the above-mentioned explosion-proof structure;

[0008] a wound core, including a positive electrode end and a negative electrode end;

[0009] a housing, the wound core is installed in the housing, one end of the housing is provided with an opening, and the cover plate is hermetically connected to the housing to block the opening.

[0010] The explosion-proof structure and battery provided by the embodiments of the present application are configured such that a first sub-groove and a second sub-groove are provided on the cover plate. The thickness of the cover plate at the location of the first sub-groove is less than that at the location of the second sub-groove. When the internal pressure of the battery increases, the position of the first sub-groove on the cover plate opens first, and then the position of the second sub-groove on the cover plate opens, forming a secondary pressure relief for the battery. The first opening can discharge combustible gases, and the second opening can discharge combustion-supporting gases, thereby achieving the purpose of discharging combustible gases and combustion-supporting gases at different times. This overcomes the problem that when the existing explosion-proof structure explodes, the interaction between combustible gases, combustion-supporting gases, and the substances inside the battery exacerbates the degree of thermal runaway and causes the battery to explode. The projections of the first sub-groove and the second sub-groove on one side of the cover plate enclose a closed circle. While ensuring the pressure relief area, after the cover plate at the position of the first sub-groove opens, the cover plate at the position of the second sub-groove is broken through from the connection between the first sub-groove and the second sub-groove, which is beneficial to the opening of the cover plate at the position of the second sub-groove and improves the reliability of the cover plate, ensuring the explosion-proof effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 FIG. is a top view of the first form of the explosion-proof structure provided by the embodiments of the present application.

[0012] Figure 2 is Figure 1 the A-A cross-sectional view in

[0013] Figure 3 is Figure 1 the partial enlarged view at B in

[0014] Figure 4 is Figure 3 the C-C cross-sectional view in

[0015] Figure 5 is Figure 4 the partial enlarged view at D in

[0016] Figure 6 is Figure 3 the E-E cross-sectional view in

[0017] Figure 7 FIG. is the marked drawing of the explosion-proof structure provided by the embodiments of the present application.

[0018] Figure 8 FIG. is the three-dimensional view of the explosion-proof structure provided by the embodiments of the present application.

[0019] Figure 9 FIG. is a top view of the second form of the explosion-proof structure provided by the embodiments of the present application.

[0020] Figure 10 FIG. is a top view of the third form of the explosion-proof structure provided by the embodiments of the present application.

[0021] Figure 11The top view of the fourth form of the explosion-proof structure provided by the embodiment of the present application.

[0022] Figure 12 The top view of the fifth form of the explosion-proof structure provided by the embodiment of the present application.

[0023] Figure 13 The top view of the sixth form of the explosion-proof structure provided by the embodiment of the present application.

[0024] Figure 14 The three-dimensional view of the battery provided by the embodiment of the present application.

[0025] Figure 15 The top view of the battery provided by the embodiment of the present application.

[0026] Figure 16 It is Figure 15 The G-G cross-sectional view in

[0027] Figure 17 It is Figure 16 The partial enlarged view at H in

[0028] Figure 18 It is Figure 16 The partial enlarged view at M in

[0029] Explanation of reference numerals:

[0030] 110, cover plate; 111, first side; 112, second side; 113, first sub-part; 114, second sub-part; 1141, counterbore; 1142, boss; 115, third sub-part; 116, fourth sub-part; 120, explosion-proof groove; 121, first sub-groove; 122, second sub-groove; 140, winding core; 150, housing; 151, opening; 152, positive terminal; 153, flange; 154, pressing plate; 155, seal; 160, first current collector plate; 170, second current collector plate; 180, insulating part. Detailed implementation manners

[0031] The embodiment of the present application provides an explosion-proof structure and a battery to solve the problem that when the explosion-proof structure in the related art explodes, the interaction of combustible gas, combustion-supporting gas and the substances in the battery intensifies the degree of thermal runaway and causes the explosion of the battery. The following will be described with reference to the drawings.

[0032] See Figure 1 , Figures 9 to 13 shown, Figure 1 The top view of the first form of the explosion-proof structure provided by the embodiment of the present application, Figure 9 The top view of the second form of the explosion-proof structure provided by the embodiment of the present application, Figure 10 The top view of the third form of the explosion-proof structure provided by the embodiment of the present application,Figure 11 The top view of the fourth form of the explosion-proof structure provided by the embodiment of the present application Figure 12 The top view of the fifth form of the explosion-proof structure provided by the embodiment of the present application Figure 13 The top view of the sixth form of the explosion-proof structure provided by the embodiment of the present application

[0033] An explosion-proof structure is applied to a battery, such as a cylindrical battery. The explosion-proof structure includes a cover plate 110. The cover plate 110 has a disc-shaped structure. The material of the cover plate 110 can be steel, such as SPCC material, stainless steel materials SUS410, SUS306, SUS316, SUS430, SUS444, etc. When using SPCC material, nickel can be plated on both surfaces of the cover plate 110, and the thickness of the plating layer is 0.3 μm to 8 μm. The plating layer thicknesses on both sides can be the same or different. An explosion-proof groove 120 is provided on the cover plate 110. The explosion-proof groove 120 includes a first sub-groove 121 and a second sub-groove 122. Both the first sub-groove 121 and the second sub-groove 122 are arc-shaped. The first sub-groove 121 and the second sub-groove 122 are located at different positions on the cover plate 110, and the projections of the first sub-groove 121 and the second sub-groove 122 on one side of the cover plate 110 enclose a closed ring. The thickness of the cover plate 110 at the position where the first sub-groove 121 is located is less than the thickness of the cover plate 110 at the position where the second sub-groove 122 is located.

[0034] It can be understood that since the thickness of the cover plate 110 at the position of the first sub-groove 121 is less than the thickness of the cover plate 110 at the position of the second sub-groove 122, as the air pressure inside the battery increases, the position of the first sub-groove 121 on the cover plate 110 opens first. The first sub-groove 121 opens for discharging combustibles. Then, the position of the second sub-groove 122 on the cover plate 110 opens. The second sub-groove 122 opens for discharging combustion-supporting substances. The cover plate 110 at the first sub-groove 121 opens under the first pressure, and the cover plate 110 at the second sub-groove 122 opens under the second pressure. The first pressure is less than the second pressure. Both the first pressure and the second pressure refer to the pressure inside the battery. Thus, secondary pressure relief of the battery is formed. The first opening can discharge combustible gases, and the second opening can discharge combustion-supporting gases, thereby achieving the purpose of discharging combustible gases and combustion-supporting gases at different times, overcoming the problem that when the explosion-proof structure in the related art explodes, due to the interaction of combustible gases, combustion-supporting gases and substances inside the battery, the degree of thermal runaway is aggravated and the battery explodes. The projections of the first sub-groove 121 and the second sub-groove 122 on one side of the cover plate 110 enclose a closed circle center. While ensuring the pressure relief area, after the cover plate 110 at the position of the first sub-groove 121 opens, it breaks through the cover plate 110 at the position of the second sub-groove 122 from the connection between the first sub-groove 121 and the second sub-groove 122, which is beneficial to the opening of the cover plate 110 at the position of the second sub-groove 122, ensuring that the explosion-proof structure can be opened smoothly, and partial cover plates 110 inside the first sub-groove 121 and the second sub-groove 122 are completely separated from partial cover plates 110 outside the first sub-groove 121 and the second sub-groove 122, realizing the complete opening of the explosion-proof structure and ensuring the explosion-proof effect.

[0035] In some embodiments, along the thickness direction of the cover plate 110, the cross-sectional shape of the explosion-proof groove 120 is V-shaped, trapezoidal, semi-circular, "U"-shaped or parabolic.

[0036] In some embodiments, referring to Figure 4 and Figure 12 as shown, the cover plate 110 includes a first side surface 111 and a second side surface 112 arranged opposite to each other. The first sub-groove 121 and the second sub-groove 122 are both arranged on the first side surface 111. The first sub-groove 121 and the second sub-groove 122 are both arc-shaped rings. The first sub-groove 121 and the second sub-groove 122 are connected end to end, and the first sub-groove 121 and the second sub-groove 122 are communicated.

[0037] It can be understood that arranging the first sub-groove 121 and the second sub-groove 122 on the first side surface 111 of the cover plate 110 facilitates the processing of the first sub-groove 121 and the second sub-groove 122.

[0038] In some embodiments, referring to Figure 7As shown, in the top view direction of the cover plate 110, the outer diameter of the ring where the explosion-proof groove 120 is located is E1, 24 mm ≤ E1 ≤ 40 mm, such as, 30 mm ≤ E1 ≤ 35 mm. Among them, the value of E1 can be 24 mm, 25 mm, 26 mm, 27 mm, 28 mm, 29 mm, 30 mm, 31 mm, 32 mm, 33 mm, 34 mm, 35 mm, 36 mm, 37 mm, 38 mm, 39 mm, 40 mm or other unlisted values. Reasonably set the position of the explosion-proof groove 120 on the cover plate 110 to form a sufficiently large pressure relief area to ensure the pressure relief effect.

[0039] In some embodiments, referring to Figure 5 and Figure 6 As shown, the thickness of the cover plate 110 at the first sub-groove 121 is H1, and the thickness of the cover plate 110 at the second sub-groove 122 is H2. Among them, 20 μm ≤ H1 ≤ 115 μm, 25 μm ≤ H2 ≤ 135 μm. Such as, 45 μm ≤ H1 ≤ 55 μm, 80 μm ≤ H2 ≤ 100 μm. Among them, the value of H1 can be 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 115 μm or other unlisted values. The value of H2 can be 25 μm, 35 μm, 45 μm, 55 μm, 65 μm, 75 μm, 85 μm, 95 μm, 105 μm, 115 μm, 125 μm, 135 μm or other unlisted values.

[0040] It can be understood that the thicker the thickness of the cover plate 110 at the position where the explosion-proof groove 120 is located, the greater the pressure required to open the explosion-proof groove 120. The thickness of the cover plate 110 at the position where the explosion-proof groove 120 is located is positively correlated with the pressure required to open the explosion-proof groove 120. If the thickness of the cover plate 110 at the position where the explosion-proof groove 120 is located is relatively thin, the explosion-proof groove 120 may open within the normal operating range of the battery, affecting the performance of the battery. If the thickness of the cover plate 110 at the position where the explosion-proof groove 120 is located is relatively thick, the pressure required to open the explosion-proof groove 120 is relatively large, and the battery is prone to explosion. In the embodiments of the present application, the thickness range of the cover plate 110 where the explosion-proof groove 120 is located is reasonably designed, which can meet the normal operation of the battery, achieve secondary pressure relief, and prevent the occurrence of battery explosion.

[0041] In some embodiments, 5 μm ≤ H2 - H1 ≤ 20 μm. Among them, the value of H2 - H1 can be 5 μm, 10 μm, 15 μm, 20 μm or other unlisted values. Setting the difference between H2 and H1 within a reasonable range can ensure the reliability of primary pressure relief and secondary pressure relief.

[0042] In some embodiments, referring to Figure 5As shown, the thickness of the area outside the explosion-proof groove 120 on the cover plate 110 is C, where 0.4 mm ≤ C ≤ 1.0 mm. Among them, the value of C can be 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm or other unlisted values. By reasonably setting the thickness of the cover plate 110, while ensuring the strength of the cover plate 110, the first sub-groove 121 and the second sub-groove 122 can be processed to achieve secondary pressure relief.

[0043] In some embodiments, the arc length of the first sub-groove 121 is less than the arc length of the second sub-groove 122. Among them, the arc length of the first sub-groove 121 refers to the length of the arc where the outer edge of the explosion-proof groove 120 where the first sub-groove 121 is located, and the arc length of the second sub-groove 122 refers to the length of the arc where the outer edge of the explosion-proof groove 120 where the second sub-groove 122 is located.

[0044] In some embodiments, the ratio of the arc length of the first sub-groove 121 to the arc length of the second sub-groove 122 is G. Among them, the value of G can be or other unlisted values. By reasonably arranging the arc lengths of the first sub-groove 121 and the second sub-groove 122, and reasonably arranging the opening sizes of the primary pressure relief and the secondary pressure relief, the explosion-proof effect is ensured.

[0045] In some embodiments, referring to Figure 6 As shown, the width of the notch of the explosion-proof groove 120 is a, where 0.6 mm ≤ a ≤ 1.5 mm. Among them, the value of a can be 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm or other unlisted values. By reasonably setting the width of the notch of the explosion-proof groove 120, the notch widths of the first sub-groove 121 and the second sub-groove 122 are the same, avoiding that the width of the notch of the explosion-proof groove 120 is too small and not conducive to processing and opening, and also avoiding that the width of the notch of the explosion-proof groove 120 is too large, increasing the area of the explosion-proof groove 120 too much and affecting the structural strength of the cover plate 110.

[0046] In some embodiments, referring to Figure 9 、 Figure 11 and Figure 13 As shown, the explosion-proof groove 120 includes a plurality of first sub-grooves 121 and a plurality of second sub-grooves 122. The first sub-grooves 121 and the second sub-grooves 122 are alternately arranged. The plurality of first sub-grooves 121 and the plurality of second sub-grooves 122 are located on the same circle. The projections of the plurality of first sub-grooves 121 and the plurality of second sub-grooves 122 on one side of the cover plate 110 enclose a closed ring.

[0047] It can be understood that in order to achieve secondary pressure relief, under the first pressure, all the cover plates 110 at the positions of the first sub-grooves 121 are opened, and under the second pressure, all the cover plates 110 at the positions of the second sub-grooves 122 are opened. The first pressure is lower than the second pressure. By arranging multiple first sub-grooves 121 and multiple second sub-grooves 122 on the cover plate 110, it is beneficial for the cover plate 110 at the position of the explosion-proof groove 120 to be fully opened, thereby ensuring the pressure relief area and guaranteeing the pressure relief effect.

[0048] In some embodiments, the cover 110 includes a first sub-portion 113 and a second sub-portion 114, the first sub-portion 113 is adjacent to the second sub-portion 114, the first sub-portion 113 is close to the edge of the cover 110, the surface of the second sub-portion 114 facing the core 140 is at least partially higher than the surface of the first sub-portion 113 facing the core 140, the surface of the second sub-portion 114 away from the core 140 is at least partially higher than the surface of the first sub-portion 113 away from the core 140, and the explosion-proof groove 120 is arranged on the second sub-portion 114.

[0049] It can be understood that the cover plate 110 is designed to have a concave-convex structure. When the cover plate 110 is deformed into a hemispherical or hat-shaped shape, the space between the cover plate 110 and the end of the winding core is increased to prevent the gas pressure in the battery from increasing sharply and causing the battery to explode.

[0050] Based on the above implementation, see Figure 2 , Figure 8 and Figure 13 As shown, the cover plate 110 includes a third sub-portion 115. Along the radial direction of the cover plate 110, the first sub-portion 113, the second sub-portion 114 and the third sub-portion 115 are concentrically arranged in sequence. The first sub-portion 113 and the second sub-portion 114 are annular, and the third sub-portion 115 is circular. The first sub-portion 113 is close to the edge of the cover plate 110, and points from the second side surface 112 to the direction of the first side surface 111. The surface of the second sub-portion 114 facing the core 140 is at least partially higher than the surface of the first sub-portion 113 facing the core 140, and the surface of the second sub-portion 114 away from the core 140 is at least partially higher than the surface of the first sub-portion 113 away from the core 140. The explosion-proof groove 120 is arranged on the second sub-portion 114, and the first sub-groove 121 and the second sub-groove 122 are concentrically arranged with the second sub-portion 114.

[0051] It can be understood that when the air pressure in the battery increases, the cover plate 110 bulges and deforms in the direction of the first side surface 111, and the heights of the second sub-portion 114 and the third sub-portion 115 are designed to be higher than the height of the first sub-portion 113. After deformation, the cover plate 110 becomes hemispherical or hat-shaped, which increases the space between the cover plate 110 and the end of the core 140, preventing the air pressure in the battery from increasing sharply and causing the battery to explode.

[0052] In some embodiments, seeFigure 8 and Figure 13 As shown in Figure 13 , the cover plate 110 further includes a fourth sub - part 116. The fourth sub - part 116 is annular. The fourth sub - part 116 is located between the second sub - part 114 and the third sub - part 115, and the fourth sub - part 116 connects the second sub - part 114 and the third sub - part 115.

[0053] It can be understood that by arranging the explosion - proof groove 120 on the second sub - part 114, during the deformation process of the cover plate 110, the deformation forces of the first sub - part 113 and the fourth sub - part 116 act on the explosion - proof groove 120, which is beneficial to the smooth opening of the explosion - proof groove 120 and the reliability of the explosion - proof structure.

[0054] In other embodiments, it is also designed that the height of the third sub - part 115 on the first side 111 is higher than the height of the second sub - part 114, the height of a part of the second sub - part 114 is higher than the height of the first sub - part 113, and the first sub - part 113 is higher than the fourth sub - part 116; on the second side 112, the fourth sub - part 116 is lower than the first sub - part 113, the first sub - part 113 is lower than the second sub - part 114 at least in part, and the second sub - part 114 is lower than the third sub - part 115.

[0055] It can be understood that when the cover plate 110 is installed on the battery for use, the fourth sub - part 116 of the cover plate 110 is connected to the electrode of the battery, and the cover plate 110 is charged. For the battery, the electric potential between the cover plate 110 and the battery housing 150 is the same, there is no potential difference, reducing the risk of corrosion of the cover plate 110 and improving the reliability of the battery pack.

[0056] Based on the above - mentioned embodiment, the surface of the first sub - part 113 facing the core 140 is higher than the surface of the fourth sub - part 116 facing the core 140, and the fourth sub - part 116 is used to connect to the electrode of the battery. When the cover plate 110 is installed on the battery for use, the fourth sub - part 116 of the cover plate 110 is connected to the electrode of the battery, and the cover plate 110 is charged. For the battery, the electric potential between the cover plate 110 and the battery housing 150 is the same, there is no potential difference, reducing the risk of corrosion of the cover plate 110 and improving the reliability of the battery pack. In addition, the surface of the first sub - part 113 away from the core 140 is higher than the surface of the fourth sub - part 116 away from the core 140.

[0057] Based on the above - mentioned embodiment, the surface of the first sub - part 113 facing the core 140, the surface of the fourth sub - part 116 facing the core 140, and the surface of the counterbore 1141 facing the core 140 are at the same height. In addition, the surface of the first sub - part 113 away from the core 140, the surface of the fourth sub - part 116 away from the core 140, and the surface of the counterbore 1141 facing the core 140 are at the same height, which is convenient for the processing and forming of the cover plate 110.

[0058] In some embodiments, refer toFigure 13 and Figure 6 As shown in Figure 6 , the distance between the first side surface 111 of the second sub - part 114 and the first side surface 111 of the first sub - part 113 is B, where 0.8C ≤ B ≤ 1.5C. Here, C is the thickness of the area on the cover plate 110 outside the explosion - proof groove 120. For example, B can take values such as 0.8C, 0.9C, 1.0C, 1.1C, 1.2C, 1.3C, 1.4C, 1.5C or other unlisted values.

[0059] In some embodiments, the outer diameter of the ring where the explosion - proof groove 120 is located is E1, the inner diameter of the second sub - part 114 is E2, the outer diameter of the second sub - part 114 is E3, and the diameter of the cover plate 110 is E4. Among them, 42mm ≤ E4 ≤ 46mm. For example, E4 can take values such as 42mm, 43mm, 44mm, 45mm, 46mm or other unlisted values; 0.75E4 ≤ E3 ≤ 0.96E4, 0.4E4 ≤ E2 ≤ 0.72E4 and 3C ≤ E3 - E2 ≤ 27.8C; E2 + C ≤ E1 ≤ E3 - C, where C is the thickness of the area on the cover plate 110 outside the explosion - proof groove 120.

[0060] It can be understood that in the embodiments of this application, the size of the diameter E4 of the cover plate 110 is related to the corresponding battery product specifications, the sizes of E2 and E3 are related to E4, the size of E1 is related to E2 and E3, and the structural size of the cover plate 110 is reasonably designed. By reasonably setting the structures and parameters of the first sub - part 113, the second sub - part 114, the third sub - part 115 and the fourth sub - part 116, while ensuring the strength of the cover plate 110 and the space size after the deformation of the cover plate 110, the primary pressure relief and secondary pressure relief of the cover plate 110 are realized, which is convenient for the processing of the explosion - proof groove 120.

[0061] In some embodiments, as shown in Figure 1 、 Figure 3 、 Figure 8 The second sub - part 114 includes a connected counterbore 1141 and a boss 1142. The counterbore 1141 and the boss 1142 enclose a closed ring. The surface of the boss 1142 facing the winding core 140 is higher than the surface of the counterbore 1141 facing the winding core 140, and the surface of the boss 1142 away from the winding core 140 is higher than the surface of the counterbore 1141 away from the winding core 140. In the direction from the second side surface 112 to the first side surface 111, the counterbore 1141 and the first sub - part 113 are at the same height, that is, the first side surface 111 of the counterbore 1141 and the first side surface 111 of the first sub - part 113 are in the same horizontal plane, and the second side surface 112 of the counterbore 1141 and the second side surface 112 of the first sub - part 113 are in the same horizontal plane. The boss 1142 is set higher than the counterbore 1141, and the first sub - groove 121 is at least partially arranged on the counterbore 1141, and the second sub - groove 122 is arranged on the boss 1142.

[0062] It is understandable that by forming a sunk platform 1141 and a boss 1142 on the second sub - part 114, the first sub - groove 121 is at least partially arranged on the sunk platform 1141, and the second sub - groove 122 is arranged on the boss 1142. When the air pressure inside the battery rises and the cover plate 110 deforms, the first sub - groove 121 at the position of the sunk platform 1141 is subjected to the acting force of the deformation of the cover plate 110, and the explosion - proof groove 120 is opened first from the sunk platform 1141, so as to realize the directional opening at the position of the first sub - groove 121 and ensure the orderly progress of secondary pressure relief. Among them, the explosion - proof groove 120 is opened first from the sunk platform 1141, and there are various opening methods. For example, the first sub - groove 121 on the sunk platform 1141 is instantaneously and completely opened, or the first sub - groove 121 has an opening point, and the first sub - groove 121 starts to open from the opening point until it is completely opened. The opening point can be the junction of the boss 1142 and the sunk platform 1141 on the first sub - groove 121, or any position on the first sub - groove 121 within the area of the sunk platform 1141.

[0063] On the basis of the above - mentioned implementation manner, in the direction from the second side surface 112 to the first side surface 111, the third sub - part 115 is higher than the boss 1142, that is, the surface of the third sub - part 115 far from the core 140 is higher than the surface of the boss 1142 far from the core 140, and the surface of the third sub - part 115 facing the core 140 is higher than the surface of the boss 1142 facing the core 140. The space after the deformation of the cover plate 110 can be increased as much as possible.

[0064] In some implementation manners, referring to Figure 2 As shown, the depth of the sunk platform 1141 is A, and 0.8C ≤ A ≤ 1.5C, where C is the thickness of the cover plate 110. For example, 1C ≤ A ≤ 1.3C, and A can be 0.8C, 0.9C, 1.0C, 1.1C, 1.2C, 1.3C, 1.4C, 1.5C or other unlisted values. The depth of the sunk platform 1141 refers to the vertical distance between the first side surface 111 of the boss 1142 and the first side surface 111 of the sunk platform 1141.

[0065] In some implementation manners, referring to Figure 7 As shown, the width of the top of the sunk platform 1141 is D1, and the width of the bottom of the sunk platform 1141 is D2, where

[0066] 4mm ≤ D1 ≤ 12mm;

[0067] D2 = D1 - 2C * tan(α - 90°), and D2 > 2mm;

[0068] α is the included angle formed between the bottom and the side of the sunk platform 1141, and 100° ≤ α ≤ 170°;

[0069] C is the thickness of the area outside the explosion - proof groove 120 on the cover plate 110.

[0070] Among them, D1 takes values of 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm or other unlisted values, and α takes values of 100°, 110°, 120°, 130°, 140°, 150°, 160°, 170° or other unlisted values. Reasonably set the size of the counterbore 1141 to ensure the effect of the directional opening of the explosion-proof structure.

[0071] In some embodiments, refer to Figure 10 As shown, the cover plate 110 includes a first side surface 111 and a second side surface 112 arranged oppositely. The first sub-groove 121 and the second sub-groove 122 are both arranged on the second side surface 112, and the first sub-groove 121 communicates with the second sub-groove 122.

[0072] It can be understood that setting the explosion-proof groove 120 on the side of the cover plate 110 close to the core is beneficial to the explosion of the explosion-proof groove 120 and ensures the explosion-proof effect.

[0073] In some embodiments, the cover plate 110 includes a first side surface 111 and a second side surface 112 arranged oppositely. The first sub-groove 121 is arranged on the first side surface 111, and the second sub-groove 122 is arranged on the second side surface 112.

[0074] As a variation, the cover plate 110 includes a first side surface 111 and a second side surface 112 arranged oppositely. The second sub-groove 122 is arranged on the first side surface 111, and the first sub-groove 121 is arranged on the second side surface 112.

[0075] It can be understood that the first sub-groove 121 and the second sub-groove 122 can be arranged on both sides of the cover plate 110 in different planes, which is convenient for processing.

[0076] In some embodiments, under the first pressure, the cover plate 110 at the first sub-groove 121 opens, and under the second pressure, the cover plate 110 at the second sub-groove 122 opens. The magnitude of the first pressure is P1, 0.5Mpa < P1 < 1.5Mpa, and the magnitude of the second pressure is P2, 1.5Mpa ≤ P2 < 2.5Mpa.

[0077] Both the first pressure and the second pressure refer to the pressure inside the battery. Under normal operating conditions, the internal pressure of the battery reaches 0.5 Mpa. Generally, within a period of time before the battery touches thermal runaway, the internal pressure will increase with temperature and the decomposition of the electrolyte. To allow the combustible gas decomposed from the electrolyte to be discharged first without affecting the normal operation of the battery, the first pressure P1 is set between 0.5 Mpa and 1.5 Mpa, such as P1 is set to 0.6 Mpa, 0.7 Mpa, 0.8 Mpa, 0.9 Mpa, 1.0 Mpa, 1.1 Mpa, 1.2 Mpa, 1.3 Mpa, 1.4 Mpa or other unlisted values. At the end stage of battery thermal runaway, when the internal pressure of the battery rises to a certain level, the explosion-proof valve needs to open and release the internal combustion substances of the battery to avoid the occurrence of battery explosion. The second pressure P2 is set between 1.5 Mpa and 2.5 Mpa, such as P2 is set to 1.6 Mpa, 1.7 Mpa, 1.8 Mpa, 1.9 Mpa, 2.0 Mpa, 2.1 Mpa, 2.2 Mpa, 2.3 Mpa, 2.4 Mpa or other unlisted values.

[0078] In some embodiments, the thickness H1 of the cover plate 110 at the first sub-tank 121 and the thickness H2 of the cover plate 110 at the second sub-tank 122 are calculated according to the following formulas (1) and (2).

[0079]

[0080]

[0081] Wherein, Q is the tensile strength of the material for preparing the cover plate 110.

[0082] E1 is the outer diameter of the ring where the explosion-proof groove 120 is located.

[0083] P1 is the pressure at which the cover plate 110 at the first sub-tank 121 opens.

[0084] P2 is the pressure at which the cover plate 110 at the second sub-tank 122 opens.

[0085] The thickness H1 of the cover plate 110 at the first sub-tank 121 and the thickness H2 of the cover plate 110 at the second sub-tank 122 are calculated using the above formulas (1) and (2). The first sub-tank 121 and the second sub-tank 122 are designed according to different positions and material properties, which is convenient for design, the calculation results are accurate, and the performance of the cover plate 110 is guaranteed.

[0086] See Figure 14 、 Figure 15 、 Figure 16 、 Figure 17 and Figure 18As shown in the figure. An embodiment of the present application further provides a battery, which may be a cylindrical battery and includes the explosion-proof structure described in any one of the above embodiments. The explosion-proof structure may be applied to the positive electrode side or the negative electrode side of the battery. Taking the case where the explosion-proof structure is applied to the negative electrode side of the battery as an example for illustration. The battery includes the above-mentioned explosion-proof structure, a winding core 140, and a housing 150. The winding core 140 is installed in the housing 150. One end of the housing 150 is provided with an opening 151, and a cover plate 110 is hermetically connected to the housing 150 to block the opening 151. The battery has the same technical effects as the battery explosion-proof structure, which will not be elaborated here.

[0087] On the basis of the above embodiment, refer to Figure 17 and Figure 18 As shown in the figure, the battery further includes a first current collector plate 160, a second current collector plate 170, and an insulating member 180. The other end of the housing 150 is provided with a positive terminal 152. The winding core 140, the first current collector plate 160, and the second current collector plate 170 are all arranged in the housing 150. The cover plate 110 is hermetically connected to the housing 150 and blocks the opening 151. The second side surface 112 of the cover plate 110 abuts against one side surface of the first current collector plate 160. The other side surface of the first current collector plate 160 is welded to the negative terminal of the winding core 140. The circumferential side of the first current collector plate 160 is connected to the inner surface of the housing 150 so that the housing 150 is electrified. There is no potential difference between the cover plate 110 and the housing 150, reducing the risk of corrosion of the cover plate 110 and improving the reliability of the battery. A positive terminal 152 is provided at the end of the housing 150 away from the cover plate 110. The positive terminal 152 is hermetically connected to the housing 150 through an insulating sealing ring. The second current collector plate 170 is welded to the positive terminal of the winding core 140 and the positive terminal 152, and the second current collector plate 170 is located between the positive terminal of the winding core 140 and the positive terminal 152. In addition, an insulating member 180 is provided between the second current collector plate 170 and the end of the housing 150 to insulate the second current collector plate 170 and the housing 150.

[0088] In some embodiments, the area of the outer circle formed by the explosion-proof groove 120 on the cover plate 110 is φ1. φ1 refers to the area calculated based on the outer diameter of the ring formed by the explosion-proof groove 120 on the cover plate 110. Along the direction perpendicular to the axis of the housing 150, the cross-sectional area of the housing 150 is φ2, where

[0089]

[0090] It can be understood that The value of can be 0.27, 0.3, 0.4, 0.5, 0.6, 0.7, 7.6 or other unlisted values. Reasonably setting the ratio of φ1 to φ2 ensures the pressure relief effect of the explosion-proof structure.

[0091] In some embodiments, a flange 153 is formed by inward contraction of a portion of the side wall of the housing 150 near the opening 151. A pressing plate 154 is provided on the opening 151 of the housing 150. The pressing plate 154 is disposed at a relative interval from the flange 153. The cover plate 110 is installed between the flange 153 and the pressing plate 154. A seal 155 is provided between the cover plate 110 and the flange 153 and the pressing plate 154 to ensure the sealing performance of the cover plate 110. The seal 155 is an O-ring, and the compression ratio of the O-ring is between 30% and 70%, improving the pressure relief effect of the explosion-proof structure.

[0092] In other embodiments, the cover plate 110 and the housing 150 are connected by laser welding. The laser welding process is simple and has good sealing performance. At this time, the first current collector plate 160 is in direct contact with the housing 150 and can also be in direct contact with the cover plate 110, so that the housing 150 is negatively charged.

[0093] The technical solutions and technical effects of the present application will be described in detail below through specific examples and comparative examples. The following examples are only partial examples of the present application and do not specifically limit the present application.

[0094] This embodiment aims to investigate the influence of the explosion-proof structure applied to the battery on the battery performance.

[0095] The first test group

[0096] In this test group, the explosion-proof structure is as follows: Refer to Figure 12 As shown, the cover plate 110 includes a first side surface 111 and a second side surface 112 disposed opposite to each other. The first sub-groove 121 and the second sub-groove 122 are both provided on the first side surface 111. The first sub-groove 121 and the second sub-groove 122 are both arc-shaped rings. The first sub-groove 121 and the second sub-groove 122 are connected end to end, and the first sub-groove 121 and the second sub-groove 122 are communicated. The parameters of the cover plate 110 involve H1, H2, H2 - H1, a, C, G, E1.

[0097] Test method: Adopt Article 6.2.4 of the standard GB / T31485 - 2015.

[0098] Evaluation criteria: The opening time of the first sub-groove 121 is T1, the opening time of the second sub-groove 122 is T2, and the opening time difference between the first sub-groove 121 and the second sub-groove 122 is ΔT. Among them, T1 and T2 meet the following conditions: 50s ≤ T1 ≤ 100s, 60s ≤ T2 ≤ 150s, 5s ≤ ΔT ≤ 50s.

[0099] Set the basic group 1. The parameters and verification results of the basic group 1 are shown in Table 1.1 below.

[0100] Table 1.1: Parameters and verification results of the basic group 1

[0101]

[0102] According to the verification results in Table 1.1, the opening times of the first sub-slot 121 and the second sub-slot 122 both meet the evaluation criteria. While meeting the performance of the explosion-proof structure, secondary pressure relief is achieved.

[0103] Based on the parameters of basic group 1, the parameters of the cover plate 110 are controlled to change by the single-variable method to set the comparative examples and embodiments. The variable parameter tables and verification results of the comparative examples and embodiments are shown in Tables 1.2 to 1.5.

[0104] Table 1.2: Verification results of the comparative examples and embodiments set by changing H1 and H2 accordingly with basic group 1 as the parameter

[0105] H1 / μm H2 / μm Verification result Example 1 20.0 25.0 T1 = 60s, T2 = 65s, ΔT = 5s Example 2 67.0 72.0 T1 = 75s, T2 = 90s, ΔT = 15s Comparative example 1 15.0 20.0 T1 = 55s, T2 = 59s, ΔT = 4s Comparative example 2 120.0 125.0 T1 = 118s, T2 = 122s, ΔT = 4s

[0106] According to Table 1.2, when H1 is within the set range, while meeting the performance of the explosion-proof structure, secondary pressure relief is achieved. When H1 is not within the set range, the time interval between the two pressure relieves is short, resulting in a reduction in the secondary pressure relief effect of the explosion-proof structure.

[0107] Table 1.3: Verification results of the comparative examples and embodiments set by changing H2 to achieve a change in H2 - H1 with basic group 1 as the parameter

[0108] H2 / μm H2 - H1 / μm Verification result Example 1 125.0 10.0 T1 = 95s, T2 = 125s, ΔT = 30s Example 2 135.0 20.0 T1 = 95s, T2 = 143s, ΔT = 48s Comparative example 1 117.0 2.0 T1 = 95s, T2 = 98s, ΔT = 3s Comparative example 2 140.0 25.0 T1 = 95s, T2 > 150s, ΔT > 45s

[0109] According to Table 1.3, when H2 and H2 - H1 are within the set range, while meeting the performance of the explosion-proof structure, secondary pressure relief is achieved. When H2 - H1 is lower than the set range, the time interval between the two pressure relieves is short. When H2 - H1 is higher than the set range, the time interval between the two pressure relieves is long, or the opening time of the second sub-slot 122 is late, resulting in a reduction in the secondary pressure relief effect of the explosion-proof structure.

[0110] Table 1.4: Verification results of the comparative examples and embodiments set by changing G with basic group 1 as the parameter

[0111] G Verification result Example 1 1 / 10 T1 = 95s, T2 = 127s, ΔT = 32s Example 2 1 / 7 T1 = 95s, T2 = 136s, ΔT = 41s Comparative example 1 1 / 5 T1 = 96s, T2 = 150s, ΔT = 54s Comparative example 2 1 / 22 T1 = 95s, T2 = 98s, ΔT = 3s

[0112] According to Table 1.4, when G is within the set range, while meeting the performance of the explosion-proof structure, secondary pressure relief is achieved. When G is lower than or higher than the set range, the time interval between the two pressure relieves is short or long, resulting in a reduction in the secondary pressure relief effect of the explosion-proof structure.

[0113] Table 1.5: Verification results of the comparative examples and embodiments set by changing E1 with basic group 1 as the parameter

[0114] E1 / mm Verification result Example 1 32.0 T1 = 87s, T2 = 116s, ΔT = 29s Example 2 40.0 T1 = 78s, T2 = 110s, ΔT = 32s Comparative example 1 20.0 T1 = 100s, T2 = 156s, ΔT = 56s Comparative example 2 45.0 T1 = 50, T2 = 105, ΔT = 55

[0115] According to Table 1.5, when E1 is within the set range, while meeting the performance of the explosion-proof structure, secondary pressure relief is achieved. When E1 is lower or higher than the set range, the time interval between the two pressure reliefs is shorter, and the secondary pressure relief effect of the explosion-proof structure is reduced.

[0116] The second test group

[0117] In this test group, the explosion-proof structure is as follows: Refer to Figure 13 As shown, the cover plate 110 includes a first side 111 and a second side 112 that are oppositely arranged. The first sub-groove 121 and the second sub-groove 122 are both arranged on the first side 111. The first sub-groove 121 and the second sub-groove 122 are both arc-shaped rings. The first sub-groove 121 and the second sub-groove 122 are connected end to end, and the first sub-groove 121 and the second sub-groove 122 are communicated. The cover plate 110 includes a first sub-part 113 and a second sub-part 114. The first sub-part 113 and the second sub-part 114 are adjacent. The first sub-part is close to the edge of the cover plate 110. In the direction from the second side 112 to the first side 111, at least part of the second sub-part 114 is higher than the first sub-part 113, that is, at least part of the surface of the second sub-part 114 facing the core 140 is higher than the surface of the first sub-part 113 facing the core 140, and at least part of the surface of the second sub-part 114 away from the core 140 is higher than the surface of the first sub-part 113 away from the core 140. The explosion-proof groove 120 is arranged on the second sub-part 114. The parameters of the cover plate 110 involve H1, H2, H2 - H1, a, C, G, B, E1, E2, E3, E4, E3 - E2.

[0118] Test method: Adopt Article 6.2.4 of the standard GB / T31485 - 2015.

[0119] Evaluation criteria: The opening time of the first sub-groove 121 is T1, and the opening time of the second sub-groove 122 is T2. Among them, T1 and T2 meet the following conditions: 50s ≤ T1 ≤ 100s, 60 ≤ T2 ≤ 150s, 5s ≤ ΔT ≤ 50s.

[0120] Set the basic group 2, and the parameters and verification results of the basic group 2 are shown in Table 2.1 below.

[0121] Table 2.1: Parameters and verification results of the basic group 2

[0122]

[0123] According to the verification results in Table 2.1, the opening time of the first sub-groove 121 and the opening time of the second sub-groove 122 both meet the evaluation criteria, and while meeting the performance of the explosion-proof structure, secondary pressure relief is achieved.

[0124] According to the comparison of the verification results of the basic group 1 and the basic group 2, it can be seen that setting the explosion-proof groove 120 on the second sub-part 114 will increase the interval difference between the two pressure relieves and improve the secondary pressure relief effect of the explosion-proof structure on the premise of ensuring the battery safety performance.

[0125] Based on the parameters of the basic group 2, the parameters of the cover plate 110 are controlled to change by the single variable method to set the comparative example and the embodiment. The changed parameters and verification results of the comparative example and the embodiment are shown in Tables 2.2 and 2.3.

[0126] Table 2.2: Verification results of the comparative example and the embodiment with the parameters of the basic group 2 by changing B

[0127] B / mm Verification result Example 1 0.48 T1 = 86s, T2 = 129s, ΔT = 43s Example 2 0.60 T1 = 84s, T2 = 123s, ΔT = 39s Comparative example 1 0.20 T1 = 94s, T2 = 97s, ΔT = 3s Comparative example 2 1.00 T1 = 78s, T2 = 81s, ΔT = 3s

[0128] According to Table 2.2, when B is within the set range, while meeting the performance of the explosion-proof structure, secondary pressure relief is achieved. When B is lower than or exceeds the set range, the time interval between the two pressure relieves is shorter, and the secondary pressure relief effect of the explosion-proof structure is reduced.

[0129] Table 2.3: Verification results of the comparative example and the embodiment with the parameters of the basic group 2 by changing E1, E2, and E3

[0130]

[0131] According to Table 2.3, when E1, E2, E3, and (E3 - E2) are all within the set range, while meeting the performance of the explosion-proof structure, secondary pressure relief is achieved. When E2 is not within the set range, the time interval between the two pressure relieves is shorter, and the secondary pressure relief effect of the explosion-proof structure is reduced.

[0132] The third test group

[0133] The explosion-proof structure in this test group is: See Figure 1As shown in the figure, the cover plate 110 includes a first side surface 111 and a second side surface 112 which are oppositely arranged. The first sub-groove 121 and the second sub-groove 122 are both arranged on the first side surface 111. The first sub-groove 121 and the second sub-groove 122 are both arc-shaped rings. The first sub-groove 121 and the second sub-groove 122 are connected end to end and communicate with each other. The cover plate 110 includes a first sub-part 113 and a second sub-part 114. The first sub-part 113 is adjacent to the second sub-part 114. The first sub-part is close to the edge of the cover plate 110. In the direction from the second side surface 112 to the first side surface 111, the second sub-part 114 is higher than the first sub-part 113. The explosion-proof groove 120 is arranged on the second sub-part 114. The second sub-part 114 includes a connected sink 1141 and a boss 1142. The sink 1141 and the boss 1142 enclose a closed ring. In the direction from the second side surface 112 to the first side surface 111, the surface of the sink 1141 facing the core 140 is at the same height as the surface of the first sub-part 113 facing the core 140. The surface of the sink 1141 away from the core 140 is at the same height as the surface of the first sub-part 113 away from the core 140. It can be understood that the first side surface 111 of the sink 1141 and the first side surface 111 of the first sub-part 113 are in the same horizontal plane, and the second side surface 112 of the sink 1141 and the second side surface 112 of the first sub-part 113 are in the same horizontal plane. The surface of the boss 1142 facing the core 140 is higher than the surface of the sink 1141 facing the core 140, and the surface of the boss 1142 away from the core 140 is higher than the surface of the sink 1141 away from the core 140. The first sub-groove 121 is at least partially arranged on the sink 1141, and the second sub-groove 122 is arranged on the boss 1142. The parameters of the cover plate 110 involve H1, H2, H2 - H1, a, C, G, A, E1, E2, E3, E4, E3 - E2, D1 / D2, and α.

[0134] Test method: Adopt Article 6.2.4 of the standard GB / T31485 - 2015.

[0135] Evaluation criteria: The opening time of the first sub-groove 121 is T1, and the opening time of the second sub-groove 122 is T2. Among them, T1 and T2 satisfy the following conditions: 50s ≤ T1 ≤ 100s, 60s ≤ T2 ≤ 150s, 15s ≤ ΔT ≤ 50s.

[0136] Set the basic group 3. The parameters and verification results of the basic group 3 are shown in Table 3.1 as follows.

[0137] Table 3.1: Parameters of the basic group 3

[0138]

[0139]

[0140] According to the verification results in Table 3.1, the opening times of the first sub-slot 121 and the second sub-slot 122 both meet the evaluation criteria. While meeting the performance of the explosion-proof structure, secondary pressure relief is achieved.

[0141] According to the comparison of the verification results of basic group 1, basic group 2, and basic group 3, it can be seen that by setting a sunken platform 1141 and a convex platform 1142 on the second sub-part 114, on the premise of ensuring the battery safety performance, the time interval between primary pressure relief and secondary pressure relief is longer, which is beneficial to secondary pressure relief and further improves the reliability of the explosion-proof structure.

[0142] Based on the parameters of basic group 3, the parameters of the cover plate 110 are controlled to change by the single variable method to set the comparative examples and the embodiments. The changed parameters and verification results of the comparative examples and the embodiments are shown in Table 3.2.

[0143] Table 3.2: Verification results of comparative examples and embodiments set by changing D1 and D2 with the change of D1 based on basic group 3

[0144] D1 / mm D2 / mm Verification result Example 1 4.00 3.20 T1 = 74s, T2 = 122s, ΔT = 48s Example 2 12.00 11.20 T1 = 97s, T2 = 126s, ΔT = 29s Comparative example 1 1.00 0.20 T1 = 60s, T2 = 124s, ΔT = 64s Comparative example 2 18.00 17.20 T1 = 100s, T2 = 104s, ΔT = 4s

[0145] According to Table 3.2: When D1 is within the set range, while meeting the performance of the explosion-proof structure, secondary pressure relief is achieved. When D1 is lower than or exceeds the set range, the time interval between the two pressure relieves is shorter or longer, and the secondary pressure relief effect of the explosion-proof structure is reduced.

Claims

1. An explosion-proof structure, applied to a battery, characterized in that: include: A cover plate (110), wherein an explosion-proof groove (120) is provided on the cover plate (110), wherein the explosion-proof groove (120) comprises a first sub-groove (121) and a second sub-groove (122), wherein projections of the first sub-groove (121) and the second sub-groove (122) on a side surface of the cover plate (110) form a closed circular ring, and the thickness of the cover plate (110) at the position where the first sub-groove (121) is located is less than the thickness of the cover plate (110) at the position where the second sub-groove (122) is located.

2. The explosion-proof structure according to claim 1, characterized in that: The cover plate (110) comprises a first side surface (111) and a second side surface (112) which are arranged opposite to each other, the first sub-groove (121) and the second sub-groove (122) are both arranged on the first side surface (111), and the first sub-groove (121) is in communication with the second sub-groove (122).

3. The explosion-proof structure according to claim 1, characterized in that: The outer diameter of the circular ring where the explosion-proof groove (120) is located is E1, 24mm≤E1≤40㎜.

4. The explosion-proof structure according to any one of claims 1 to 3, characterized in that: The thickness of the cover plate (110) at the first sub-groove (121) is H1, and the thickness of the cover plate (110) at the second sub-groove (122) is H2, wherein 20 μm≤H1≤115 μm, and 25 μm≤H2≤135 μm.

5. The explosion-proof structure according to any one of claims 1 to 3, characterized in that: The thickness of the cover plate (110) at the first sub-groove (121) is H1, the thickness of the cover plate (110) at the second sub-groove (122) is H2, and 5 μm≤H2-H1≤20 μm.

6. The explosion-proof structure according to any one of claims 1 to 3, characterized in that: The arc length of the first sub-groove (121) is smaller than the arc length of the second sub-groove (122).

7. The explosion-proof structure according to any one of claims 1 to 3, characterized in that: The ratio of the arc length of the first sub-groove (121) to the arc length of the second sub-groove (122) is G, 8. The explosion-proof structure according to any one of claims 1 to 3, characterized in that: The thickness of the area outside the explosion-proof groove (120) on the cover plate (110) is C, and 0.4 mm≤C≤1.0 mm.

9. The explosion-proof structure according to any one of claims 1 to 3, characterized in that: The width of the notch of the explosion-proof groove (120) is a, 0.6 mm≤a≤1.5 mm.

10. The explosion-proof structure according to any one of claims 1 to 3, characterized in that: The explosion-proof groove (120) comprises a plurality of the first sub-grooves (121) and a plurality of the second sub-grooves (122), and the first sub-grooves (121) and the second sub-grooves (122) are arranged alternately.

11. The explosion-proof structure according to any one of claims 1 to 3, characterized in that: The cover plate (110) comprises a first sub-portion (113) and a second sub-portion (114); the first sub-portion (113) and the second sub-portion (114) are adjacent to each other; the first sub-portion (113) is close to the edge of the cover plate (110) and points from the second side surface (112) to the direction of the first side surface (111); the second sub-portion (114) is at least partially higher than the first sub-portion (113); and the explosion-proof groove (120) is arranged on the second sub-portion (114).

12. The explosion-proof structure according to claim 11, characterized in that: The second sub-section (114) includes a connected sink (1141) and a boss (1142); the sink (1141) and the boss (1142) are located on the same circumference; the surface of the boss (1142) facing the winding core (140) is higher than the surface of the sink (1141) facing the winding core (140) and the surface of the first sub-section (113) facing the winding core (140); the surface of the boss (1142) away from the winding core (140) is higher than the surface of the sink (1141) away from the winding core (140) and the surface of the first sub-section (113) away from the winding core (140); the first sub-groove (121) is at least partially arranged on the sink (1141), and the second sub-groove (122) is arranged on the boss (1142).

13. The explosion-proof structure according to claim 12, characterized in that: The cover plate (110) further comprises a third sub-portion (115), the third sub-portion (115) is circular, the third sub-portion (115) is arranged concentrically with the second sub-portion (114), and the sink (1141) and the convex platform (1142) form a closed ring.

14. The explosion-proof structure according to claim 13, characterized in that: The cover plate (110) further comprises a fourth sub-portion (116), the fourth sub-portion (116) being annular and located between the second sub-portion (114) and the third sub-portion (115), and the fourth sub-portion (116) connecting the second sub-portion (114) and the third sub-portion (115).

15. The explosion-proof structure according to claim 14, characterized in that: The surface of the first sub-portion (113) facing the winding core (140) is higher than the surface of the fourth sub-portion (116) facing the winding core (140), and the fourth sub-portion (116) is used to connect to the electrode of the battery; Or, the surface of the first sub-portion (113) facing the winding core (140) is higher than the surface of the fourth sub-portion (116) facing the winding core (140), and the surface of the first sub-portion (113) facing the winding core (140), the surface of the fourth sub-portion (116) facing the winding core (140), and the surface of the sink (1141) facing the winding core (140) are located at the same height.

16. The explosion-proof structure according to claim 13, characterized in that: The height of the surface of the third sub-portion (115) facing the winding core (140) is not lower than the height of the surface of the boss (1142) facing the winding core (140), and the height of the surface of the third sub-portion (115) away from the winding core (140) is not lower than the height of the surface of the boss (1142) away from the winding core (140).

17. The explosion-proof structure according to any one of claims 12 to 16, characterized in that: The depth of the sink (1141) is A, 0.8C≤A≤1.5C, wherein C is the thickness of the area outside the explosion-proof groove (120) on the cover plate (110).

18. The explosion-proof structure according to any one of claims 12 to 16, characterized in that: The width of the top of the sink (1141) is D1, and the width of the bottom of the sink (1141) is D2, wherein 4 mm ≤ D1 ≤ 12 mm; D2=D1-2C*tan(α-90°), and D2>2mm; α is the angle formed between the bottom and the side of the sink (1141), 100°≤α≤170°; C is the thickness of the area outside the explosion-proof groove (120) on the cover plate (110).

19. The explosion-proof structure according to any one of claims 12 to 16, characterized in that: The outer diameter of the ring where the explosion-proof groove (120) is located is E1, the inner diameter of the second sub-section (114) is E2, the outer diameter of the second sub-section (114) is E3, the diameter of the cover plate (110) is E4, and the thickness of the area outside the explosion-proof groove (120) on the cover plate (110) is C, wherein 42 mm ≤ E4 ≤ 46 mm; 0.75E4≤E3≤0.96E4, 0.4E4≤E2≤0.72E4 and 3C≤E3-E2≤27.8C; E2+C≤E1≤E3-C.

20. The explosion-proof structure according to claim 11, characterized in that: The distance between the first side surface (111) of the second sub-section (114) and the first side surface (111) of the first sub-section (113) is B, 0.8C≤B≤1.5C, wherein C is the thickness of the area outside the explosion-proof groove (120) on the cover plate (110).

21. The explosion-proof structure according to claim 1, characterized in that: The cover plate (110) comprises a first side surface (111) and a second side surface (112) which are arranged opposite to each other, the first sub-groove (121) and the second sub-groove (122) are both arranged on the second side surface (112), and the first sub-groove (121) is in communication with the second sub-groove (122); Alternatively, the cover plate (110) comprises a first side surface (111) and a second side surface (112) that are arranged opposite to each other, the first sub-groove (121) is arranged on the first side surface (111), and the second sub-groove (122) is arranged on the second side surface (112); Alternatively, the cover plate (110) comprises a first side surface (111) and a second side surface (112) which are arranged opposite to each other, the second sub-groove (122) is arranged on the first side surface (111), and the first sub-groove (121) is arranged on the second side surface (112).

22. The explosion-proof structure according to any one of claims 1 to 3, characterized in that: The thickness H1 of the cover plate (110) at the first sub-groove (121) and the thickness H2 of the cover plate (110) at the second sub-groove (122) are calculated according to the following formulas (1) and (2): Wherein, Q is the tensile strength of the material used to make the cover plate (110); E1 is the outer diameter of the circular ring where the explosion-proof groove (120) is located; P1 is the pressure at which the cover plate (110) at the first sub-groove (121) is opened; P2 is the pressure at which the cover plate (110) at the second sub-groove (122) opens.

23. The explosion-proof structure according to any one of claims 1 to 3, characterized in that: Along the thickness direction of the cover plate (110), the cross-sectional shape of the first sub-groove (121) and / or the second sub-groove (122) is V-shaped, semicircular, trapezoidal, "U"-shaped or parabolic.

24. A battery, characterized in that: include: The explosion-proof structure according to any one of claims 1 to 23; A winding core (140) including a positive terminal and a negative terminal; A shell (150), the winding core (140) is installed in the shell (150), one end of the shell (150) is provided with an opening (151), and the cover plate (110) is sealedly connected to the shell (150) to block the opening (151).

25. The battery according to claim 24, characterized in that The invention also includes a positive terminal (152), a first current collecting disk (160), a second current collecting disk (170) and an insulating member (180); the positive terminal (152) is arranged at one end of the shell (150) away from the cover plate (110); the first current collecting disk (160) is welded to the winding core (140) and is arranged between the cover plate (110) and one end of the winding core (140); the second current collecting disk (170) is welded to the winding core (140) and the positive terminal (152) and is arranged between the winding core (140) and the positive terminal (152); and the insulating member (180) is arranged between the second current collecting disk (170) and the shell (150).

26. The battery according to claim 24, characterized in that The outer circular area of ​​the explosion-proof groove (120) formed on the cover plate (110) is φ1, and the cross-sectional area of ​​the shell (150) along the direction perpendicular to the axis of the shell (150) is φ2.

27. The battery according to claim 26, characterized in that The side wall of the shell (150) is contracted inwardly near the opening (151) to form a flange (153); a pressure plate (154) is provided on the opening (151) of the shell (150); the pressure plate (154) and the flange (153) are arranged with a relative spacing; and the cover plate (110) is installed between the flange (153) and the pressure plate (154).

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