Cover plate, battery, and battery pack

Abstract

Disclosed in the present application are a cover plate, a battery, and a battery pack. The cover plate comprises a body and an anti-explosion structure; the body comprises a first sub-portion and a second sub-portion, wherein the second sub-portion comprises a recessed platform and a protruding platform that are connected together, the second sub-portion has a first side face and a second side face that are opposingly arranged, and the height of the protruding platform is higher than the recessed platform and the first sub-portion; an anti-explosion recess is arranged on the first side face, a first sub-recess of the anti-explosion recess is at least partially located on the recessed platform, and a second sub-recess of the anti-explosion recess is located on the protruding platform.

Description

Covers, batteries, and battery packs Technical Field

[0001] The present application belongs to the field of battery technology, and in particular to a cover plate, a battery and a battery pack. Background Art

[0002] During use, power batteries may experience internal pressure buildup exceeding safety limits due to short circuits or other factors, potentially creating explosion hazards. To minimize these risks, the battery cover is typically equipped with an explosion-proof structure. This structure gradually deforms as internal pressure increases until it opens. As the structure opens, the contents of the battery are ejected. Because the opening direction of the structure is uncertain, the direction of the ejected material is also uncertain. This material can randomly flow onto surrounding batteries, impacting them and expanding the scope of thermal runaway. Technical issues

[0003] The embodiments of the present application provide a cover plate, a battery, and a battery pack to solve the problem of uncertain opening direction of explosion-proof structures in related technologies. Technical Solutions

[0004] In a first aspect, an embodiment of the present application provides a cover plate for use with a battery, comprising: a body, comprising a first sub-section and a second sub-section, wherein the first sub-section is adjacent to the second sub-section and, along a radial direction of the body, the first sub-section is close to an edge of the body, wherein the second sub-section comprises a connected sink and a boss, the sink and the boss being located on the same circumference, the second sub-section having a first side surface and a second side surface oppositely disposed, and the boss being higher than the sink and the first sub-section in a direction pointing from the second side surface to the first side surface;

[0005] The explosion-proof groove includes a first sub-groove and a second sub-groove, wherein the first sub-groove is at least partially located on the sunken platform, and the second sub-groove is located on the raised platform.

[0006] In a second aspect, a battery comprises the cover plate described in any one of the above items;

[0007] A winding core, including a positive terminal and a negative terminal;

[0008] The shell is provided with an opening at one end of the shell, and the body is sealedly connected to the shell to block the opening.

[0009] In a third aspect, a battery pack includes a plurality of the batteries described above. Beneficial effects

[0010] The beneficial effects of the present application are as follows: the cover plate, battery and battery pack provided in the embodiments of the present application, the cover plate includes a main body and an explosion-proof groove, the main body includes a first sub-section and a second sub-section adjacent to each other, the explosion-proof groove is arranged on the second sub-section, the second sub-section has a boss and a sink, the boss is higher than the sink and the first sub-section, the first sub-groove is located on the sink, and the second groove is located on the boss. When the cover plate is depressurized, the force acting on the sink position is relatively large, and the explosion-proof groove is opened first from the sink, thereby overcoming the problem of uncertain opening direction of the explosion-proof structure in related technologies and realizing directional opening when the cover plate is depressurized. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG1 is a top view of a first form of a cover provided in an embodiment of the present application.

[0012] FIG2 is a cross-sectional view taken along line AA in FIG1 .

[0013] FIG3 is a partial enlarged view of point B in FIG1 .

[0014] FIG4 is a CC cross-sectional view in FIG3 .

[0015] FIG5 is a partial enlarged view of point D in FIG4 .

[0016] FIG6 is a cross-sectional view taken along line EE in FIG3 .

[0017] FIG7 is a marked diagram of the cover plate provided in an embodiment of the present application.

[0018] FIG8 is a three-dimensional view of the cover provided in an embodiment of the present application.

[0019] FIG9 is a three-dimensional diagram of a battery provided in an embodiment of the present application.

[0020] FIG10 is a top view of a battery provided in an embodiment of the present application.

[0021] FIG11 is a cross-sectional view of GG in FIG10 .

[0022] FIG12 is a partial enlarged view of point H in FIG11 .

[0023] FIG13 is a partial enlarged view of point M in FIG11 .

[0024] FIG14 is a three-dimensional schematic diagram of a battery pack provided in an embodiment of the present application.

[0025] FIG15 is a side view of FIG14 .

[0026] FIG16 is a cross-sectional view taken along line HH in FIG15 .

[0027] Explanation of the accompanying drawings: 100, battery; 110, cover plate; 111, main body; 113, first sub-section; 114, second sub-section; 1141, sink; 1142, boss; 1143 first side; 1144 second side; 115, third sub-section; 116, fourth sub-section; 120, explosion-proof groove; 121, first sub-groove; 1211, first groove wall; 1212, second groove wall; 122, second sub-groove; 130, mounting seat; 131, mounting groove; 132, baffle; 133, first sub-plate; 134, second sub-plate; 140, winding core; 150, shell; 151, opening; 152, positive terminal; 153, flange; 154, pressure plate; 155, seal; 160, first collecting disc; 170, second collecting disc; 180, insulating member. Modes for Carrying Out the Invention

[0028] The embodiments of the present application provide a cover plate, a battery, and a battery pack to solve the problem of uncertain opening direction of explosion-proof structures in related technologies. The embodiments will be described below with reference to the accompanying drawings.

[0029] 1 , 2 and 8 , an embodiment of the present application provides a cover plate 110 , including a body 111 and an explosion-proof groove 120 .

[0030] In this embodiment, the main body 111 includes a first sub-section 113 and a second sub-section 114, and the first sub-section 113 is adjacent to the second sub-section 114. Along the radial direction of the main body 111, the first sub-section 113 is close to the edge of the main body 111, wherein the second sub-section 114 includes a connected sink 1141 and a boss 1142, and the sink 1141 and the boss 1142 are located on the same circumference. The second sub-section 114 has a first side surface 1143 and a second side surface 1144 that are oppositely arranged. The first side surface 1143 is the surface of the second sub-section 114 facing away from the winding core 140, and the second side surface 1144 is the surface of the second sub-section 114 facing the winding core 140, and the direction from the second side surface 1144 to the first side surface 1143 is higher than the sink 1141 and the first sub-section 113. The explosion-proof groove 120 is opened on the first side surface 1143 or the second side surface 1144 , and includes a first sub-groove 121 and a second sub-groove 122 that are connected. The first sub-groove 121 is at least partially located on the sink 1141 , and the second sub-groove 122 is located on the boss 1142 .

[0031] In this embodiment, a second sub-section 114 is provided on the body 111. The second sub-section 114 has a boss 1142 and a recessed platform 1141. The boss 1142 is higher than the recessed platform 1141 and the first sub-section 113. The first side 1143 of the boss 1142 is higher than the first side 1143 of the recessed platform 1141. The second side 1144 of the boss 1142 is higher than the second side 1144 of the recessed platform 1141. When the cover 110 is depressurized, the recessed platform 1141 is subjected to a greater force, and the explosion-proof groove 120 is first opened from the recessed platform 1141. This overcomes the problem of uncertain opening direction of explosion-proof structures in related technologies and achieves directional opening of the cover 110 when depressurized. The explosion-proof groove 120 is first opened from the recessed platform 1141 and can be opened in a variety of ways, such as instantaneous full opening of the first sub-groove 121 on the recessed platform 1141, or the first sub-groove 121 has an opening point and opens from the opening point until the first sub-groove 121 is fully opened. The opening point may be the intersection of the protrusion 1142 and the sink 1141 on the first sub-groove 121 , or any position on the first sub-groove 121 within the area of ​​the sink 1141 .

[0032] In some embodiments, as shown in Figures 2 and 4 , the surface of the first sub-portion 113 facing the winding core 140 is at the same height as the surface of the sinking platform 1141 facing the winding core 140, and the surface of the first sub-portion 113 away from the winding core 140 is at the same height as the surface of the sinking platform 1141 away from the winding core 140. When the cover plate 110 is depressurized, the force acting on the sinking platform 1141 is greater, and the explosion-proof groove 120 opens first from the sinking platform 1141, which facilitates the directional opening of the explosion-proof groove 120.

[0033] In some embodiments, as shown in Figure 1, the main body 111 also includes a third sub-section 115, the first sub-section 113 and the second sub-section 114 are annular, and the third sub-section 115 is circular. Along the radial direction of the main body 111, the first sub-section 113, the second sub-section 114 and the third sub-section 115 are concentrically arranged in sequence, and the sink 1141 and the boss 1142 form a closed ring.

[0034] It will be appreciated that in this embodiment, the second sub-section 114 is annular and consists of a sink 1141 and a projection 1142. Both the sink 1141 and the projection 1142 are arcuate rings, and have the same inner and outer diameters. When the cover 110 is in use, the first sub-section 113 of the cover 110 is compressed and fixed by the other components of the battery. When the air pressure within the battery increases, the cover 110 deforms, and the third sub-section 115 bulges outward. The first and third sub-sections 113 and 115 exert forces in different directions on both sides of the second sub-section 114, causing it to split at the explosion-proof groove 120, facilitating the opening of the explosion-proof groove 120.

[0035] In some embodiments, as shown in Figure 1, the main body 111 also includes a fourth sub-section 116, which is annular and located between the second sub-section 114 and the third sub-section 115. The fourth sub-section 116 connects the second sub-section 114 and the third sub-section 115.

[0036] When the cover plate 110 deforms under pressure, it bulges upward into a hemispherical or hat-like shape, increasing the space between the cover plate 110 and the end of the battery cell. This prevents a sudden increase in pressure within the battery, which could lead to an explosion. Furthermore, an explosion-proof recess 120 is positioned within the second subsection 114. During the deformation of the cover plate 110, the deformation forces of the first and fourth subsections 113 and 116 act on the recess 120, facilitating its smooth opening and enhancing the reliability of the explosion-proof structure.

[0037] In some embodiments, the surface of the first sub-section 113 facing the winding core 140, the surface of the sinking platform 1141 facing the winding core 140, and the surface of the fourth sub-section 116 facing the winding core 140 are located at the same height. Furthermore, the surface of the first sub-section 113 away from the winding core 140, the surface of the sinking platform 1141 away from the winding core 140, and the surface of the fourth sub-section 116 away from the winding core 140 are located at the same height.

[0038] It can be understood that when the boss 1142 is deformed, a force is generated between the first sub-portion 113 and the boss 1142 and acts on the body 111 at the position of the second sub-groove 122, which is conducive to opening the second sub-groove 122 and ensuring the explosion-proof effect.

[0039] In some embodiments, the surface of the first subsection 113 facing the winding core 140 and the surface of the sinking platform 1141 facing the winding core 140 are both higher than the surface of the fourth subsection 116 facing the winding core 140. The fourth subsection 116 is used to contact the battery electrodes. In addition, the surface of the first subsection 113 facing away from the winding core 140 and the surface of the sinking platform 1141 facing away from the winding core 140 are both higher than the surface of the fourth subsection 116 facing the winding core 140.

[0040] It can be understood that the fourth sub-portion 116 is the portion of the cover 110 that is closest to the battery cell. The fourth sub-portion 116 is fitted and connected to the electrode. The fourth sub-portion 116 has the same potential as the electrode. When the cover 110 contacts the shell 150, there is no potential difference between the battery cover 110 and the shell 150, which reduces the risk of corrosion of the cover 110 and improves the reliability of the battery.

[0041] In some embodiments, the surface of the third sub-portion 115 facing the core 140 is not lower than the surface of the boss 1142 facing the core 140 , and the surface of the third sub-portion 115 facing away from the core 140 is not lower than the surface of the boss 1142 facing away from the core 140 .

[0042] It can be understood that the cover 110 has an uneven structure, with the third sub-section 115 being the highest. As the air pressure in the battery increases, the cover 110 deforms, and the third sub-section 115 bulges outward and deforms, thereby increasing the space after the deformation of the cover 110 as much as possible, which is conducive to the opening of the explosion-proof groove 120 and preventing the cover 110 from exploding.

[0043] In some embodiments, the cross-sectional shape of the explosion-proof groove 120 along the thickness direction of the cover plate 110 is V-shaped, trapezoidal, U-shaped, or parabolic. The cross-sectional shape of the explosion-proof groove 120 can be set as needed.

[0044] In some embodiments, the cover plate 110 may be made of steel, such as SPCC material, stainless steel materials such as SUS410, SUS306, SUS316, SUS430, and SUS444. When SPCC material is used, both sides of the cover plate 110 may be nickel plated with a thickness of 0.3 μm to 8 μm. The thickness of the nickel plated layers on both sides may be the same or different.

[0045] In some embodiments, as shown in FIG. 1 , when viewed from above the cover plate 110 , the explosion-proof groove 120 is in the shape of a closed circular ring.

[0046] It can be understood that the explosion-proof groove 120 is set in a circular ring shape. When the cover plate 110 releases pressure, the part of the cover plate 110 inside the explosion-proof groove 120 is completely separated from the part of the cover plate 110 outside the explosion-proof groove 120, thereby realizing the full opening of the explosion-proof structure, unobstructed pressure relief, and ensuring the explosion-proof effect.

[0047] In some embodiments, as shown in Figures 1 and 2, the depth of the sink 1141 is A, 0.8C≤A≤1.5C, where C is the thickness of the area outside the explosion-proof groove 120 on the body 111. For example, 1C≤A≤1.3C, where A can be 0.8C, 0.9C, 1.0C, 1.1C, 1.2C, 1.3C, 1.4C, 1.5C, or other unspecified values.

[0048] It can be understood that the main body 111 is formed in one piece, and the depth A of the sink 1141 is associated with the thickness of the main body 111 to avoid a situation where the depth of the sink 1141 and the thickness of the main body 111 are too different, which is not conducive to processing, and to ensure that the sink 1141 is formed and the processing technology is simple.

[0049] In some embodiments, the thickness of the area outside the explosion-proof groove 120 on the body 111 is C, 0.4 mm ≤ C ≤ 1.0 mm, where 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 unspecified values.

[0050] It can be understood that the thicker the body 111 is, the better the structural strength of the cover 110 is, but the greater the pressure required to open the explosion-proof groove 120 is. In the embodiment of the present application, the thickness of the body 111 is designed within a reasonable range, taking into account both the structural strength of the cover 110 and the opening pressure of the explosion-proof groove 120, thereby improving the overall performance of the cover 110.

[0051] In some embodiments, referring to FIG. 1 and FIG. 7 , the width of the top of the sink 1141 is D1, and the width of the bottom of the sink 1141 is D2, wherein:

[0052] 4mm≤D1≤12mm;

[0053] D2 = D1 - 2C*tan(α-90°), and D2 > 2 mm;

[0054] α is the angle formed between the bottom and the side of the sink 1141, 100°≤α≤170°;

[0055] C is the thickness of the area outside the explosion-proof groove 120 on the main body 111.

[0056] For example, D1 can be 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, or other unspecified values, and α can be 100°, 110°, 120°, 130°, 140°, 150°, 160°, 170°, or other unspecified values. The bottom width D2 can be calculated based on D1 and α.

[0057] It is understandable that the larger D1 and D2 of the sink 1141 are, the larger the area of ​​directional opening is, which can achieve rapid pressure relief and prevent battery explosion. However, if D1 and D2 of the sink 1141 are too large, the area of ​​battery liquid splashing is also larger, affecting the surrounding batteries. In the embodiment of the present application, the size of the sink 1141 is reasonably set to ensure the directional opening and pressure relief effect of the explosion-proof structure.

[0058] In some embodiments, as shown in FIG7 , in a top view of the body 111 , the outer diameter of the ring in which the explosion-proof groove 120 is located is E1, the inner diameter of the second sub-portion 114 is E2, the outer diameter of the second sub-portion 114 is E3, and the diameter of the body 111 is E4, wherein 42 mm ≤ E4 ≤ 46 mm, for example, E4 is 42 mm, 43 mm, 44 mm, 45 mm, 46 mm, or other unspecified values;

[0059] 0.75E4≤E3≤0.96E4, 0.4E4≤E2≤0.72E4 and 3C≤E3-E2≤22.8C;

[0060] E2+C≤E1≤E3-C, where C is the thickness of the area outside the explosion-proof groove 120 on the main body 111.

[0061] It is understood that in the embodiment of the present application, the diameter E4 of the body 111 is associated with the corresponding battery product specifications, the dimensions of E2 and E3 are associated with E4, and the dimension of E1 is associated with E2 and E3. The structural dimensions of the cover 110 are rationally designed. The area of ​​the second sub-section 114 is reasonably set to facilitate the processing of the explosion-proof groove 120. The larger the E1, the larger the area of ​​the explosion-proof groove 120, and the better the pressure relief effect.

[0062] On the basis of the above embodiment, the thickness of the body 111 where the explosion-proof groove 120 is located is H, 50 μm≤H≤120 μm.

[0063] It can be understood that the thicker the thickness of the body 111 at the location of the explosion-proof groove 120, the greater the pressure required to open the explosion-proof groove 120. The thickness of the body 111 at the location of the explosion-proof groove 120 is positively correlated with the pressure required to open the explosion-proof groove 120. If the thickness of the body 111 at the location of the explosion-proof groove 120 is thinner, the explosion-proof groove 120 may be opened within the normal working range of the battery, affecting the performance of the battery. If the thickness of the body 111 at the location of the explosion-proof groove 120 is thicker, the pressure required to open the explosion-proof groove 120 is greater, and the battery is prone to explosion. In the embodiment of the present application, the thickness of the first sub-groove 121 and the second sub-groove 122 are the same. The thickness of the main body 111 where the explosion-proof groove 120 is located can be 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm or other unspecified values. The thickness range of the main body 111 where the explosion-proof groove 120 is located is reasonably designed to ensure the normal operation of the battery while preventing the battery from exploding.

[0064] In some embodiments, as shown in FIG6 , the width of the notch of the explosion-proof groove 120 is a, 0.6 mm ≤ a ≤ 1.5 mm. 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 unspecified values.

[0065] It can be understood that the width of the notch of the explosion-proof groove 120 is reasonably designed, which is conducive to the processing and forming of the explosion-proof groove 120 on the second sub-section 114.

[0066] 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 unspecified values.

[0067] The arc lengths of the first sub-groove 121 and the second sub-groove 122 are reasonably arranged, and the opening sizes of the primary pressure relief and the secondary pressure relief are reasonably arranged to ensure explosion-proof effect.

[0068] In some embodiments, the thickness of the body 111 where the explosion-proof groove 120 is located is H.

[0069] Wherein, E1 is the outer diameter of the ring where the explosion-proof groove 120 is located;

[0070] P is the pressure at which the cover plate 110 at the explosion-proof groove 120 opens;

[0071] Q is the tensile strength of the material of the cover plate 110 .

[0072] The thickness H of the body 111 where the explosion-proof groove 120 is located can be designed according to the required pressure, the material of the cover plate 110 , and the circumference of the explosion-proof groove 120 . The design is simple and ensures the performance of the cover plate 110 .

[0073] In some embodiments, the thickness of the main body 111 at the location of the explosion-proof groove 120 is H, 50μm≤H≤120μm, and the depth of the first sub-groove 121 and the second sub-groove 122 is the same, where the value of H can be 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 110μm, 120μm or other unlisted values.

[0074] In some embodiments, referring to FIG. 5 and FIG. 6 , the thickness of the body 111 at the location of the first sub-groove 121 is H1 , and the thickness of the body 111 at the location of the second sub-groove 122 is H2 , and H1 < H2 .

[0075] It can be understood that the first sub-groove 121 and the second sub-groove 122 are arranged on the first side surface 1143. By arranging the first sub-groove 121 and the second sub-groove 122 on the body 111, the thickness of the body 111 at the position of the first sub-groove 121 is less than the thickness of the body 111 at the position of the second sub-groove 122. When the internal pressure of the battery increases, the position of the first sub-groove 121 on the body 111 is opened first, and the position of the second sub-groove 122 on the body 111 is opened again, forming a secondary pressure relief of the battery. The first opening can discharge the combustible gas. The second opening can discharge the combustion-supporting gas, thereby achieving the purpose of time-sharing discharge of the combustible gas and the combustion-supporting gas, overcoming the problem that when the explosion-proof structure of the related technology explodes, the combustible gas, the combustion-supporting gas and the substances in the battery interact with each other, aggravating the degree of thermal runaway and causing the battery to explode. After the main body 111 at the position of the first sub-groove 121 is opened, the main body 111 at the position of the second sub-groove 122 is broken through from the connection between the first sub-groove 121 and the second sub-groove 122, which is conducive to the opening of the main body 111 at the position of the second sub-groove 122, thereby improving the reliability of the cover and ensuring the explosion-proof effect.

[0076] In some embodiments, as shown in FIG5 and FIG6 , the thickness of the body 111 at the location of the first sub-groove 121 is H1, and the thickness of the body 111 at the location of the second sub-groove 122 is H2, 20 μm ≤ H1 ≤ 115 μm, 25 μm ≤ H2 ≤ 135 μm, and 5 μm ≤ H2 - H1 ≤ 20 μm. For example, 45 μm ≤ H1 ≤ 55 μm, and 80 μm ≤ H2 ≤ 100 μm. 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 unspecified values. The value of H2 can be 25μm, 35μm, 45μm, 55μm, 65μm, 75μm, 85μm, 95μm, 105μm, 115μm, 125μm, 135μm or other unlisted values, and the value of H2-H1 can be 5μm, 10μm, 15μm, 20μm or other unlisted values.

[0077] It can be understood that the thickness of the main body 111 at the position of the first sub-groove 121 and the thickness of the main body 111 at the position of the second sub-groove 122 are positively correlated with the pressure required to open the explosion-proof groove 120. The thickness of the main body 111 at the position of the first sub-groove 121 and the thickness of the main body 111 at the position of the second sub-groove 122 are reasonably designed to meet the normal operation of the battery, achieve secondary pressure relief, and prevent battery explosion.

[0078] Referring to Figures 9, 10, 11 and 12, an embodiment of the present application further provides a battery, which is a cylindrical battery, comprising a cover plate 110 of any one embodiment. It can be applied to the positive or negative side of the battery, and the cover plate 110 is applied to the negative side of the cylindrical battery as an example. The battery includes the above-mentioned cover plate 110, a winding core 140 and a shell 150, the winding core 140 is installed in the shell 150, and an opening 151 is provided at one end of the shell 150. The cover plate 110 is sealed to the shell 150 to block the opening 151. The battery has the same technical effect as the battery explosion-proof structure, which will not be repeated.

[0079] On the basis of the above embodiment, referring to FIG11 and FIG12 , the battery further includes a first current collecting disc 160, a second current collecting disc 170 and an insulating member 180. A positive terminal 152 is provided at the other end of the shell 150. The winding core 140, the first current collecting disc 160 and the second current collecting disc 170 are all arranged in the shell 150. The cover plate 110 is sealed and connected to the shell 150, and blocks the opening 151. The second side surface 1144 of the cover plate 110 abuts against one side surface of the first current collecting disc 160. The other side surface of the first current collecting disc 160 is welded to the negative terminal of the winding core 140. The peripheral side of the first current collecting disc 160 is connected to the inner surface of the shell 150 so that the shell 150 is charged. There is no potential difference between the cover plate 110 and the shell 150, which reduces the risk of corrosion of the cover plate 110 and improves the reliability of the battery. A positive terminal 152 is provided at the end of the 50 charged body facing away from the cover plate 110, and the positive terminal 152 is sealed to the shell 150 by a sealing ring. The second collecting disc 170 is welded to the winding core 140 and the positive terminal 152, and the second collecting disc 170 is provided between the positive end of the winding core 140 and the positive terminal 152. In addition, an insulating member 180 is provided between the second collecting disc 170 and the end of the shell 150, and the second collecting disc 170 and the shell 150 are insulated by the insulating member 180.

[0080] In some embodiments, the side wall of the shell 150 near the opening 151 is contracted inward 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 spaced relative to each other. The cover 110 is installed between the flange 153 and the pressure plate 154. A seal 155 is provided between the cover 110 and the flange 153 and the pressure plate 154 to ensure the sealing of the cover 110. The seal 155 is a sealing ring with a compression rate of 30% to 70%, thereby improving the pressure relief effect of the explosion-proof structure.

[0081] In other embodiments, the cover plate 110 and the shell 150 are connected by laser welding. The laser welding process is simple and has good sealing. At this time, the first collecting plate 160 is in direct contact with the shell 150 and can also be in direct contact with the cover plate 110 to make the shell 150 negatively charged.

[0082] As shown in FIG14 , a battery pack according to an embodiment of the present application includes the above-mentioned battery.

[0083] In some embodiments, as shown in Figures 14, 15, and 16, the battery pack further includes a mounting base 130 having a plurality of mounting slots 131 and a plurality of baffles 132. The batteries, mounting slots 131, and baffles 132 correspond one to one. The end of the battery 100 closest to the cover plate 110 is mounted in the mounting slot 131. The baffles 132 are located on the side of the mounting slot 131 facing away from the battery 100. The first sub-slot 121 has a first slot wall 1211 and a second slot wall 1212. The second slot wall 1212 is closer to the center of the cover plate 110 than the first slot wall 1211. The projection of the baffle 132 on a side of the cover plate 110 is located on the side of the first slot wall 1211 facing away from the second slot wall 1212. The width of the baffle 132 is greater than or equal to the length of the first sub-slot 121. The baffles 132 can be flat or curved.

[0084] It can be understood that as the pressure inside the battery 100 increases, the first sub-groove 121 in the sink 1141 opens, and the gas and substances in the battery 100 are ejected from the side of the first sub-groove 121. By setting a baffle 132 on the mounting base 130, the baffle 132 is located below the sink 1141, and the projection of the baffle 132 on the plane where the cover 110 is located is aligned with the sink 1141. The baffle 132 blocks the substances ejected from the battery 100, thereby preventing the ejected substances from entering the adjacent battery 100 and contaminating the adjacent battery 100.

[0085] 16 , the baffle 132 is an arc-shaped plate, the arc length of the baffle 132 is L4, and the arc length in the area where the sink 1141 is located is L5, L4 ≥ L5, so that the baffle 132 has a larger blocking area and a better blocking effect.

[0086] Based on the above embodiment, as shown in FIG14 , the mounting base 130 includes a first sub-plate 133 and a second sub-plate 134. The first sub-plate 133 and the second sub-plate 134 are spaced apart from each other and connected to each other. A mounting groove 131 is defined in the first sub-plate 133, and a baffle 132 is positioned between the first sub-plate 133 and the second sub-plate 134 and connected to the first sub-plate 133. This facilitates the processing and molding of the mounting base 130, and the gap between the first sub-plate 133 and the second sub-plate 134 can contain substances ejected from the battery, preventing the ejected substances from affecting other batteries.

[0087] The technical solutions and technical effects of the present application are described in detail below through specific examples and comparative examples. The following examples are only some examples of the present application and do not specifically limit the present application.

[0088] This example aims to investigate the impact of the explosion-proof structure on battery performance.

[0089] First test group

[0090] The structure of the cover plate 110 in this test group is as follows: the main body 111 includes a first sub-section 113, a second sub-section 114, a third sub-section 115, and a fourth sub-section 116. 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 second sub-section 114 has a first side surface 1143 and a second side surface 1144 that are oppositely disposed. The first side surface 1143 is the surface of the second sub-section 114 facing away from the winding core 140, and the second side surface 1144 is the surface of the second sub-section 114 facing the winding core 140. The direction from the second side surface 1144 to the first side surface 1143 is the same. The boss 1142 is higher than the sink 1141 and the first sub-section 113. The explosion-proof groove 120 is opened on the first side surface 1143 or the second side surface 1144 and includes a first sub-groove 121 and a second sub-groove 122 that are connected. The first sub-groove 121 is at least partially located on the sink 1141 , and the second sub-groove 122 is located on the protrusion 1142 .

[0091] Test method: Adopt Article 6.2.4 of GB / T31485-2015 standard.

[0092] Evaluation criteria: The opening time of the first sub-slot 121 is T1, the opening time of the second sub-slot 122 is T2, and the opening time difference between the first sub-slot 121 and the second sub-slot 122 is ΔT, wherein T1 and T2 meet the following conditions: 50s≤T1≤100s, 60s≤T2≤150s, 5s≤ΔT≤50s.

[0093] It is understandable that when the T1 time is too short, within 50s, the battery may have a problem of valve leakage when it opens. If it exceeds 100s, the temperature when it is opened is too high, and a large amount of combustible gas will explode when it comes into contact with the air when the valve opens instantly after reaching the flash point. In the embodiment of the present application, the T1 time is set reasonably, and a pressure relief is achieved within the T1 time period to release the combustible gas.

[0094] The parameters involved in the cover plate 110 include: H1, H2, H2-H1, a, C, G, A, E1, E2, E3, E4, E3-E2, D1 and D2. The parameters of the basic group 1 are shown in Table 1.1 below.

[0095] Set basic group 1. The parameters and verification results of basic group 1 are shown in Table 1.1 below.

[0096] Table 1.1: Parameters of basic group 1

[0097] According to the verification results in Table 1.1, when the cover 110 is opened in a directional manner, the opening time of the first sub-groove 121 and the opening time of the second sub-groove 122 both meet the evaluation criteria, thereby meeting the performance of the explosion-proof structure and achieving secondary pressure relief.

[0098] Based on the parameters of basic group 1, the parameter changes of the cover plate 110 are controlled by the single variable method to set the comparative example and the embodiment. The variable parameters and verification results of the comparative example and the embodiment are shown in Table 1.2.

[0099] Table 1.2: Verification results of comparative examples and examples based on basic group 1, where D1 and D2 are changed as D1 is changed

[0100] According to Table 1.2: When the cover 110 is directional opened, when D1 is within the set range, the performance of the explosion-proof structure is met and secondary pressure relief is achieved. When D1 is lower than or exceeds the set range, the time interval between the two pressure reliefs is shorter or longer, and the secondary pressure relief effect of the explosion-proof structure is reduced.

Claims

1. A cover plate, applied to a battery, comprising: A body (111), including a first sub - part (113) and a second sub - part (114), the first sub - part (113) being adjacent to the second sub - part (114). Along the radial direction of the body (111), the first sub - part (113) is close to the edge of the body (111). Wherein, the second sub - part (114) includes a connected counter - sink (1141) and a boss (1142), the counter - sink (1141) and the boss (1142) are located on the same circumference, the second sub - part (114) has a first side surface (1143) and a second side surface (1144) arranged oppositely, and in the direction from the second side surface (1144) to the first side surface (1143), the height of the boss (1142) is higher than that of the counter - sink (1141) and the first sub - part (113); An explosion - proof groove (120), including a first sub - groove (121) and a second sub - groove (122), the first sub - groove (121) is at least partially located on the counter - sink (1141), and the second sub - groove (122) is located on the boss (1142).

2. The cover plate according to claim 1, wherein, The body (111) further includes a third sub - part (115), the third sub - part (115) is circular, the third sub - part (115) is concentrically arranged with the second sub - part (114), and the counter - sink (1141) and the boss (1142) enclose a closed ring.

3. The cover plate according to claim 2, wherein, The body (111) 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).

4. The cover plate according to claim 3, wherein, The surface of the first sub - part (113) facing the core (140), the surface of the counter - sink (1141) facing the core (140), and the surface of the fourth sub - part (116) facing the core (140) are at the same height; Or, the surface of the first sub - part (113) facing the core (140) and the surface of the counter - sink (1141) facing the core (140) are both higher than the surface of the fourth sub - part (116) facing the core (140), and the fourth sub - part (116) is used to contact the electrode of the battery.

5. The cover plate according to claim 2, wherein, The surface of the third sub - part (115) facing the core (140) is not lower than the surface of the boss (1142) facing the core (140), and the surface of the third sub - part (115) facing away from the core (140) is not lower than the surface of the boss (1142) facing away from the core (140).

6. The cover plate according to claim 2, wherein, The shape of the explosion-proof groove (120) is an annular ring. 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, the diameter of the body (111) is E4, and the thickness of the area on the body (111) outside the explosion-proof groove (120) is C. Among them, 42mm ≤ E4 ≤ 46mm; 0.75E4 ≤ E3 ≤ 0.96E4, 0.4E4 ≤ E2 ≤ 0.72E4 and 3C ≤ E3 - E2 ≤ 27.8C; E2 + C ≤ E1 ≤ E3 - C.

7. The cover plate according to claim 1, wherein, The surface of the first sub-part (113) facing the core (140) and the surface of the sunk platform (1141) facing the core (140) are at the same height. The surface of the first sub-part (113) away from the core (140) and the surface of the sunk platform (1141) away from the core (140) are at the same height.

8. The cover plate according to claim 1, wherein The depth of the sunk platform (1141) is A, 0.8C ≤ A ≤ 1.5C, where C is the thickness of the area on the body (111) outside the explosion-proof groove (120).

9. The cover plate according to claim 1, wherein, The thickness of the body (111) is C, 0.4mm ≤ C ≤ 1.0mm.

10. The cover plate according to claim 1, wherein, 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. Among them, 4mm ≤ D1 ≤ 12mm; D2 = D1 - 2C * tan(α - 90°), and D2 > 2mm; α is the angle formed between the bottom and the side of the sunk platform (1141), 100° ≤ α ≤ 170°; C is the thickness of the area on the body (111) outside the explosion-proof groove (120).

11. The cover plate according to any one of claims 1 to 10, wherein, The thickness of the body (111) at the location of the explosion-proof groove (120) is H, Among them, E1 is the outer diameter of the ring where the explosion-proof groove (120) is located; P is the opening pressure of the body (111) at the position of the explosion-proof groove (120); Q is the tensile strength of the material for preparing the cover plate (110).

12. The cover plate according to any one of claims 1 to 10, wherein, The thickness of the body (111) at the position of the explosion-proof groove (120) is H, 50μm ≤ H ≤ 120μm.

13. The cover plate according to any one of claims 1 to 10, wherein, The thickness of the body (111) at the position of the first sub-groove (121) is H1, and the thickness of the body (111) at the position of the second sub-groove (122) is H2, and H1 < H2.

14. The cover plate according to claim 13, wherein, 20μm ≤ H1 ≤ 115μm, 25μm ≤ H2 ≤ 135μm, and 5μm ≤ H2 - H1 ≤ 20μm.

15. The cover plate according to claim 13, wherein, The shape of the explosion-proof groove (120) is an annular shape, and the ratio of the arc length of the first sub-groove (121) to the arc length of the second sub-groove (122) is G.

16. A battery, comprising: The cover plate according to any one of claims 1 to 15; A core (140), including a positive extreme and a negative extreme; A housing (150), the core (140) is installed in the housing (150), one end of the housing (150) is provided with an opening (151), and the body (111) is hermetically connected to the housing (150) to block the opening (151).

17. The battery according to claim 16 further comprises: A positive terminal (152), a first current collecting plate (160), a second current collecting plate (170), and an insulating member (180), wherein the positive terminal (152) is disposed at an end of the housing (150) away from the body (111), the first current collecting plate (160) is welded to the wound core (140) and disposed between one end of the body (111) and the wound core (140), the second current collecting plate (170) is welded to the wound core (140) and the positive terminal (152) and disposed between the wound core (140) and the positive terminal (152), and the insulating member (180) is disposed between the second current collecting plate (170) and the housing (150).

18. A battery pack, comprising a plurality of batteries as claimed in claim 16 or 17.

19. The battery pack according to claim 18, further comprising: A mounting seat (130) having a plurality of mounting grooves (131) and a plurality of baffles (132), one end of the battery close to the body (111) is mounted in the mounting grooves (131), the baffles (132) are located on a side of the mounting grooves (131) away from the battery, the first sub-groove (121) has a first groove wall (1211) and a second groove wall (1212), the second groove wall (1212) is closer to the center of the body (111) than the first groove wall (1211), and the projection of the baffle (132) on one side of the body (111) is located on a side of the first groove wall (1211) away from the second groove wall (1212).

20. The battery pack according to claim 19, wherein The mounting seat (130) includes a first sub-board (133) and a second sub-board (134) which are relatively spaced apart, the mounting grooves (131) are formed in the first sub-board (133), the baffles (132) are located between the first sub-board (133) and the second sub-board (134), and the baffles (132) are connected to the first sub-board (133).

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