Cap assembly and battery

Abstract

A cap assembly (100), wherein the orthographic projection of at least part of an insulating gasket (130) on an orifice plate (120) is located within a first exhaust hole (K1). Part of an explosion-proof sheet (140) passes through a central hole (K2) and abuts against the orifice plate (120), such that when other parts of the explosion-proof sheet (140) are connected to the orifice plate (120), short circuits are caused. During the process of the safety testing of a battery (1000), at least part of the insulating gasket (130) is isolated between the first exhaust hole (K1) of the orifice plate (120) and the explosion-proof sheet (140), such that the probability of short circuits caused due to the orifce plate (120) coming into contact with the explosion-proof sheet (140) at a pressure relief position of the first exhaust hole (K1) is reduced.

Description

Cap assembly and battery

[0001] This application claims priority to Chinese Patent Application No. 202421649962.5, filed with the Chinese Patent Office on July 11, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, specifically to a cap assembly and a battery. Background Technology

[0003] Typically, a battery cap assembly includes a top cover, an explosion-proof plate, a perforated plate, and an insulating gasket disposed between the explosion-proof plate and the perforated plate. Technical issues

[0004] In related technologies, the vent holes of the orifice plate and the vent holes of the insulating gasket have the same shape and size. During battery safety testing, when the orifice plate and the insulating gasket rotate or translate relative to each other and become offset, the orifice plate is prone to contact with the explosion-proof sheet and short-circuit, thus failing to meet the insulation requirements of the orifice plate and the explosion-proof sheet, affecting the safety performance of the battery. Technical solutions

[0005] In a first aspect, this application provides a cap assembly for use in a battery, comprising:

[0006] The perforated plate has a first exhaust hole.

[0007] Explosion-proof sheet; and

[0008] An insulating gasket is placed between the perforated plate and the explosion-proof sheet, and the insulating gasket has a central hole.

[0009] Among them, some explosion-proof sheets are inserted through the central hole and abut against the perforated plate, and some insulating gaskets are projected onto the perforated plate and located inside the first vent hole.

[0010] Secondly, this application provides a battery, including the cap assembly provided in this application, and also includes a housing and a battery cell disposed within the housing, the cap assembly being assembled on the housing. Beneficial effects

[0011] The beneficial effects of the cap assembly provided in this application are as follows: Compared with related technologies, in the cap assembly of this application, at least a portion of the insulating gasket's orthogonal projection on the orifice plate is located within the first vent hole. Since a portion of the explosion-proof sheet passes through the central hole and abuts against the orifice plate, further connection of the other portion of the explosion-proof sheet to the orifice plate would lead to a short circuit. During battery safety testing, at least a portion of the insulating gasket is isolated between the first vent hole of the orifice plate and the explosion-proof sheet, reducing the probability of short circuit due to contact between the orifice plate and the explosion-proof sheet at the pressure relief point of the first vent hole. The cap assembly of this application can meet the insulation requirements of the orifice plate and the explosion-proof sheet. In addition, since a portion of the insulating gasket is isolated between the first vent hole of the orifice plate and the explosion-proof sheet, the friction between the insulating gasket and the orifice plate, as well as between the insulating gasket and the explosion-proof sheet, increases. During battery safety testing, the rotation or translation of the insulating gasket is restricted, thereby reducing the possibility of short circuit due to contact between the orifice plate and the explosion-proof sheet caused by the movement of the insulating gasket. Attached Figure Description

[0012] Figure 1 is a cross-sectional structural schematic diagram of a cap assembly provided in one embodiment of this application;

[0013] Figure 2 is an orthographic projection of the insulating gasket in the cap assembly provided in one embodiment of this application onto the perforated plate;

[0014] Figure 3 is an orthographic projection of the insulating gasket in the cap assembly provided in another embodiment of this application onto the perforated plate;

[0015] Figure 4 is a top view of the insulating pad in a cap assembly provided in one embodiment of this application;

[0016] Figure 5 is a top view of the perforated plate in a cap assembly provided in one embodiment of this application;

[0017] Figure 6 is a cross-sectional structural schematic diagram of a cap assembly provided in another embodiment of this application;

[0018] Figure 7 is an orthographic projection of the insulating gasket on the perforated plate in a cap assembly provided in another embodiment of this application;

[0019] Figure 8 is a schematic diagram of the exploded structure of a battery provided in another embodiment of this application;

[0020] The following are the labeling elements in the figure:

[0021] 1000, Battery; 100, Cap assembly; 200, Battery cell; 300, Casing;

[0022] 110. Sealing ring; 120. Orifice plate; 130. Insulating gasket; 140. Explosion-proof sheet; 150. Top cover;

[0023] K1, First vent; K2, Center vent; K3, Second vent;

[0024] A. Welding area;

[0025] C. Centerline; 131. First sub-section; 132. Second sub-section;

[0026] 141. Body part; 142. Protrusion; I. Engraved line. Embodiments of the present invention

[0027] Please refer to Figures 1 and 2 together. An embodiment of the cap assembly 100 provided in this application will now be described. The cap assembly 100 of this application is applied to a battery. As shown in Figure 1, the cap assembly 100 includes a top cover 150, a sealing ring 110, an explosion-proof sheet 140, an insulating gasket 130, and a perforated plate 120. The sealing ring 110 has a receiving space, and the perforated plate 120, the insulating gasket 130, and the explosion-proof sheet 140 are stacked from bottom to top in the receiving space of the sealing ring 110. The top cover 150 is disposed at the end of the sealing ring 110 and is located on the side of the explosion-proof sheet 140 away from the perforated plate 120. The explosion-proof sheet 140 is disposed on one side of the perforated plate 120, and the insulating gasket 130 is disposed between the perforated plate 120 and the explosion-proof sheet 140.

[0028] The perforated plate 120 has a welding area A on its side near the explosion-proof sheet 140 for welding to form an electrical path with the explosion-proof sheet 140. The explosion-proof sheet 140 includes a body portion 141 and a protrusion 142. The protrusion 142 is provided on the surface of the body portion 141 near the perforated plate 120 and is used for welding to the perforated plate 120. The insulating gasket 130 has a central hole K2. The protrusion 142 of the explosion-proof sheet 140 passes through the central hole K2, abuts against the welding area A of the perforated plate 120, and is welded to the welding area A of the perforated plate 120. The side of the explosion-proof sheet 140 facing away from the perforated plate 120 is welded to the top cover 150. In one embodiment, the explosion-proof sheet 140 can also be welded to the top cover 150 by providing a welding portion on the side facing away from the perforated plate 120.

[0029] A first vent hole K1 is also provided on the orifice plate 120, extending axially along the orifice plate 120. This first vent hole K1 is used for explosion-proof pressure relief of the battery. The first vent hole K1 is located on the outer side of the welding area A. A central hole K2 is provided on the insulating gasket 130. The explosion-proof sheet 140 is connected to the orifice plate 120 through the central hole K2.

[0030] As shown in Figure 2, the orthographic projection of a portion of the insulating gasket 130 onto the orifice plate 120 is located within the first vent hole K1. That is, at least a portion of the insulating gasket 130 is located between the first vent hole K1 and the body portion 141 of the explosion-proof plate 140.

[0031] Since the protrusion 142 of the explosion-proof plate 140 passes through the central hole K2 and abuts against the orifice plate 120, any further connection between the other parts of the explosion-proof plate 140 and the orifice plate 120 would result in a short circuit. In this embodiment, by setting a portion of the insulating gasket 130 whose orthogonal projection on the orifice plate 120 is located within the first vent hole K1, during battery safety testing, at least a portion of the insulating gasket 130 is isolated between the first vent hole K1 of the orifice plate 120 and the body portion 141 of the explosion-proof plate 140, reducing the probability of the orifice plate 120 and the explosion-proof plate 140 coming into contact and short-circuiting at the pressure relief point of the first vent hole K1. The cap assembly 100 of this embodiment can meet the insulation requirements of the orifice plate 120 and the explosion-proof plate 140. In addition, since at least part of the insulating pad 130 is isolated between the first vent hole K1 of the orifice plate 120 and the body portion 141 of the explosion-proof plate 140, the friction between the insulating pad 130 and the orifice plate 120 and between the insulating pad 130 and the explosion-proof plate 140 increases. During the battery safety test, the rotation or translation of the insulating pad 130 is restricted, thereby reducing the possibility of short circuit between the orifice plate 120 and the explosion-proof plate 140 due to the movement of the insulating pad 130.

[0032] In this embodiment, a second vent hole K3 is formed on the insulating gasket 130, extending axially through the insulating gasket 130. The second vent hole K3 is located around the central hole K2. The orthographic projection of the second vent hole K3 onto the perforated plate 120 lies within the first vent hole K1, and the second vent hole K3 communicates with the first vent hole K1. The orthographic projection of the second vent hole K3 onto the perforated plate 120 lying within the first vent hole K1 means that the entire edge of the second vent hole K3 lies within the first vent hole K1, or a portion of its edge coincides with the edge of the first vent hole K1. The area of ​​the second vent hole K3 is smaller than the area of ​​the first vent hole K1.

[0033] In the orthographic projection of the perforated plate 120, one side edge of the second vent K3 may coincide with one side edge of the first vent K1, and a portion of the insulating pad 130 may have an edge protruding from the first vent K1 and not coinciding with the edge of the second vent K3. Alternatively, both sides of the second vent K3 may coincide with both sides of the first vent K1, and a portion of the insulating pad 130 may have an edge protruding from the first vent K1 and not coinciding with the edge of the second vent K3. As shown in Figure 2, in this embodiment, one side edge of the second vent K3 coincides with one side edge of the first vent K1, and the insulating pad 130 protrudes from the other edges of the first vent K1 and does not coincide with the edge of the second vent K3. As shown in Figure 3, in some other embodiments, three sides of the second vent K3 coincide with the edge of the first vent K1, and a portion of the insulating pad 130 protrudes from the opposite sidewall edges of the first vent K1.

[0034] Please refer to Figures 2, 4, and 5. The second vent K3 connects with the first vent K1 to form a venting channel. The second vent K3 is correspondingly positioned to the first vent K1 and is connected to it. One end of the first vent K1 connects to the inner cavity of the battery, and the other end connects to the second vent K3. When the internal pressure of the battery is too high, the gas inside the battery will be released through the first vent K1 and the second vent K3 to relieve pressure and prevent the battery from exploding.

[0035] In one embodiment, the explosion-proof plate 140 has a etched line I on its surface opposite to the perforated plate 120. The etched line I is located within the orthographic projection of the second vent hole K3 onto the explosion-proof plate 140. The etched line I can be an annular groove structure. The explosion-proof plate 140 at the etched line I is thinner, making it easier to break and form a crack under the action of high-pressure gas, thereby releasing the high-pressure gas. When the internal pressure of the battery is too high, the high-pressure gas is released from the second vent hole K3. The position of the etched line I corresponding to the second vent hole K3 makes it easier for the explosion-proof plate 140 to break and form a crack at the etched line I.

[0036] As shown in Figure 5, there are multiple first vent holes K1. These multiple first vent holes K1 are rotationally symmetrical about the center of the perforated plate 120, meaning that one first vent hole K1 can coincide with another first vent hole K1 after rotating a certain angle around the center of the perforated plate 120. Correspondingly, there are multiple second vent holes K3, and these multiple second vent holes K3 are rotationally symmetrical about the center of the insulating gasket 130. In this embodiment, one first vent hole K1 corresponds to two second vent holes K3. The number of first vent holes K1 is 5, and correspondingly, the number of second vent holes K3 is 10.

[0037] In one embodiment, the number of first vent holes K1 can also be 4, and one first vent hole K1 corresponds to two second vent holes K3. Accordingly, the total number of second vent holes K3 on the insulating gasket 130 is 8.

[0038] In other embodiments, one first exhaust port K1 may also be provided with one second exhaust port K3, or one first exhaust port K1 may be provided with three second exhaust ports K3, etc.

[0039] In one embodiment, the interval G2 between two adjacent second vent holes K3 is greater than the interval G1 between two adjacent first vent holes K1. As shown in FIG2, in the cap assembly 100, the interval G1 between two adjacent first vent holes K1 corresponds to the interval G2 between two adjacent second vent holes K3. The side of the insulating gasket 130 between two adjacent second vent holes K3 that is close to the perforated plate 120 contacts the interval G1 between the corresponding two adjacent first vent holes K1, thereby generating friction. If the insulating gasket 130 and the perforated plate 120 are compressed and rotate or translate relative to each other, since the interval G2 between two adjacent second vent holes K3 is greater than the interval G1 between two adjacent first vent holes K1, the intervals G1 and G2 still contact and generate friction, thereby restricting the rotation and translation of the insulating gasket 130.

[0040] Furthermore, the side of the insulating gasket 130 near the explosion-proof sheet 140 between two adjacent second vent holes K3 comes into contact with the explosion-proof sheet 140, thereby generating friction. The larger the gap G2 between the two adjacent second vent holes K3, the greater the friction between the insulating gasket 130 and the explosion-proof sheet 140, thus restricting the movement of the insulating gasket 130.

[0041] In this embodiment, the interval G1 between two adjacent first exhaust holes K1 is 1 mm. The interval G2 between two adjacent second exhaust holes K3 is 2.2 mm.

[0042] As shown in Figures 2 and 4, in this embodiment, one first vent hole K1 corresponds to two second vent holes K3. In the orthographic projection of the orifice plate, the two second vent holes K3 are distributed on both sides of the center line C of the first vent hole K1, and are arranged symmetrically about the center line C. When the internal pressure of the battery is too high, high-pressure gas is discharged from the second vent holes K3 on both sides of the center line C of the first vent hole K1. The two second vent holes K3 are symmetrical about the center line C of the first vent hole K1, that is, the two second vent holes K3 are symmetrically arranged about the portion of the insulating pad 130 inside the first vent hole K1. The pressure on the portion of the insulating pad 130 inside the first vent hole K1 is more uniform, and the venting is also more uniform.

[0043] As shown in Figures 4 and 5, the plurality of second vent holes K3 are rotationally symmetrical about the center of the insulating gasket 130. The plurality of first vent holes K1 are rotationally symmetrical about the center of the orifice plate 120. The rotation angle α2 between two adjacent second vent holes K3 is half the rotation angle α1 of the plurality of first vent holes K1. In this embodiment, there are 5 first vent holes K1, and the rotation angle α1 between two adjacent first vent holes K1 is 72°, so that the plurality of first vent holes K1 are evenly spaced on the orifice plate 120. Correspondingly, the rotation angle α2 between the two second vent holes K3 on the insulating gasket 130 is 36°, so that the plurality of second vent holes K3 are evenly spaced on the insulating gasket 130, thereby uniformly venting pressure.

[0044] In some other embodiments, there are four first vent holes K1, and the rotation angle α1 between two adjacent first vent holes K1 is 90°. Correspondingly, the rotation angle α2 between two adjacent second vent holes K3 on the insulating pad 130 is 45°.

[0045] In the orthographic projection of the orifice plate 120, the ratio of the area of ​​the portion of the insulating pad 130 located within a first vent K1 to the area of ​​the first vent K1 is 1:5 to 3:5, for example, 1:5, 1.25:5, 1.5:5, 2:5, 2.5:5, or 3:5. Correspondingly, in the orthographic projection of the orifice plate 120, the ratio of the total area of ​​the second vent K3 located within a first vent K1 to the area of ​​the first vent K1 is 2:5 to 4:5. That is, the ratio of the total area of ​​the second vent K3 corresponding to a first vent K1 to the area of ​​the first vent K1 is between 2:5 and 4:5, for example, 4:5, 3.75:5, 3.5:5, 3:5, 2.5:5, or 2:5. In this embodiment, in the orthographic projection of the perforated plate 120, the ratio of the area of ​​the portion of the insulating pad 130 located within a first vent K1 to the area of ​​the first vent K1 is 2:5, and the ratio of the total area of ​​the second vent K3 corresponding to a first vent K1 to the area of ​​the first vent K1 is 3:5. If the area of ​​the portion of the insulating pad 130 located within a first vent K1 is too large in the orthographic projection of the perforated plate 120, the venting speed of the battery will be too slow, and the explosion-proof effect will be weak. If the area of ​​the second vent K3 is too large, the area of ​​the insulating pad 130 protruding from the first vent K1 will be small, and the insulation effect between the hole wall of the first vent K1 of the perforated plate 120 and the explosion-proof sheet 140 will decrease. In the orthogonal projection of the orifice plate 120, the ratio of the area of ​​the partial insulating pad 130 located in a first vent hole K1 to the area of ​​the first vent hole K1 is 1:5 to 3:5, which can increase the insulation area of ​​the orifice plate 120 and the explosion-proof sheet 140 while ensuring smooth venting and pressure relief.

[0046] In this embodiment, the second vent K3 is a circular hole with a diameter of 1 mm. The distance from the center of the second vent K3 to the center of the insulating gasket 130 is 5.15 mm. The first vent K1 is an oblong hole with an inner radius of 4.2 mm and an outer radius of 5.65 mm. The minor axis of the first vent K1 is 1.45 mm, and the major axis is approximately 5~5.2 mm.

[0047] Please refer to Figures 6 and 7 together. The structure of this embodiment is generally the same as that of other embodiments of this application, except that the specific structure of the insulating gasket 130 and the number, shape and position of the second vent holes K3 are different.

[0048] As shown in Figure 6, the insulating gasket 130 includes a first sub-part 131 and a second sub-part 132 connected to each other, with the first sub-part 131 circumferentially disposed outside the second sub-part 132. The second vent hole K3 is located in the first sub-part 131, and the central hole K2 is formed in the second sub-part 132.

[0049] Along the stacking direction of the perforated plate 120, insulating gasket 130, and explosion-proof plate 140, the inner diameter of the second sub-part 132 increases. The maximum inner diameter D1 of the second sub-part 132 is less than or equal to the maximum diameter D2 of the protrusion 142. The inner wall of the second sub-part 132 is the wall of the central hole K2, that is, the inner diameter of the second sub-part 132 is the diameter of the central hole K2. The diameter of the central hole K2 gradually decreases along the stacking direction of the perforated plate 120, insulating gasket 130, and explosion-proof plate 140. The maximum diameter of the central hole K2 is greater than or equal to the maximum diameter D2 of the protrusion 142. In this application, the diameter of the protrusion 142 gradually increases along the stacking direction of the perforated plate 120, insulating gasket 130, and explosion-proof plate 140.

[0050] In this embodiment, the maximum inner diameter D1 of the second sub-part 132 is equal to the maximum diameter D2 of the protrusion 142. The maximum diameter of the central hole K2 is equal to the maximum diameter D2 of the protrusion 142.

[0051] Along the stacking direction of the perforated plate 120, insulating gasket 130, and explosion-proof plate 140, the inner diameter of the second sub-part 132 gradually increases. The second sub-part 132 can isolate the body part 141 of the perforated plate 120 and the explosion-proof plate 140 around the protrusion 142, thereby increasing the insulation area. Furthermore, due to the gradually increasing inner diameter of the second sub-part 132, a gap is formed between the second sub-part 132 and the perforated plate 120. Even if the second sub-part 132 deforms within the gap, it can still provide insulation. Moreover, due to its insufficient length, the second sub-part 132 will not interfere with the protrusion 142 and affect the connection between the protrusion 142 and the welding area A of the perforated plate 120.

[0052] As shown in Figure 7, one first vent hole K1 corresponds to one second vent hole K3. The shape of the first vent hole K1 is the same as that of the second vent hole K3, and they are coaxially arranged, so that high-pressure gas can pass more smoothly from the first vent hole K1 to the second vent hole K3. In this embodiment, both the first vent hole K1 and the second vent hole K3 are oblong holes. In other embodiments, the first vent hole K1 and the second vent hole K3 can also be round holes or elliptical holes, etc. The inner diameter of the second vent hole K3 is smaller than the inner diameter of the first vent hole K1. Insulating gaskets 130 are used to isolate the four sides of the first vent hole K1 from the explosion-proof plate 140, thereby reducing the possibility of short circuit due to contact between the hole wall of the first vent hole K1 and the explosion-proof plate 140. The distance between the wall of the second vent hole K3 and the wall of the first vent hole K1 is greater than or equal to 0.2 mm. Even if the orifice plate 120 and the insulating gasket 130 move relative to each other by 0.2 mm, there is still an insulating gasket 130 between the first vent hole K1 of the orifice plate 120 and the explosion-proof sheet 140, which reduces the possibility of short circuit between the orifice plate 120 and the explosion-proof sheet 140.

[0053] In this embodiment, in the orthogonal projection of the perforated plate 120, the ratio of the area of ​​the portion of the insulating pad 130 located within a first vent hole K1 to the area of ​​the first vent hole K1 is 1:5 to 3:5.

[0054] In this embodiment, the distance between the wall of the second exhaust hole K3 and the wall of the first exhaust hole K1 is between 0.2mm and 1mm. In specific implementations, the distance between the wall of the second exhaust hole K3 and the wall of the first exhaust hole K1 is 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, or 1mm, etc. It can be specifically set according to the dimensions of the first exhaust hole K1 and the second exhaust hole K3.

[0055] Referring to Figure 8, this application embodiment also provides a battery 1000. The battery 1000 includes the cap assembly 100 provided in this application embodiment, a housing 300, and a battery cell 200 disposed within the housing 300. The cap assembly 100 is assembled onto the housing 300. Because a portion of the insulating gasket 130 is isolated between the pressure relief area of ​​the orifice plate 120 and the explosion-proof sheet 140, the probability of short-circuiting between the orifice plate 120 and the explosion-proof sheet 140 is reduced during the safety testing of the battery 1000. This prevents the orifice plate 120 and the explosion-proof sheet 140 from connecting and short-circuiting at the pressure relief area. The battery 1000 of this application can meet the insulation requirements of the orifice plate 120 and the explosion-proof sheet 140.

[0056] The above is a description of the cap assembly 100 and battery 1000 provided in the embodiments of this application.

[0057] In the cap assembly provided in this application embodiment, at least a portion of the insulating gasket's orthogonal projection on the orifice plate is located within the first vent hole. Since a portion of the explosion-proof sheet passes through the central hole and abuts against the orifice plate, further connection of the remaining portion of the explosion-proof sheet to the orifice plate would result in a short circuit. During battery safety testing, at least a portion of the insulating gasket is isolated between the first vent hole of the orifice plate and the explosion-proof sheet, reducing the probability of a short circuit due to contact between the orifice plate and the explosion-proof sheet at the pressure relief point of the first vent hole. The cap assembly of this application can meet the insulation requirements of the orifice plate and the explosion-proof sheet. Furthermore, because a portion of the insulating gasket is isolated between the first vent hole of the orifice plate and the explosion-proof sheet, the friction between the insulating gasket and the orifice plate, and between the insulating gasket and the explosion-proof sheet, increases. During battery safety testing, the rotation or translation of the insulating gasket is restricted, thereby reducing the possibility of a short circuit due to contact between the orifice plate and the explosion-proof sheet caused by the movement of the insulating gasket.

Claims

1. A cap assembly for use in a battery, the cap assembly comprising: A perforated plate, wherein a first exhaust hole is provided on the perforated plate; Explosion-proof sheet; as well as An insulating gasket is disposed between the perforated plate and the explosion-proof sheet, and the insulating gasket has a central hole. Among them, some of the explosion-proof sheets pass through the central hole and abut against the perforated plate, and the orthogonal projection of some of the insulating gaskets on the perforated plate is located in the first vent hole.

2. The cap assembly according to claim 1, wherein, The insulating pad has a second vent hole that extends through the axial direction. The second vent hole is located on the periphery of the central hole. The orthographic projection of the second vent hole on the perforated plate is located inside the first vent hole. The second vent hole communicates with the first vent hole.

3. The cap assembly according to claim 2, wherein, The first exhaust port has multiple first exhaust ports, and the multiple first exhaust ports are rotationally symmetrical about the center of the orifice plate; The second vent has multiple second vents, which are rotationally symmetrical about the center of the insulating pad, and the interval between two adjacent second vents is greater than the interval between two adjacent first vents.

4. The cap assembly according to claim 2, wherein, Each first exhaust hole corresponds to two second exhaust holes. In the orthographic projection of the orifice plate, the two second exhaust holes are distributed on both sides of the center line of the corresponding first exhaust hole and are arranged symmetrically about the center line of the first exhaust hole.

5. The cap assembly according to claim 4, wherein, The second vent has multiple vents, and the multiple second vents are rotationally symmetrical about the center of the insulating gasket; The first exhaust port has multiple first exhaust ports, and the multiple first exhaust ports are rotationally symmetrical about the center of the orifice plate; The rotation angle between two adjacent second exhaust ports is half the rotation angle between two adjacent first exhaust ports.

6. The cap assembly according to claim 2, wherein, Each first exhaust hole corresponds to a second exhaust hole. The shape of the first exhaust hole is the same as that of the second exhaust hole, and they are coaxially arranged. The inner diameter of the second exhaust hole is smaller than that of the first exhaust hole.

7. The cap assembly according to any one of claims 1 to 6, wherein, In the orthographic projection of the orifice plate, the ratio of the total area of ​​the second exhaust hole located within a first exhaust hole to the area of ​​the first exhaust hole is 2:5 to 4:

5.

8. The cap assembly according to any one of claims 2 to 6, wherein, The distance between the wall of the second exhaust port and the wall of the first exhaust port is greater than or equal to 0.2 mm.

9. The cap assembly according to any one of claims 2 to 6, wherein, The explosion-proof sheet has a etched line on its surface opposite to the perforated plate, and the etched line is located within the orthogonal projection of the second vent hole on the explosion-proof sheet.

10. The cap assembly according to any one of claims 1 to 6, wherein, The explosion-proof sheet includes a body and a protrusion. The protrusion is disposed on the side surface of the body near the perforated plate, and the protrusion passes through the central hole and abuts against the perforated plate. The insulating pad includes a first sub-part and a second sub-part connected to each other. The first sub-part is circumferentially disposed on the outside of the second sub-part. The second vent hole is located in the first sub-part. The central hole is opened in the second sub-part. Along the stacking direction of the perforated plate, insulating gasket, and explosion-proof sheet, the inner diameter of the second sub-part increases, and the maximum inner diameter of the second sub-part is less than or equal to the maximum diameter of the protrusion.

11. A battery comprising a cap assembly as described in any one of claims 1 to 10, further comprising a housing and a battery cell disposed within the housing, the cap assembly being assembled onto the housing.

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