Cover plate assembly and battery monomer

Abstract

The utility model belongs to the technical field of batteries, and discloses a cover plate assembly and a battery monomer. The cover plate assembly comprises a cover plate and an anti-explosion valve plate, the cover plate is provided with a first surface arranged away from the interior of the battery monomer and a second surface arranged away from the first surface in the thickness direction, the first surface of the cover plate is provided with an exhaust hole, the anti-explosion valve plate is arranged on the second surface, and the exhaust hole is communicated with the exhaust hole. The exhaust hole is sealed by the anti-explosion valve plate; the exhaust hole comprises a first hole section and a second hole section; the first hole section and the second hole section are sequentially communicated in the direction from the first surface to the second surface. The contour line of the hole wall II of the second hole section is in an arc shape protruding in the direction close to the center line of the exhaust hole. According to the cover plate assembly provided by the utility model, the situation that the explosion-proof valve plate is opened in advance due to failure of a non-nick part can be prevented, the function of the explosion-proof valve plate is ensured, and the service life and the safety of the battery monomer applying the cover plate assembly are prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a cover plate assembly and a battery monomer. Background Art

[0002] The battery is an important part of the vehicle, especially for new energy vehicles. The safety of the battery directly affects the safety performance of new energy vehicles. It is an important part of the battery, used to release the pressure through the explosion-proof valve when the internal pressure of the battery is too high to prevent the battery from exploding.

[0003] Normally, during the use of the battery, the pressure inside the battery is generally the same as the external environment, and the internal and external air pressures are balanced to avoid loads on the components. However, during the driving of the vehicle, it is inevitable that the atmospheric pressure will change. At the same time, as the battery cell is used, the air pressure inside the battery will fluctuate up and down, which is equivalent to applying internal and external circulating air pressure to the battery's explosion-proof valve.

[0004] Since the explosion-proof valve plate is used to seal the exhaust hole of the battery cover, after the explosion-proof valve plate is subjected to multiple internal and external circulating air pressures, the explosion-proof valve plate will undergo irregular deformation under the action of the circulating air pressure, which can easily cause the explosion-proof valve plate to be cut by the edge of the exhaust hole, thereby causing the explosion-proof valve plate to fail and open the valve prematurely. Moreover, this failure is not a failure of the valve opening at the notch. The failure of the explosion-proof valve plate will cause damage to the battery, thereby reducing the battery life.

[0005] Therefore, there is an urgent need for a cover plate assembly to solve the above problems. Utility Model Content

[0006] The utility model aims to provide a cover plate assembly, which can prevent the explosion-proof valve plate from opening prematurely due to failure of the non-score portion, thereby ensuring the function of the explosion-proof valve plate.

[0007] As conceived above, the technical solution adopted by the utility model is:

[0008] A cover plate assembly, comprising a cover plate and an explosion-proof valve sheet, wherein the cover plate has a first surface disposed away from the interior of the battery cell and a second surface disposed away from the first surface in a thickness direction thereof, an exhaust hole is disposed on the first surface of the cover plate, the explosion-proof valve sheet is disposed on the second surface, and the explosion-proof valve sheet seals the exhaust hole;

[0009] The exhaust hole includes a first hole segment and a second hole segment; the first hole segment and the second hole segment are connected in sequence along the direction from the first surface to the second surface; the contour line of the hole wall II of the second hole segment is an arc convex toward the center line of the exhaust hole.

[0010] Optionally, on a longitudinal section passing through the center line of the second hole segment, a contour line of the hole wall II of the second hole segment is an arc line protruding toward the center line of the exhaust hole, and a radius of the arc line is 0.05 mm to 0.3 mm.

[0011] Optionally, in the thickness direction of the cover plate, the explosion-proof valve plate has a first end face arranged toward the exhaust hole; the area in the second surface of the cover plate that contacts the first end face is tangent to the hole wall II of the second hole segment, and the hole wall II of the second hole segment is tangent to the hole wall I of the first hole segment.

[0012] Optionally, the second surface of the cover plate has a hole wall III and a step surface, the hole wall III surrounds the mounting hole, and the hole wall III of the mounting hole and the hole wall II of the second hole section are connected via the step surface;

[0013] The explosion-proof valve plate is arranged in the mounting hole, the first end surface of the explosion-proof valve plate is in contact with the step surface, and the explosion-proof valve plate is connected to the cover plate.

[0014] Optionally, the explosion-proof valve disc has a second end face arranged away from the first end face, and the installation longitudinal gap between the first surface of the cover plate and the second end face of the explosion-proof valve disc is d, wherein 0≤d≤0.08mm.

[0015] Optionally, in a preset direction, the width of the mounting hole is x, the width of the explosion-proof valve plate is y, (xy)=2k, wherein 0<k≤0.08mm, and the preset direction and the thickness direction of the cover plate are perpendicular to each other.

[0016] Optionally, there is an orifice at the intersection of the first hole segment and the second hole segment; a groove is provided on the first end face of the explosion-proof valve plate facing the exhaust hole, the area of ​​the orthogonal projection of the groove on the projection plane is equal to the area of ​​the orthogonal projection of the orifice of the first hole segment on the projection plane, and the orthogonal projection of the groove on the projection plane coincides with the orthogonal projection of the orifice of the first hole segment on the projection plane; or, the area of ​​the orthogonal projection of the groove on the projection plane is larger than the area of ​​the orthogonal projection of the orifice of the first hole segment on the projection plane, and the orthogonal projection of the first hole segment on the projection plane is located within the orthogonal projection of the groove on the projection plane, and the projection plane and the thickness direction of the cover plate are perpendicular to each other.

[0017] Optionally, in the thickness direction of the cover plate, the distance from the bottom of the groove to the second end surface of the explosion-proof valve plate is h, the thickness of the explosion-proof valve plate is H, and 0.4H≤h≤0.6H.

[0018] Optionally, a notch is provided at the bottom of the groove, and in a preset direction, a distance between a center line of the notch and a hole wall III of the mounting hole is L, 2mm≤L≤3mm.

[0019] The utility model aims to provide a battery cell which can prevent the explosion-proof valve sheet from opening prematurely due to failure at a non-score portion, thereby extending the service life and safety of the battery cell using the cover plate assembly.

[0020] As conceived above, the technical solution adopted by the utility model is:

[0021] A battery cell comprises the cap plate assembly as described above.

[0022] The cover plate assembly and battery cell provided by the utility model have at least the following beneficial effects:

[0023] The cover plate assembly of the utility model is designed such that the contour line of the hole wall II of the second hole section is in the shape of an arc that bulges toward the center line of the exhaust hole, so that when the explosion-proof valve sheet is deformed in the direction of the center line of the exhaust hole, it contacts the hole wall II with the arc-shaped contour line, so that the explosion-proof valve sheet will not be cut by the edge of the exhaust hole, thereby preventing the explosion-proof valve sheet from opening prematurely due to failure at a non-notched portion, thereby ensuring the function and service life of the explosion-proof valve sheet, and further ensuring the service life of the cover plate assembly and the battery cell using the cover plate assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is an exploded schematic diagram of a cover plate assembly provided in an embodiment of the utility model;

[0025] Figure 2 is a top view of a cover plate assembly provided by an embodiment of the utility model;

[0026] Figure 3 This utility model Figure 2 AA section view shown;

[0027] Figure 4 This utility model Figure 3 The enlarged view of point B is shown;

[0028] Figure 5 It is a partial cross-sectional view of a cover plate provided by an embodiment of the utility model;

[0029] Figure 6 It is a cross-sectional view of the explosion-proof valve plate provided by the embodiment of the utility model;

[0030] Figure 7 This utility model Figure 4 The enlarged view of point D is shown;

[0031] Figure 8 This utility model Figure 4 The enlarged view of point E is shown;

[0032] Fig. 9It is a partial cross-sectional view of the cover plate assembly provided in an embodiment of the utility model.

[0033] In the figure:

[0034] 1. Cover plate; 11. Mounting hole; 111. Hole wall III; 112. Step surface; 12. Exhaust hole; 121. First hole section; 1211. Hole wall I; 122. Second hole section; 1221. Hole wall II; 13. First surface; 14. Second surface; 2. Explosion-proof valve plate; 21. First end face; 22. Second end face; 23. Groove; 24. Notch; 25. Arc chamfer; Y, thickness direction. DETAILED DESCRIPTION

[0035] In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved clearer, the technical solutions of the present invention are further described below in conjunction with the accompanying drawings and through specific implementation methods. It is understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for the convenience of description, only the parts related to the present invention are shown in the accompanying drawings, rather than all of them.

[0036] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0037] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0039] In the description of this embodiment, the terms "upper", "lower", "right", etc., are based on the directions or positions shown in the drawings, and are only for the convenience of description and simplified operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0040] This embodiment provides a cover plate assembly, which can prevent the explosion-proof valve sheet from being cut, avoid failure of the non-score portion of the explosion-proof valve sheet, and improve the reliability and service life of the battery using the cover plate assembly.

[0041] As 1 to Fig. 9 As shown, the cover plate assembly includes a cover plate 1 and an explosion-proof valve plate 2. Figure 4 As shown, the cap plate 1 has, in the thickness direction Y thereof, a first surface 13 configured to be disposed away from the interior of the battery cell and a second surface 14 disposed away from the first surface 13 .

[0042] like Figure 5 As shown, the first surface 13 of the cover plate 1 is provided with an exhaust hole 12 , the explosion-proof valve plate 2 is provided on the second surface 14 , and the explosion-proof valve plate 2 seals the exhaust hole 12 .

[0043] like Figure 5 As shown, the exhaust hole 12 includes a first hole section 121 and a second hole section 122. The first hole section 121 and the second hole section 122 are sequentially connected along the direction from the first surface 13 to the second surface 14, that is, the first hole section 121 is closer to the first surface 13 than the second hole section 122, and the explosion-proof valve plate 2 is located on the side of the second hole section 122 away from the first hole section 121. It should be noted that the first hole section 121 and the second hole section 122 can be coaxially arranged.

[0044] like Figure 6 As shown, the contour line of the hole wall II1221 of the second hole segment 122 is an arc convex in the direction close to the center line of the exhaust hole 12, so that there is no sharp corner at the second hole segment 122, and further, when the explosion-proof valve plate 2 is deformed in the direction of the center line of the exhaust hole 12, it is in contact with the hole wall II1221 with an arc-shaped contour line, so that the explosion-proof valve plate 2 will not be cut by the edge of the exhaust hole 12, thereby preventing the explosion-proof valve plate 2 from opening prematurely due to failure at non-notched locations, thereby ensuring the function and service life of the explosion-proof valve plate 2, and further ensuring the service life of the cover plate assembly and the battery cell using the cover plate assembly.

[0045] It should be noted that the shape of the orthographic projection of the exhaust hole 12 on the projection plane is the same as the shape of the orthographic projection of the explosion-proof valve plate 2 on the projection plane, where the projection plane and the thickness direction Y of the cover plate 1 are perpendicular to each other; wherein the explosion-proof valve plate 2 is circular, elliptical, square or runway-shaped.

[0046] Optionally, on the longitudinal section passing through the center line of the second hole segment 122, the contour line of the hole wall II 1221 of the second hole segment 122 is a circular arc line protruding toward the center line of the exhaust hole 12, and the radius of the circular arc line is 0.05 mm to 0.3 mm. By setting the contour line of the hole wall II 1221 of the second hole segment 122 to be a circular arc line protruding toward the center line of the exhaust hole 12, on the one hand, it is possible to further prevent damage to the explosion-proof valve plate 2, and on the other hand, it is also convenient for standardized processing and forming of the second hole segment 122. For example, the radius of the circular arc line is 0.05 mm, 0.1 mm, 0.15 mm, 0.25 mm or 0.3 mm, etc. This embodiment only provides several numerical values ​​by way of example, but is not limited thereto.

[0047] Further optionally, in the thickness direction Y of the cover plate 1, the explosion-proof valve plate 2 has a first end surface 21 disposed toward the exhaust hole 12. The area in the second surface 14 of the cover plate 1 that contacts the first end surface 21 is tangent to the hole wall II1221 of the second hole section 122, so as to achieve a smooth transition between the second surface 14 and the hole wall II1221 of the second hole section 122, thereby preventing the explosion-proof valve plate 2 from being cut due to a sharp angle between the second surface 14 and the hole wall II1221 of the second hole section 122.

[0048] Furthermore, the hole wall II1221 of the second hole segment 122 is tangent to the hole wall I1211 of the first hole segment 121, so as to achieve a smooth transition between the hole wall II1221 of the second hole segment 122 and the hole wall II1221 of the first hole segment 121, thereby preventing the explosion-proof valve plate 2 from being cut due to a sharp angle between the hole wall II1221 of the second hole segment 122 and the hole wall II1221 of the first hole segment 122.

[0049] In some embodiments, Figure 5 As shown, the second surface 14 of the cover plate 1 has a hole wall III 111 and a step surface 112. The hole wall III 111 surrounds the mounting hole 11, that is, the hole wall III 111 is the inner wall of the mounting hole 11. The hole wall III 111 of the mounting hole 11 and the hole wall II 1221 of the second hole section 122 are connected through the step surface 112. In this embodiment, the hole diameter of the mounting hole 11 is larger than the hole diameter of the second hole section 122.

[0050] See also Figure 4, the explosion-proof valve sheet 2 is arranged in the mounting hole 11, the first end face 21 of the explosion-proof valve sheet 2 is in contact with the step face 112, and the explosion-proof valve sheet 2 is connected to the cover plate 1. By providing the explosion-proof valve sheet 2 with the mounting hole 11 on the cover plate 1, the connection reliability between the explosion-proof valve sheet 2 and the cover plate 1 can be improved, and the probability of the explosion-proof valve sheet 2 being touched and dropped by the battery cell or other structures during the assembly of the cover plate assembly can be reduced, thereby reducing the difficulty of battery assembly. For example, the first end face 21 and the step face 112 can be welded to connect the explosion-proof valve sheet 2 to the cover plate 1. Of course, it can be understood that the first end face 21 and the step face 112 can also only be in contact without being connected, and this embodiment is not limited to this.

[0051] Optionally, the explosion-proof valve plate 2 has a second end face 22 that is arranged away from the first end face 21, that is, the first end face 21 and the second end face 22 are arranged opposite to each other in the thickness direction Y of the cover plate 1. The installation longitudinal gap between the first surface 13 of the cover plate 1 and the second end face 22 of the explosion-proof valve plate 2 is d, 0≤d≤0.08mm. It should be noted that the installation longitudinal gap refers to the distance between the first surface 13 and the second end face 22 in the thickness direction Y of the cover plate 1. For example, d=0.05mm, 0.06mm, 0.7mm, 0.8mm, etc. This embodiment only provides several numerical values ​​for example, but is not limited thereto.

[0052] In this embodiment, the explosion-proof valve disc 2 can be completely located in the mounting hole 11. At this time, the distance between the second end surface 22 and the step surface 112 is smaller than the distance between the first surface 13 and the step surface 112, so as to prevent the explosion-proof valve disc 2 from protruding from the first surface 13. Of course, it can be understood that the distance between the second end surface 22 and the step surface 112 can also be equal to the distance between the first surface 13 and the step surface 112, and at this time, d=0.

[0053] Further optionally, in a preset direction, such as Figure 5 As shown, the width of the mounting hole 11 is x. Figure 6 As shown, the width of the explosion-proof valve disc 2 is y, (xy) = 2k, that is, the installation transverse gap between the outer wall of the explosion-proof valve disc 2 and the hole wall III 111 is k, where 0≤k≤0.08mm. For example, k = 0.05mm, 0.06mm, 0.7mm, 0.8mm, etc. This embodiment only provides several numerical values ​​by way of example, but is not limited thereto.

[0054] In this embodiment, by setting the installation transverse gap to meet the above range, light leakage during laser welding can be avoided, and in addition, the processing accuracy requirements for the installation hole 11 and the explosion-proof valve plate 2 can be reduced. Among them, the preset direction and the thickness direction Y of the cover plate 1 are perpendicular to each other.

[0055] In some optional embodiments, in order to ensure that the explosion-proof valve disc 2 has a good explosion-proof effect and is installed firmly, the first end face 21 of the explosion-proof valve disc 2 facing the exhaust hole 12 is designed to be provided with a groove 23, that is, the explosion-proof valve disc 2 includes an opening portion and a mounting portion connected to the outer periphery of the opening portion, the inner peripheral wall of the mounting portion and the side wall of the opening portion facing the exhaust hole 12 form the groove 23, and a notch 24 is provided at the bottom of the groove 23.

[0056] In this embodiment, the thickness of the mounting portion is greater than the thickness of the opening portion. Here, by thinning the explosion-proof valve plate 2, it can not only meet the explosion-proof requirements, but also avoid the explosion-proof valve plate 2 being too thick and not easy to explode, and can also meet the welding requirements, and avoid the explosion-proof valve plate 2 being too thin and welded through. In addition, the design of the notch 24 makes the opening portion of the explosion-proof valve plate 2 easier to explode.

[0057] In this embodiment, the first case is that after the explosion-proof valve plate 2 and the top cover plate are respectively manufactured, the size relationship between the groove 23 and the orifice is that the area of ​​the orthogonal projection of the groove 23 on the projection plane is equal to the area of ​​the orthogonal projection of the orifice of the first hole segment 121 on the projection plane, and the orthogonal projection of the groove 23 on the projection plane coincides with the orthogonal projection of the orifice of the first hole segment 121 on the projection plane.

[0058] The second situation is that after the explosion-proof valve plate 2 and the top cover plate are respectively manufactured, the size relationship between the groove 23 and the orifice is that the area of ​​the orthogonal projection of the groove 23 on the projection plane is larger than the area of ​​the orthogonal projection of the orifice of the first hole segment 121 on the projection plane, and the orthogonal projection of the orifice of the first hole segment 121 on the projection plane is located within the orthogonal projection of the groove 23 on the projection plane.

[0059] However, errors often occur during the processing and assembly of the mounting holes on the top cover plate and the explosion-proof valve plate 2 itself. Therefore, after the explosion-proof valve plate 2 and the top cover plate are assembled, whether it is the first case or the second case, there is a problem that the orifice on the explosion-proof valve plate 2 is projected within the groove 23 or intersects with the groove 23. In other words, there is a problem that the opening portion of the explosion-proof valve plate 2 will open prematurely due to being cut by the edge of the exhaust hole. For this reason, the contour line of the hole wall II1221 of the second hole section 122 is set to be an arc-shaped convex in the direction close to the center line of the exhaust hole 12, so that when the opening portion of the explosion-proof valve plate 2 is deformed toward the exhaust hole, it will not be cut by the edge of the exhaust hole 12, thereby ensuring the service life of the explosion-proof valve plate.

[0060] In some embodiments, in the thickness direction Y of the cover plate 1, the distance from the bottom of the groove 23 to the second end surface 22 of the explosion-proof valve plate 2 is h, the thickness of the explosion-proof valve plate 2 is H, 0.4H≤h≤0.6H, on the one hand, it is convenient for the subsequent stamping of the notch 24, and can also ensure the stability of the explosion of the notch 24. For example, h=1 / 2H.

[0061] Alternatively, if Figure 6 As shown, a notch 24 is provided at the bottom of the groove 23. In a preset direction, the distance between the center line of the notch 24 and the hole wall III111 of the mounting hole 11 is L, 2mm≤L≤3mm, so that the notch 24 can avoid the heat affected zone during laser welding and ensure the normal function of the notch 24.

[0062] In some optional embodiments, the thickness of the explosion-proof valve plate 2 is greater than 0.3 mm, when the explosion-proof valve plate 2 is laser welded to the cover plate 1. For example, the thickness of the explosion-proof valve plate 2 is 0.5 mm, 0.6 mm or 0.7 mm, etc. This embodiment only provides several numerical values ​​by way of example, but is not limited thereto.

[0063] Alternatively, if Fig. 9 As shown, the edge of the notch of the explosion-proof valve disc 2 located in the groove 23 is provided with an arc chamfer 25. The setting of the arc chamfer 25 prevents the thinner part of the explosion-proof valve disc 2 from being cut by its own sharp corners, further ensuring the function of the explosion-proof valve disc 2.

[0064] The cover assembly provided in this embodiment has an explosion-proof valve sheet 2 that will not be cut by the edge of the exhaust hole 12 under normal operating conditions of battery vibration after being deformed by the internal pressure cycle, thereby avoiding premature failure of the explosion-proof valve sheet 2 and increasing the safety of the battery cell of the cover assembly.

[0065] The present embodiment further provides a battery cell, comprising the cover plate assembly as described above. The battery cell provided by the present embodiment has higher reliability and longer service life.

[0066] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention is described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A cover plate assembly, comprising a cover plate (1) and an explosion-proof valve sheet (2), wherein the cover plate (1) has a first surface (13) arranged away from the interior of a battery cell and a second surface (14) arranged away from the first surface (13) in a thickness direction (Y) thereof, characterized in that: The first surface (13) of the cover plate (1) is provided with an exhaust hole (12), the explosion-proof valve plate (2) is provided on the second surface (14), and the explosion-proof valve plate (2) seals the exhaust hole (12); The exhaust hole (12) comprises a first hole segment (121) and a second hole segment (122); the first hole segment (121) and the second hole segment (122) are connected in sequence along the direction from the first surface (13) to the second surface (14); the contour line of the hole wall II (1221) of the second hole segment (122) is in the shape of an arc that bulges in a direction close to the center line of the exhaust hole (12).

2. The cover plate assembly according to claim 1, characterized in that: On a longitudinal section passing through the center line of the second hole segment (122), the contour line of the hole wall II (1221) of the second hole segment (122) is an arc line protruding in a direction close to the center line of the exhaust hole (12), and the radius of the arc line is 0.05 mm to 0.3 mm.

3. The cover plate assembly according to claim 1, characterized in that: In the thickness direction (Y) of the cover plate (1), the explosion-proof valve plate (2) has a first end face (21) arranged toward the exhaust hole (12); the area in the second surface (14) of the cover plate (1) that contacts the first end face (21) is tangent to the hole wall II (1221) of the second hole section (122), and the hole wall II (1221) of the second hole section (122) is tangent to the hole wall I (1211) of the first hole section (121).

4. The cover plate assembly according to any one of claims 1 to 3, characterized in that: The second surface (14) of the cover plate (1) has a hole wall III (111) and a step surface (112), the hole wall III (111) surrounding a mounting hole (11), and the hole wall III (111) of the mounting hole (11) and the hole wall II (1221) of the second hole section (122) are connected via the step surface (112); The explosion-proof valve plate (2) is arranged in the mounting hole (11), the first end surface (21) of the explosion-proof valve plate (2) is in contact with the step surface (112), and the explosion-proof valve plate (2) is connected to the cover plate (1).

5. The cover plate assembly according to claim 4, characterized in that: The explosion-proof valve plate (2) has a second end surface (22) disposed away from the first end surface (21), and a longitudinal installation gap between the first surface (13) of the cover plate (1) and the second end surface (22) of the explosion-proof valve plate (2) is d, wherein 0≤d≤0.08mm.

6. The cover plate assembly according to claim 5, characterized in that: In a preset direction, the width of the mounting hole (11) is x, the width of the explosion-proof valve plate (2) is y, (xy)=2k, wherein 0<k≤0.08mm, and the preset direction and the thickness direction (Y) of the cover plate (1) are perpendicular to each other.

7. The cover plate assembly according to claim 4, characterized in that: There is an orifice at the intersection of the first hole section (121) and the second hole section (122); a groove (23) is provided on the first end surface (21) of the explosion-proof valve plate (2) facing the exhaust hole (12); the area of ​​the orthogonal projection of the groove (23) on the projection plane is equal to the area of ​​the orthogonal projection of the orifice of the first hole section (121) on the projection plane, and the orthogonal projection of the groove (23) on the projection plane coincides with the orthogonal projection of the orifice of the first hole section (121) on the projection plane; Alternatively, the area of ​​the orthographic projection of the groove (23) on the projection plane is larger than the area of ​​the orthographic projection of the opening of the first hole segment (121) on the projection plane, and the opening of the first hole segment (121) on the projection plane is located within the orthographic projection of the groove (23) on the projection plane, and the projection plane and the thickness direction (Y) of the cover plate (1) are perpendicular to each other.

8. The cover plate assembly according to claim 7, characterized in that: In the thickness direction (Y) of the cover plate (1), the distance from the bottom of the groove (23) to the second end surface (22) of the explosion-proof valve plate (2) is h, the thickness of the explosion-proof valve plate (2) is H, and 0.4H≤h≤0.6H.

9. The cover plate assembly according to claim 7, characterized in that: The groove bottom of the groove (23) is provided with a notch (24), and in a preset direction, the distance between the center line of the notch (24) and the hole wall III (111) of the mounting hole (11) is L, 2mm≤L≤3mm.

10. A battery cell, characterized in that: The cover plate assembly comprises the cover plate assembly according to any one of claims 1 to 9.

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