Cover plate assembly for battery, battery and electrical apparatus

Abstract

A cover plate assembly for a battery, a battery, and an electrical apparatus. The cover plate assembly comprises a cover plate (2) and a sealing cover (1), the cover plate (2) being provided with a through hole (25) and the sealing cover (1) being arranged on the cover plate (2) so as to block the through hole (25). The sealing cover (1) is provided with a first bent portion (11), a lap joint portion (12) and a second bent portion (13), the first bent portion (11) being connected to the cover plate (2), the lap joint portion (12) being located between the first bent portion (11) and the second bent portion (13), the first bent portion (11), the lap joint portion (12) and the second bent portion (13) being sequentially connected to form a recess, and the width L of the lap joint portion (12) being not less than 0.5 mm and not greater than 1.5 mm.

Description

Cover plate assembly for battery, battery and electrical device

[0001] This application claims priority to Chinese patent application number 202322957480.8, filed on November 1, 2023, entitled “Cover assembly for battery, battery and electrical device”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present application relates to a battery sealing device, specifically a cover plate assembly for a battery, and also to a battery and an electrical device. Background Art

[0003] With the development of science and technology, electric vehicles are being used more and more widely. As an indispensable part of electric vehicles, the power battery of electric vehicles has an important role to play in the sealing performance of the battery filling hole.

[0004] In the battery filling hole sealing structure of the prior art, the filling hole is provided on the battery cover plate, and the sealing cover is welded to the battery cover plate to seal the filling hole. Since the sealing cover and the cover plate are connected by butt welding, the risk of stress concentration at the weld here is relatively high, which is prone to defects such as weld shrinkage cracks, explosions, and weld holes, resulting in a low helium inspection yield of the power battery sealing weld.

[0005] Therefore, how to ensure the helium inspection yield of battery sealing welding has become a technical problem that needs to be solved urgently.

[0006] Summary of the Invention

[0007] The purpose of this application is to provide a cover plate assembly for a battery. This cover plate assembly can ensure that the welding area is at a distance from the center of the sealing cover, forming a stress buffer area, and improving the helium inspection yield of the battery sealing weld. The second purpose of this application is to provide a battery. The third purpose of this application is to provide an electrical device.

[0008] In order to achieve the above objectives, the present application provides, in a first aspect, a cover assembly for a battery, comprising:

[0009] a cover plate, wherein a through hole is formed on the cover plate;

[0010] A sealing cover, which is provided on the cover plate to seal the through hole; the sealing cover has a first bending portion, an overlapping portion, and a second bending portion, wherein the first bending portion is connected to the cover plate;

[0011] The overlapping portion is located between the first bending portion and the second bending portion. The first bending portion, the overlapping portion and the second bending portion are sequentially connected to form a groove. The width L of the overlapping portion is not less than 0.5 mm and not greater than 1.5 mm.

[0012] Optionally, the through hole includes a mounting groove and a liquid injection channel connected in sequence, and the sealing cover is installed in the mounting groove.

[0013] Optionally, the cover plate assembly further includes a welding portion, the welding portion is connected to the first bending portion to connect the sealing cover and the cover plate, the shortest distance between the edges opposite to the welding portion and the second bending portion is N3, and N3≥L.

[0014] Optionally, the distance from the bottom of the weld portion to the outer bottom surface of the overlap portion is N2, the thickness of the sealing cover is t, and N2 and t satisfy 0.5t≤N2≤t.

[0015] Optionally, the minimum distance from the weld portion to the inner side wall of the corresponding side of the injection channel is N1, and N1 is ≥ 0.5 mm.

[0016] Optionally, N3=(ht)*tan(γ / 2)+L+(vt)*tan(β)≥0.5t, wherein h is the height of the first bending portion, t is the thickness of the sealing cover, γ is the inclination angle between the outer side surfaces at the opposite ends of the first bending portion, v is the distance from the upper surface of the avoidance portion to the outer bottom surface of the overlapping portion, and β is the bending angle of the second bending portion.

[0017] Optionally, a sealing pin is sealed in the injection channel.

[0018] Optionally, a step structure is provided on the outer side of the liquid injection channel, and a transition slope is provided between the step structure and the surface of the cover plate.

[0019] Optionally, the mounting groove and the injection channel are connected via a fillet transition. Optionally, the second bending portion is arc-shaped, and the radius R2 of its inner contour surface is twice the radius R1 of its outer contour surface.

[0020] Optionally, the sealing cover further includes a relief portion protruding in a direction away from the through hole, and the second bent portion is arranged around the relief portion.

[0021] Optionally, a projection of the avoidance portion toward the through hole at least partially overlaps with the through hole.

[0022] Optionally, a distance between a side of the avoidance portion facing the through hole and a side of the overlapping portion facing the through hole is not less than 0.5 mm and not more than 4 mm.

[0023] Optionally, an inclined angle between outer side surfaces at opposite ends of the first bending portion is γ, and 0°≤γ≤90°.

[0024] Optionally, the first bending portion is arranged obliquely toward the inner side wall of the through hole.

[0025] Optionally, the second bending portion is arranged to be inclined in a direction away from the first bending portion.

[0026] Optionally, the outer bottom surface of the overlapping portion is connected to the cover plate.

[0027] A second aspect of the present application provides a battery, comprising the above-mentioned cover assembly for the battery, a battery shell and a battery cell, wherein the cover assembly is covered on the battery shell to form a sealed cavity, and the battery cell is located in the sealed cavity.

[0028] A third aspect of the present application provides an electrical device comprising the above-mentioned battery.

[0029] Through the above technical solution, the present application forms a groove by sequentially connecting the first bending portion, the overlapping portion and the second bending portion, and the width L of the overlapping portion is not less than 0.5 mm and not more than 1.5 mm, thereby effectively ensuring the distance between the welding area and the center of the sealing cover, forming a stress buffer area, avoiding stress concentration at the weld, and improving the helium inspection yield of the battery sealing weld.

[0030] Other features and advantages of the present application will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0032] FIG1 is a schematic diagram of the three-dimensional structure of a sealing cover in a specific embodiment of the present application;

[0033] FIG2 is a schematic structural diagram of a cover plate in a specific embodiment of the present application;

[0034] FIG3 is a schematic diagram of the assembly of the sealing cover and the cover plate in a specific embodiment of the present application, wherein the sealing pin and the injection hole have an interference fit;

[0035] FIG4 is a schematic cross-sectional view of a sealing cover in a specific embodiment of the present application;

[0036] FIG5 is a second structural diagram of a cover plate in a specific embodiment of the present application;

[0037] FIG6 is a schematic structural diagram of a sealing pin in a specific embodiment of the present application;

[0038] FIG7 is a schematic structural diagram of a sealing cover in a specific embodiment of the present application;

[0039] FIG8 is a schematic diagram of the assembly of the sealing cover and the cover plate in the first specific embodiment of the present application, wherein v=t;

[0040] FIG9 is a schematic diagram of the assembly of the sealing cover and the cover plate in the second specific embodiment of the present application, wherein t<v<h;

[0041] FIG10 is a schematic diagram of the assembly of the sealing cover and the cover plate in the third specific embodiment of the present application, wherein v>h;

[0042] FIG11 is a schematic diagram of the assembly of the sealing cover and the cover plate in the fourth specific embodiment of the present application, wherein β=90° and t<v<h;

[0043] FIG12 is a schematic diagram of the assembly of the sealing cover and the cover plate in the fifth specific embodiment of the present application, wherein β=90° and v>h;

[0044] FIG13 is a schematic diagram of the assembly of the sealing cover and the cover plate in the sixth specific embodiment of the present application, wherein β=90° and v=h;

[0045] FIG14 is a schematic diagram of welding the sealing cover and the cover plate in the sixth specific embodiment of the present application;

[0046] FIG15 is a second schematic diagram of the assembly of the sealing cover and the cover plate in a specific embodiment of the present application, wherein the sealing pin is connected to the injection hole in a countersunk manner;

[0047] FIG16 is a third schematic diagram of the assembly of the sealing cover and the cover plate in a specific embodiment of the present application, wherein the sealing pin is removed from the injection hole;

[0048] FIG17 is a schematic structural diagram of a battery in a specific embodiment of the present application;

[0049] FIG18 is a schematic structural diagram of an electrical device in a specific embodiment of the present application.

[0050] Description of reference numerals:

[0051] 1: Sealing cover

[0052] 11: First bending part

[0053] 12: Overlap

[0054] 13: Second bending part

[0055] 14: Avoidance

[0056] 141: First surface

[0057] 142: Second surface

[0058] 111: Welding seam

[0059] 2: Cover

[0060] 21: Mounting slot

[0061] 22: Injection channel

[0062] 23: Step structure

[0063] 24: Transition bevel

[0064] 25: Through hole

[0065] 3: Sealing nails

[0066] 4: Cover assembly

[0067] 5: Battery

[0068] 6: Electrical devices DETAILED DESCRIPTION

[0069] The following describes the specific embodiments of the present application in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present application and are not intended to limit the present application.

[0070] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "disposed," or "connected" should be understood in a broad sense. For example, the term "connected" may refer to a fixed connection, a detachable connection, or an integral connection; it may refer to a direct connection or an indirect connection through an intermediate medium; it may refer to internal communication between two components or an interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0071] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features.

[0072] In this application, the directional terms used are based on the orientation or positional relationship shown in the drawings, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as a limitation of this application; the directional terms in this application should be understood in conjunction with the actual installation status.

[0073] As shown in FIG1 to FIG16 , an embodiment of the present application provides a cover plate assembly 4 for a battery, comprising:

[0074] The cover plate 2 is formed with a through hole 25;

[0075] The sealing cover 1 is arranged on the cover plate 2 to block the through hole 25; the sealing cover 1 has a first bending portion 11, an overlapping portion 12 and a second bending portion 13, and the first bending portion 11 is connected to the cover plate 2;

[0076] The overlap portion 12 is located between the first bending portion 11 and the second bending portion 13. The first bending portion 11, the overlap portion 12 and the second bending portion 13 are sequentially connected to form a groove. The width L of the overlap portion 12 is not less than 0.5 mm and not more than 1.5 mm.

[0077] It should be noted that there is an angle transition between the first bending portion 11 and the overlapping portion 12 and between the second bending portion 13 and the overlapping portion 12 , with the turning point of the angle as the boundary, and the portion between the two boundaries is the overlapping portion 12 .

[0078] Among them, the first bending portion 11, the overlapping portion 12 and the second bending portion 13 are connected in sequence to form a groove, and the width L of the overlapping portion 12 refers to the distance between the two boundaries of the above-mentioned first bending portion 11 and the second bending portion 13 along the radial direction of the sealing cover 1, and the width L of the overlapping portion 12 is not less than 0.5 mm and not more than 1.5 mm; so that a certain distance is formed between the welding area and the center of the sealing cover 1, thereby forming a stress buffer area, which can have a good flexible buffering effect on the stress at the weld, avoid stress concentration at the weld, and improve the helium inspection yield of the battery sealing weld.

[0079] In some embodiments, the first bend 11 is tilted toward the inner sidewall of the through-hole 25, while the second bend 13 is tilted away from the first bend 11. This provides a larger stress buffering area. The first bend 11 is tilted toward the inner sidewall of the through-hole 25, allowing the sealing cover 1 to elastically mate with the cover plate 2 laterally. If the dimensions of the incoming sealing cover 1 approach or exceed the upper tolerance limit, the grooves at both ends of the sealing cover 1 provide dimensional tolerance for elastic deformation, ensuring dimensional fit and reducing scrap production costs.

[0080] In some embodiments, as shown in Figure 2, the through hole 25 of the cover plate 2 includes a mounting groove 21 and a liquid injection channel 22 connected in sequence. As shown in Figure 3, the sealing cover 1 is installed in the mounting groove 21, and the first bending portion 11 is arranged inclined toward the inner side wall of the mounting groove 21.

[0081] As shown in FIG9 , a sealing nail 3 can be used to seal the through hole 25 of the cover plate 2, that is, a sealing nail 3 is sealed and installed in the injection channel 22 to isolate the sealing cover 1 from contact with the electrolyte, thereby preventing the seal from failing due to weld corrosion. Moreover, the sealing nail 3 can isolate the welding slag from falling into the battery cell during welding. As shown in FIG5 , the diameter of the injection channel 22 is D1, and as shown in FIG6 , the diameter of the sealing nail 3 is D2. As shown in FIG8 , D2 is greater than D1, so that the sealing nail 3 is connected to the injection channel 22 with an interference fit, thereby preventing the sealing nail 3 from falling into the battery cell. Compared with the prior art, the sealing cover 1 and the injection hole are butt-welded, which requires a relatively high precision of the incoming material; and after injection, there is a problem of electrolyte crystallization remaining on the sealing cover 1, resulting in poor fit between the sealing cover 1 and the cover plate, and finally resulting in a low sealing welding yield. As shown in FIG6 , the bottom of the sealing nail 3 of the present application adopts a cone and a rounded form to connect, which can avoid electrolyte residue and backflow after injection. Furthermore, as shown in FIG15 , a countersunk head may be provided on the top of the sealing pin 3 to catch the cover plate 2 and prevent it from falling into the battery cell. The sealing pin 3 may be made of at least one of fluororubber, EPDM rubber, EPDM rubber, and fusible polytetrafluoroethylene plastic.

[0082] As shown in FIG. 16 , if the electrolyte has a low corrosive effect on the weld, the sealing nail 3 can be eliminated and the sealing cover 1 can be used directly to seal the through hole 25 of the cover plate 2 .

[0083] In some embodiments, as shown in Figures 2 to 4, the outer bottom surface of the overlap portion 12 is connected to the cover plate 2. Specifically, the mounting groove 21 can be a step structure, the sealing cover 1 is installed in the mounting groove 21, the bottom surface of the overlap portion 12 is in contact with the bottom of the mounting groove 21, the outer side surface of the first bend portion 11 is laterally elastically matched with the inner side wall of the mounting groove 21, the step depth of the mounting groove 21 is H, the height of the first bend portion 11 is h, and in the preferred case, H≥h, the value range of h is 0.5mm≤h≤2mm, and the mounting groove 21 and the injection channel 22 are connected in a rounded transition form. In order to prevent stress concentration here, a contoured design is adopted to meet the principle of wall thickness uniformity, which can effectively reduce material consumption and reduce manufacturing costs; for example, as shown in Figure 2, a step structure 23 is provided on the outer side of the injection channel 22, and a transition slope 24 is provided between the step structure 23 and the surface of the cover plate 2, which can effectively reduce material consumption and reduce manufacturing costs.

[0084] Furthermore, as shown in FIG4 , in order to ensure uniform wall thickness, the second bending portion 13 is arc-shaped, and the radius R2 of the inner contour surface of the second bending portion 13 is twice the radius R1 of the outer contour surface of the second bending portion 13 , ie R2 = 2R1.

[0085] In some embodiments, the sealing cover 1 also includes a avoidance portion 14, which protrudes in a direction away from the through hole 25, and the second bending portion 13 is arranged around the avoidance portion 14. The avoidance portion 14 has a first surface 141 and a second surface 142, and the first surface 141 and the second surface 142 are arranged relative to each other. In the embodiment shown in Figure 9, the first surface 141 is located on the upper surface of the sealing cover 1, and the second surface 142 is located on the lower surface of the sealing cover 1. The first surface 141 and the second surface 142 are both convex and curved upward, as shown in Figure 3, so that an avoidance space is formed under the second surface 142 to avoid the sealing pin 3, and an insulating cavity is added to the welding to ensure that the sealing pin 3 is not burned during welding and its sealing is affected.

[0086] In some embodiments, as shown in FIG14 , the cover plate assembly 4 further includes a weld 111. During welding, the first bend 11 is welded to the inner sidewall of the through hole 25 of the cover plate 2 using a wraparound welding method to form the weld 111. That is, the weld 111 is connected to the first bend 11, thereby connecting the sealing cover 1 to the cover plate 2. The shortest horizontal straight-line distance between the weld 111 and the second bend 13 is N3, and N3 ≥ L. Preferably, the shortest distance between the weld 111 and the opposing edges of the second bend 13 is N3 = L, which can just wrap around the entire first bend 11. Compared to the butt welding method used in the prior art, this wraparound welding method has a wider weld width margin, allowing the weld to directly contact the air, improving heat dissipation, reducing the risk of stress concentration at the weld, and less likely to cause weld shrinkage cracks, fire explosions, and weld hole defects. This can enhance the reliability of the weld seal and improve the helium inspection yield rate of the power battery sealing weld.

[0087] Furthermore, as shown in Figures 4 and 14, in order to prevent the heat of the widening melt during welding from burning the avoidance portion 14 and affecting its sealing, the shortest distance N3 between the edges opposite to the weld portion 111 and the second bending portion 13 is (ht)*tan(γ / 2)+L+(vt)*tan(β)≥0.5t, wherein h is the height of the first bending portion 11, t is the thickness of the sealing cover 1, γ is the inclination angle between the outer side surfaces at the opposite ends of the first bending portion 11, v is the distance from the upper surface of the avoidance portion 14 to the outer bottom surface of the overlapping portion 12, L is the width of the overlapping portion 12 along the radial direction of the sealing cover 1, and β is the bending angle of the second bending portion 13.

[0088] In some embodiments, the inclined angle between the outer side surfaces at the two opposite ends of the first bent portion 11 is γ, and 0°≤γ≤90°.

[0089] Furthermore, as shown in Figures 4 and 14, to prevent the heat of penetration during welding from burning the sealing pin 3 and affecting the welding process capability and structural sealing, the minimum distance between the weld portion 111 and the inner sidewall corresponding to the injection channel 22 is N1, where N1 ≥ 0.5 mm. The distance from the bottom of the weld portion 111 to the outer bottom surface of the overlap portion 12 is N2. The thickness of the sealing cover 1 is t, and N2 and t satisfy 0.5t ≤ N2 ≤ t.

[0090] During welding, Figure 14 shows a schematic diagram of the weld between the sealing cover 1 and the cover plate 2, wherein the weld is a simple schematic diagram, the weld width T is the maximum distance between welds, and in order to ensure the sealing performance of the weld, the weld width T is t≤T≤4t, and the depth from the weld surface to the deepest part of the weld is the weld depth W. In order to ensure the sealing performance of the weld, the weld depth W is 0.5t≤W≤2t.

[0091] In some embodiments, the projection of the avoidance portion 14 toward the through hole 25 at least partially overlaps with the through hole 25, that is, the avoidance portion 14 is directly opposite the through hole 25, and the projection area of ​​the avoidance portion 14 toward the through hole 25 is greater than the area of ​​the through hole 25, or the projection area of ​​the avoidance portion 14 toward the through hole 25 is equal to the area of ​​the through hole 25.

[0092] Specifically, the distance from the upper surface of the avoidance portion 14 to the outer bottom surface of the overlapping portion 12 is v, the thickness of the sealing cover 1 is t, vt represents the size of the avoidance space, and the depth of the avoidance space is 0≤vt≤4mm.

[0093] Furthermore, as shown in FIG3 , in order to leave sufficient escape space in the height direction to prevent welding from affecting the sealing pin 3 , the distance between the side of the escape portion 14 facing the through hole 25 and the side of the overlapping portion 12 facing the through hole 25 is not less than 0.5 mm and not more than 4 mm, that is, the depth of the escape space below the second surface 142 of the escape portion 14 is not less than 0.5 mm and not more than 4 mm, that is, the difference between the distance v from the upper surface of the escape portion 14 to the outer bottom surface of the overlapping portion 12 and the thickness t of the sealing cover 1 is 0.5≤vt≤4 mm.

[0094] As a specific embodiment of the sealing cover 1, in the embodiment of Figure 8, v = t, indicating that the size of the escape space is 0. In the embodiment of Figure 9, 0° < β < 90°, and t < v < h, in which case the first surface 141 of the escape portion 14 is lower than the upper surface of the cover plate 2; alternatively, 0° < β < 90°, and t < v = h, in which case the first surface 141 of the escape portion 14 is flush with the upper surface of the cover plate 2. In the embodiment of Figure 10, 0° < β < 90°, and h < v, in which case the first surface 141 of the escape portion 14 protrudes from the upper surface of the cover plate 2.

[0095] As another specific embodiment of the sealing cover 1, as shown in Figures 11 to 13, β = 90°, that is, the bend position of the avoidance portion 14 is a right angle. In the embodiment of Figure 11, t < v < h, in which case the first surface 141 of the avoidance portion 14 is lower than the upper surface of the cover plate 2; in the embodiment of Figure 12, h < v, and the first surface 141 of the avoidance portion 14 protrudes from the upper surface of the cover plate 2; in the embodiment of Figure 12, v = h, and the first surface 141 of the avoidance portion 14 is flush with the upper surface of the cover plate 2.

[0096] In some embodiments, as shown in FIG7 , the sealing cover 1 has a long side a and a short side b. When a=b, the sealing cover 1 can be a circular structure, and the values ​​of the long side a and the short side b can be selected according to the design. When a>b, the sealing cover 1 can be an elliptical structure, and the long side a is in the range of 1mm≤a≤20mm, the short side b is in the range of 1mm≤b≤20mm, and 1≤a / b≤2.

[0097] As shown in Figures 3 and 14, by sequentially connecting the first bend 11, the overlap 12, and the second bend 13 to form a groove, and by ensuring that the width L of the overlap 12 along the radial direction of the sealing cover 1 is no less than 0.5 mm and no more than 1.5 mm, the welding area is kept away from the center of the sealing cover 1, forming a stress buffer area and avoiding stress concentration at the weld. Furthermore, the sealing cover 1 elastically fits laterally with the inner sidewall of the through hole 25 of the cover plate 2 via the first bend 11. When the sealing cover 1 exceeds the upper tolerance limit of the incoming material size, the groove areas at both ends of the sealing cover 1 provide dimensional tolerance for elastic deformation, ensuring dimensional fit and reducing scrap production costs. The grooves at both ends of the sealing cover 1 allow the first bent portion 11 to be connected to the inner wall of the through hole 25 of the cover plate 2 by edge welding. During the welding process, the weld portion 111 can directly contact the air, which can better dissipate heat, reduce the risk of stress concentration at the weld, and is less likely to cause weld shrinkage cracks, fire, and weld hole defects; compared with the butt welding method of the prior art, this edge welding has a wider weld width margin, which can increase the reliability of the welding seal and finally improve the helium inspection yield of the sealing weld of the power battery.

[0098] As shown in Figure 17, an embodiment of the present application also provides a battery 5, including a cover assembly 4 for the battery, a battery shell and a battery cell as described in any one of the above embodiments. The cover assembly 4 is an important component of the battery 5. The cover assembly 4 is covered on the battery shell to seal the battery shell, thereby forming a sealed cavity, and the battery cell is installed in the sealed cavity.

[0099] As shown in FIG18 , an embodiment of the present application further provides an electrical device 6 , comprising the battery 5 described in the above embodiment.

[0100] The preferred embodiments of the present application have been described in detail above with reference to the accompanying drawings. However, the present application is not limited thereto. Within the scope of the technical concept of the present application, the technical solution of the present application may be subjected to a variety of simple modifications, including combining various specific technical features in any suitable manner. To avoid unnecessary repetition, the present application will not further describe various possible combinations. However, these simple modifications and combinations should also be regarded as the contents disclosed in the present application and fall within the scope of protection of the present application.

Claims

1. A cover plate assembly for a battery, characterized in that: include: A cover plate (2), wherein a through hole (25) is formed on the cover plate (2); A sealing cover (1), the sealing cover (1) being arranged on the cover plate (2) to seal the through hole (25); the sealing cover (1) comprising a first bending portion (11), an overlapping portion (12) and a second bending portion (13); the first bending portion (11) being connected to the cover plate (2); The overlapping portion (12) is located between the first bending portion (11) and the second bending portion (13); the first bending portion (11), the overlapping portion (12) and the second bending portion (13) are sequentially connected to form a groove; and a width L of the overlapping portion (12) is not less than 0.5 mm and not more than 1.5 mm.

2. The cover plate assembly for a battery according to claim 1, characterized in that: The through hole (25) comprises: Mounting slot (21); The liquid injection channel (22) is connected in sequence to the mounting groove (21) and the liquid injection channel (22), and the sealing cover (1) is installed in the mounting groove (21).

3. The cover plate assembly for a battery according to claim 2, characterized in that: The cover plate assembly also includes: A welding seam portion (111), the welding seam portion (111) is connected to the first bent portion (11) to connect the sealing cover (1) and the cover plate (2), the shortest distance between the edges of the welding seam portion (111) and the second bent portion (13) opposite to each other is N3, and N3≥L.

4. The cover plate assembly for a battery according to claim 3, characterized in that: The distance from the bottom of the weld portion (111) to the outer bottom surface of the overlap portion (12) is N2, the thickness of the sealing cover (1) is t, and N2 and t satisfy 0.5t≤N2≤t.

5. The cover plate assembly for a battery according to claim 3, characterized in that: The minimum distance from the welding seam (111) to the inner wall of the corresponding side of the injection channel (22) is N1, and N1 is ≥ 0.5 mm.

6. The cover plate assembly for a battery according to claim 3, characterized in that: N3=(ht)*tan(γ / 2)+L+(vt)*tan(β)≥0.5t; Wherein, h is the height of the first bending portion, t is the thickness of the sealing cover (1), γ is the inclined angle between the outer side surfaces at the two opposite ends of the first bending portion, v is the distance from the upper surface of the avoidance portion to the outer bottom surface of the overlapping portion, and β is the bending angle of the second bending portion.

7. The cover plate assembly for a battery according to any one of claims 2 to 6, characterized in that: A sealing pin (3) is installed in the liquid injection channel (22) for sealing.

8. The cover plate assembly for a battery according to any one of claims 2 to 7, characterized in that: A step structure (23) is provided on the outer side of the injection channel (22), and a transition slope (24) is provided between the step structure (23) and the surface of the cover plate (2).

9. The cover plate assembly for a battery according to any one of claims 2 to 8, characterized in that: The installation groove (21) and the injection channel (22) are connected via a rounded transition.

10. The cover plate assembly for a battery according to any one of claims 1 to 9, characterized in that: The second bending portion (13) is in an arc shape, and the radius R2 of its inner contour curved surface is twice the radius R1 of its outer contour curved surface.

11. The cover plate assembly for a battery according to any one of claims 1 to 10, characterized in that: The sealing cover (1) further comprises: An escape portion (14), the escape portion (14) protruding in a direction away from the through hole (25), and the second bent portion (13) being arranged around the escape portion (14).

12. The cover plate assembly for a battery according to claim 11, characterized in that: A projection of the avoidance portion (14) toward the through hole (25) at least partially overlaps with the through hole (25).

13. The cover plate assembly for a battery according to claim 11, characterized in that: The distance between the side of the avoidance portion (14) facing the through hole (25) and the side of the overlap portion facing the through hole (25) is not less than 0.5 mm and not more than 4 mm.

14. The cover plate assembly for a battery according to any one of claims 1 to 13, characterized in that: The inclined angle between the outer side surfaces at the two opposite ends of the first bent portion (11) is γ, and 0°≤γ≤90°.

15. The cover plate assembly for a battery according to any one of claims 1 to 13, characterized in that: The first bent portion (11) is arranged obliquely toward the inner side wall of the through hole (25).

16. The cover plate assembly for a battery according to any one of claims 1 to 13, characterized in that: The second bent portion (13) is arranged obliquely in a direction away from the first bent portion (11).

17. The cover plate assembly for a battery according to any one of claims 1 to 13, characterized in that: The outer bottom surface of the overlapping portion (12) is connected to the cover plate (2).

18. A battery, characterized in that: It comprises a cover plate assembly (4) for a battery, a battery shell and a battery cell as described in any one of claims 1 to 17, wherein the cover plate assembly is covered on the battery shell to form a sealed cavity, and the battery cell is located in the sealed cavity.

19. An electrical device, characterized in that: Comprising the battery (5) as claimed in claim 18.

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