Battery cover plate and secondary battery

Abstract

The application provides a battery cover plate and a secondary battery. The battery cover plate is connected with a battery shell. A plurality of recesses are arranged at intervals on a side of the battery cover plate away from the battery shell. Each of the plurality of recesses has a first end close to an edge of the battery cover plate and an extension end extending from the first end in a first extension direction. The distance between the first end and the edge of the battery cover plate is less than or equal to the welding width of the battery cover plate and the battery shell. The extension end is located outside the welding area of the battery cover plate and the battery shell. The application can avoid particle splashing during the welding of the cover plate and improve the welding quality of the cover plate and the shell.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to a battery cover and a secondary battery. Background Technology

[0002] Currently, battery casings and covers are mostly made of metal and connected by laser welding. This welding method has the following problems: 1. Welding spatter: Molten metal particles splatter everywhere during welding, easily entering the battery and causing a short circuit risk; 2. Pinholes in the weld: If the welding material contains a large amount of impurities or gases, these substances will be released during welding, forming pores inside the weld, resulting in pinholes during laser welding and affecting the welding effect. Utility Model Content

[0003] In order to overcome the defects in the prior art, this utility model provides a battery cover and a secondary battery, which can avoid particle splashing during the welding process of the cover and improve the welding quality of the cover and the shell.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0005] The first aspect of this utility model discloses a battery cover plate, which is connected to a battery housing. The battery cover plate has a plurality of spaced grooves on the side away from the battery housing. Each of the plurality of grooves has a first end near the edge of the battery cover plate and an extension end extending from the first end in a first extending direction. The distance between the first end and the edge of the battery cover plate is less than or equal to the welding width between the battery cover plate and the battery housing. The extension end is located outside the welding area between the battery cover plate and the battery housing.

[0006] The groove provided on the cover plate of this application can communicate with the welding area between the cover plate and the shell, so that the laser welding fluid can form a turbulent effect in the groove, slow down the movement speed of metal particles, thereby effectively suppressing metal particle splashing during welding and preventing metal particles from splashing into the battery.

[0007] Furthermore, the surfaces of the multiple grooves are all coated. By applying a coating to the surface of the grooves, the surface of the grooves becomes rougher, and the porous medium in the coating can generate capillary action and physical adsorption, which can capture the spatter particles generated during the welding process and dissipate welding steam, thereby reducing the probability of welding pinholes, ensuring the welding quality of the cover plate and the shell, and reducing battery welding costs and scrap rate.

[0008] Furthermore, each of the plurality of grooves has an extension end facing away from the first end, the extension end having a first extending direction, and the angle between the first extending direction and the welding direction of the battery cover and the battery casing is 45° to 90°. This enhances the turbulence effect within the grooves, allowing the flowing solder to enter the grooves more smoothly and improving the welding effect.

[0009] Furthermore, the length of the extended end along the first extending direction is greater than the width of the weld between the battery cover and the battery casing. If the length of the groove is too small, the welding area will cover the groove, failing to form a turbulent region and thus failing to suppress particle spatter during welding.

[0010] Furthermore, viewed from the first extending direction, the cross-sectional shape of each of the plurality of grooves is configured to include a bottom edge and side edges on both sides of the bottom edge, with the angle between the side edges and the plane containing the bottom edge being 60° to 80°. When the angle between the inclined edge of the groove and the bottom edge is too small, a local turbulent zone cannot be effectively formed, resulting in poor suppression of welding particle spatter. When the angle between the inclined edge of the groove and the bottom edge is too large, the turbulent flow velocity in the groove is too fast, which can easily cause the molten pool liquid to splash out from the edge of the groove and form tiny particles after cooling, which then enter the battery interior.

[0011] Furthermore, the coating includes a substrate disposed on the surface of the groove, a coating disposed on the surface of the substrate, and a film disposed on the surface of the coating. The micropores formed by the coating can adsorb and filter splashed droplets. Through the synergistic effect of multiple coating layers, dust and impurities carried by the splashed molten metal can be filtered, and the splashed molten metal can be guided to the molten pool.

[0012] Furthermore, the substrate is anodic aluminum oxide, the coating is silica aerogel, and the membrane is a graphene-modified polytetrafluoroethylene membrane.

[0013] Furthermore, the surface roughness of the coating is 3.2–6.3 μm. If the roughness is too low, the capillary adsorption effect of the coating micropores will be reduced, while if the roughness is too high, the edge of the groove will not be able to make sufficient contact with the molten pool, resulting in cracks at the contact surface.

[0014] Furthermore, the extended end has a second extending direction and extends to a depth of 0.15–0.25 mm along the second extending direction. If the groove depth is too small, an effective turbulence zone cannot be formed, reducing the effect of suppressing welding particle spatter; if the groove depth is too large, it will affect the strength of the cover plate itself.

[0015] The second aspect of this utility model discloses a secondary battery, including the battery cover plate described in any one of the first aspects.

[0016] Due to the application of the above technical solution, this utility model has the following advantages compared with the prior art:

[0017] 1. This application provides a groove on the cover plate, which connects to the welding area between the cover plate and the casing. This allows the laser welding fluid to form a turbulent effect within the groove, slowing down the movement speed of metal particles and effectively suppressing metal particle splashing during welding. This prevents metal particles from splashing into the battery.

[0018] 2. This application makes the groove surface rougher by setting a coating on the groove surface, and the porous medium in the coating can generate capillary action and physical adsorption, which can capture the spatter particles generated during the welding process and dissipate welding steam, thereby reducing the probability of welding pinholes, ensuring the welding quality of the cover plate and the shell, and reducing the battery welding cost and scrap rate.

[0019] To make the above and other objects, features and advantages of this utility model more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a structural diagram of a secondary battery provided in an embodiment of this application;

[0022] Figure 2 This is a top view of a secondary battery provided in an embodiment of this application;

[0023] Figure 3 This is an enlarged structural diagram of a groove provided in an embodiment of this application;

[0024] Figure 4 This is a side view of a groove provided in an embodiment of this application.

[0025] The reference numerals in the above figures are: 1. Battery cover; 2. Groove; 3. Groove spacing; 4. Housing. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. In addition, the accompanying drawings of the present invention are only simple schematic illustrations and are not depictions based on actual dimensions, as stated in advance.

[0027] In this utility model, it should be noted that the terms "upper," "lower," "inner," "outer," "forward," "backward," "between," "nearer," and "farthest" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. It should also be noted that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0028] It should be understood that while terms such as "first," "second," and "third" may be used in this document to describe various components or signals, these components or signals should not be limited by these terms. These terms are primarily used to distinguish one component from another, or one signal from another. Furthermore, the term "or" as used herein should, as appropriate, include any combination of one or more of the related listed items.

[0029] Reference Figures 1-4 This application provides a battery cover 1, which can be disposed on the top of the battery housing 4. The battery cover 1 has a plurality of spaced grooves 2 on the side away from the battery housing 4. Each of the plurality of grooves 2 has a first end near the edge of the battery cover 1 and an extension end extending from the first end in a first extending direction. The distance between the first end and the edge of the battery cover 1 is less than or equal to the width of the welding between the battery cover 1 and the battery housing 4. The extension end is located outside the welding area between the battery cover 1 and the battery housing 4.

[0030] Specifically, this application uses a square battery as an example for illustration. For example... Figure 2 and Figure 3 As shown, each groove 2 has a first extending direction extending from one side edge near the battery cover 1 to the other side of the battery cover 1, and a second extending direction extending from one side of the battery cover 1 away from the inside of the battery housing 4 to the other side. The first extending direction is set according to the welding direction between the battery cover 1 and the battery housing 4. The end of the groove 2 near the side edge of the battery cover 1 is the first end, and the end away from that side edge of the battery cover 1 is the extending end.

[0031] When the battery cover 1 is welded to the battery casing 4, it has a first welding direction. In some embodiments, the angle between the first extending direction and the first welding direction is 45° to 90°, so that the welding fluid can enter the groove 2 more smoothly and prevent welding slag particles from splashing. In this embodiment, along the length direction of the battery cover 1, the first extending direction is as shown by arrow a, and the first welding direction is as shown by arrow b. Along the width direction of the battery cover 1, the first extending direction is perpendicular to the width direction of the battery cover 1, and the first welding direction is parallel to the width direction of the battery cover 1, specifically as follows: Figure 2 As shown.

[0032] The shape of the groove 2 extending along the first extending direction can be flexibly set. In some embodiments, the shape of the groove 2 extending along the first extending direction is a straight line, a curve, a broken line, or other shapes.

[0033] like Figure 2 As shown, the width W of the battery cover 1 welded along the first welding direction is the width from the dotted line in the figure to the edge of the battery cover 1. The length L of the groove 2 extending along the first extension direction is D, and the distance D between the first end of the groove 2 and the edge of the battery cover 1 is D. Then D≤W<L, so that the welding area of ​​the battery cover 1 and the battery casing 4 is connected to the groove 2. Optionally, the difference between the extension length L and the width W is 2~3mm.

[0034] Optionally, the groove spacing 3 between any two adjacent grooves 2 is 1 to 2 mm, so as to provide a relatively large number of grooves on the battery cover plate 1, improve the effect of suppressing particle splashing, and avoid the effect of affecting the turbulence effect between adjacent grooves and reducing the effect of suppressing welding pool splashing when the groove spacing is too small.

[0035] It should be noted that the shape of the multiple grooves spaced apart on the edge of the same battery cover 1, the spacing between the grooves, and the distance from the edge of the battery cover 1 can be the same or different. The specific settings can be made according to the actual situation, and this application does not make specific limitations here.

[0036] To ensure that the groove 2 can generate a turbulent effect, the side surfaces on both sides of the bottom surface of the groove 2 are inclined surfaces. For example... Figure 3 and Figure 4 As shown, in this embodiment, viewed from the first extending direction, the cross-sectional shape of the groove 2 is trapezoidal, and the angle between the hypotenuse and the base of the trapezoid is 60° to 80°. To ensure the effect of suppressing particle splashing, the width of the groove can optionally be 2 to 3 mm, where the groove width is the width of the groove opening opposite the base of the trapezoid.

[0037] In other possible embodiments, the groove 2 may also be V-shaped or other shapes, which are not limited herein.

[0038] In some embodiments, the groove 2 extends to a depth h of 0.15 to 0.25 mm along the second extending direction, as shown by arrow c in the figure.

[0039] The surface of the groove 2 is coated. The coating includes a substrate on the surface of the groove 2, a coating layer on the surface of the substrate, and a film on the surface of the coating layer. Specifically, after forming multiple grooves on the surface of the cover plate 2 by laser etching according to the set groove size, the coating is applied to the groove surface according to preset parameters.

[0040] Optionally, the substrate is anodic aluminum oxide, the coating is silica aerogel, and the membrane is a graphene-modified polytetrafluoroethylene (PTFE) membrane. The porosity of the anodic aluminum oxide is 25%–35%, the thickness of the silica aerogel coating is 50–100 μm, and the pore size of the graphene-modified PTFE membrane is 0.2–0.5 μm. The three coating layers work together to form micropores, making the surface of the groove 2 rougher and enabling the welding fluid to diffuse uniformly.

[0041] Optionally, the surface roughness of the coating is 3.2 to 6.3 μm.

[0042] like Figure 1 As shown in the illustration, this application also provides a secondary battery, which includes the battery cover 1 and battery casing 4 from the above embodiments, as well as the battery cells disposed within the battery casing 4. It should be noted that the secondary battery can be a prismatic battery, a cylindrical battery, or a battery with other structures; this application does not limit the structure of the battery.

[0043] In this embodiment of the application, during the welding of the battery cover plate 1 and the battery casing 4, a turbulence effect is formed through the groove 2, which can suppress welding slag spatter and prevent welding slag particles from entering the battery cell during the welding process, thereby reducing the safety hazards of the battery. The turbulence effect affects the welding quality by influencing the flow and distribution of the solder.

[0044] This utility model uses specific embodiments to illustrate the principle and implementation of the utility model. The above description of the embodiments is only for the purpose of helping to understand the method and core idea of ​​the utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the utility model. Therefore, the content of this specification should not be construed as a limitation of the utility model.

Claims

1. A battery cover plate connected with a battery case, characterized by, The battery cover has a plurality of spaced grooves on the side away from the battery housing. Each of the grooves has a first end near the edge of the battery cover and an extension end extending from the first end in a first extending direction. The distance between the first end and the edge of the battery cover is less than or equal to the welding width between the battery cover and the battery housing. The extension end is located outside the welding area between the battery cover and the battery housing.

2. The battery cover plate of claim 1, wherein, The surfaces of all of the grooves are coated.

3. The battery cover plate of claim 1, wherein, Each of the grooves has an extension end facing away from the first end, the extension end having a first extension direction, and the angle between the first extension direction and the welding direction between the battery cover and the battery casing is 45° to 90°.

4. The battery cover plate of claim 1, wherein, The length of the extension end along the first extension direction is greater than the width of the weld between the battery cover and the battery casing.

5. The battery cover plate of claim 1, wherein, Viewed from the first extending direction, the cross-sectional shape of the plurality of grooves is configured to include a bottom edge and side edges on both sides of the bottom edge, and the angle between the side edges and the plane in which the bottom edge is located is 60° to 80°.

6. The battery cover plate of claim 2, wherein, The coating includes a substrate disposed on the surface of the groove, a coating disposed on the surface of the substrate, and a film disposed on the surface of the coating.

7. A battery cover plate according to claim 6, wherein The substrate is anodic aluminum oxide, the coating is silica aerogel, and the membrane is a graphene-modified polytetrafluoroethylene membrane.

8. The battery cover plate of claim 2, wherein, The surface roughness of the coating is 3.2–6.3 μm.

9. The battery cover plate of claim 1, wherein, The extension end has a second extension direction and extends to a depth of 0.15 to 0.25 mm along the second extension direction.

10. A secondary battery characterized by comprising: Includes the battery cover as described in any one of claims 1 to 9.

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