End cover assembly, battery, battery pack and electric equipment

Abstract

The utility model discloses an end cap assembly, battery, battery pack and electric equipment, the end cap assembly comprises: a cover plate, the cover plate is provided with a liquid injection hole, the liquid injection hole comprises a first hole section, a second hole section and a sealing hole section, the inner diameters of the first hole section, the second hole section and the sealing hole section are sequentially reduced, a first step surface is formed between the first hole section and the second hole section, and a second step surface is formed between the second hole section and the sealing hole section; a second step surface is formed between the second hole section and the sealing hole section; the end, close to the liquid injection hole, of the sealing cover comprises a first end face and a second end face, and the end, away from the liquid injection hole, of the sealing cover is a third end face; the sealing cover is embedded in the liquid injection hole, the first end face is in lap joint with the first step face, the second end face is in lap joint with the second step face, and the sealing cover and the cover plate are connected at the joint of the third end face and the cover plate in a welded mode. According to the technical scheme, the welding quality can be improved, so that the sealing performance and the connecting strength between the cover plate and the sealing cover are improved.

Description

Technical Field

[0001] The present application belongs to the field of battery technology, and in particular relates to an end cover assembly, a battery, a battery pack, and an electrical device. Background Art

[0002] With the development of battery technology, lithium batteries are being used more and more widely, and people are requiring higher and higher performance of batteries.

[0003] The end cover assembly of the battery includes a cover plate with a liquid injection hole, a rubber nail and a sealing cover. After the liquid injection is completed, the rubber nail is inserted into the liquid injection hole, and then the sealing cover is used for sealing welding.

[0004] In the prior art, a step is usually provided in the injection hole, and the sealing cover is arranged on the step and connected to the cover plate by welding. However, some electrolyte often remains on the step in the injection hole. When the sealing cover is welded to the cover plate, the residual electrolyte may cause fire or explosion due to the high temperature, thereby affecting the welding quality. Utility Model Content

[0005] The purpose of the embodiments of the present application is to provide an end cover assembly, a battery, a battery pack, and an electrical device.

[0006] According to a first aspect of an embodiment of the present application, there is provided an end cover assembly, comprising:

[0007] A cover plate, wherein the cover plate is provided with a liquid injection hole, wherein the liquid injection hole comprises a first hole section, a second hole section and a sealing hole section with inner diameters decreasing in sequence, a first step surface is formed between the first hole section and the second hole section, and a second step surface is formed between the second hole section and the sealing hole section;

[0008] A sealing cover, wherein one end of the sealing cover close to the liquid injection hole comprises a first end surface and a second end surface, and one end of the sealing cover away from the liquid injection hole is a third end surface;

[0009] The sealing cover is embedded in the injection hole, the first end surface overlaps the first step surface, the second end surface overlaps the second step surface, and the sealing cover and the cover plate are welded at the connection between the third end surface and the cover plate.

[0010] Optionally, the third end surface is flush with or lower than the outer end surface of the cover plate.

[0011] Optionally, the end cover assembly further comprises a sealing member, wherein the sealing member is at least partially embedded in the sealing hole section and seals the sealing hole section.

[0012] Optionally, the sealing hole segment includes a third hole segment and a fourth hole segment, the third hole segment and the second hole segment form the second step surface, and the third hole segment and the fourth hole segment form a third step surface;

[0013] The sealing member comprises a sealing section and a limiting section which are connected to each other. The lower surface of the limiting section abuts against the third step surface. The sealing section is embedded in the fourth hole section and seals the fourth hole section.

[0014] Optionally, the sealing cover includes a protruding portion and a connecting portion, the protruding portion is connected to the connecting portion and protrudes from the cover plate in a direction away from the injection hole, a receiving cavity is formed inside the protruding portion, and a portion of the sealing member protruding from the injection hole is received in the receiving cavity.

[0015] Optionally, the cover plate is provided with a first annular groove, and the sealing cover and the cover plate form an edge weld at the first annular groove.

[0016] Optionally, the third end surface is located at the outer end surface of the connecting portion.

[0017] Optionally, a welding protrusion is formed between the first annular groove and the first hole segment, and the welding protrusion is at least partially melted to form the edge welding seam with the sealing cover.

[0018] Optionally, the thickness of the welding protrusion is greater than or equal to the thickness of the sealing cover.

[0019] Optionally, the injection hole also includes a fifth hole segment, the first hole segment is located between the fifth hole segment and the second hole segment, the inner diameter of the fifth hole segment is larger than the inner diameter of the first hole segment, the fifth hole segment and the first hole segment form a fourth step surface, the first annular groove is opened on the fourth step surface, and the edging weld is located in the fifth hole segment or the first hole segment.

[0020] Optionally, the third end surface is flush with the fourth step surface.

[0021] Optionally, an adhesive layer is provided at the edge welding seam.

[0022] Optionally, at least one second annular groove is formed on the third end surface.

[0023] According to a second aspect of an embodiment of the present application, a battery is provided, comprising the above-mentioned end cover assembly.

[0024] According to a third aspect of the embodiments of the present application, a battery pack is provided, comprising the above-mentioned end cover assembly; or

[0025] Including the battery mentioned above.

[0026] According to a fourth aspect of the embodiments of the present application, there is provided an electrical device, comprising the above-mentioned end cover assembly; or

[0027] Including a battery as described above; or

[0028] Including the above-mentioned battery pack.

[0029] One technical effect of the embodiments of the present application is that when the sealing cover and the cover plate are welded, since the second step surface is separated from the welding position of the sealing cover and the cover plate by the first step surface, the temperature transmitted to the second step surface during welding can be reduced. If the electrolyte remaining at the second step surface explodes due to the high temperature, the boss formed by the first end face and the second end face will block the electrolyte from being transmitted to the welding position of the sealing cover and the cover plate after the explosion, thereby avoiding affecting the welding point, thereby improving the welding quality, and improving the sealing performance and connection strength between the cover plate and the sealing cover.

[0030] Other features and advantages of the present application will become apparent from the following detailed description of exemplary embodiments of the present application with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the application and, together with the description, serve to explain the principles of the application.

[0032] Figure 1 A top view of a battery in an embodiment of the present application;

[0033] Figure 2 for Figure 1 A cross-sectional view of the end cap assembly at AA in FIG.

[0034] Figure 3 for Figure 2 A partial cross-sectional view of the cover plate and the sealing cover after welding in the illustrated embodiment;

[0035] Figure 4 is a cross-sectional view of an end cap assembly in another embodiment of the present application;

[0036] Figure 5 for Figure 4 A partial cross-sectional view of the cover plate and the sealing cover after welding in the illustrated embodiment;

[0037] Figure 6 is a cross-sectional view of an end cap assembly in another embodiment of the present application;

[0038] Figure 7 for Figure 6 A local enlarged view of point B in FIG.

[0039] Figure 8 for Figure 6A partial cross-sectional view of the cover plate and the sealing cover after welding in the illustrated embodiment;

[0040] Fig. 9 for Figure 8 A local enlarged view of point C in FIG.

[0041] Fig.10 is a cross-sectional view of an end cap assembly in another embodiment of the present application;

[0042] Fig.11 for Fig.10 A partial cross-sectional view of the cover plate and the sealing cover after welding in the illustrated embodiment;

[0043] Fig.12 for Fig.11 A local enlarged view of D in FIG.

[0044] Fig.13 This is a schematic diagram of the structure of a battery in one of the embodiments of the present application;

[0045] Fig.14 for Fig.13 A local enlarged view of point E in FIG.

[0046] Fig.15 This is a schematic diagram of the structure of a battery in another embodiment of the present application;

[0047] Fig.16 for Fig.15 A local enlarged view of point F in FIG.

[0048] Description of reference numerals: end cap assembly 100;

[0049] Cover plate 1; injection hole 11; first hole section 111; second hole section 112; sealing hole section 113; third hole section 1131; fourth hole section 1132; fifth hole section 114; first step surface 115; second step surface 116; third step surface 117; fourth step surface 118; first annular groove 12; welding protrusion 13; inner end surface 14; outer end surface 15;

[0050] Sealing cover 2; connecting portion 21; protruding portion 22; accommodating cavity 23; first end surface 24; second end surface 25; third end surface 26; boss 27; accommodating cavity 28; second annular groove 29;

[0051] Edge welding seam 3; adhesive layer 4; sealing member 5; sealing section 51; limiting section 52; battery 200. DETAILED DESCRIPTION

[0052] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0053] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present application, its application, or uses.

[0054] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0055] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0056] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0057] like Figure 1-Figure 12 As shown, according to the first aspect of the embodiment of the present application, an end cover assembly 100 is provided, including a cover plate 1 and a sealing cover 2, the cover plate 1 is provided with an injection hole 11, the injection hole 11 includes a first hole section 111, a second hole section 112 and a sealing hole section 113 with successively decreasing inner diameters, a first step surface 115 is formed between the first hole section 111 and the second hole section 112, and a second step surface 116 is formed between the second hole section 112 and the sealing hole section 113; the end of the sealing cover 2 close to the injection hole 11 includes a first end surface 24 and a second end surface 25, and the end of the sealing cover 2 away from the injection hole 11 is a third end surface 26; the sealing cover 2 is embedded in the injection hole 11, the first end surface 24 overlaps with the first step surface 115, the second end surface 25 overlaps with the second step surface 116, and the sealing cover 2 is welded to the cover plate 1 at the connection between the third end surface 26 and the cover plate.

[0058] An embodiment of the present application provides an end cap assembly 100 , which is configured to be used in a battery 200 .

[0059] like Figure 2 and Figure 4 As shown, the end cap assembly 100 includes a cover plate 1 and a sealing cover 2. The cover plate 1 is the top cover of the shell of the battery 200, and the cover plate 1 is provided with a liquid injection hole 11, which penetrates the thickness of the cover plate 1 itself, and electrolyte is injected into the battery 200 through the liquid injection hole 11. The sealing cover 2 is embedded in the liquid injection hole 11, and the sealing cover 2 and the cover plate 1 are fixed together by welding to perform secondary sealing on the liquid injection hole 11.

[0060] The cover plate 1 may be a metal plate, such as an aluminum plate, a steel plate, a copper plate or an iron plate.

[0061] The thickness of the cover plate 1 refers to the distance between the outer end surface 15 of the cover plate 1 and the inner end surface 14 of the cover plate 1 .

[0062] like Figure 2 , Figure 4 , Figure 6 and Fig.10 As shown, the injection hole 11 is a stepped hole. Along the direction from the outer end surface 15 of the cover plate 1 to the inner end surface 14 of the cover plate 1, the injection hole 11 includes a first hole section 111, a second hole section 112 and a sealing hole section 113 which are arranged in sequence. In other words, the first hole section 111 is close to the outer end surface 15 of the cover plate 1, the sealing hole section 113 is close to the inner end surface 14 of the cover plate 1, and the second hole section 112 is located between the first hole section 111 and the sealing hole section 113; the inner diameters of the first hole section 111, the second hole section 112 and the sealing hole section 113 decrease in sequence, in other words, the inner diameter of the first hole section 111 is larger than the inner diameter of the second hole section 112, and the inner diameter of the second hole section 112 is larger than the inner diameter of the sealing hole section 113; a first step surface 115 is formed between the first hole section 111 and the second hole section 112, and a second step surface 116 is formed between the second hole section 112 and the sealing hole section 113.

[0063] The end of the sealing cover 2 close to the injection hole 11 includes a first end face 24 and a second end face 25, and a boss 27 is formed between the first end face 24 and the second end face 25. The sealing cover 2 is embedded in the injection hole 11, the first end face 24 overlaps the first step face 115, the boss 27 is embedded in the second hole section 112, and the second end face 25 overlaps the second step face 116. The end of the sealing cover 2 away from the injection hole 11 is a third end face 26, and the sealing cover 2 and the cover plate 1 are welded at the third end face 26.

[0064] When the electrolyte is injected into the battery 200 through the injection hole 11, some electrolyte will remain on the step in the injection hole 11, which will cause the electrolyte remaining on the step in the injection hole 11 to produce fire or explosion points due to high temperature when the cover plate 1 and the sealing cover 2 are welded, thereby affecting the welding and further affecting the sealing performance and connection strength between the cover plate 1 and the sealing cover 2.

[0065] Therefore, the end cover assembly 100 provided in the present application forms a first step surface 115 and a second step surface 116 in the injection hole 11. When the electrolyte is injected into the battery 200, the first step surface 115 will be farther away from the interior of the battery 200 than the second step surface 116. After the electrolyte splashes out from the interior of the battery 200, it will usually remain on the second step surface 116, which can reduce or even prevent the electrolyte from splashing onto the first step surface 115. When the sealing cover 2 is embedded in the injection hole 11, the first end face 24 overlaps the first step surface 115, the boss 27 is located in the second hole section 112, and the second end face 25 overlaps the second step surface 116; when the sealing cover 2 and the cover plate 1 are welded at the connection between the third end face 26 and the cover plate 1, since the second end face 25 is separated from the third end face 26 by the first end face 24, the temperature at the second step surface 116 transmitted during welding can be reduced. If the electrolyte remaining at the second step surface 116 explodes due to high temperature, the boss 27 is embedded in the second hole section 112, and the second end face 25 overlaps the second step surface 116. The boss 27 will block the electrolyte from being transmitted to the welding position after the explosion, thereby avoiding affecting the welding position, thereby improving the welding quality, so as to improve the sealing performance and connection strength between the cover plate 1 and the sealing cover 2.

[0066] The cross-sections of the first hole section 111, the second hole section 112 and the sealing hole section 113 can be circular, rectangular, square or other shapes. The shapes of these cross-sections can be the same or different. The cross-section here refers to the cross-section perpendicular to the thickness direction of the cover plate 1 itself.

[0067] The inner diameters of the first hole segment 111, the second hole segment 112 and the sealing hole segment 113 decrease in sequence, which means that the cross-sectional area of ​​the first hole segment 111 is larger than the cross-sectional area of ​​the second hole segment 112, and the cross-sectional area of ​​the second hole segment 112 is larger than the cross-sectional area of ​​the sealing hole segment 113. The first hole segment 111, the second hole segment 112 and the sealing hole segment 113 are concentrically arranged.

[0068] In an optional embodiment, the third end face 26 is flush with or lower than the outer end face 15 of the cover plate 1. When the sealing cover 2 is welded to the cover plate 1, the third end face 26 is flush with or lower than the outer end face of the cover plate 1, so as to prevent the weld between the sealing cover 2 and the cover plate 1 from protruding from the outer end face of the cover plate 1, and when the battery 200 is wrapped with a blue film, the weld can be prevented from scratching the blue film.

[0069] In an optional implementation, the end cover assembly 100 further includes a sealing member 5 , and the sealing member 5 is at least partially embedded in the sealing hole section 113 and seals the sealing hole section 113 .

[0070] like Figure 2 , Figure 4 , Figure 6 and Fig.10 The end cap assembly 100 further includes a seal 5. Since the sealing hole section 113 is close to the inner end surface 14 of the cover plate 1, the seal 5 is embedded in the sealing hole section 113 to seal the injection hole 11 to prevent the electrolyte from leaking from the inside of the battery 200.

[0071] In an optional embodiment, the sealing cover 2 includes a protrusion 22 and a connecting portion 21, the protrusion 22 is connected to the connecting portion 21 and protrudes from the sealing cover in a direction away from the injection hole 11, and a receiving cavity 23 is formed inside the protrusion 22, and the sealing member 5 is partially embedded in the sealing hole section 113, and the portion protruding from the injection hole 11 is received in the receiving cavity 23.

[0072] like Figure 4 , Fig.10 , Fig.15 and Fig.16 As shown, the sealing cover 2 includes a protruding portion 22 and a connecting portion 21, the protruding portion 22 is connected to the connecting portion 21, the connecting portion 21 is annular, the protruding portion 22 is hollow columnar, the edge of one end of the protruding portion 22 is connected to the inner edge of the connecting portion 21, and the protruding portion 22 and the connecting portion 21 are cap-shaped; the protruding portion 22 protrudes in a direction away from the injection hole 11 and protrudes from the cover plate 1, and an accommodating cavity 23 is formed inside the protruding portion 22; the sealing member 5 is partially embedded in the sealing hole section 113 to perform primary sealing on the injection hole 11, and partially protrudes from the injection hole 11 to be accommodated in the accommodating cavity 23. In this embodiment, when the cover plate 1 and the sealing cover 2 are welded, when the air pressure in the sealed space formed between the sealing cover 1, the injection hole 11 and the sealing member 5 increases, the sealing member 5 will be squeezed so that the sealing member 5 moves toward the inner end surface 14 of the cover plate 1. When the portion of the sealing member 5 that is not embedded in the sealing hole section 113 protrudes from the injection hole 11, the sealing member 5 has enough margin to move toward the inner end surface 14 of the cover plate 1, thereby preventing the sealing member 5 from falling into the interior of the battery 200. In addition, while the sealing member 5 can seal the injection hole 11, the space occupied inside the battery 200 can be reduced, thereby increasing the space utilization rate inside the battery 200.

[0073] In an alternative embodiment, Figure 4 , Fig.10 , Fig.15 and Fig.16 As shown, the third end face 26 is located on the outer end face of the connecting portion 21. The connecting portion 21 is used to connect with the cover plate 1, and the third end face 26 is located on the outer end face of the connecting portion 21, which facilitates welding of the cover plate 1 and the sealing cover 2 at the connection.

[0074] like Figure 4 and Fig.10As shown, in an optional embodiment, the inner diameter of the sealing hole section 113 close to the inner end surface 14 of the cover plate 1 is smaller than the inner diameter of the sealing hole section 113 away from the inner end surface 14 of the cover plate 1; the inner diameter of the end of the sealing member 5 close to the inner end surface 14 of the cover plate 1 is smaller than the inner diameter of the end of the sealing member 5 away from the inner end surface 14 of the cover plate 1, the inner diameter of the end of the sealing member 5 away from the inner end surface 14 of the cover plate 1 is larger than the inner diameter of the side of the sealing hole section 113 away from the inner end surface 14 of the cover plate 1, and the inner diameter of the end of the sealing member 5 close to the inner end surface 14 of the cover plate 1 is smaller than the inner diameter of the side of the sealing hole section 113 close to the inner end surface 14 of the cover plate 1. The sealing member 5 is embedded in the sealing hole section 113, which can improve the sealing performance of the sealing hole section 113 on the one hand, and can also prevent the sealing member 5 from falling into the interior of the battery 200.

[0075] In an optional embodiment, a circle of limiting protrusions is provided at one end of the sealing member 5 close to the inner end surface 14 of the cover plate 1, and the inner diameter of the limiting protrusions is larger than the inner diameter of the sealing hole section 113 close to the inner end surface 14 of the cover plate 1. When the internal air pressure of the battery 200 increases, the limiting protrusions can prevent the sealing member 5 from falling off from the sealing hole section 113.

[0076] Preferably, the sealing member 5 may be made of rubber material, which has good elasticity, wear resistance and corrosion resistance.

[0077] In another optional embodiment, the sealing hole section 113 includes a third hole section 1131 and a fourth hole section 1132, the third hole section 1131 and the second hole section 112 form the second step surface 116, and the third hole section 1131 and the fourth hole section 1132 form the third step surface 117; the sealing member 5 includes a connected sealing section 51 and a limiting section 52, the lower surface of the limiting section 52 abuts against the third step surface 117, and the sealing section 51 is embedded in the fourth hole section 1132 and seals the fourth hole section 1132.

[0078] like Figure 2 and Figure 6As shown, the sealing hole section 113 includes a third hole section 1131 and a fourth hole section 1132, the third hole section 1131 and the second hole section 112 form a second step surface 116, and the third hole section 1131 and the fourth hole section 1132 form a third step surface 117; the sealing member 5 includes a sealing section 51 and a limiting section 52, the sealing section 51 is embedded in the fourth hole section 1132, and the lower surface of the limiting section 52 abuts against the third step surface 117 to perform primary sealing on the sealing hole section 113. In this embodiment, since the sealed space formed among the sealing cover 2, the cover plate 1 and the sealing member 5 is relatively small, when the cover plate 1 and the sealing cover 2 are welded, the air pressure in the sealed space formed among the sealing cover 2, the injection hole 11 and the sealing member 5 increases, and the sealing member 5 will be squeezed, thereby causing the sealing member 5 to move toward the inner end surface 14 of the cover plate 1. The lower surface of the limiting section 52 abuts against the third step surface 117, which can block the sealing member 5 from moving toward the inner end surface 14 of the cover plate 1, thereby preventing the sealing member 5 from falling into the interior of the battery 200; the structural strength of the sealing cover 2 can also be ensured; and the overall volume of the battery 200 can be reduced while ensuring that the sealing member 5 can seal the injection hole 11.

[0079] To further illustrate, the seal 5 includes a connected sealing section 51 and a limiting section 52. In one embodiment, the sealing section 51 and the limiting section 52 are integrally formed, and the sealing section 51 and the limiting section 52 are in a T-shaped structure; in this embodiment, the structure of the seal 5 is simple. In another embodiment, a connecting groove is provided inside the sealing section 51, and the limiting section 52 is in a T-shaped structure, and part of the limiting section 52 is embedded in the connecting groove and part is exposed from the connecting groove, so that the seal 5 still has a T-shaped structure; wherein, the sealing section 51 can be made of rubber material, and the limiting part can be made of metal material, rubber material or other hard materials; in this embodiment, the sealing effect of the seal 5 is better.

[0080] In the above embodiment, if Fig.15 and Fig.16 As shown, the third end face 26 of the sealing cover 2 is flush with or lower than the outer end face 15 of the cover plate 1, the second end face 26 is provided with a receiving cavity 28, and a gap is formed between the limiting portion and the top of the receiving cavity 28. Since the sealing member 5 is completely located in the injection hole 11, the overall volume of the battery 200 can be reduced. The gap formed between the limiting portion and the top of the receiving cavity 28 is conducive to the airtightness detection of the sealing cover 2 and the improvement of the safety of the battery 200.

[0081] like Figure 3 , Figure 5 , Figure 8 and Fig.11As shown, in an optional embodiment, the cover plate 1 is provided with a first annular groove 12 , and the sealing cover 2 and the cover plate 1 are connected by welding at the first annular groove 12 to form an edge weld 3 .

[0082] In the prior art, the sealing cover 2 and the cover plate 1 are usually connected by butt welding. Since the wall thickness of the sealing cover 2 is thinner and the wall thickness of the cover plate 1 is thicker, the thickness of the cover plate 1 is usually several times the thickness of the sealing cover 2. When laser welding is used for the sealing cover 2 and the cover plate 1, due to the large difference in wall thickness between the sealing cover 2 and the cover plate 1, the laser welding speed is fast and the instantaneous heat input is high, resulting in large welding residual stress and easy formation of microcracks and micropores in the weld.

[0083] The present application provides an end cap assembly 100, in which a first annular groove 12 is provided on the outer end surface 15 of the cover plate 1, and the first annular groove 12 is arranged concentrically with the injection hole 11. The cover plate 1 and the sealing cover 2 are welded in the first annular groove 12, and an edge weld 3 is formed. By changing the butt weld between the sealing cover 2 and the cover plate 1 to an edge weld 3, the melting amount can be increased, the flow and shrinkage compensation of the weld pool can be improved, the crack sensitivity can be reduced, and the yield rate of the first helium inspection can be improved; and the adaptability of different types of lasers can be increased, and conduction welding and deep fusion welding can be used to broaden the process adaptability; and the first annular groove 12 can reduce stress concentration, help release welding stress, and improve welding quality.

[0084] In an optional implementation, a welding protrusion 13 is formed between the first annular groove 12 and the first hole section 111 , and the welding protrusion 13 is at least partially melted to form the edge weld 3 with the sealing cover 2 .

[0085] like Figure 2 , Figure 4 , Figure 6 and Fig.10 Before the cover plate 1 and the sealing cover 2 are welded, a welding protrusion 13 is formed between the first annular groove 12 and the first hole section 111. The weld pool formed by the welding protrusion 13 is formed during welding. Figure 3 , Figure 5 , Figure 7 and Fig.10 As shown, the welding protrusion 13 is melted by high temperature, thereby increasing the melting amount of the molten pool to improve the flow and shrinkage compensation of the molten pool during welding, thereby reducing the occurrence of cracks in the weld, improving the welding quality, and enhancing the sealing performance and connection strength between the cover plate 1 and the sealing cover 2.

[0086] To further illustrate, the welding protrusion 13 can be partially melted or completely melted, and can be selected according to the gap spacing between the sealing cover 2 and the cover plate 1. If the gap between the sealing cover 2 and the cover plate 1 is large, a larger amount of the welding protrusion 13 needs to be melted to fill the gap between the sealing cover 2 and the cover plate 1, thereby improving the sealing performance and connection strength between the sealing cover 2 and the cover plate 1; if the gap between the sealing cover 2 and the cover plate 1 is small, a smaller amount of the welding protrusion 13 needs to be melted to fill the gap between the sealing cover 2 and the cover plate 1.

[0087] In an optional implementation, the thickness of the welding protrusion 13 is greater than, equal to, or less than the thickness of the sealing cover 2 .

[0088] like Figure 7 As shown, the thickness H1 of the welding protrusion 13 refers to the distance between the side wall of the first annular groove 12 close to the first hole segment 111 and the inner wall of the first hole segment 111 , which is the thickness of the welding protrusion 13 .

[0089] like Figure 7 As shown, the thickness H2 of the sealing cover 2 refers to the distance between the first end surface 24 and the third end surface 26 of the sealing cover 2 .

[0090] The thickness is equal, which can be the same thickness or similar thickness within the allowable error range in the mechanical field.

[0091] If the thickness of the welding protrusion 13 is greater than the thickness of the sealing cover 2 , it is beneficial to improve the connection firmness between the cover plate 1 and the sealing cover 2 .

[0092] If the thickness of the welding protrusion 13 is equal to the thickness of the sealing cover 2, it is convenient to transform the weld from a single butt weld to an edge weld 3. The welding protrusion 13 melts at high temperature during welding to increase the melting amount of the molten pool, improve the flow and shrinkage compensation of the molten pool during welding, and reduce the defect sensitivity; and it is beneficial to release the welding stress between the cover plate 1 and the sealing cover 2 during welding.

[0093] If the thickness of the welding protrusion 13 is smaller than the thickness of the sealing cover 2 , the edge welding structure can be achieved by adjusting the laser process parameters, so that the edge welding seam 3 formed between the sealing cover 2 and the cover plate 1 can have good sealing performance.

[0094] Preferably, the edge weld 3 is lower than the outer end face 15 of the cover plate 1. Since the outer surface of the battery 200 is covered with a layer of blue film, if the edge weld 3 protrudes from the outer end face 15 of the cover plate 1, the edge weld 3 will scratch the blue film when the blue film is covered. Therefore, making the edge weld 3 lower than the outer end face 15 of the cover plate 1 can prevent the edge weld 3 from scratching the blue film.

[0095] In a specific embodiment, the depth of the first hole section 111 is greater than the thickness of the sealing cover 2, and the depth of the second hole section 112 is the same as the thickness of the boss 27. The thickness of the boss 27 refers to the distance between the first end face 24 and the second end face 25. When the sealing cover 2 is embedded in the first hole section 111 and the second hole section 112, the boss 27 is embedded in the second hole section 112, and the third end face 26 is lower than the outer end face 15 of the cover plate 1. When the sealing cover 2 is welded to the cover plate 1, the edge weld 3 can be located in the first hole section 111. In other words, the edge weld 3 will not protrude from the outer end face 15 of the cover plate 1. When the battery 200 is wrapped with a blue film, the edge weld 3 is located in the first hole section 111, so that the edge weld 3 can be prevented from scratching the blue film.

[0096] In another specific embodiment, the injection hole 11 also includes a fifth hole segment 114, the first hole segment 111 is located between the fifth hole segment 114 and the second hole segment 112, the inner diameter of the fifth hole segment 114 is larger than the inner diameter of the first hole segment 111, the fifth hole segment 114 and the first hole segment 111 form a fourth step surface 118, the first annular groove 12 is opened on the fourth step surface 118, and the edging weld 3 is located in the fifth hole segment 114 or the first hole segment 111.

[0097] like Figure 6 and Fig.10 As shown, the injection hole 11 also includes a fifth hole segment 114, and the first hole segment 111 is located between the fifth hole segment 114 and the second hole segment 112. In other words, from the outer end surface 15 to the inner end surface 14 of the cover plate 1, the injection hole 11 sequentially includes the fifth hole segment 114, the first hole segment 111, the second hole segment 112 and the sealing hole segment 113, and the inner diameter of the fifth hole segment 114 is greater than the inner diameter of the first hole segment 111, and a fourth step surface 118 is formed between the fifth hole segment 114 and the first hole segment 111, and the first annular groove 12 is opened on the fourth step surface 118. At the first annular groove 12 of the fourth step surface 118, the sealing cover 2 and the cover plate 1 are welded together to form a rim weld 3, and the rim weld 3 is located in the fifth hole segment 114 or the first hole segment 111, so as to avoid the rim weld 3 protruding from the outer end surface 15 of the cover plate 1.

[0098] In an optional implementation, the third end surface 26 is flush with the fourth step surface 118. When the sealing cover 2 and the cover plate 1 are welded, it is possible to avoid the formation of a step between the sealing cover 2 and the cover plate 1 to affect the welding, thereby improving the welding quality.

[0099] In an alternative embodiment, Figure 8 and Fig.11As shown, an adhesive layer 4 is provided at the edge weld 3. In order to improve the sealing performance and connection strength between the cover plate 1 and the sealing cover 2, an adhesive layer 4 is provided at the edge weld 3, that is, after the cover plate 1 and the sealing cover 2 are welded to form the edge weld 3, a layer of adhesive is applied at the edge weld 3, and the adhesive forms the adhesive layer 4, so as to improve the sealing performance and connection strength between the cover plate 1 and the sealing cover 2 through the adhesive layer 4.

[0100] To further illustrate, the first annular groove 12 can provide a location for accommodating the overflow of glue when the adhesive layer 4 is coated with glue, which is beneficial for scraping the glue.

[0101] In the implementation mode where the edging weld 3 is located in the first hole segment 111 or the fifth hole segment 114, the adhesive layer 4 is also located in the first hole segment 111 or the fifth hole segment 114. After the surface of the edging weld 3 is coated with glue, the adhesive layer 4 is located in the first hole segment 111 or the fifth hole segment 114, so the adhesive layer 4 does not affect the blue film on the outer surface of the battery 200.

[0102] In an optional implementation, at least one second annular groove 29 is formed on the third end surface 26 .

[0103] To further explain, the third end surface 26 is provided with a second annular groove 29 , and the number of the second annular grooves 29 may be one, two, or three.

[0104] Preferably, if Figure 2 , Figure 4 , Figure 6 and Fig.10 The third end surface 26 is provided with a second annular groove 29, which works together with the first annular groove 12 to increase the heat dissipation area during welding, reduce the poor heat dissipation caused by the large difference in wall thickness at the weld, reduce stress concentration, reduce the sensitivity of micropores and microcracks, so as to improve the welding quality, enhance the sealing performance and connection strength between the cover plate 1 and the sealing cover 2. It can also ensure the self strength of the sealing cover 2.

[0105] In the case of 4 and Fig.10 In the illustrated embodiment, the third end face 26 is located on the outer end face of the connecting portion 21, that is, the second annular groove 29 is provided on the outer end face of the connecting portion 21. Compared with the second annular groove 29 provided on the outer end face of the protruding portion 22, the second annular groove 29 is closer to the welding point, thereby increasing the heat dissipation speed and being able to quickly release welding stress, thereby reducing poor heat dissipation caused by the large difference in wall thickness at the weld, reducing stress concentration, and reducing the sensitivity to micropores and microcracks, thereby improving welding quality.

[0106] In an optional embodiment, the second annular groove 29 is disposed opposite to the second end face 25. The second annular groove 29 extends toward the injection hole 11 and is disposed opposite to the second end face 25, which can increase the depth of the second annular groove 29 without affecting the structural strength of the sealing cover 2.

[0107] According to a second aspect of an embodiment of the present application, a battery 200 is provided, comprising the above-mentioned end cover assembly 100.

[0108] The end cap assembly 100 of the embodiment of the present application can be applied to various types of battery 200 cells.

[0109] The battery 200 may include a lithium-ion secondary battery, a lithium-ion primary battery, a lithium-sulfur battery, a sodium-lithium-ion battery, a sodium-ion battery, or a magnesium-ion battery, etc., which is not limited in the embodiments of the present disclosure. The battery 200 may be cylindrical, flat, rectangular, or in other shapes, which is not limited in the embodiments of the present disclosure.

[0110] According to a third aspect of an embodiment of the present application, there is provided a battery pack, comprising the above-mentioned end cover assembly 100; or comprising the above-mentioned battery 200.

[0111] The battery 200 of the embodiment of the present application can be applied to various types of battery packs.

[0112] The battery pack can be used to power electrical equipment such as vehicles, for example, to provide power for vehicle operation or driving.

[0113] According to a fourth aspect of the embodiments of the present application, there is provided an electrical device, comprising the above-mentioned end cover assembly 100; or comprising the above-mentioned battery 200; or comprising the above-mentioned battery pack.

[0114] The battery pack of the embodiment of the present application can be applied to various types of electrical equipment using batteries.

[0115] The electrical equipment may be a battery vehicle, an electric vehicle, a ship, a spacecraft, etc. The embodiments of the present disclosure do not impose any particular restrictions on the above-mentioned electrical equipment.

[0116] Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are only for illustration, not for limiting the scope of the present application. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. An end cap assembly, characterized in that: include: A cover plate, wherein the cover plate is provided with a liquid injection hole, wherein the liquid injection hole comprises a first hole section, a second hole section and a sealing hole section with inner diameters decreasing in sequence, a first step surface is formed between the first hole section and the second hole section, and a second step surface is formed between the second hole section and the sealing hole section; A sealing cover, wherein one end of the sealing cover close to the liquid injection hole comprises a first end surface and a second end surface, and one end of the sealing cover away from the liquid injection hole is a third end surface; The sealing cover is embedded in the injection hole, the first end surface overlaps the first step surface, the second end surface overlaps the second step surface, and the sealing cover and the cover plate are welded at the connection between the third end surface and the cover plate.

2. The end cap assembly according to claim 1, characterized in that: The third end surface is flush with or lower than the outer end surface of the cover plate.

3. The end cap assembly according to claim 1, characterized in that: The end cover assembly further comprises a sealing member, which is at least partially embedded in the sealing hole section and seals the sealing hole section.

4. The end cap assembly according to claim 3, characterized in that: The sealing hole segment comprises a third hole segment and a fourth hole segment, the third hole segment and the second hole segment form the second step surface, and the third hole segment and the fourth hole segment form a third step surface; The sealing member comprises a sealing section and a limiting section which are connected to each other. The lower surface of the limiting section abuts against the third step surface. The sealing section is embedded in the fourth hole section and seals the fourth hole section.

5. The end cap assembly according to claim 3, characterized in that: The sealing cover includes a protruding portion and a connecting portion, wherein the protruding portion is connected to the connecting portion and protrudes from the cover plate in a direction away from the injection hole, and an accommodating cavity is formed inside the protruding portion, and a portion of the sealing member protruding from the injection hole is accommodated in the accommodating cavity.

6. The end cap assembly according to claim 5, characterized in that: The third end surface is located at the outer end surface of the connecting portion.

7. The end cap assembly according to any one of claims 1 to 6, characterized in that: The cover plate is provided with a first annular groove, and the sealing cover and the cover plate form an edge welding seam at the first annular groove.

8. The end cap assembly according to claim 7, characterized in that: A welding protrusion is formed between the first annular groove and the first hole segment. The welding protrusion is at least partially melted to form the edge welding seam with the sealing cover.

9. The end cap assembly according to claim 7, characterized in that: The injection hole also includes a fifth hole segment, the first hole segment is located between the fifth hole segment and the second hole segment, the inner diameter of the fifth hole segment is larger than the inner diameter of the first hole segment, the fifth hole segment and the first hole segment form a fourth step surface, the first annular groove is opened on the fourth step surface, and the edging weld is located in the fifth hole segment or the first hole segment.

10. The end cap assembly according to claim 9, characterized in that: The third end surface is flush with the fourth step surface.

11. The end cap assembly according to claim 7, characterized in that: An adhesive layer is provided at the edge welding seam.

12. The end cap assembly according to claim 7, characterized in that: At least one second annular groove is formed on the third end surface.

13. A battery, characterized in that: Comprising the end cover assembly according to any one of claims 1-12.

14. A battery pack, characterized in that: comprising an end cap assembly as claimed in any one of claims 1 to 12; or Comprising the battery of claim 13.

15. An electrical equipment, characterized in that: comprising an end cap assembly as claimed in any one of claims 1 to 12; or comprising a battery as claimed in claim 13; or Comprising the battery pack as claimed in claim 14.

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