Cover plate assembly and battery cell

Abstract

The utility model provides a cover plate assembly and a battery cell, the cover plate assembly comprises: a cover plate body for cooperating with a shell of the battery cell, at least part of the edge of the cover plate body being located in the outer contour of the shell; a lug boss facing an electrode assembly of the battery cell is arranged on one side of the cover plate body along the thickness direction of the cover plate body, and a groove corresponding to the lug boss is formed in one side, far away from the electrode assembly, of the cover plate body; a welding part is arranged on the outer edge of the protruding part and used for sealing the shell. The thickness of the welding part is smaller than or equal to the thickness of a base body of the cover plate body, and the width of the welding part is smaller than or equal to the thickness of the side wall of the shell. The cover plate assembly and the battery cell provided by the utility model are simple in structure and convenient to manufacture, the cover plate assembly can effectively prevent the blue film wrapping the battery cell from being scratched, and the energy density and stability of the battery cell are ensured.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a cover plate assembly and a battery cell. Background Technology

[0002] With the continuous development of the new energy industry, higher requirements are being placed on batteries. As a crucial component of the battery structure, the cover plate assembly has also undergone several rounds of development. Currently, steel is used to manufacture cover plate assemblies to improve battery safety. However, during the stamping process, steel can easily form a raised rib around the edge of the cover plate assembly, which can easily tear the blue film covering the battery cell. Alternatively, when the cover plate assembly is fitted to the casing, its edges may bulge out of the casing, also easily tearing the blue film and reducing the external insulation performance of the battery cell. Therefore, there is an urgent need for a cover plate assembly that can avoid tearing the blue film. Utility Model Content

[0003] In view of this, the purpose of this application is to provide a cover plate assembly and a battery cell to solve the related problems mentioned in the background art.

[0004] A first aspect of this application provides a cover plate assembly, comprising: a cover plate body for cooperating with a housing of a battery cell, wherein at least a portion of the edge of the cover plate body is located within the outer contour of the housing; a protrusion facing an electrode assembly of the battery cell is provided on one side of the cover plate body along its thickness direction, and a groove corresponding to the protrusion is provided on the side of the cover plate body away from the electrode assembly; a welding portion is provided on the outer edge of the protrusion, the welding portion being used to seal the housing; the thickness of the welding portion is less than or equal to the base thickness of the cover plate body, and the width of the welding portion is less than or equal to the sidewall thickness of the housing.

[0005] Furthermore, the protrusion has a first sidewall perpendicular to the weld on the side near the weld, and the first sidewall is used to abut against the inner sidewall of the housing.

[0006] Furthermore, the distance between the end of the protrusion away from the welded part and the welded part is greater than or equal to 0.5 mm; the length of the first sidewall along the thickness direction is greater than or equal to 0.1 mm and less than or equal to 5 mm, and the wall thickness of at least a portion of the first sidewall is less than or equal to the base thickness of the cover plate body.

[0007] Furthermore, the first sidewall has an inlet portion at the end away from the weld portion, the inlet portion being used to guide the protrusion into the housing.

[0008] Furthermore, the cover plate assembly further includes a lower insulating member located between the cover plate body and the electrode assembly, wherein the orthographic projection of the lower insulating member on the cover plate assembly at least partially covers the protrusion; and / or, the protrusion has an ejector portion at one end near the electrode assembly, the ejector portion being used to cooperate with the lower insulating member.

[0009] Furthermore, a first transition portion is provided on the edge of the welding portion away from the electrode assembly; a second transition portion is provided at the end of the first sidewall near the welding portion; a third transition portion is provided on the outer edge of the groove, and a fourth transition portion is provided on the inner edge; the side of the groove near the protrusion is the bottom of the groove, a fifth transition portion is provided at the end of the bottom of the groove near the first sidewall, and a sixth transition portion is provided at the end away from the first sidewall; the side of the protrusion away from the welding portion is the second sidewall, a seventh transition portion is provided at the end of the second sidewall near the cover plate body, and an eighth transition portion is provided at the end of the second sidewall away from the cover plate body.

[0010] Furthermore, the inlet portion, the first transition portion, the second transition portion, the third transition portion, the fourth transition portion, the fifth transition portion, the sixth transition portion, the seventh transition portion, and the eighth transition portion all have rounded corners. The radius of the rounded corners of the inlet portion is 0.1mm to 5mm, the radius of the rounded corners of the first transition portion is 0.05mm to 3mm, the radius of the rounded corners of the second transition portion is 0.05mm to 2mm, the radius of the rounded corners of the third transition portion is 0.1mm to 5mm, the radius of the rounded corners of the fourth transition portion is 0.1mm to 5mm, the radius of the rounded corners of the fifth transition portion is 0.05mm to 3mm, the radius of the rounded corners of the sixth transition portion is 0.05mm to 3mm, the radius of the rounded corners of the seventh transition portion is 0.05mm to 3mm, and the radius of the rounded corners of the eighth transition portion is 0.1mm to 5mm.

[0011] Further, the fillet radius of the inlet portion is 0.7 mm, the fillet radius of the first transition portion is 0.05 mm, the fillet radius of the second transition portion is 0.1 mm, the fillet radius of the third transition portion is 0.8 mm, the fillet radius of the fourth transition portion is 0.8 mm, the fillet radius of the fifth transition portion is 0.4 mm, the fillet radius of the sixth transition portion is 0.4 mm, the fillet radius of the seventh transition portion is 0.2 mm, and the fillet radius of the eighth transition portion is 0.9 mm; the width of the ejector portion is 0.9 mm, the thickness of the welded portion is 0.8 mm, the length of the first sidewall along the thickness direction is 0.6 mm, and the distance between the side of the ejector portion away from the welded portion and the side of the welded portion away from the ejector portion is 2.1 mm.

[0012] In a second aspect of this application, a battery cell is provided, including a housing, the housing being welded to a welded portion of a cover plate assembly as described in the first aspect above, and an electrode assembly being disposed inside the housing.

[0013] Furthermore, after the welded portion is welded to the housing, a molten pool is formed inside the welded portion that is recessed toward the groove, the molten pool being spaced apart from the groove; and / or, a weld transition portion is formed on the edge of the welded portion away from the electrode assembly.

[0014] As can be seen from the above description, the cover plate assembly and battery cell provided in this application include a cover plate body for mating with the housing of the battery cell. At least a portion of the edge of the cover plate body is located within the outer contour of the housing. A protrusion facing the electrode assembly of the battery cell is provided on one side of the cover plate body along its thickness direction, and a groove corresponding to the protrusion is provided on the side of the cover plate body away from the electrode assembly. A welding portion is provided on the outer edge of the protrusion, which is used to seal the housing. The thickness of the welding portion is less than or equal to the base thickness of the cover plate body, and the width of the welding portion is less than or equal to the sidewall thickness of the housing. By forming a groove in the cover plate assembly, a capacity space is provided for material movement during the stamping process, avoiding the formation of protruding ribs at the edges. By setting at least a portion of the edge of the cover plate body to be located within the outer contour of the housing, and the width of the welding portion being less than or equal to the sidewall thickness of the housing, redundant space is provided at the mating point when the cover plate assembly mates with the housing. Even if the cover plate body is squeezed by the housing, it will not protrude from the housing, resulting in good overall flatness. This effectively avoids tearing the blue film covering the battery cell, providing good insulation performance. The cover plate assembly and the battery cell have a simple structure and are easy to manufacture. The cover plate assembly can effectively prevent the blue film covering the battery cell from being scratched, thus ensuring the energy density and stability of the battery cell. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a three-dimensional structural diagram of a cover plate assembly according to an embodiment of this application;

[0017] Figure 2 for Figure 1 Top view of the middle cover assembly and the housing;

[0018] Figure 3 This is a schematic diagram of a partial cross-section of a cover plate assembly and its corresponding housing.

[0019] Figure 4 This is a partial cross-sectional schematic diagram of another cover plate assembly in an embodiment of this application;

[0020] Figure 5 for Figure 4 A partial cross-sectional schematic diagram of the welding between the middle cover plate assembly and the shell.

[0021] Reference numerals: 1. Cover plate body; 2. Housing; 3. Electrode assembly; 4. Groove; 4-1. Third transition section; 4-2. Fourth transition section; 4-3. Fifth transition section; 4-4. Sixth transition section; 5. Protrusion; 5-1. First side wall; 5-2. Inlet section; 5-3. Outlet section; 5-4. Second transition section; 5-5. Second side wall; 5-6. Seventh transition section; 5-7. Eighth transition section; 6. Welding section; 6-1. First transition section; 6-2. Molten pool; 6-3. Welding transition section; 7. Lower insulating component. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0023] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0024] With the continuous development of the new energy industry, higher requirements are being placed on batteries. As a crucial component of the battery structure, the cover plate assembly has undergone several rounds of development. Currently, to improve the energy density and cell safety of rechargeable batteries, attention is increasingly focused on steel. For batteries of the same model, cells made of steel can achieve a cell energy density increase of over 3% compared to those made of aluminum. However, because steel is 2-3 times harder than aluminum, it is not easily thinned during the stamping process. When stamping steel into cover plate assemblies, a raised rib easily appears around the perimeter. This rib makes it easy to tear the blue film when the cell is wrapped, reducing the cell's external insulation performance. Furthermore, when the cover plate assembly is fitted to the casing, the edges of the cover plate assembly protrude from the casing, also easily tearing the blue film and reducing the cell's external insulation performance. Therefore, there is an urgent need for a cover plate assembly that can prevent tearing of the blue film.

[0025] The following describes specific embodiments in conjunction with the appendix. Figure 1 and Figure 5 The technical solution of this application will be described in further detail.

[0026] In some embodiments of this application, a cover plate assembly is provided, including: a cover plate body 1 for cooperating with a housing 2 of a battery cell, wherein at least a portion of the edge of the cover plate body 1 is located within the outer contour of the housing 2; a protrusion 5 is provided on one side of the cover plate body 1 along its thickness direction, facing the electrode assembly 3 of the battery cell, and a groove 4 corresponding to the protrusion 5 is provided on the side of the cover plate body 1 away from the electrode assembly 3; a welding portion 6 is provided on the outer edge of the protrusion 5, the welding portion 6 being used to seal the housing 2; the thickness of the welding portion 6 is less than or equal to the base thickness of the cover plate body 1, and the width of the welding portion 6 is less than or equal to the sidewall thickness of the housing 2.

[0027] like Figure 1 The diagram shows a schematic of a cover plate assembly. In the diagram, the L direction is the length direction of the cover plate body 1, and the W direction is the width direction of the cover plate body 1. The cover plate body 1 is, for example, a steel plate, which can be welded to the housing 2 to protect the internal electrode assembly 3.

[0028] like Figure 2 As shown, this is a top view of the cover plate body 1 and the housing 2. At least a portion of the edge of the cover plate body 1 is located within the outer contour of the housing 2. For example, at least one long side or short side of the cover plate body 1 is located within the outer contour of the housing 2, or all the long and short sides of the cover plate body 1 are located within the outer contour of the housing 2, or a portion of the edge of the long or short side of the cover plate body 1 is located within the outer contour of the housing 2. The specific details are not limited.

[0029] like Figure 3 As shown, Figure 1The diagram shows a cross-sectional view of the cover plate assembly and the housing 2, where direction T represents the thickness direction of the cover plate body 1. A protrusion 5 facing the electrode assembly 3 is provided on one side of the cover plate body 1 along its thickness direction, and a groove 4 corresponding to the protrusion 5 is provided on the side of the cover plate body 1 away from the electrode assembly 3. For example, the edge of the cover plate body 1 can be stretched towards the electrode assembly 3 and then away from the electrode assembly 3, simultaneously forming the protrusion 5 and the groove 4. This process is simple and easy to manufacture.

[0030] The cross-sectional shapes of the protrusion 5 and the groove 4 are matched. The cross-sectional shape of the protrusion 5 can be arc-shaped, trapezoidal, or V-shaped, etc. Both the protrusion 5 and the groove 4 are spaced apart from the edge of the cover plate body 1, and can extend circumferentially along the edge of the cover plate body 1 to form a ring structure. By forming the groove 4 in the cover plate assembly, a capacity space can be provided for material movement during the stamping process of the cover plate assembly, avoiding the formation of ribs at the edge. The protrusion 5 can abut against the inner wall of the housing 2, playing a limiting and supporting role, and strengthening the cover plate body 1.

[0031] like Figure 3 As shown, the outer edge of the protrusion 5 is provided with a welding part 6, which is used to seal the housing 2. The thickness of the welding part 6 is less than or equal to the base thickness of the cover plate body 1, which is the thickness of the main body of the cover plate body 1. This setting can meet the requirements of the stretching process.

[0032] By setting at least a portion of the edge of the cover plate body 1 to be located within the outer contour of the housing 2, and the width of the welded part 6 to be less than or equal to the side wall thickness of the housing 2, redundant space is provided at the mating point when the cover plate assembly mates with the housing 2. Even if the cover plate body 1 is squeezed by the housing 2, it will not protrude from the housing 2, resulting in good overall flatness. This effectively avoids tearing the blue film covering the battery cell, resulting in good insulation performance.

[0033] The cover plate assembly has a simple structure and is easy to manufacture. It can effectively prevent the blue film covering the battery cell from being scratched, thus ensuring the energy density and stability of the battery cell.

[0034] In some embodiments, the protrusion 5 has a first sidewall 5-1 perpendicular to the weld 6 on the side near the weld 6, and the first sidewall 5-1 is used to abut against the inner sidewall of the housing 2.

[0035] like Figure 4 As shown, a cross-sectional schematic diagram of another cover plate assembly is provided. The protrusion 5 is provided with a first sidewall 5-1 perpendicular to the welding part 6 on the side near the welding part 6. The first sidewall 5-1 is used to abut against the inner sidewall of the housing 2, so as to facilitate the fit with the housing 2 and ensure the overall flatness and structural stability of the battery cell.

[0036] In some embodiments, the distance between the end of the protrusion 5 away from the welded portion 6 and the welded portion 6 is greater than or equal to 0.5 mm; the length of the first sidewall 5-1 along the thickness direction is greater than or equal to 0.1 mm and less than or equal to 5 mm, and the wall thickness of at least a portion of the first sidewall 5-1 is less than or equal to the base thickness of the cover plate body 1.

[0037] The distance between the end of the protrusion 5 away from the welding part 6 and the welding part 6 is greater than or equal to 0.5 mm, for example, the distance is 0.5 mm, 1 mm, 2 mm, 5 mm or 10 mm, etc., and there is no specific limitation, to ensure the strength of the cover plate body 1; the length of the first side wall 5-1 along the thickness direction is greater than or equal to 0.1 mm and less than or equal to 5 mm, for example, the length is 0.1 mm, 1 mm, 2 mm or 5 mm, etc., so that it can be stably matched with the shell 2; at least a part of the wall thickness of the first side wall 5-1 is less than or equal to the base thickness of the cover plate body 1, which can meet the requirements of the stretching process.

[0038] In some embodiments, the first sidewall 5-1 is provided with an inlet portion 5-2 at one end away from the welding portion 6, and the inlet portion 5-2 is used to guide the protrusion 5 into the housing 2.

[0039] like Figure 4 As shown, the first sidewall 5-1 has an inlet 5-2 at the end away from the welding part 6. The inlet 5-2 is, for example, a chamfer, a rounded corner or an inclined angle, etc., which is not limited to any specific feature. It facilitates the guidance of the protrusion 5 into the housing 2, so as to realize the assembly of the cover plate assembly and the housing 2.

[0040] In some embodiments, the cover plate assembly further includes a lower insulating member 7, which is located between the cover plate body 1 and the electrode assembly 3. The orthographic projection of the lower insulating member 7 on the cover plate assembly at least partially covers the protrusion 5; and / or, the protrusion 5 has an ejector portion 5-3 at one end near the electrode assembly 3, which is used to cooperate with the lower insulating member 7.

[0041] like Figure 4 As shown, the cover assembly also includes a lower insulating member 7, which is, for example, a plastic part, to prevent the cover body 1 from contacting the electrode assembly 3 and causing a short circuit in the battery cell. The orthogonal projection of the lower insulating member 7 on the cover assembly at least partially covers the protrusion 5, serving as a barrier and limiting element.

[0042] like Figure 4 As shown, the protrusion 5 has an ejector portion 5-3 at one end near the electrode assembly 3. The ejector portion 5-3 is, for example, a flat area, which can cooperate with the lower insulating member 7 to limit the position while improving space utilization.

[0043] In some embodiments, a first transition portion 6-1 is provided on the edge of the welding portion 6 away from the electrode assembly 3; a second transition portion 5-4 is provided on the end of the first sidewall 5-1 near the welding portion 6; a third transition portion 4-1 is provided on the outer edge of the groove 4, and a fourth transition portion 4-2 is provided on the inner edge; the side of the groove 4 near the protrusion 5 is the bottom of the groove, a fifth transition portion 4-3 is provided on the end of the bottom of the groove near the first sidewall 5-1, and a sixth transition portion 4-4 is provided on the end away from the first sidewall 5-1; the side of the protrusion 5 away from the welding portion 6 is the second sidewall 5-5, a seventh transition portion 5-6 is provided on the end of the second sidewall 5-5 near the cover plate body 1, and an eighth transition portion 5-7 is provided on the end away from the cover plate body 1.

[0044] like Figure 4 As shown, a first transition portion 6-1 is provided on the edge of the welding portion 6 away from the electrode assembly 3 to prevent the welding portion 6 from scratching the blue film at that location.

[0045] The first sidewall 5-1 has a second transition part 5-4 at one end near the welding part 6, which can smoothly transition and avoid damage to the protrusion 5.

[0046] The outer edge of the groove 4 is provided with a third transition part 4-1, and the inner edge is provided with a fourth transition part 4-2, which can smoothly transition and avoid damage to the groove 4.

[0047] The side of the groove 4 near the protrusion 5 is the bottom of the groove. The end of the groove bottom near the first side wall 5-1 is provided with a fifth transition part 4-3, and the end away from the first side wall 5-1 is provided with a sixth transition part 4-4, which can smoothly transition and avoid damage to the groove 4.

[0048] The side of the protrusion 5 away from the welded part 6 is the second sidewall 5-5. The second sidewall 5-5 can be inclined, and there is no specific limitation. The end of the second sidewall 5-5 near the cover plate body 1 is provided with a seventh transition part 5-6, which can make a smooth transition and avoid damage to the protrusion 5. The end of the second sidewall 5-5 away from the cover plate body 1 is provided with an eighth transition part 5-7 to avoid damage to other components.

[0049] Each transition section can be set as a rounded corner, chamfered corner, or have its corners cleared; there are no specific limitations.

[0050] In some embodiments, the inlet portion 5-2, the first transition portion 6-1, the second transition portion 5-4, the third transition portion 4-1, the fourth transition portion 4-2, the fifth transition portion 4-3, the sixth transition portion 4-4, the seventh transition portion 5-6, and the eighth transition portion 5-7 are all rounded corners. The radius of the rounded corner of the inlet portion 5-2 is 0.1 mm to 5 mm, the radius of the rounded corner of the first transition portion 6-1 is 0.05 mm to 3 mm, the radius of the rounded corner of the second transition portion 5-4 is 0.05 mm to 2 mm, the radius of the rounded corner of the third transition portion 4-1 is 0.1 mm to 5 mm, the radius of the rounded corner of the fourth transition portion 4-2 is 0.1 mm to 5 mm, the radius of the rounded corner of the fifth transition portion 4-3 is 0.05 mm to 3 mm, the radius of the rounded corner of the sixth transition portion 4-4 is 0.05 mm to 3 mm, the radius of the rounded corner of the seventh transition portion 5-6 is 0.05 mm to 3 mm, and the radius of the rounded corner of the eighth transition portion 5-7 is 0.1 mm to 5 mm.

[0051] The fillet radius of the inlet section 5-2 is, for example, 0.1mm, 0.5mm, 1mm, 3mm, or 5mm; the fillet radius of the first transition section 6-1 is, for example, 0.05mm, 0.1mm, 0.5mm, 1mm, or 3mm; the fillet radius of the second transition section 5-4 is, for example, 0.05mm, 0.1mm, 0.5mm, 1mm, or 2mm; the fillet radius of the third transition section 4-1 is, for example, 0.1mm, 0.5mm, 1mm, 3mm, or 5mm; and the fillet radius of the fourth transition section 4-2 is, for example, 0.1mm, 0.5mm, 1mm, 3mm, or 5mm. The fillet radii of the fifth transition section 4-3 are, for example, 0.05mm, 0.1mm, 0.5mm, 1mm, or 3mm; the fillet radii of the sixth transition section 4-4 are, for example, 0.05mm, 0.1mm, 0.5mm, 1mm, or 3mm; the fillet radii of the seventh transition section 5-6 are, for example, 0.05mm, 0.1mm, 0.5mm, 1mm, or 3mm; and the fillet radii of the eighth transition section 5-7 are, for example, 0.1mm, 0.5mm, 1mm, 3mm, or 5mm.

[0052] By limiting the radius of the rounded corners, we can avoid making the radius too large, which would reduce space utilization, and also avoid making the radius too small, which would make it difficult to manufacture.

[0053] In some embodiments, the fillet radius of the inlet portion 5-2 is 0.7 mm, the fillet radius of the first transition portion 6-1 is 0.05 mm, the fillet radius of the second transition portion 5-4 is 0.1 mm, the fillet radius of the third transition portion 4-1 is 0.8 mm, the fillet radius of the fourth transition portion 4-2 is 0.8 mm, the fillet radius of the fifth transition portion 4-3 is 0.4 mm, the fillet radius of the sixth transition portion 4-4 is 0.4 mm, the fillet radius of the seventh transition portion 5-6 is 0.2 mm, and the fillet radius of the eighth transition portion 5-7 is 0.9 mm; the width of the ejector portion 5-3 is 0.9 mm, the thickness of the welding portion 6 is 0.8 mm, the length of the first sidewall 5-1 along the thickness direction is 0.6 mm, and the distance between the side of the ejector portion 5-3 away from the welding portion 6 and the side of the welding portion 6 away from the ejector portion 5-3 is 2.1 mm. The cover plate assembly has a stable structure and good flatness.

[0054] In some embodiments of this application, a battery cell is provided, including a housing 2, which is welded to a welding portion 6 of a cover plate assembly as described in any of the above embodiments, and an electrode assembly 3 is provided inside the housing 2.

[0055] The housing 2 is, for example, a steel housing, welded to the cover plate assembly. This battery cell boasts high stability and can be applied to various electrical devices, including vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles. Spacecraft include airplanes, rockets, space shuttles, and spacecraft. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers.

[0056] In some embodiments, after the welding part 6 is welded to the housing 2, a molten pool 6-2 is formed inside the welding part 6 that is recessed toward the groove 4, and the molten pool 6-2 is spaced apart from the groove 4; and / or, a welding transition part 6-3 is formed on the edge of the welding part 6 away from the electrode assembly 3.

[0057] like Figure 5 The diagram shows a cross-sectional view of a battery cell after welding. After the welding part 6 is welded to the shell 2, a molten pool 6-2 is formed inside the welding part 6, which is recessed towards the groove 4. The molten pool 6-2 refers to the portion of the base material that melts into a pool shape due to the heat of the welding arc. The molten pool 6-2 is spaced apart from the groove 4 to avoid penetrating the groove 4 and damaging the cover plate assembly.

[0058] like Figure 5As shown, after the welding part 6 is welded to the housing 2, a welding transition part 6-3 is formed on the edge of the welding part 6 away from the electrode assembly 3. The welding transition part 6-3 is, for example, an arc-shaped rounded corner that covers the welding part 6. This ensures the connection effect and avoids scratching the blue film.

[0059] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this application is limited to these examples; under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the embodiments of this application as described above, which are not provided in detail for the sake of brevity.

[0060] Furthermore, given that details have been set forth to describe exemplary embodiments of this application, it will be apparent to those skilled in the art that embodiments of this application may be practiced without these details or with variations thereof. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0061] Although this application has been described in conjunction with embodiments thereof, many substitutions, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description.

[0062] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of this application.

Claims

1. A cover plate assembly, characterized by The cover plate assembly comprises: a cover plate body configured to cooperate with a housing of a battery cell, at least a part of an edge of the cover plate body being located within an outer contour of the housing; a protrusion is provided on one side of the cover plate body along a thickness direction of the cover plate body, the protrusion being configured to face an electrode assembly of the battery cell, and a groove corresponding to the protrusion is provided on a side of the cover plate body away from the electrode assembly; an outer edge of the protrusion is provided with a welding portion, the welding portion being configured to seal the housing; a thickness of the welding portion is less than or equal to a base thickness of the cover plate body, and a width of the welding portion is less than or equal to a thickness of a side wall of the housing.

2. The cover plate assembly of claim 1, wherein, a first side wall of the protrusion is provided on a side of the protrusion close to the welding portion, the first side wall being configured to abut an inner side wall of the housing.

3. The cover plate assembly of claim 2, wherein, a distance between an end of the protrusion away from the welding portion and the welding portion is greater than or equal to 0.5 mm; a length of the first side wall along the thickness direction is greater than or equal to 0.1 mm and less than or equal to 5 mm, and a wall thickness of at least a part of the first side wall is less than or equal to the base thickness of the cover plate body.

4. The cover plate assembly of claim 3, wherein, an introduction portion is provided on an end of the first side wall away from the welding portion, the introduction portion being configured to guide the protrusion into the housing.

5. The cover plate assembly of claim 4, wherein, the cover plate assembly further comprises a lower insulating member located between the cover plate body and the electrode assembly, a normal projection of the lower insulating member on the cover plate assembly at least partially covers the protrusion; and / or, an ejection portion is provided on an end of the protrusion close to the electrode assembly, the ejection portion being configured to cooperate with the lower insulating member.

6. The cover plate assembly of claim 5, wherein, a first transition portion is provided on a side edge of the welding portion away from the electrode assembly; a second transition portion is provided on an end of the first side wall close to the welding portion; a third transition portion is provided on an outer edge of the groove, and a fourth transition portion is provided on an inner edge of the groove; a bottom of the groove close to the protrusion is provided with a fifth transition portion on an end close to the first side wall and a sixth transition portion on an end away from the first side wall; a second side wall of the protrusion away from the welding portion is provided with a seventh transition portion on an end close to the cover plate body and an eighth transition portion on an end away from the cover plate body.

7. The cover plate assembly of claim 6, wherein, the introduction portion, the first transition portion, the second transition portion, the third transition portion, the fourth transition portion, the fifth transition portion, the sixth transition portion, the seventh transition portion and the eighth transition portion are all rounded, a radius of the rounded corner of the introduction portion is 0.1 mm to 5 mm, a radius of the rounded corner of the first transition portion is 0.05 mm to 3 mm, a radius of the rounded corner of the second transition portion is 0.05 mm to 2 mm, a radius of the rounded corner of the third transition portion is 0.1 mm to 5 mm, a radius of the rounded corner of the fourth transition portion is 0.1 mm to 5 mm, a radius of the rounded corner of the fifth transition portion is 0.05 mm to 3 mm, a radius of the rounded corner of the sixth transition portion is 0.05 mm to 3 mm, a radius of the rounded corner of the seventh transition portion is 0.05 mm to 3 mm, and a radius of the rounded corner of the eighth transition portion is 0.1 mm to 5 mm.

8. The cover plate assembly of claim 7, wherein, The fillet radius of the lead-in portion is 0.7 mm, the fillet radius of the first transition portion is 0.05 mm, the fillet radius of the second transition portion is 0.1 mm, the fillet radius of the third transition portion is 0.8 mm, the fillet radius of the fourth transition portion is 0.8 mm, the fillet radius of the fifth transition portion is 0.4 mm, the fillet radius of the sixth transition portion is 0.4 mm, the fillet radius of the seventh transition portion is 0.2 mm, the fillet radius of the eighth transition portion is 0.9 mm; the width of the ejection portion is 0.9 mm, the thickness of the welding portion is 0.8 mm, the length of the first side wall along the thickness direction is 0.6 mm, and the distance between the side of the ejection portion away from the welding portion and the side of the welding portion away from the ejection portion is 2.1 mm.

9. An electric cell characterized by The shell is welded to the welding portion of the cover plate assembly of any one of claims 1-8, and an electrode assembly is arranged in the shell.

10. The electric cell of claim 9, wherein, After the welding portion is welded to the shell, a molten pool recessed towards the groove is formed in the interior of the welding portion, and the molten pool is arranged apart from the groove. And / or, a welding transition portion is formed at the edge of the side of the welding portion away from the electrode assembly.

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