Cell cover, cell and battery pack

Abstract

This invention relates to the field of battery technology and discloses a cell cover, a cell, and a battery pack. The cell cover includes: a cover body; an annular groove formed by stamping at least one edge along the Z direction; and an extension surrounding the outside of the groove. The extension protrudes from the surface of the cover body in the Z direction. The cover body is adapted to cover the opening of the cell's casing and is welded to the inner wall of the casing through the sidewall of the extension. The groove depth is H1, and the extension height is H2, satisfying 0.3 ≤ H1 / H2 ≤ 0.75. This invention uses stamping to form the annular extension on the cover body, which increases the weld depth between the cover body and the casing and enhances the structural strength of the cover body without thickening it. Furthermore, controlling H1 / H2 within a suitable range ensures material flow during stamping, facilitating the processing and forming of the extension.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to cell cover plates, cells, and battery packs. Background Technology

[0002] During vehicle operation, power batteries are subjected to vibrations and impacts transmitted from the road surface over a long period of time, especially at the cell cover, which is susceptible to continuous shear forces. Traditional cell covers mostly use flat aluminum sheets, which are insufficient in terms of shear and impact resistance. Under long-term bumpy conditions, weak areas of the cover (such as around the explosion-proof valve, welded parts of the cover, etc.) are prone to cracking or failure due to stress concentration, seriously affecting the safety and service life of the battery.

[0003] To meet structural strength requirements, existing cell covers are generally made thicker to improve rigidity. However, this not only increases material usage and cost, but also increases the overall weight of the cell, resulting in lower battery energy density. Summary of the Invention

[0004] In view of this, the present invention provides a cell cover plate, a cell, and a battery pack to solve the problems of existing cell covers that increase rigidity by increasing plate thickness, resulting in increased material usage, increased cost, and lower battery energy density.

[0005] In a first aspect, the present invention provides a battery cell cover plate, comprising: a cover plate body, wherein an annular groove is formed by stamping at least one edge of the cover plate body along the Z direction and an extension portion surrounding the outside of the groove, the extension portion protruding from the surface of the cover plate body in the Z direction, the cover plate body being adapted to cover the housing opening of the battery cell and welded to the inner wall of the housing through the sidewall of the extension portion, the groove having a groove depth of H1 along the Z direction, and the extension portion having an extension height of H2 along the Z direction, satisfying 0.3≤H1 / H2≤0.75.

[0006] Beneficial Effects: The battery cell cover plate of the present invention has an annular extension formed by stamping around the periphery of the cover plate body. This extension extends beyond the surface of the cover plate body, increasing the weld depth space between the cover plate body and the shell, and ensuring the welding strength between the cover plate body and the shell. The extension forms a reinforcing structure, which can also enhance the structural strength of the cover plate body without thickening it, improving its resistance to bending, shearing, and impact. In addition, by controlling H1 / H2 within a suitable range, the material flowability during stamping can be ensured, reducing defects such as cracking and wrinkling, facilitating the processing and forming of the extension, and ensuring the structural strength of the cover plate body.

[0007] In one alternative implementation, 0.3 mm ≤ H1 ≤ 12 mm, and 1 mm ≤ H2 ≤ 16 mm.

[0008] Beneficial effects: By controlling the groove depth within a suitable range, excessive stamping of the cover plate body can be avoided, preventing the area corresponding to the groove from becoming too thin and causing stress concentration. By controlling the height of the extension within a suitable range, the bending strength of the cover plate body can be significantly improved, and sufficient melting depth space can be provided.

[0009] In one optional embodiment, the thickness of the cover plate body is H3, satisfying 0.5 mm ≤ H3 ≤ 10 mm.

[0010] Beneficial effects: By utilizing the extension to increase the melting depth space between the cover plate body and the housing, the thickness of the cover plate body can be reduced, thereby improving the overall energy density of the battery pack.

[0011] In one optional embodiment, the distance between the bottom of the groove and the outer side of the cover plate body along the X or Y direction is W1, and the groove width is W2, satisfying 1.1≤W2 / W1≤2 and 0.1 mm≤W2≤10 mm.

[0012] Beneficial effects: By controlling W2 / W1 within a suitable range, it is possible to ensure good material flow during stamping, which facilitates the forming of the extension section. If W2 is too small, the forming punch will be too narrow and prone to wear; if W2 is too large, the material flow will be insufficient, making it difficult to form the extension section.

[0013] In one optional embodiment, the cover plate body is welded to the housing to form a weld mark, the distance between the groove and the weld mark is W3, and the weld width on the cover plate body is W4, satisfying 0.5×(W3+W4)mm≤W1≤8 mm.

[0014] Beneficial effects: If W1 is too large, the material will not have enough fluidity and the extension will be difficult to process and form. If W1 is too small, it will easily lead to W3 and W4 being too small. During the use of the battery cell, the cover plate body is prone to deformation and breakage.

[0015] In one alternative implementation, 0.3 mm ≤ W3 ≤ 15 mm, and 0.2 mm ≤ W4 ≤ 2 mm; And / or, along the Z direction, the distance between the solder mark and the bottom surface of the extension is H4, satisfying 0.5 mm ≤ H4 ≤ 20 mm.

[0016] Beneficial effects: If W3 is too small, welding stress will easily act on the groove during the welding of the cover plate body and the shell, leading to structural strength failure. Under stress during use, the cover plate body is prone to deformation and fracture after long-term fatigue. If W4 is too small, the weld strength between the cover plate body and the shell will be weak, and the weld between the cover plate body and the shell will easily fail under stress during use. If H4 is too small, the molten metal in the weld pool will drip downwards into the cell during welding, causing a short circuit.

[0017] In one alternative embodiment, a chamfer is formed on the outer bottom of the extension along the X or Y direction, and the width of the bottom surface of the extension is W5, satisfying 0.3 mm ≤ W5 ≤ 5 mm.

[0018] Beneficial effects: A chamfer is formed on the outer bottom of the extension to facilitate its insertion into the housing. A supporting bevel is provided on the housing corresponding to the chamfer to support the extension. Furthermore, the extension also serves as a limit for the welding of the cover plate body to the housing. By controlling the bottom width of the extension within a suitable range, excessively sharp chamfers can be avoided, and the processing difficulty of the chamfer can be reduced.

[0019] In one alternative embodiment, the groove has opposing first and second groove walls, wherein the first groove wall also serves as the inner wall of the extension. The included angle between the first groove wall and the bottom of the groove is θ1, which satisfies 100°≤θ1≤150°; And / or, the angle between the second groove wall and the bottom of the groove is θ2, satisfying 95°≤θ2≤150°.

[0020] Beneficial effects: If θ1 is too small, insufficient material flow during stamping will prevent the extrusion of the extension, making it difficult to form the extension. If θ1 is too large, the width of the first groove wall will be too large, occupying a large space and resulting in insufficient space for the cover plate body. If θ2 is too small, mold demolding will be inconvenient, and stress concentration may easily occur, leading to cracking of the cover plate body. If θ2 is too large, the material flow during stamping will be biased towards the two side groove walls, making it difficult to concentrate and flow towards the middle, resulting in difficulty in extruding the extension and making it difficult to form the extension.

[0021] Secondly, the present invention also provides a battery cell, comprising: The housing has an opening at at least one end; The aforementioned cell cover plate has its main body covering the opening and welded to the inner wall of the housing through the side wall of the extension.

[0022] Beneficial effects: The battery cell of the present invention has an annular extension formed by stamping around the periphery of the cover plate body. This extension extends beyond the surface of the cover plate body, increasing the weld depth space between the cover plate body and the shell, and ensuring the weld strength between the cover plate body and the shell. The extension forms a reinforcing structure, which can also enhance the structural strength of the cover plate body without thickening it, and improve the cover plate body's resistance to bending, shearing, and impact. In addition, by controlling H1 / H2 within a suitable range, the material flowability during stamping can be ensured, reducing defects such as cracking and wrinkling, facilitating the processing and forming of the extension, and ensuring the structural strength of the cover plate body.

[0023] Thirdly, the present invention also provides a battery pack comprising: at least one of the above-described battery cells.

[0024] Beneficial effects: Since the battery pack includes battery cells, it has the same effects as the battery cells, which will not be repeated here. Attached Figure Description

[0025] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 This is a front view of a battery cell according to an embodiment of the present invention; Figure 2 for Figure 1 Cross-sectional view at point AA; Figure 3 for Figure 2 A magnified view of part B in the diagram; Figure 4 This is a schematic diagram of the structure of a battery cell cover plate according to an embodiment of the present invention; Figure 5 This is a bottom view of a battery cell cover plate according to an embodiment of the present invention; Figure 6 This is a side view of a battery cell cover plate according to an embodiment of the present invention; Figure 7 for Figure 6 Cross-sectional view at point CC; Figure 8 for Figure 7 A magnified view of part of D.

[0027] Explanation of reference numerals in the attached figures: 1. Cover plate body; 101. Groove; 102. Extension; 103. Chamfer; 2. Housing; 3. Weld mark. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] In embodiments of the present invention, a "cell" refers to a single battery cell capable of independent charging and discharging. The components of a cell may include a positive electrode, a negative electrode, a separator, an electrolyte, and a casing for encapsulating the positive and negative electrode, the separator, and the electrolyte. The positive and negative electrode constitute an electrode assembly. The casing includes a housing and a cover plate. The housing is generally a hollow cylindrical structure with an opening at one end, used to house the electrode assembly. During encapsulation, the cover plate covers the opening of the housing, forming a closed, sealed space that isolates the inside of the cell from the outside environment.

[0030] This invention does not impose any particular limitations on the type or shape of the battery cell; it can be a blade cell, a prismatic cell, or any other type of cell. The battery cell in this invention can be a lithium-ion cell, a potassium-ion cell, a sodium-ion cell, a lithium-sulfur cell, etc., with lithium-ion cells being particularly preferred. During the charging and discharging process, active ions repeatedly insert and extract between the positive and negative electrode plates. The electrolyte acts as a conductor of ions between the positive and negative electrode plates.

[0031] In the embodiments of the invention, the "battery pack" is formed by combining a certain number of battery cells into a battery module and placing them in a housing in order to protect the battery cells from external impacts, heat, vibration, etc. The battery pack also includes a battery management system (BMS), a thermal management system, an electrical connection system (high-voltage / low-voltage connectors, wiring harnesses, etc.), structural components (casing, brackets, etc.), and protective components, forming a complete functional unit that can directly output electrical energy.

[0032] Battery packs serve as a rechargeable power source in electrical devices. These devices include, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, and spacecraft. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. Spacecraft include airplanes, rockets, space shuttles, and spacecraft. Electric vehicles include pure electric vehicles, hybrid electric vehicles, and range-extended electric vehicles.

[0033] The following is combined Figures 1 to 8 The following describes embodiments of the present invention.

[0034] According to an embodiment of the present invention, in one aspect, such as Figure 4 and Figure 5 As shown, a battery cell cover is provided, including: a cover body 1, an annular groove 101 formed by stamping at least one edge of the cover body 1 along the Z direction, and an extension 102 surrounding the outside of the groove 101. The extension 102 protrudes from the surface of the cover body 1 in the Z direction. The cover body 1 is adapted to cover the opening of the housing 2 of the battery cell and to connect with the inner wall of the housing 2 through the side wall of the extension 102.

[0035] like Figure 8 As shown, the groove depth of the groove 101 along the Z direction is H1, and the extension height of the extension 102 along the Z direction is H2, satisfying 0.3≤H1 / H2≤0.75.

[0036] Therefore, the battery cell cover plate provided in this embodiment of the invention has an annular extension 102 stamped around the periphery of the cover plate body 1. This extension 102 extends beyond the surface of the cover plate body 1, which can increase the weld depth space between the cover plate body 1 and the shell 2, ensuring the welding strength between the cover plate body 1 and the shell 2. The extension 102 constitutes a reinforcing structure, and can also enhance the structural strength of the cover plate body 1 without thickening it, thereby improving the cover plate body 1's resistance to bending, shearing, and impact.

[0037] In addition, by controlling H1 / H2 within a suitable range, the material flow during stamping can be ensured, defects such as cracking and wrinkling can be reduced, the processing and forming of the extension 102 can be facilitated, and the structural strength of the cover plate body 1 can be guaranteed.

[0038] Specifically, in the Z direction, such as Figure 4 and Figure 6 As indicated by arrow Z, this indicates the thickness direction of the cover plate body 1. The "inner" and "outer" sides of the groove 101 are relative to the interior and exterior of the housing 2, as shown in the image. Figure 3 As shown. The cover body 1 needs to be stamped to form the groove 101 and the extension 102, so the cover body 1 is generally made of metal material, such as plain aluminum plate.

[0039] like Figure 8 As shown, when the extension 102 extends downward, it is formed by pressing the material of the cover body 1, originally located in the groove 101, to the outer edge. The extension height H2 of the extension 102 refers to the distance in the Z direction from the bottom of the groove 101 to the bottom surface of the extension 102. The bottom surface of the extension 102 is generally flat and parallel to the top surface of the cover body 1. The outer surface of the extension 102 is flush with the outer surface of the cover body 1 to facilitate insertion into the shell. The groove depth H1 of the groove 101 refers to the distance in the Z direction from the bottom of the groove 101 to the bottom surface of the cover body 1.

[0040] Specifically, at least one end of the housing 2 is provided with an opening. The cover plate body 1 covers the opening and has opposing top and bottom surfaces along the Z direction, wherein the top surface of the cover plate body 1 faces away from the housing 2, and the bottom surface of the cover plate body 1 faces the housing 2 and is located inside the housing 2.

[0041] It should be noted that the extension 102 in this embodiment of the invention can be provided on the top surface of the cover plate body 1, or on the bottom surface of the cover plate body 1, or the extension 102 can be provided on both the top and bottom surfaces of the cover plate body 1.

[0042] For example, such as Figure 3 As shown, the extension 102 is provided on the bottom surface of the cover plate body 1, the top surface of the cover plate body 1 is flush with the opening end face of the housing 2 and is welded and fixed at the joint, the groove 101 is provided on the bottom surface of the cover plate body 1, the extension 102 extends out of the bottom surface of the cover plate body 1, and the extension 102 is located below the welding area between the cover plate body 1 and the housing 2, so as to provide the welding depth and improve the structural strength.

[0043] For example, in embodiments of the present invention, the value of H1 / H2 can be 0.3, 0.4, 0.5, 0.55, 0.6, 0.7, 0.75, etc.

[0044] In one embodiment, 0.3 mm ≤ H1 ≤ 12 mm, and 1 mm ≤ H2 ≤ 16 mm. By controlling the groove depth H1 of the groove 101 within a suitable range, excessive stamping of the cover plate body 1 can be avoided, which would cause the area of ​​the cover plate body 1 corresponding to the groove 101 to be too thin, resulting in stress concentration. By controlling the height H2 of the extension 102 within a suitable range, the bending strength of the cover plate body 1 can be significantly improved, and sufficient melting depth space can be provided.

[0045] In one embodiment, such as Figure 8 As shown, the thickness of the cover plate body 1 is H3, which satisfies 0.5 mm ≤ H3 ≤ 10 mm.

[0046] Traditional square power batteries typically have a minimum cover plate thickness of around 1 mm. However, this embodiment of the invention utilizes the extension 102 to increase the fusion depth space between the cover plate body 1 and the housing 2, thus allowing for a reduction in the thickness of the cover plate body 1 and improving the overall energy density of the battery pack.

[0047] For example, in embodiments of the present invention, the value of H3 can be 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 1 mm, 2 mm, 5 mm, 10 mm, etc.

[0048] In one embodiment, such as Figure 8As shown, the distance between the bottom of the groove 101 and the outer side of the cover plate body 1 along the X or Y direction is W1. The groove width of the groove 101 along the X or Y direction is W2, satisfying 1.1≤W2 / W1≤2, 0.1 mm≤W2≤10 mm. By controlling W2 / W1 within a suitable range, it can be ensured that the material has good flowability during stamping, which facilitates the processing and forming of the extension 102. If W2 is too small, the forming punch will be too narrow and prone to wear; if W2 is too large, the material flow will be insufficient, and the extension 102 will be difficult to process and form.

[0049] Specifically, the X direction is as follows: Figure 4 and Figure 5 As indicated by arrow X, which represents the length direction of the cover plate body 1. The Y direction is as follows... Figure 4 and Figure 5 As indicated by arrow Y, this is the width direction of the cover plate body 1.

[0050] For example, in embodiments of the present invention, the value of W2 / W1 can be 1.1, 1.3, 1.5, 1.7, 1.9, 2, etc.

[0051] Furthermore, in one embodiment, such as Figure 3 As shown, after the cover plate body 1 is welded to the shell 2, a weld mark 3 is formed. The distance between the groove 101 and the weld mark 3 is W3, and the weld width of the weld mark 3 on the cover plate body 1 is W4, satisfying 0.5×(W3+W4)mm≤W1≤8 mm. If W1 is too large, the material flowability will be insufficient, and the extension 102 will be difficult to process and form. If W1 is too small, it will easily lead to W3 and W4 being too small, and the cover plate body 1 will easily deform and break during the use of the battery cell.

[0052] Furthermore, in one embodiment, 0.3 mm ≤ W3 ≤ 15 mm, and 0.2 mm ≤ W4 ≤ 2 mm. If W3 is too small, the welding stress will easily act on the groove 101 when the cover plate body 1 is welded to the shell 2, leading to structural strength failure. When the battery cell is under stress during use, the cover plate body 1 is prone to deformation and is prone to breakage after long-term fatigue. If W4 is too small, the welding strength between the cover plate body 1 and the shell 2 is weak, and the weld between the cover plate body 1 and the shell 2 is prone to failure when the battery cell is under stress during use.

[0053] For example, in embodiments of the present invention, the value of W3 can be 0.3 mm, 0.5 mm, 1.5 mm, 3 mm, 7 mm, 10 mm, 15 mm, etc. The value of W4 can be 0.2 mm, 0.3 mm, 0.5 mm, 1 mm, 1.2 mm, 1.5 mm, 2 mm, etc.

[0054] In one embodiment, such as Figure 3As shown, along the Z direction, the distance between the bottom of the solder mark 3 and the bottom surface of the extension 102 is H4, which satisfies 0.5 mm ≤ H4 ≤ 20 mm. If H4 is too small, the molten metal in the molten pool will form molten beads that drip into the battery cell during welding, causing a short circuit.

[0055] For example, in embodiments of the present invention, the value of H4 can be 0.5 mm, 1.5 mm, 3 mm, 7 mm, 10 mm, 15 mm, 20 mm, etc.

[0056] In one embodiment, such as Figure 7 and Figure 8 As shown, a chamfer 103 is formed on the outer bottom surface of the extension 102. Along the X or Y direction, the width of the bottom surface of the extension 102 is W5, satisfying 0.3 mm ≤ W5 ≤ 5 mm. The chamfer 103 on the outer bottom surface of the extension 102 facilitates its insertion into the housing. By controlling the bottom surface width W5 of the extension 102 within a suitable range, the chamfer 103 can be prevented from being too sharp, and the processing difficulty of the chamfer 103 can be reduced.

[0057] For example, in embodiments of the present invention, the value of W5 can be 0.3 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 5 mm, etc.

[0058] Furthermore, such as Figure 3 As shown, a supporting slope is provided at the chamfer 103 of the housing 2 so that the housing 2 can support the extension 102. In addition, the extension 102 is also used for limiting the position when the cover plate body 1 is welded to the housing 2.

[0059] In one embodiment, such as Figure 8 As shown, the groove 101 has a first groove wall and a second groove wall, wherein the first groove wall also serves as the inner wall of the extension 102. The angle between the first groove wall and the bottom of the groove 101 is θ1, satisfying 100°≤θ1≤150°. The angle between the second groove wall and the bottom of the groove 101 is θ2, satisfying 95°≤θ2≤150°.

[0060] If θ1 is too small, the material flow during stamping will be insufficient, making it impossible to extrude the extension 102, and the extension 102 will be difficult to form. If θ1 is too large, the width of the first groove wall will be too large, occupying a large space and resulting in insufficient arrangement space for the cover plate body 1. If θ2 is too small, it will be inconvenient for the mold to demold, and stress concentration will easily occur, causing the cover plate body 1 to crack. If θ2 is too large, the material flow during stamping will be biased towards the two side groove walls and will not be easy to concentrate and flow to the middle, making it difficult to extrude the extension 102, and the extension 102 will be difficult to form.

[0061] For example, in an embodiment of the present invention, the value of θ1 can be 100°, 110°, 120°, 130°, 140°, 150°, etc., and the value of θ2 can be 95°, 100°, 110°, 120°, 130°, 140°, 150°, etc.

[0062] The process parameters of the battery cell cover plate of the present invention will be further described in detail below with reference to specific embodiments. These examples should not be construed as limiting the scope of protection claimed by the present invention.

[0063] Example 1: The groove depth H1 of the groove 101 along the Z direction is 2 mm, and the extension height H2 of the extension 102 along the Z direction is 4 mm, so H1 / H2 is 0.5. Along the Z direction, the distance H4 between the solder mark 3 and the bottom surface of the extension 102 is 0.8 mm. Along the X or Y direction, the distance W1 between the bottom of the groove 101 and the outer surface of the cover plate body 1 is 2 mm, and the groove width W2 of the groove 101 along the X or Y direction is 2.4 mm, so W2 / W1 is 1.2. The spacing W3 between the groove 101 and the solder mark 3 is 1 mm. The results of battery production line testing and verification are shown in Table 1.

[0064] Example 2: The groove depth H1 of groove 101 along the Z direction is 7 mm, and the extension height H2 of extension 102 along the Z direction is 10 mm, so H1 / H2 is 0.7. Along the Z direction, the distance H4 between the solder mark 3 and the bottom surface of extension 102 is 1.5 mm. Along the X or Y direction, the distance W1 between the bottom of groove 101 and the outer surface of cover plate body 1 is 3 mm, and the groove width W2 of groove 101 along the X or Y direction is 6 mm, so W2 / W1 is 2. The spacing W3 between groove 101 and solder mark 3 is 1 mm. The results of battery production line testing and verification are shown in Table 1.

[0065] Example 3: The groove depth H1 of the groove 101 along the Z direction is 1.6 mm, and the extension height H2 of the extension 102 along the Z direction is 5 mm, so H1 / H2 is 0.32. Along the Z direction, the distance H4 between the solder mark 3 and the bottom surface of the extension 102 is 2 mm. Along the X or Y direction, the distance W1 between the bottom of the groove 101 and the outer surface of the cover plate body 1 is 5 mm, and the groove width W2 of the groove 101 along the X or Y direction is 7.5 mm, so W2 / W1 is 1.5. The spacing W3 between the groove 101 and the solder mark 3 is 2 mm. The results of battery production line testing and verification are shown in Table 1.

[0066] Example 4: The groove depth H1 of groove 101 along the Z direction is 6 mm, and the extension height H2 of extension 102 along the Z direction is 15 mm, so H1 / H2 is 0.4. Along the Z direction, the distance H4 between the solder mark 3 and the bottom surface of extension 102 is 0.5 mm. Along the X or Y direction, the distance W1 between the bottom of groove 101 and the outer surface of cover plate body 1 is 5.5 mm, and the groove width W2 of groove 101 along the X or Y direction is 7.7 mm, so W2 / W1 is 1.4. The spacing W3 between groove 101 and solder mark 3 is 4 mm. The results of battery production line testing and verification are shown in Table 1.

[0067] Example 5: The groove depth H1 of groove 101 along the Z direction is 1.8 mm, and the extension height H2 of extension 102 along the Z direction is 3 mm, so H1 / H2 is 0.6. Along the Z direction, the distance H4 between the solder mark 3 and the bottom surface of extension 102 is 5 mm. Along the X or Y direction, the distance W1 between the bottom of groove 101 and the outer surface of cover plate body 1 is 7 mm, and the groove width W2 of groove 101 along the X or Y direction is 8.4 mm, so W2 / W1 is 1.2. The spacing W3 between groove 101 and solder mark 3 is 0.33 mm. The results of battery production line testing and verification are shown in Table 1.

[0068] Comparative Example 1: The groove depth H1 of groove 101 along the Z direction is 2.5 mm, and the extension height H2 of extension 102 along the Z direction is 3.9 mm, so H1 / H2 is 0.64. Along the Z direction, the distance H4 between the solder mark 3 and the bottom surface of extension 102 is 0.8 mm. Along the X or Y direction, the distance W1 between the bottom of groove 101 and the outer surface of cover plate body 1 is 2 mm, and the groove width W2 of groove 101 along the X or Y direction is 2 mm, so W2 / W1 is 1, which is less than 1.1. The spacing W3 between groove 101 and solder mark 3 is 1 mm. The results of battery production line testing and verification are shown in Table 1.

[0069] Comparative Example 2: The groove depth H1 of groove 101 along the Z direction is 6.8 mm, and the extension height H2 of extension 102 along the Z direction is 9.9 mm, so H1 / H2 is 0.69. Along the Z direction, the distance H4 between the solder mark 3 and the bottom surface of extension 102 is 1.5 mm. Along the X or Y direction, the distance W1 between the bottom of groove 101 and the outer surface of cover plate body 1 is 3 mm, and the groove width W2 of groove 101 along the X or Y direction is 6.3 mm, so W2 / W1 is 2.1, which is greater than 2. The spacing W3 between groove 101 and solder mark 3 is 1 mm. The results of battery production line testing and verification are shown in Table 1.

[0070] Comparative Example 3: The groove depth H1 of groove 101 along the Z direction is 1.4 mm, and the extension height H2 of extension 102 along the Z direction is 5 mm, so H1 / H2 is 0.28, which is less than 0.3. Along the Z direction, the distance H4 between the solder mark 3 and the bottom surface of extension 102 is 2 mm. Along the X or Y direction, the distance W1 between the bottom of groove 101 and the outer surface of cover plate body 1 is 5 mm, and the groove width W2 of groove 101 along the X or Y direction is 7.5 mm, so W2 / W1 is 1.5. The spacing W3 between groove 101 and solder mark 3 is 2 mm. The results of battery production line testing and verification are shown in Table 1.

[0071] Comparative Example 4: The groove depth H1 of groove 101 along the Z direction is 6 mm, and the extension height H2 of extension 102 along the Z direction is 15 mm, so H1 / H2 is 0.4. Along the Z direction, the distance H4 between the solder mark 3 and the bottom surface of extension 102 is 0.48 mm, which is less than 0.5 mm. Along the X or Y direction, the distance W1 between the bottom of groove 101 and the outer surface of cover plate body 1 is 5.5 mm, and the groove width W2 of groove 101 along the X or Y direction is 7.7 mm, so W2 / W1 is 1.4. The spacing W3 between groove 101 and solder mark 3 is 4 mm. The results of battery production line testing and verification are shown in Table 1.

[0072] Comparative Example 5: The groove depth H1 of groove 101 along the Z direction is 1.8 mm, and the extension height H2 of extension 102 along the Z direction is 3 mm, so H1 / H2 is 0.6. Along the Z direction, the distance H4 between the solder mark 3 and the bottom surface of extension 102 is 5 mm. Along the X or Y direction, the distance W1 between the bottom of groove 101 and the outer surface of cover plate body 1 is 7 mm, and the groove width W2 of groove 101 along the X or Y direction is 8.4 mm, so W2 / W1 is 1.2. The spacing W3 between groove 101 and solder mark 3 is 0.29 mm, which is less than 0.3 mm. The test verification results from the battery production line are shown in Table 1.

[0073] Table 1: Test Results

[0074] As can be seen from Table 1, in Examples 1 to 5, the following conditions are met: 0.3≤H1 / H2≤0.75, 0.3 mm≤H1≤12 mm, 1 mm≤H2≤16 mm, 0.5 mm≤H4≤20 mm, 1.1≤W2 / W1≤2, 0.1 mm≤W2≤10 mm, and 0.3 mm≤W3≤15 mm. Therefore, when the cover plate body 1 is stamped, the extension 102 can be successfully processed, and the cover plate body 1 has good structural stability after being welded to the shell 2, which can meet the testing requirements of the battery production line.

[0075] In Comparative Example 1, W2 / W1 is less than 1.1, which is lower than the lower limit value of the embodiment of the present invention. When the cover plate body 1 is stamped, the extension 102 fails to form, the height of the extension 102 is insufficient and the bottom surface is uneven, and the connection strength of the cover plate body 1 and the shell 2 is poor.

[0076] In Comparative Example 2, W2 / W1 is greater than 2, exceeding the upper limit value of the embodiment of the present invention. When the cover plate body 1 is stamped, the extension 102 has crack defects after forming.

[0077] In Comparative Example 3, H1 / H2 is less than 0.3, which is lower than the lower limit value of the embodiment of the present invention. When the cover plate body 1 is stamped, the extension 102 fails to form, the height of the extension 102 is insufficient and the bottom surface is uneven, and the connection strength of the cover plate body 1 and the shell 2 is poor.

[0078] In Comparative Example 4, H4 is less than 0.5 mm, which is lower than the lower limit value of the embodiment of the present invention. When the cover plate body 1 is welded to the shell 2, molten beads drip into the inside of the battery cell, causing a short circuit in the battery cell.

[0079] In Comparative Example 5, W3 is less than 0.3 mm, which is lower than the lower limit value of the embodiment of the present invention. After the battery pack vibration test, the cover plate body 1 deformed and cracked, causing the seal between the cover plate body 1 and the shell 2 to fail, resulting in leakage of the battery cell.

[0080] According to an embodiment of the present invention, on the other hand, such as Figure 1 and Figure 2 As shown, a battery cell is also provided, including: a housing 2 and a battery cell cover plate. The housing 2 has an opening at at least one end. The cover plate body 1 covers the opening and is welded to the inner wall of the housing 2 through the side wall of the extension 102.

[0081] Therefore, the battery cell provided in this embodiment of the invention has an annular extension 102 stamped around the periphery of the cover plate body 1. This extension 102 extends beyond the surface of the cover plate body 1, increasing the weld depth between the cover plate body 1 and the housing 2, thus ensuring the welding strength between them. The extension 102 constitutes a reinforcing structure, enhancing the structural strength of the cover plate body 1 without thickening it, and improving its resistance to bending, shearing, and impact. Furthermore, by controlling H1 / H2 within a suitable range, material flowability during stamping can be ensured, reducing defects such as cracking and wrinkling, facilitating the processing and forming of the extension 102, and guaranteeing the structural strength of the cover plate body 1.

[0082] According to an embodiment of the present invention, in another aspect, a battery pack is also provided, comprising: at least one of the above-described battery cells.

[0083] Since the battery pack includes battery cells and has the same effect as the battery cells, it will not be elaborated on here.

[0084] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and all such modifications and variations fall within the scope defined by the appended claims.

Claims

1. A battery cell cover plate, characterized in that, include: The cover plate body has an annular groove formed by stamping at least one edge along the Z direction and an extension surrounding the outside of the groove. The extension protrudes from the surface of the cover plate body in the Z direction. The cover plate body is adapted to cover the housing opening of the battery cell and is welded to the inner wall of the housing through the sidewall of the extension. The groove depth along the Z direction is H1, and the extension height along the Z direction is H2, satisfying 0.3≤H1 / H2≤0.

75.

2. The cell cover plate according to claim 1, characterized in that, 0.3 mm≤H1≤12 mm, 1 mm≤H2≤16mm.

3. The cell cover plate according to claim 2, characterized in that, The thickness of the cover plate body is H3, which satisfies 0.5mm≤H3≤10 mm.

4. The cell cover plate according to claim 1, characterized in that, Along the X or Y direction, the distance between the bottom of the groove and the outer side of the cover plate body is W1, and the groove width is W2, satisfying 1.1≤W2 / W1≤2, 0.1mm≤W2≤10 mm.

5. The cell cover plate according to claim 4, characterized in that, The extension of the cover plate body is welded to the shell to form a weld mark. The distance between the groove and the weld mark is W3, and the weld width on the cover plate body is W4, satisfying 0.5×(W3+W4)mm≤W1≤8 mm.

6. The cell cover plate according to claim 5, characterized in that, 0.3 mm≤W3≤15 mm, 0.2 mm≤W4≤2mm; And / or, along the Z direction, the distance between the solder mark and the bottom surface of the extension is H4, satisfying 0.5 mm ≤ H4 ≤ 20 mm.

7. The cell cover plate according to any one of claims 1 to 6, characterized in that, The bottom outer side of the extension is chamfered, and the width of the bottom surface of the extension is W5 along the X or Y direction, satisfying 0.3 mm ≤ W5 ≤ 5 mm.

8. The cell cover plate according to any one of claims 1 to 6, characterized in that, The groove has a first groove wall and a second groove wall, wherein the first groove wall also serves as the inner wall of the extension. The included angle between the first groove wall and the bottom of the groove is θ1, which satisfies 100°≤θ1≤150°; And / or, the angle between the second groove wall and the bottom of the groove is θ2, satisfying 95°≤θ2≤150°.

9. A battery cell, characterized in that, include: The housing has an opening at at least one end; The cell cover plate according to any one of claims 1 to 8, wherein the cover plate body is disposed over the opening and welded to the inner wall of the housing through the side wall of the extension.

10. A battery pack, characterized in that, include: At least one battery cell as described in claim 9.

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