Button cell top cover assembly and lithium battery

Abstract

The button cell top cover assembly comprises the top cover assembly, the top cover assembly comprises an annular cover plate and a pole column, an annular insulating layer is arranged between the annular cover plate and the pole column, the annular cover plate comprises an inclined cover plate, the inclined cover plate is designed to be inclined downwards, and the annular insulating layer is arranged between the inclined cover plate and the pole column. An inclination angle alpha is formed between the inclined cover plate and the horizontal direction and ranges from 5 degrees to 15 degrees; according to the button cell top cover assembly and the lithium battery provided by the utility model, part or all of the annular cover plate is designed to be inclined downwards, so that expansive force is decomposed and expansive force in the vertical direction is inhibited, thus the reserved space is reduced, and the energy density is improved.

Description

A button cell battery top cover assembly and a lithium battery Technical Field

[0001] This utility model relates to the field of lithium battery technology, and in particular to a button cell battery top cover assembly and a lithium battery. Background Technology

[0002] Lithium-ion batteries are currently the most advanced commercially available rechargeable batteries and are widely used in various electronic products. Based on packaging materials, lithium-ion batteries can be divided into steel-cased lithium-ion batteries, aluminum-cased lithium-ion batteries, and pouch lithium-ion batteries.

[0003] Currently, steel-cased button or cylindrical batteries, as shown in Figure 1, have horizontal surfaces on both the top and bottom. During battery use, the internal materials expand in volume during charging and discharging, resulting in significant battery expansion. This expansion generates internal pressure, which acts directly and perpendicularly on the connecting cover and sidewalls. If the expansion is excessive, the force exerted on the cover can cause casing deformation or even rupture and leakage, affecting battery performance and safety. The traditional planar battery sealing design cannot effectively address the issue of cyclic expansion, resulting in low safety. To mitigate these risks, lithium battery design requires internal space to allow the internal cells to expand to a certain volume, thereby reducing the force on the top cover. This reduces the cell volume and active material, lowering the battery's energy density. Summary of the Invention

[0004] The purpose of this invention is to overcome the defect of excessive force exerted on the cover plate by battery expansion in the prior art, and to provide a button battery top cover assembly and lithium battery, which designs part or all of the annular cover plate to tilt downwards, decompose the expansion force and suppress the vertical expansion force, thereby reducing the reserved space and increasing the energy density.

[0005] To achieve the above objectives, this utility model provides a button cell battery top cover assembly, including a top cover assembly. The top cover assembly includes an annular cover plate and a terminal post. An annular insulating layer is installed between the annular cover plate and the terminal post. The annular cover plate includes an inclined cover plate. The inclined cover plate is designed to be inclined downwards. The inclined cover plate has an inclination angle α with respect to the horizontal direction. The inclination angle α is between 5° and 15°.

[0006] Preferably, the annular cover plate further includes a flat cover plate, which is located outside the inclined cover plate; a connecting portion is provided between the flat cover plate and the inclined cover plate, and the flat cover plate, the connecting portion and the inclined cover plate are integrally formed.

[0007] Preferably, the connecting part is a right-angle bend connecting part or an arc bend connecting part.

[0008] Preferably, the pole post is further provided with a convex cover plate in the middle, and the upper surface of the convex cover plate is higher than the upper surface of the pole post.

[0009] Preferably, the annular insulating layer has an insulating protrusion on one side, and an annular cover plate is installed on the outside of the insulating protrusion.

[0010] Preferably, the top surface of the insulating protrusion is flush with the top surface of the annular cover plate.

[0011] Preferably, the outer diameter of the pole is smaller than the outer diameter of the annular insulating layer, the inner diameter of the annular insulating layer is larger than the inner diameter of the annular cover plate, and the outer diameter of the annular insulating layer is smaller than the outer diameter of the annular cover plate.

[0012] Preferably, the connection between the convex cover plate and the pole post is provided with a rounded chamfer.

[0013] Preferably, the bonding method between the annular cover plate, the pole post and the annular insulating layer is hot pressing bonding or sintering bonding.

[0014] This utility model also provides a lithium battery, including the button battery top cover assembly described above; it also includes a housing, in which a battery cell is installed in the internal cavity of the housing, a positive electrode tab is installed on one side of the battery cell, a negative electrode tab is installed on the other side, the battery cell and the housing are connected by the negative electrode tab, the upper end of the housing is connected to an annular cover plate by welding, and the battery cell and the terminal are connected by the positive electrode tab.

[0015] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0016] 1. The top cover assembly of this utility model includes an annular cover plate and a terminal post; the annular cover plate includes an inclined cover plate, the inclined cover plate is designed to be inclined downward, the inclined cover plate has an inclination angle α with the horizontal direction, the inclination angle α is between 5° and 15°; by designing part or all of the annular cover plate to be inclined downward, the principle of force decomposition is used to suppress the battery cycle expansion, reduce the expansion rate, thereby increasing the effective space inside the lithium battery, increasing the amount of active material filled inside the battery, and improving the energy density and safety performance of the battery.

[0017] 2. This utility model features a downward-sloping cover plate, which decomposes the expansion force into horizontal and vertical components. Compared with the traditional planar sealing structure, this significantly reduces the upward vertical expansion force, significantly lowers the battery expansion rate, and suppresses the deformation of the battery casing.

[0018] 3. After significantly reducing the expansion rate of the battery, this utility model can increase the effective space inside the battery, thereby filling more active materials and improving the energy density of the battery.

[0019] 4. This utility model reduces the risk of battery casing deformation and rupture by suppressing expansion, thereby improving battery safety.

[0020] 5. The preparation process of this utility model is simple and easy to implement, and is suitable for large-scale production. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 is a cross-sectional view of a lithium battery provided by the prior art;

[0023] Figure 2 is a schematic diagram of the forces acting on a lithium battery provided by the prior art;

[0024] Figure 3 is a cross-sectional view of a button battery top cover assembly provided by this utility model;

[0025] Figure 4 is a cross-sectional view of a lithium battery provided by this utility model;

[0026] Figure 5 is a force diagram of a lithium battery provided by this utility model;

[0027] Figure 6 is a partially enlarged schematic diagram of a button battery top cover assembly provided by this utility model;

[0028] Figure 7 is a schematic diagram of the right-angle bend connection part provided by this utility model;

[0029] Figure 8 is a schematic diagram of the arc-shaped transition connection part provided by this utility model;

[0030] Figure 9 is a cross-sectional view of the push rod provided by this utility model;

[0031] Figure 10 is a schematic diagram of the expansion force decomposition of a lithium battery provided by this utility model.

[0032] The diagram includes:

[0033] 1. Top cover assembly; 2. Annular cover plate; 3. Terminal post; 4. Annular insulation layer; 21. Inclined cover plate; 22. Flat cover plate; 51. Connecting part; 31. Convex cover plate; 41. Insulating protrusion; 32. Rounded chamfer; 7. Housing; 8. Battery cell. Detailed Implementation

[0034] The technical solution of this embodiment of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiment is one embodiment of the present invention, and not all embodiments thereof. Based on this embodiment 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.

[0035] Example 1

[0036] Please refer to Figures 3 to 10. This utility model provides a button battery top cover assembly.

[0037] As shown in Figure 3, the top cover assembly 1 includes an annular cover plate 2 and a pole post 3. The annular cover plate 2 and the pole post 3 can be either positive or negative electrodes. In this embodiment, the pole post 3 is the positive electrode and the annular cover plate 2 is the negative electrode. In this embodiment, since the annular cover plate 2 is annular and the pole post 3 is circular, the pole post 3 can only be installed in the middle of the annular cover plate 2 to achieve sealing. In this embodiment, the annular cover plate 2 is installed above the pole post 3. In other embodiments, the pole post 3 can also be installed above the center of the annular cover plate 2. The upper and lower positions are not limited in this embodiment.

[0038] In order to achieve insulation between the annular cover plate 2 and the pole post 3, and to achieve isolation between the positive and negative poles, an annular insulating layer 4 is installed between the annular cover plate 2 and the pole post 3.

[0039] As shown in Figures 7 and 8, the annular cover plate 2 includes an inclined cover plate 21. The inclined cover plate 21 is designed to be inclined downwards, and the inclined cover plate 21 has an inclination angle α with the horizontal direction. The inclination angle α can be freely selected according to the actual expansion rate of the battery cell. When the selected angle is too small, the improvement effect may not be obvious. When the selected angle is too large, it will reduce the internal volume of the lithium battery itself, making the improvement effect not obvious. Therefore, in this embodiment, it is recommended that the inclination angle α be between 5° and 15°.

[0040] After cell 8 expands, a certain internal pressure will be generated inside the lithium battery. The internal expansion force will be perpendicular to the inclined cover plate 21, and will have an expansion force that causes the inclined cover plate 21 to return to its original position. This expansion force can be decomposed into horizontal and vertical expansion forces. Compared with a traditional planar sealing structure, the vertical expansion force is significantly reduced, significantly lowering the battery's expansion rate and suppressing the deformation of the battery casing. The reduced internal pressure decreases the required space and increases energy density.

[0041] As shown in Figure 5, when the lithium battery expands during charging and discharging, the expansion force F acts on the inclined cover plate 21. Due to the inclination angle of the inclined cover plate 21, the expansion force F is decomposed into a normal force Fn and a tangential force Ft according to the principle of force decomposition. The normal force Fn and the tangential force Ft are decomposed into horizontal components Fn1 and Ft1, which are absorbed by the structural strength of the casing or canceled out by force balance, and into vertically upward components Fn2 and Ft2. The resultant force of Fn2 and Ft2 is significantly less than F, thereby suppressing the vertical expansion of the battery casing and reducing the expansion rate of the lithium battery.

[0042] As shown in Figure 5, compared with the traditional planar sealing structure (Figure 2), the inclined cover plate 21 design of the present invention can significantly reduce the expansion rate of the battery, thereby improving the energy density of the battery.

[0043] The normal force Fn and the tangential force Ft can be obtained from the trigonometric functions sinα and cosα, as shown in Figure 5. Fn1 = Fncosα, Fn2 = Fnsinα, Ft1 = Ftsinα, Ft2 = Ftcosα.

[0044] In Embodiment 2, the inclined cover plate 21 needs to be welded to the housing 7. Due to the expansion and contraction of the battery cell 8, a certain cyclic force will be generated on the weld at the welding point. To solve the above problem, in this embodiment, a flat cover plate 22 is added to the outside of the inclined cover plate 21. The flat cover plate 22 is connected to the housing 7 by welding, and the weld is more regular. The connection between the flat cover plate 22 and the inclined cover plate 21 will distribute the stress generated by the cyclic expansion of the weld, reducing the risk of weld fracture under stress.

[0045] As shown in Figures 7 and 8, the annular cover plate 2 further includes a flat cover plate 22, which is located outside the inclined cover plate 21; a connecting part 51 is provided between the flat cover plate 22 and the inclined cover plate 21, and the flat cover plate 22, the connecting part 51 and the inclined cover plate 21 are integrally formed.

[0046] In the manufacturing of the annular cover plate 2, the annular cover plate 2 can be stamped to form an inclined angle α when the material is received, or it can be vertically pressed by a top rod 55 when the sealing is manufactured. The end of the top rod 55 is provided with an arc surface with an inclined angle α, as shown in Figure 9. When sealing, the inclined angle α is formed by the downward pressure.

[0047] As shown in Figures 7 and 8, the connecting part 51 is a right-angle bend connecting part or an arc bend connecting part; the corner of the above structure can distribute the stress generated by the cyclic expansion of the weld, reduce the risk of weld fracture under stress, and improve the safety of the battery.

[0048] As shown in Figure 3, a convex cover plate 31 is also provided in the middle of the electrode post 3, and the upper surface of the convex cover plate 31 is higher than the upper surface of the electrode post 3. Furthermore, in this embodiment, the thickness of the convex cover plate 31 is greater than the sum of the thicknesses of the electrode post 3, the annular insulating layer 4, and the annular cover plate 2, and the upper surface of the convex cover plate 31 is higher than the upper surface of the annular cover plate 2, which facilitates the identification of lithium batteries and subsequent welding.

[0049] As shown in Figure 6, an insulating protrusion 41 is provided on one side of the annular insulating layer 4, and an annular cover plate 2 is installed on the outer side of the insulating protrusion 41. Furthermore, the top surface of the insulating protrusion 41 is flush with the top surface of the annular cover plate 2. The installation of the insulating protrusion 41 can prevent the inclined cover plate 21 from approaching the convex cover plate 31, and can prevent the inclined cover plate 21 from connecting with the convex cover plate 31, thereby reducing the occurrence of short circuits in the lithium battery and improving the safety of the lithium battery.

[0050] As shown in Figure 3, the outer diameter of the electrode post 3 is smaller than the outer diameter of the annular insulating layer 4, the inner diameter of the annular insulating layer 4 is larger than the inner diameter of the annular cover plate 2, and the outer diameter of the annular insulating layer 4 is smaller than the outer diameter of the annular cover plate 2. With the above structure, the annular insulating layer 4 can better isolate the annular cover plate 2 and the electrode post 3, reduce the occurrence of short circuits in the lithium battery, and improve the safety of the lithium battery.

[0051] As shown in Figure 3, the connection between the convex cover plate 31 and the pole post 3 is provided with a rounded chamfer 32.

[0052] As shown in Figure 3, the bonding method between the annular cover plate 2, the pole post 3 and the annular insulating layer 4 is either hot-press bonding or sintering bonding; specifically, if the annular insulating layer 4 is a hot melt adhesive, the bonding method is hot-press bonding, and if the annular insulating layer 4 is a ceramic material component, the bonding method is sintering bonding.

[0053] Example 2

[0054] Please refer to Figures 3 to 10. This utility model provides a lithium battery.

[0055] As shown in Figure 4, the lithium battery includes a button cell top cover assembly as described in Embodiment 1; it also includes a housing 7, in which a battery cell 8 is installed in the internal cavity of the housing 7. A positive electrode tab is installed on one side of the battery cell 8, and a negative electrode tab is installed on the other side. The battery cell 8 and the housing 7 are connected by the negative electrode tab. The negative electrode tab is welded to the housing 7 to form a negative electrode tab weld point. The upper end of the housing 7 is welded to the annular cover plate 2 to form a positive electrode housing weld point. The battery cell 8 and the terminal post 3 are connected by the positive electrode tab. The positive electrode tab is welded to the terminal post 3 to form a positive electrode tab weld point. The sealing and connection are achieved through welding, which simplifies the sealing structure, improves production economy, and makes the sealing more precise and robust. It also makes it difficult for moisture to enter the battery and cause adverse reactions, resulting in more stable battery performance, longer storage time, and longer battery range.

[0056] The above embodiments are preferred embodiments of the present utility model, but the embodiments of the present utility model are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present utility model shall be considered equivalent substitutions and shall be included within the protection scope of the present utility model.

Claims

1. A button cell battery top cover assembly, characterized in that: The device includes a top cover assembly (1), which includes an annular cover plate (2) and a pole post (3). An annular insulating layer (4) is installed between the annular cover plate (2) and the pole post (3). The annular cover plate (2) includes an inclined cover plate (21), which is designed to be inclined downward. The inclined cover plate (21) has an inclination angle α with respect to the horizontal direction, and the inclination angle α is between 5° and 15°.

2. The button cell battery top cover assembly according to claim 1, characterized in that: The annular cover plate (2) further includes a flat cover plate (22), which is located outside the inclined cover plate (21); a connecting part (51) is provided between the flat cover plate (22) and the inclined cover plate (21), and the flat cover plate (22), the connecting part (51) and the inclined cover plate (21) are integrally formed.

3. The button cell battery top cover assembly according to claim 2, characterized in that: The connecting part (51) is a right-angle bend connecting part or a circular arc bend connecting part.

4. The button cell battery top cover assembly according to claim 1, characterized in that: The pole post (3) is also provided with a convex cover plate (31) in the middle, and the upper surface of the convex cover plate (31) is higher than the upper surface of the pole post (3).

5. A button cell battery top cover assembly according to claim 1, characterized in that: An insulating protrusion (41) is provided on one side of the annular insulating layer (4), and an annular cover plate (2) is installed on the outside of the insulating protrusion (41).

6. A button cell battery top cover assembly according to claim 5, characterized in that: The top surface of the insulating protrusion (41) is flush with the top surface of the annular cover plate (2).

7. A button cell battery top cover assembly according to claim 1, characterized in that: The outer diameter of the pole post (3) is smaller than the outer diameter of the annular insulating layer (4), the inner diameter of the annular insulating layer (4) is larger than the inner diameter of the annular cover plate (2), and the outer diameter of the annular insulating layer (4) is smaller than the outer diameter of the annular cover plate (2).

8. A button cell battery top cover assembly according to claim 4, characterized in that: The connection between the convex cover plate (31) and the pole post (3) is provided with a rounded chamfer (32).

9. A button cell battery top cover assembly according to claim 1, characterized in that: The bonding method between the annular cover plate (2), the pole post (3) and the annular insulating layer (4) is either hot pressing bonding or sintering bonding.

10. A lithium battery, characterized in that: The invention includes a button cell top cover assembly as described in any one of claims 1 to 9; it also includes a housing (7), wherein a cell (8) is installed in the internal cavity of the housing (7), a positive electrode tab is installed on one side of the cell (8), a negative electrode tab is installed on the other side, the cell (8) and the housing (7) are connected by the negative electrode tab, the upper end of the housing (7) is connected to the annular cover plate (2) by welding, and the cell (8) and the terminal post (3) are connected by the positive electrode tab.

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