Top cover and cap cover for cylindrical lithium ion battery and structure capable of realizing thermal instability through battery core

Abstract

The utility model discloses a top cover, a cap and a structure capable of losing stability through battery cell heat for a cylindrical lithium ion battery, the top cover comprises a top cover body, the top cover body comprises an annular part, a central pressure relief hole and a convex shielding part, and the convex shielding part comprises an inclined support leg part and a flat top shielding part; the inclined supporting leg parts incline in the direction away from the annular part, and the top ends of the inclined supporting leg parts are connected with the flat-top shielding part. A thinning structure is arranged on the inner wall of the joint of the inclined supporting leg part and the flat-top shielding part; the edge, located between every two adjacent inclined supporting leg parts, of the flat-top shielding part is a straight line edge. A pressure relief channel is formed by the straight line edge, the corresponding part, exposed out of the flat-top shielding part, of the central pressure relief hole and the two inclined supporting leg parts; the cap comprises a top cover, an anti-explosion piece, a connecting piece, an isolation ring and a sealing ring. According to the utility model, the edge of the flat-top shielding part is adjusted to be the linear edge, the area of the pressure relief channel is increased compared with the traditional arc-shaped edge, the thinning structure is arranged at the joint of the flat-top shielding part and the inclined supporting leg part, so that the flat-top shielding part is easier to break, the pressure relief speed is increased, the pressure relief time is advanced, and the thickness of the steel shell is increased, so that the steel shell can bear higher pressure; the battery adopting the structure provided by the utility model can safely pass through the thermal instability test, and the passing rate is high.

Description

Technical Field

[0001] The utility model belongs to the structure of cylindrical lithium secondary batteries, and particularly relates to a top cover, a cap and a structure capable of passing through the thermal instability of battery cells for a cylindrical lithium ion battery. Background Art

[0002] With the increasingly wide application of cylindrical lithium ion batteries, the safety and service life of the batteries have also received more and more attention. A cylindrical lithium ion battery generally consists of a steel shell, a battery electrode group, a cap and other structures. Among them, the cylindrical steel shell and the cap play the roles of accommodating the electrode group and sealing the battery, and are crucial for the safety of the battery monomer.

[0003] There are two types of existing cylindrical shells for lithium secondary batteries: explosion-proof and non-explosion-proof. The explosion-proof steel shell is relatively easy to pass the thermal instability test. However, due to different welding and assembly methods of the Pack factory, it may cause the pressure relief valve of the explosion-proof steel shell not to open, resulting in a chamber explosion. For the traditional non-explosion-proof steel shell with a conventional cap, the passing probability of the thermal instability of the battery cell is very low, and the chamber explosion phenomenon is more serious. Summary of the Utility Model

[0004] The utility model provides a top cover, a cap and a structure capable of passing through the thermal instability of battery cells for a cylindrical lithium ion battery, which are used to solve the technical problems of low passing rate of the existing thermal instability of battery cells and serious chamber explosion.

[0005] The technical solution adopted by the utility model is as follows:

[0006] A top cover for a cylindrical lithium ion battery, including a top cover body, the top cover body includes an annular part, a central pressure relief hole and a convex shielding part, the convex shielding part includes an inclined leg part and a flat top shielding part; the inclined leg part inclines away from the annular part, and the top end part of the inclined leg part is connected to the flat top shielding part; a thinning structure is arranged on the inner wall at the connection of the inclined leg part and the flat top shielding part; and the side of the flat top shielding part located between two adjacent inclined leg parts is a straight side; the straight side, the corresponding part of the central pressure relief hole exposing the flat top shielding part and the two inclined leg parts form a pressure relief channel. The structure of the used top cover is improved, the side of the flat top shielding part is adjusted to be a straight side, which increases the area of the pressure relief channel compared with the traditional arc side, and a thinning structure is arranged at the connection of the flat top shielding part and the inclined leg part to make it easier to break, so as to accelerate the pressure relief speed and advance the pressure relief time, and avoid the occurrence of chamber explosion.

[0007] As a preferred scheme of the utility model, the thinning structure is a thinning groove, and the bottom of the thinning groove is flush with the inner end surface of the flat top shielding part. It only needs to be thinned at the connection of the flat top shielding part and the inclined leg part, which can accelerate the pressure relief and advance the pressure relief.

[0008] As a preferred embodiment of the present utility model, the bottom end of the inclined leg is disposed on the annular wall of the central pressure relief hole, and the thickness of the inclined leg is the same as that of the annular portion.

[0009] As a preferred embodiment of the present utility model, the inclined leg, the flat top shielding portion and the annular portion are integrally formed structures.

[0010] As a preferred embodiment of the present utility model, there are three inclined legs, and the inclined legs are symmetrically distributed along the center of the central pressure relief hole.

[0011] The present utility model also provides a cap for a cylindrical lithium-ion battery, including the above-mentioned top cover, explosion-proof sheet, connecting sheet, isolation ring and sealing ring; the annular portion of the top cover contacts the explosion-proof sheet, and the annular portion and the explosion-proof sheet are laser welded together. There are three laser welding positions, which are annularly distributed on the edge of the annular portion.

[0012] The present utility model also provides a structure that can pass through the thermal instability of the battery cell, including the above-mentioned cap and the steel shell, and the steel shell is provided with a thickened portion. The steel shell is thicker than the existing steel shell used, can withstand greater pressure, and to a certain extent prevent the battery cell from bursting. And the structure of the top cover in the used cap is improved, increasing the top pressure relief area, advancing the pressure relief time of the top cover, reducing the pressure inside the battery cell, and avoiding the explosion of the steel shell.

[0013] The present utility model improves the structure of the used top cover, adjusts the edge of the flat top shielding portion to a straight edge, increases the area of the pressure relief channel compared with the traditional arc edge, and sets a thinning structure at the connection between the flat top shielding portion and the inclined leg to make it easier to break, accelerating the pressure relief speed and advancing the pressure relief time, increasing the thickness of the steel shell so that it can withstand greater pressure and avoid bursting. The battery using the structure of the present utility model can safely pass the thermal instability test with a high passing rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0015] Figure 1 It is a schematic structural view of the top cover of the present utility model.

[0016] Figure 2 It is a sectional view of the top cover of the present utility model.

[0017] Figure 3 It is a top view of the cap of the present utility model.

[0018] Figure 4 This is the bottom view of the cap of the present utility model.

[0019] Figure 5 This is the cross-sectional view of the cap of the present utility model. Specific embodiments

[0020] The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0021] Embodiment 1:

[0022] A top cover for a cylindrical lithium-ion battery, as Figure 1 and 2 shown, includes a top cover body 1, the top cover body 1 includes an annular portion 11, a central pressure relief hole 12 and a convex shielding portion 13, and the convex shielding portion 13 includes inclined support legs 131 and a flat top shielding portion 132; there are three inclined support legs 131, and the inclined support legs 131 are symmetrically distributed along the center of the central pressure relief hole. And the inclined support legs 131, the flat top shielding portion 132 and the annular portion 11 are an integrally formed structure.

[0023] Each inclined support leg 131 inclines away from the annular portion, the bottom end of the inclined support leg 131 is arranged on the annular wall of the central pressure relief hole 12 and the thickness of the inclined support leg is the same as the thickness of the annular portion 11.

[0024] The top ends of the three inclined support legs 131 are all connected to the same flat top shielding portion 132; a thinning structure 134 is provided on the inner wall at the connection between the inclined support leg 131 and the flat top shielding portion 132. As Figure 2 shown, in this embodiment, the thinning structure 134 adopts a thinning groove, and the bottom of the thinning groove is flush and butt-jointed with the inner end face of the flat top shielding portion. It only needs to be thinned at the connection between the flat top shielding portion and the inclined support leg, which can accelerate pressure relief and relieve pressure in advance.

[0025] The edge of the flat top shielding portion 132 between adjacent two inclined support legs 131 is a straight edge 133; the straight edge and the corresponding part of the central pressure relief hole 12 exposing the flat top shielding portion and the two inclined support legs form a pressure relief channel 3.

[0026] Improve the top cover structure to be used, adjust the edge of the flat top shielding part to a straight edge, increase the area of the pressure relief channel compared with the traditional arc edge, and set a thinning structure at the connection between the flat top shielding part and the inclined supporting leg to make it easier to rupture, accelerate the pressure relief speed and advance the pressure relief time, and avoid chamber explosion.

[0027] Embodiment 2:

[0028] A cap for a cylindrical lithium-ion battery, as Figures 3 - 5 shown, includes the top cover in Embodiment 1, an explosion-proof sheet 4, a connecting sheet 5, an isolation ring 6 and a sealing ring 7; the annular part 11 of the top cover contacts the explosion-proof sheet 4, and they are laser welded together between the annular part 11 and the explosion-proof sheet 4. There are three laser welding positions, which are distributed in a ring at the edge of the annular part. The assembly relationship among the top cover, the explosion-proof sheet 4, the connecting sheet 5, the isolation ring 6 and the sealing ring 7 is the same as the connection relationship of the cap for a cylindrical lithium-ion battery with the authorization publication number CN207676956U and the patent name of cap for a cylindrical lithium-ion battery, which will not be elaborated herein.

[0029] Embodiment 3:

[0030] A structure that can be thermally unstable through the battery cell, includes the cap in Embodiment 2 and a steel shell, and the steel shell is provided with a thickening part. The steel shell is thicker than the existing steel shell used, can withstand greater pressure, and to a certain extent prevent the chamber explosion of the battery cell. And the top cover structure in the used cap is improved, increasing the top pressure relief area, advancing the top cover pressure relief time, reducing the pressure inside the battery cell, and avoiding the steel shell explosion.

[0031] In the description of this specification, the descriptions with reference to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0032] The above is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and the inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A top cover for a cylindrical lithium-ion battery, comprising a top cover body (1), wherein the top cover body (1) includes an annular portion (11), a central pressure relief hole (12), and a raised shielding portion (13), and is characterized in that: The convex shielding portion (13) includes an inclined support leg portion (131) and a flat top shielding portion (132); the inclined support leg portion (131) inclines away from the annular portion, and the top end portion of the inclined support leg portion (131) is connected to the flat top shielding portion (132); a thinning structure is provided on the inner wall at the connection of the inclined support leg portion (131) and the flat top shielding portion (132); and the side of the flat top shielding portion (132) located between two adjacent inclined support leg portions (131) is a straight edge; the straight edge, the corresponding part of the central pressure relief hole (2) exposed from the flat top shielding portion, and the two inclined support leg portions form a pressure relief channel (3).

2. The top cover for a cylindrical lithium-ion battery according to claim 1, wherein: The thinning structure is a thinning groove, and the bottom of the thinning groove is flush and butt-jointed with the inner end face of the flat top shielding portion.

3. The top cover for a cylindrical lithium-ion battery according to claim 1 or 2, characterized in that: The bottom end portion of the inclined support leg portion (131) is arranged on the annular wall of the central pressure relief hole (12), and the thickness of the inclined support leg portion is the same as the thickness of the annular portion (11).

4. The top cover for a cylindrical lithium-ion battery according to claim 3, characterized in that: The inclined support leg portion (131), the flat top shielding portion (132), and the annular portion (11) are an integrally formed structure.

5. The top cover for a cylindrical lithium-ion battery according to claim 3, characterized in that: There are three inclined support leg portions (131), and the inclined support leg portions (131) are symmetrically distributed along the center of the central pressure relief hole.

6. A cap for a cylindrical lithium-ion battery, characterized in that: It includes a top cover, an explosion-proof sheet (4), a connecting sheet (5), a spacer ring (6), and a sealing ring (7) as described in any one of claims 1-5; the annular portion (11) of the top cover contacts the explosion-proof sheet (4), and the annular portion (11) and the explosion-proof sheet (4) are laser welded together.

7. A structure that can be caused by thermal instability of the battery cell, characterized in that: It includes a cap and a steel shell as described in claim 6, and the steel shell is provided with a thickening portion.

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