Cylindrical secondary battery

Abstract

The utility model belongs to the technical field of batteries, and particularly relates to a cylindrical secondary battery. The device comprises: a housing, the interior of which is suitable for loading a battery; the top cover is suitable for covering the opening of the shell; wherein the top cover comprises a first platform, a second platform and a plurality of bridging parts which are arranged in parallel; the first platform is located on the side, away from the shell, of the second platform, and the bridging part is connected with the edges of the first platform and the second platform. The thickness of the bridging part is smaller than that of the first platform or the second platform; the bridging parts are arranged at intervals, so that a notch part is formed between every two adjacent bridging parts. The bridging parts are arranged to connect the first platform and the second platform, and the bridging parts are consistent with the internal pressure direction of the battery, so that the connection strength of the first platform and the second platform is improved, and meanwhile, the gap parts between the bridging parts can also be used as exhaust ports to discharge gas in the battery, so that the effect of adjusting the air pressure is achieved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to battery technical field, and specifically relates to a cylindrical secondary battery. BACKGROUND

[0002] The existing cylindrical secondary battery top cover is provided with a plurality of holes to facilitate the discharge of the gas in the cylindrical secondary battery and prevent the cylindrical secondary battery from exploding.

[0003] However, the strength of the top cover is reduced after the holes are opened, but if the thickness of the top cover is set to be too large, the top cover may not be disconnected when necessary, the pressure in the battery is not released, and an explosion is caused.

[0004] Therefore, it is urgent to provide a cylindrical secondary battery to solve the technical problem that the top cover cannot be disconnected to release the pressure when the top cover is too thick.

[0005] It should be noted that the above information disclosed in the background section is only used to understand the background of the present application, and therefore, it can contain information that does not constitute prior art. SUMMARY

[0006] The present disclosure provides at least a cylindrical secondary battery.

[0007] In a first aspect, the present disclosure provides a cylindrical secondary battery, comprising: a shell, the inside of which is suitable for loading a battery roll core;

[0008] a top cover suitable for covering the opening of the shell;

[0009] wherein the top cover comprises a first platform, a second platform and a plurality of bridge portions arranged in parallel;

[0010] The first platform is located on the side of the second platform away from the roll core, and the bridge portions connect the edges of the first platform and the second platform;

[0011] The thickness of the bridge portion is less than the thickness of the first platform or the second platform;

[0012] The bridge portions are arranged at intervals to form at least one gap portion between adjacent two bridge portions.

[0013] The ratio of the vertical projection area of all gap portions along the height direction of the core to the area of the first platform is between 10.7% and 28.7%.

[0014] In an optional embodiment, the distance H1 between the first platform and the second platform is 1-5mm.

[0015] In an optional embodiment, the edge of the second platform has at least 2 welding marks, and the welding marks are uniformly distributed along the circumference of the second platform.

[0016] The length of the welding mark is 5-23 mm;

[0017] The welding mark is in an arc shape or a straight line shape.

[0018] In an alternative embodiment, the cylindrical secondary battery further comprises an anti-explosion sheet, an insulating ring and a lower cover plate, the anti-explosion sheet and the lower cover plate are sequentially arranged on the side of the top cover facing the inside of the shell;

[0019] The insulating ring is arranged between the anti-explosion sheet and the lower cover plate;

[0020] And, the insulating ring is provided with a groove.

[0021] In an alternative embodiment, the lower cover plate has a thinning portion and a thickening portion, the thinning portion is arranged in close contact with the anti-explosion sheet, and the thickness of the thinning portion is 40%-50% of the thickness of the anti-explosion sheet;

[0022] The thickness of the thinning portion is 10%-70% of the thickness of the thickening portion.

[0023] In an alternative embodiment, the lower cover plate is engraved with a V-shaped groove, the angle of the engraved line of the V-shaped groove is 20°-60°, and the ratio of the depth to the width of the engraved groove is 90%-120%;

[0024] The lower cover plate is further provided with a plurality of exhaust holes.

[0025] In an alternative embodiment, the cylindrical secondary battery further comprises an outer rubber ring, the outer rubber ring covers the top cover and the anti-explosion sheet from the outside.

[0026] In an alternative embodiment, the top of the shell has a U-shaped groove, and the outer rubber ring is arranged above the U-shaped groove;

[0027] The depth H3 of the U-shaped groove is 1.2-2 mm, and the width H2 is 0.1-0.3 mm.

[0028] In an alternative embodiment, the shell further comprises an upper wrapping edge, and the outer rubber ring is arranged between the upper wrapping edge and the U-shaped groove;

[0029] The U-shaped groove extrudes the bottom of the outer rubber ring, and the compression amount is 30%-60%;

[0030] The upper wrapping edge extrudes the top of the outer rubber ring, and the compression amount is 20%-50%.

[0031] In an alternative embodiment, the outer rubber ring covers the edge of the upper surface of the top cover, and the covering distance L is 1.8-2.2 mm.

[0032] In an alternative embodiment, the Vickers hardness of the anti-explosion sheet and the lower cover plate is 12%-20% of the Vickers hardness of the top cover.

[0033] In an alternative embodiment, the lower cover plate breaks the current at a working pressure of 0.8-1.3 MPa, and the rupture disc releases pressure at a working pressure of 1.5-2.3 MPa.

[0034] The utility model discloses the beneficial effect is, the utility model discloses a bridge part is connected first platform and second platform to set up, and because the bridge part is with the pressure direction of battery inside consistent, thereby improve the connection strength of first platform and second platform, the gap part between bridge part can also be as exhaust port and discharge the gas in battery, reach the effect of pressure regulation.

[0035] Other features and advantages of the present application will be set forth in the following description of the drawings, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the application. The objects and other advantages of the present application will be realized and attained by the structure particularly pointed out in the description and claims of the present application.

[0036] In order to make the above-mentioned purpose, features and advantages of the utility model more obvious and easy to understand, the following preferred embodiments are taken as an example, and the detailed description is as follows in combination with the attached drawings. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the specific embodiment of the utility model or the technical scheme in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiment or the prior art description. Obviously, the drawings in the following description are some embodiments of the utility model, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0038] Figure 1 A cross-sectional view of a cylindrical secondary battery is provided for the embodiments of the present disclosure;

[0039] Figure 2 For Figure 1 A partial enlarged view of part A;

[0040] Figure 3 For Figure 1 A partial enlarged view of part B;

[0041] Figure 4 For Figure 1 A partial enlarged view of part C;

[0042] Figure 5 A top view of a top cover is provided for the embodiments of the present disclosure;

[0043] Figure 6 A cross-sectional view of a top cover is provided for the embodiments of the present disclosure;

[0044] Figure 7 A partial view of a housing is provided for the embodiments of the present disclosure.

[0045] In the drawings:

[0046] 1, housing; 11, U-shaped groove; 12, upper cover; 1, housing; 11, U-shaped groove; 12, upper cover;

[0047] 2, top cover; 21, first platform; 22, second platform; 23, bridge; 24, notch; 25, welding mark;

[0048] 3, rupture disc; 4, insulating ring; 41, groove;

[0049] 5, lower cover plate; 51, thinning portion; 52, thickening portion; 53, V-shaped groove;

[0050] 6, outer rubber ring. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme of the present application will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0052] It is found through research that the strength is reduced after the top cover is opened, but if the thickness of the top cover is set too large, the top cover may not be disconnected when necessary, the pressure inside the battery is not released, and an explosion is caused.

[0053] The defects of the above-mentioned solutions are the results obtained by the inventors after practice and careful research, therefore, the discovery process of the above-mentioned problems and the solutions proposed by the present disclosure to solve the above-mentioned problems should be the contributions made by the inventors to the present disclosure in the process of the present disclosure.

[0054] Some embodiments of the present application will be described in detail below with reference to the drawings. In the case of no conflict, the embodiments described below and the features in the embodiments can be combined with each other. In addition, in the drawings, in order to effectively describe the technical content, the thickness of the components can be exaggerated or reduced.

[0055] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0056] Based on the above research, with reference to Figure 1The cylindrical secondary battery provided by the embodiments of the present disclosure comprises: a shell 1, a top cover 2, an explosion-proof sheet 3, an insulating ring 4, a lower cover plate 5 and an outer rubber ring 6. The shell 1 is an external protective shell of the whole cylindrical secondary battery, the inside of the shell 1 is suitable for loading a battery roll core, and the top of the shell 1 is provided with an opening. The top cover 2 is suitable for covering the opening of the shell 1 to form a closed space.

[0057] With reference to Figure 5 In order to ensure that the top cover 2 can be broken under the impact of the internal pressure of the battery when necessary, the thickness of the top cover 2 should not be designed too thick, but too thin will also cause the strength of the top cover 2 to be insufficient. Therefore, in at least one embodiment, the top cover 2 comprises a first platform 21, a second platform 22 and a plurality of bridge portions 23 arranged in parallel. The first platform 21 and the second platform 22 are arranged concentrically, and the first platform 21 is located on the inner side of the second platform 22, and the first platform 21 is located on the side of the second platform 22 away from the shell 1, so that the first platform 21 and the second platform 22 have different heights. The bridge portion 23 connects the edges of the first platform 21 and the second platform 22. The thickness of the bridge portion is smaller than the thickness of the first platform 21 or the second platform 22. Through the above arrangement, the length direction of the bridge portion 23 is consistent with the pressure direction inside the cylindrical secondary battery, that is, the bridge portion 23 can support the first platform 21 and the second platform 22, thereby improving the strength of the top cover 2 without increasing the overall thickness of the top cover 2. At the same time, the bridge portions 23 are arranged at intervals, so that a gap portion 24 is formed between adjacent two bridge portions 23, and the gas inside the cylindrical secondary battery can be discharged through the gap portion 24. The area ratio of the vertical projection of all gap portions 24 along the height direction of the battery core to the area of the first platform 21 is between 10.7% and 28.7%. Preferably, the area ratio is between 14.7% and 24.7%. If the area ratio is too large, the strength of the top cover is low and cannot adapt to the use scene of the power tool. If the area ratio is too small, the exhaust effect is too poor, which affects the safety of the battery use.

[0058] As an option, the number of bridge portions 23 is 2-6. At the same time, with reference to Figure 6 In some embodiments, the bridge portion 23 is designed with a round corner, and the radius of the round corner is 0.5-1mm, so as to further enhance the strength of the first platform 21.

[0059] With reference to Figure 6 The distance between the first platform 21 and the second platform 22 is H1, and the value range of H1 is 1-5mm, that is, the length of the bridge portion 23 is equal to H1, so as to prevent the stress of the bridge portion 23 from being difficult to be normally released during the stamping and stretching process of the top cover 2 during manufacturing, causing the end strength of the bridge portion 23 to be insufficient or even broken.

[0060] With reference to Figure 5In some embodiments, the edge of the second platform 22 has at least two welds 25 evenly distributed along the circumference of the second platform 22. Optionally, the welds 25 are arc-shaped, linear, or irregularly curved to make the connection between the top cover 2 and the rupture disc 3 more stable. In at least one embodiment, the length of the welds 25 is 5-23 mm, and the welds 25 are arc-shaped or linear.

[0061] Referring to Figure 3 In at least one embodiment, the cylindrical secondary battery further includes a rupture disc 3, an insulating ring 4, and a lower cover plate 5, which are sequentially arranged on the side of the top cover 2 facing the winding core. The insulating ring 4 is provided with a groove 41 to accommodate the rupture disc 3 with a stepped shape, and the groove 41 is embedded with the step of the rupture disc 3 through adhesive sealing to enhance the internal sealing of the battery.

[0062] The insulating ring 4 is arranged between the rupture disc 3 and the lower cover plate 5. When the lower cover plate 5 is disconnected from the rupture disc 3, the battery is disconnected, and the insulating ring 4 acts as a barrier to prevent the internal pressure from lifting the lower cover plate 5 to contact the rupture disc 3 again, thereby improving safety performance. The material of the insulating ring 4 is PBT plastic, which has a high melting point to prevent the insulating ring 4 from melting due to excessive heat inside the battery. PBT can effectively prevent the leakage of materials inside the battery and prevent foreign matter from entering the battery, thereby protecting the integrity and safety of the internal structure of the battery. The battery generates heat during charging and discharging, and PBT plastic has excellent thermal stability and heat dissipation. Therefore, the PBT plastic ring of the cylindrical battery can withstand the high temperature generated during the operation of the battery, ensuring that the battery can still maintain stable performance in a high-temperature environment. In addition, PBT plastic also has good electrical insulation performance, which can prevent short circuits between different components inside the battery, further improving the safety and reliability of the battery.

[0063] Referring to Figure 2 In at least one embodiment, the lower cover plate 5 has a thinned portion 51 and a thickened portion 52. The thinned portion 51 is arranged to fit the rupture disc 3, and the thickness of the thinned portion 51 is 40-50% of the thickness of the rupture disc 3. The thickness of the thinned portion 51 is 10-70% of the thickness of the thickened portion 52. The lower cover plate 5 is fixed by laser welding at the position of the thinned portion 51 and the rupture disc 3. The thinned portion 51 is beneficial to laser penetration welding.

[0064] Referring to Figure 2 In at least one embodiment, the lower cover plate 5 is engraved with a V-shaped groove 53, and the angle of the engraved line of the V-shaped groove 53 is 20°-60°. The ratio of the depth to the width of the groove is 90%-120%. The lower cover plate 5 is also provided with a plurality of exhaust holes. When the internal pressure of the battery is higher than the safety pressure threshold, the lower cover plate 5 can impact the V-shaped groove 53 through the pressure impact, so that the lower cover plate 5 breaks along the V-shaped groove 53, the battery current is disconnected, and safety is ensured.

[0065] Referring to Figure 4 In order to improve the sealing performance of the battery, in at least one embodiment, the cylindrical secondary battery further comprises an outer rubber ring 6, which covers the top cover 2 and the explosion-proof sheet 3 from the outside. The outer rubber ring 6 is made of a flexible material, so that the outer rubber ring 6 can stretch and deform to a certain extent under pressure. That is, the outer rubber ring 6 can press the edges of the top cover 2 and the explosion-proof sheet 3 together under pressure and seal the gap between the top cover 2, the explosion-proof sheet 3 and the shell 1.

[0066] Referring to Figure 4 In some embodiments, the top of the shell 1 has a U-shaped groove 11, and the outer rubber ring 6 is arranged above the U-shaped groove 11. In the manufacturing process, the top of the shell 1 is first pressed into a V-shaped groove, and then the V-shaped groove is extruded into a U-shaped groove 11 by a grinding tool. In this way, the parallelism of the two side walls of the U-shaped groove 11 after forming can be improved. Figure 7 The depth H3 of the U-shaped groove 11 is 1.2-2mm, and the width H2 is 0.1-0.3mm.

[0067] Referring to Figure 4 In at least one embodiment, the shell 1 further comprises an upper wrapping edge 12, and the outer rubber ring 6 is arranged between the upper wrapping edge 12 and the U-shaped groove 11. The upper wrapping edge 12 and the U-shaped groove 11 respectively cover and extrude the outer rubber ring 6 from both sides, so that the outer rubber ring 6 tightly wraps the top cover 2 and the explosion-proof sheet 3. The U-shaped groove 11 extrudes the bottom of the outer rubber ring 6, and the compression amount is 30%-60%. The upper wrapping edge 12 extrudes the top of the outer rubber ring 6, and the compression amount is 20%-50%. The outer rubber ring 6 covers the edge of the upper surface of the top cover 2, and the covering distance is 1.8-2.2mm. The shell 1 covers the edge of the upper surface of the outer rubber ring 6, and the covering distance L is 1.3-1.8mm. The Vickers hardness of the explosion-proof sheet 3 and the lower cover plate 5 is 12%-20% of that of the top cover 2. The ratio of the electrolyte injection amount to the total weight of the battery is 7%-13%. The working pressure of the lower cover plate 5 to break the current is 0.8-1.3MPa, and the working pressure of the explosion-proof sheet 3 to release pressure is 1.5-2.3MPa.

[0068] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other ways. The above-described device embodiments are only illustrative, for example, the division of the units is only a logical function division, and actual implementation can have another division manner, and for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. With the above ideal embodiments of the present application as the inspiration, through the above description, relevant personnel can make various changes and modifications without deviating from the technical idea of the present application. The technical scope of the present application is not limited to the content in the specification, and the technical scope must be determined according to the scope of claims.

Claims

1. A cylindrical secondary battery characterized by comprising: The application relates to a cylindrical secondary battery, which comprises: a shell (1) with an inner part suitable for loading a battery roll core; a top cover (2) suitable for covering the opening of the shell (1); wherein the top cover (2) comprises a first platform (21), a second platform (22) and a plurality of bridge portions (23) arranged in parallel; the first platform (21) is located on the side of the second platform (22) away from the roll core, and the bridge portions (23) connect the edges of the first platform (21) and the second platform (22); the thickness of the bridge portions is smaller than the thickness of the first platform (21) or the second platform (22); the bridge portions (23) are arranged at intervals so that at least one gap portion (24) is formed between two adjacent bridge portions (23), and the area ratio of the vertical projection of all gap portions (24) along the height direction of the battery core to the area of the first platform (21) is between 10.7% and 28.7%.

2. The cylindrical secondary battery according to claim 1, wherein the distance H1 between the first platform (21) and the second platform (22) is 1-5 mm.

3. The cylindrical secondary battery according to claim 1, wherein the edge of the second platform (22) has at least two welding marks (25) which are uniformly distributed along the circumferential direction of the second platform (22); the length of the welding mark (25) is 5-23 mm; the welding mark (25) is in the shape of an arc or a straight line.

4. The cylindrical secondary battery according to claim 1, wherein the cylindrical secondary battery further comprises an explosion-proof sheet (3), an insulating ring (4) and a lower cover plate (5), the explosion-proof sheet (3) and the lower cover plate (5) are sequentially arranged on the side of the top cover (2) facing the roll core; the insulating ring (4) is arranged between the explosion-proof sheet (3) and the lower cover plate (5); and a groove (41) is arranged on the insulating ring (4).

5. The cylindrical secondary battery according to claim 4, wherein the lower cover plate (5) has a thinned portion (51) and a thickened portion (52), the thinned portion (51) is arranged in close contact with the explosion-proof sheet (3), and the thickness of the thinned portion (51) is 40%-50% of the thickness of the explosion-proof sheet (3); the thickness of the thinned portion (51) is 10%-70% of the thickness of the thickened portion (52).

6. The cylindrical secondary battery according to claim 4, wherein the lower cover plate (5) is engraved with a V-shaped groove (53), the angle of the engraved line of the V-shaped groove (53) is 20-60 degrees, and the ratio of the groove depth to the groove width is 90%-120%; the lower cover plate (5) is further provided with a plurality of exhaust holes.

7. The cylindrical secondary battery according to claim 4, wherein the cylindrical secondary battery further comprises an outer rubber ring (6), and the outer rubber ring (6) covers the top cover (2) and the explosion-proof sheet (3) from the outside.

8. The cylindrical secondary battery according to claim 7, wherein the top of the shell (1) has a U-shaped groove (11), and the outer rubber ring (6) is arranged above the U-shaped groove (11); the depth H3 of the U-shaped groove (11) is 1.2-2 mm, and the width H2 is 0.1-0.3 mm.

9. The cylindrical secondary battery according to claim 8, wherein ​ ​ ​ ​ ​ ​ ​ The shell (1) further comprises an upper wrapping edge (12), and the outer rubber ring (6) is arranged between the upper wrapping edge (12) and the U-shaped groove (11); The U-shaped groove (11) extrudes the bottom of the outer rubber ring (6), and the compression amount is 30%-60%; The upper wrapping edge (12) extrudes the top of the outer rubber ring (6), and the compression amount is 20%-50%.

10. The cylindrical secondary battery of claim 7, wherein The outer rubber ring (6) covers the edge of the upper surface of the top cover (2), and the covering distance L is 1.8-2.2 mm.

11. The cylindrical secondary battery of claim 4, wherein The Vickers hardness of the rupture disc (3) and the lower cover plate (5) is 12%-20% of that of the top cover (2).

12. The cylindrical secondary battery of claim 4, wherein The working pressure of the lower cover plate (5) for breaking the current is 0.8-1.3 MPa, and the working pressure of the rupture disc (3) for pressure relief is 1.5-2.3 MPa.

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