Cylindrical lithium battery

Abstract

The utility model relates to the technical field of lithium ion batteries, and discloses a cylindrical lithium battery which comprises a metal shell with an opening at the upper end, the positive electrode cover covers the opening, and a pressure relief hole is formed in the central part of the positive electrode cover; the positive electrode cap comprises a tubular side wall and a cap surface connected to the upper end of the tubular side wall, and the lower end of the tubular side wall is fixed on the positive electrode cap and surrounds the pressure relief hole; the conductive sealing column comprises a vertically arranged columnar main body and a lower end part, the columnar main body is arranged in the positive electrode cap in a non-contact manner, the lower end part is arranged in the pressure relief hole, a gap is formed between the lower end part and the pressure relief hole, and an insulating sealing ring is arranged at the gap in an extruding manner; the sealing column can be pushed by high-pressure gas in the metal shell to open the pressure relief hole; the two ends of the welding wire are fixedly connected with the sealing column and the positive electrode cap respectively, and the welding wire can be snapped when the sealing column is pushed. The cylindrical lithium battery can release high-pressure gas in the cylindrical lithium battery in time, open-circuit protection is formed, and the safety performance is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium-ion batteries, and particularly relates to a cylindrical lithium battery. Background Art

[0002] The cylindrical lithium battery is a commonly used lithium-ion battery, and is widely used in many fields such as electric vehicles, electric tools, electronic products and energy storage products due to its advantages such as high energy density and long cycle life. When the cylindrical lithium battery has short circuit, overcharge, over-discharge and extrusion phenomena, it will fail, and violent reactions will occur inside the battery, generating a large amount of gas and a sudden increase in pressure. Along with the increase in the surface temperature of the battery, continuous occurrence of this phenomenon will cause the battery to deform and expand, and even cause fire and explosion. At present, the battery generally adopts a current cut-off device (CID) for protection. When the internal pressure of the battery is too high, the pressure relief piece in the CID flips to form an open circuit protection. When the battery fails, if there is too much gas inside the battery, even if the CID can instantly cut off the current, the internal high-pressure gas cannot be released in time, and there will still be safety risks such as battery deformation, expansion, fire and explosion. Summary of the Utility Model

[0003] The purpose of the utility model is to provide a cylindrical lithium battery to solve the problem of safety risks caused by too high internal pressure of the existing cylindrical lithium battery.

[0004] In order to achieve the above purpose, the utility model provides a cylindrical lithium battery, including:

[0005] A cylindrical metal shell, with an opening formed at the upper end of the metal shell;

[0006] A positive electrode cover, which is covered at the opening, and a pressure relief hole is opened in the central part of the positive electrode cover;

[0007] A positive electrode cap, which includes a tubular side wall and a cover surface connected to the upper end of the tubular side wall. The lower end of the tubular side wall is fixed on the positive electrode cover and surrounds the pressure relief hole;

[0008] A conductive sealing column, which includes a vertically arranged columnar main body and a lower end part. The columnar main body is arranged non-contactingly inside the positive electrode cap, and the lower end part is arranged in the pressure relief hole and forms a gap with the pressure relief hole. An insulating sealing ring is squeezed at the gap. The sealing column is arranged to be pushed by the high-pressure gas in the metal shell to open the pressure relief hole; and

[0009] A welding wire, the first end of the welding wire is welded and fixed to the sealing column, and the second end of the welding wire is welded and fixed to the positive electrode cap. When the sealing column is pushed, the welding wire can be broken.

[0010] Preferably, an installation groove is provided in the central part of the cover surface, and a pressure sensor is arranged in the installation groove; a through hole penetrating the cover surface downward is opened at the bottom of the installation groove, and the upper end of the sealing column can pass through the through hole to contact the sensing surface of the pressure sensor; the pressure sensor is configured to detect the pressure received from the upper end of the sealing column.

[0011] Preferably, the pressure sensor is connected to an alarm, and the alarm is configured to receive the pressure detected by the pressure sensor and execute an alarm when the pressure exceeds a preset value.

[0012] Preferably, an annular groove is formed on the side wall of the lower end portion of the sealing column, and the inner ring of the insulating sealing ring is in sealing fit with the annular groove.

[0013] Preferably, the pressure relief hole is a frustum-shaped hole, and the lower end portion of the sealing column is frustum-shaped to cooperate with the frustum-shaped hole.

[0014] Preferably, the sealing column further includes a lug arranged on the side surface of the columnar main body, and the first end of the welding wire is welded to the lug; and / or, a welding hole is formed in the tubular side wall, and the second end of the welding wire is welded and fixed in the welding hole.

[0015] Preferably, the cylindrical lithium battery further includes a return spring sleeved on the outer periphery of the columnar main body, the lower end of the return spring is fixed to the lower end portion of the sealing column, and the upper end of the return spring is fixed to the lower surface of the cover surface.

[0016] Preferably, the material of the welding wire is tin.

[0017] Preferably, an electric core is arranged in the metal shell, a gap is formed between the side wall of the electric core and the metal shell, and the positive electrode tab of the electric core is connected to the lower end of the sealing column.

[0018] Preferably, an insulating pressure ring is fixedly arranged on the lower surface of the positive electrode cover, and the insulating pressure ring is embedded in the gap.

[0019] Compared with the prior art, the utility model has the following beneficial effects:

[0020] (1) For this cylindrical lithium battery, the pressure relief hole is sealed by arranging a movable sealing column. The sealing column is pushed by the high-pressure gas in the metal shell to open the pressure relief hole, and the high-pressure gas is discharged from the metal shell through the pressure relief hole and the exhaust hole, so that the high-pressure gas inside the battery can be released in time, avoiding accidents such as fire and explosion, and improving the safety performance of the battery;

[0021] (2) The sealing column and the positive electrode cap are connected by a welding wire, and the welding wire can be broken when the sealing column is pushed, so that the connection between the sealing column and the positive electrode cap is disconnected, ensuring open-circuit protection when the internal pressure of the battery is too high, further improving the safety performance of the battery, and facilitating the subsequent recycling of faulty batteries;

[0022] (3) The strength requirement for the metal casing of this cylindrical lithium battery is reduced, improving its practicality and enabling the reduction of production costs.

[0023] Other features and advantages of the present utility model will be described in detail in the following specific implementation section. Description of the Drawings

[0024] Figure 1 is a cross-sectional view of a cylindrical battery in an embodiment.

[0025] Figure 2 is Figure 1 an enlarged view of part A of the cylindrical battery in

[0026] Figure 3 is a cross-sectional view of the assembled structure of a positive electrode cover, a positive electrode cap, and a sealing post in an embodiment.

[0027] Figure 4 is a schematic structural view of a sealing post in an embodiment.

[0028] Among them, the description of the reference numerals is as follows:

[0029] 1 - metal casing; 2 - positive electrode cover; 201 - pressure relief hole; 3 - positive electrode cap; 301 - tubular side wall; 302 - cover surface; 303 - exhaust hole; 4 - sealing post; 401 - columnar main body; 402 - lower end portion; 403 - lug; 5 - insulating sealing ring; 6 - welding wire; 7 - installation groove; 8 - pressure sensor; 9 - return spring; 10 - battery cell; 11 - insulating pressing ring. Specific Embodiments

[0030] The following details the specific embodiments of the present utility model with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for explaining and illustrating the present utility model and are not intended to limit the present utility model.

[0031] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "set", "installed", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0032] In the description of the present invention, unless otherwise stated, the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or the directions or positional relationships in which the product of the application is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0033] In addition, if there are descriptions involving "first", "second", etc. in the utility model, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0034] Reference Figures 1-4 , an embodiment provides a cylindrical lithium battery, comprising:

[0035] A cylindrical metal shell 1, wherein an opening is formed at the upper end of the metal shell 1;

[0036] The positive electrode cover 2 is provided at the opening, and a pressure relief hole 201 is provided in the central part of the positive electrode cover 2;

[0037] The positive electrode cap 3 includes a tubular side wall 301 and a cover surface 302 connected to the upper end of the tubular side wall 301. The lower end of the tubular side wall 301 is fixed to the positive electrode cover 2 and surrounds the pressure relief hole 201. The tubular side wall 301 is provided with an exhaust hole 303.

[0038] A conductive sealing column 4, the sealing column 4 comprises a vertically arranged columnar body 401 and a lower end 402, the columnar body 401 is arranged inside the positive electrode cap 3 in a non-contact manner, the lower end 402 is arranged in the pressure relief hole 201 and forms a gap between the pressure relief hole 201, an insulating sealing ring 5 is squeezed and arranged in the gap, and the sealing column 4 is arranged to be pushed by the high-pressure gas in the metal shell 1 to open the pressure relief hole 201; and

[0039] The welding wire 6 has a first end that is welded and fixed to the sealing column 4 and a second end that is welded and fixed to the positive electrode cap 3 . The welding wire 6 can be broken when the sealing column 4 is pushed.

[0040] It should be noted that when the sealing column 4 is pushed to open the pressure relief hole 201, it is not necessary for the sealing column 4 to completely detach from the pressure relief hole 201. It is only necessary to ensure that the seal between the sealing column 4 and the pressure relief hole 201 fails after the sealing column 4 is loosened. At this time, the high-pressure gas in the metal shell 1 can be discharged through the pressure relief hole 201 and the exhaust port.

[0041] For this cylindrical lithium battery, the relief hole 201 is sealed by arranging a movable sealing post 4. The sealing post 4 is pushed by the high-pressure gas in the metal casing 1 to open the relief hole 201, and the high-pressure gas is discharged from the metal casing 1 through the relief hole 201 and the exhaust hole 303. Thus, the high-pressure gas inside the battery can be released in time, avoiding accidents such as fire and explosion, and improving the safety performance of the battery. The sealing post 4 is connected to the positive electrode cap 3 through a welding wire 6, and the welding wire 6 can be broken when the sealing post 4 is pushed, so that the connection between the sealing post 4 and the positive electrode cap 3 is disconnected, ensuring open-circuit protection when the internal pressure of the battery is too high, further improving the safety performance of the battery, and facilitating the recycling of faulty batteries. In addition, the requirement for the strength of the metal casing 1 of this cylindrical lithium battery is reduced, improving the practicability and reducing the production cost.

[0042] Continue to refer to Figures 2-3 , in an embodiment, an installation groove 7 is provided in the central part of the cover surface 302, and a pressure sensor 8 is arranged in the installation groove 7; a through hole penetrating the cover surface 302 downward is opened at the bottom of the installation groove 7, and the upper end of the sealing post 4 can pass through the through hole to contact the sensing surface of the pressure sensor 8; the pressure sensor 8 is arranged to be able to detect the pressure received from the upper end of the sealing post 4. When the sealing post 4 is pushed upward by the high-pressure gas in the metal casing 1, the upper end of the sealing post 4 forms a pressure on the sensing surface of the pressure sensor 8, and then this pressure is detected by the pressure sensor 8. When the pressure sensor 8 shows pressure, it indicates that the sealing post 4 is pushed, and thus it can reflect that high pressure has been formed inside the metal casing 1. Further, the pressure sensor 8 is connected to an alarm, and the alarm is arranged to receive the pressure detected by the pressure sensor 8 and execute an alarm when the pressure exceeds a preset value. The alarm can timely remind the operator that the cylindrical lithium battery has a fault and help the operator quickly lock the faulty battery.

[0043] The insulating sealing ring 5 arranged at the gap between the lower end portion 402 of the sealing post 4 and the relief hole 201 can not only ensure that the sealing post 4 is firmly sealed and connected to the relief hole 201, but also prevent direct contact and conduction between the lower end portion 402 of the sealing post 4 and the positive electrode cover 2; furthermore, conduction between the sealing post 4 and the positive electrode cap 3 can only be achieved through the welding wire 6. In an embodiment, an annular groove is provided on the side wall of the lower end portion 402 of the sealing post 4, and the inner ring of the insulating sealing ring 5 is in sealing cooperation with the annular groove. The annular groove can limit the insulating sealing ring 5, improve the stability of the insulating sealing ring 5, and improve the sealing effect. The outer ring of the insulating sealing ring 5 is closely attached to the inner wall of the relief hole 201 to ensure the sealing effect. Exemplarily, the insulating sealing ring 5 is a rubber sealing ring.

[0044] In one embodiment, the pressure relief hole 201 is a frustum-shaped hole, and the lower end portion 402 of the sealing column 4 is frustum-shaped to cooperate with the frustum-shaped hole. The side wall of the frustum-shaped hole can provide an upward supporting force for the insulating sealing ring 5 and the sealing column 4, improving the stability of the sealing column 4.

[0045] Continuing to refer to Figure 4 , in one embodiment, the sealing column 4 further includes a lug 403 disposed on the side surface of the columnar main body 401. The first end of the welding wire 6 is welded to the lug 403. The lug 403 extends radially outward along the columnar main body 401. A welding hole 304 is formed in the tubular side wall 301, and the second end of the welding wire 6 is welded and fixed in the welding hole 304 to improve the stability of the welding wire 6 and prevent the welding wire 6 from falling off during the production, testing or transportation of the cylindrical battery. The number of lugs 403 can be set as required. Exemplarily, two lugs 403 are provided. The number of welding wires 6, the number of welding holes 304 and the number of lugs 403 are the same.

[0046] Continuing to refer to Figure 3 , in one embodiment, the cylindrical lithium battery further includes a return spring 9. The return spring 9 is sleeved on the outer periphery of the columnar main body 401. The lower end of the return spring 9 is fixed to the lower end portion 402 of the sealing column 4, and the upper end of the return spring 9 is fixed to the lower surface of the cover plate 302. To better fix the lower end of the return spring 9 to the lower end portion 402 of the sealing column 4, a surface can be formed at the upper end of the lower end portion 402 of the sealing column 4, and the area of this surface exceeds the area of the lower end of the columnar main body 401 connected thereto, so that a part of this surface is exposed, and the lower end of the spring can be fixed to this exposed part.

[0047] In one embodiment, the material of the welding wire 6 is tin, and tin has the characteristic of being easily broken, so as to ensure that when the sealing column 4 is pushed, the welding wire 6 can be broken in time. The material of the welding wire 6 can also be selected as other brittle conductive materials, such as aluminum.

[0048] In one embodiment, a battery cell 10 is disposed in the metal shell 1, and a gap is formed between the side wall of the battery cell 10 and the metal shell 1. The positive electrode tab of the battery cell 10 is connected to the lower end of the sealing column 4. This gap can ensure insulation between the battery cell 10 and the metal shell 1. Further, an insulating pressure ring 11 is fixedly disposed on the lower surface of the positive electrode cover 2, and the insulating pressure ring 11 is embedded in the gap. This insulating pressure ring 11 can further ensure insulation between the battery cell 10 and the metal shell 1 and improve the safety performance.

[0049] In the description of this specification, the description referring to terms such as "one embodiment" or "example" means 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 this. In this specification, the schematic expression of the above terms does 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. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification.

[0050] The preferred embodiments of the present utility model have been described in detail above in conjunction with the accompanying drawings. However, the present utility model is not limited thereto. Within the scope of the technical concept of the present utility model, various simple modifications can be made to the technical solutions of the present utility model, including the combination of each specific technical feature in any suitable manner. To avoid unnecessary repetition, the present utility model will not separately describe various possible combination methods. However, these simple modifications and combinations should also be regarded as the content disclosed by the present utility model and all fall within the protection scope of the present utility model.

Claims

1. A cylindrical lithium battery, characterized in that: include: A cylindrical metal shell (1), wherein an opening is formed at the upper end of the metal shell (1); A positive electrode cover (2), the positive electrode cover (2) being arranged on the opening, and a pressure relief hole (201) being provided in the central part of the positive electrode cover (2); A positive electrode cap (3), the positive electrode cap (3) comprising a tubular side wall (301) and a cover surface (302) connected to the upper end of the tubular side wall (301), the lower end of the tubular side wall (301) being fixed to the positive electrode cap (2) and surrounding the pressure relief hole (201); a conductive sealing column (4), the sealing column (4) comprising a vertically arranged columnar body (401) and a lower end (402), the columnar body (401) being arranged inside the positive electrode cap (3) in a non-contact manner, the lower end (402) being arranged in the pressure relief hole (201) and forming a gap with the pressure relief hole (201), an insulating sealing ring (5) being extruded and arranged in the gap, the sealing column (4) being arranged to be pushed by the high-pressure gas in the metal housing (1) to open the pressure relief hole (201); and A welding wire (6), wherein a first end of the welding wire (6) is welded and fixed to the sealing column (4), and a second end of the welding wire (6) is welded and fixed to the positive electrode cap (3), and the welding wire (6) can be broken when the sealing column (4) is pushed.

2. The cylindrical lithium battery according to claim 1, characterized in that: The central portion of the cover surface (302) is provided with a mounting groove (7), and a pressure sensor (8) is arranged in the mounting groove (7); a through hole is provided at the bottom of the mounting groove (7) and penetrates downwardly through the cover surface (302), and the upper end of the sealing column (4) can pass through the through hole and contact the sensing surface of the pressure sensor (8); the pressure sensor (8) is configured to detect the pressure exerted on it from the upper end of the sealing column (4).

3. The cylindrical lithium battery according to claim 2, characterized in that: The pressure sensor (8) is connected to an alarm, and the alarm is configured to receive the pressure detected by the pressure sensor (8) and to issue an alarm when the pressure exceeds a preset value.

4. The cylindrical lithium battery according to claim 1, characterized in that: An annular groove is provided on the side wall of the lower end portion (402) of the sealing column (4), and the inner ring of the insulating sealing ring (5) is sealingly matched with the annular groove.

5. The cylindrical lithium battery according to claim 1, characterized in that: The pressure relief hole (201) is a truncated cone hole, and the lower end portion (402) of the sealing column (4) is a truncated cone shape that matches the truncated cone hole.

6. The cylindrical lithium battery according to claim 1, characterized in that: The sealing column (4) further comprises a lug (403) arranged on the side of the columnar body (401), and the first end of the welding line (6) is welded to the lug (403); and / or, a welding hole (304) is opened on the tubular side wall (301), and the second end of the welding line (6) is welded and fixed in the welding hole (304).

7. The cylindrical lithium battery according to claim 1, characterized in that: The cylindrical lithium battery also includes a return spring (9), which is sleeved on the outer circumference of the columnar body (401), the lower end of the return spring (9) is fixed to the lower end (402) of the sealing column (4), and the upper end of the return spring (9) is fixed to the lower surface of the cover surface (302).

8. The cylindrical lithium battery according to claim 1, characterized in that: The material of the welding wire (6) is tin.

9. The cylindrical lithium battery according to any one of claims 1 to 8, characterized in that: A battery cell (10) is arranged in the metal shell (1), a gap is formed between the side wall of the battery cell (10) and the metal shell (1), and the positive electrode ear of the battery cell (10) is connected to the lower end of the sealing column (4).

10. The cylindrical lithium battery according to claim 9, characterized in that: An insulating pressure ring (11) is fixedly arranged on the lower surface of the positive electrode cover (2), and the insulating pressure ring (11) is embedded in the gap.

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