Lithium battery top cover capable of being filled with liquid repeatedly

Abstract

The invention discloses a lithium battery top cover capable of repeatedly injecting liquid, and relates to the technical field of lithium batteries, the lithium battery top cover comprises a top cover sheet, a liquid injection hole and a pole, the liquid injection hole is arranged on the pole, and a sealing assembly capable of realizing a sealing effect is detachably arranged on the liquid injection hole. According to the invention, the position of the liquid injection hole is moved to the pole from the light aluminum sheet, so that the habitual thinking in the prior art is changed, the defect that a stable threaded structure cannot be formed in the top cover sheet due to the fact that the liquid injection hole is formed in the top cover sheet is overcome, and a feasible technical basis is provided for realizing detachable sealing of the liquid injection hole. Meanwhile, a liquid injection hole does not need to be formed in the bright aluminum sheet, so that the completeness of the bright aluminum sheet is ensured, the structure of the battery top cover is simplified to a certain extent, the cracking probability of the bright aluminum sheet is reduced, and the service life of the bright aluminum sheet can be prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and specifically to a lithium battery top cover that can be refilled with liquid repeatedly. Background Art

[0002] Lithium batteries are a type of battery with lithium metal or lithium alloy as the positive / negative electrode material and using a non-aqueous electrolyte solution. With the development of science and technology, they have become the mainstream batteries. The liquid injection and encapsulation of lithium batteries are very important steps in their manufacturing process. As Figure 1 shown (in the figure, the reference numeral 1 is the top cover sheet, 2 is the liquid injection hole, and 3 is the sealing aluminum nail), currently the liquid injection holes are all integrated on the light aluminum sheet of the lithium battery top cover. After the liquid injection is completed, laser welding is used with the sealing aluminum nail to complete the sealing. The defects of this technology are:

[0003] (1) Since the light aluminum sheet is very thin, less than 1 cm, the sealing aluminum nail is also extremely short. Its assembly and welding belong to high-precision technology, with great processing difficulty and it is difficult to control the product qualification rate;

[0004] (2) During the welding process, explosion points and welding holes are easily generated. Such defects cannot be repaired, and once they occur, the entire top cover will be scrapped directly;

[0005] (3) As the use time of the lithium battery increases, the battery core will gradually age. When the internally injected electrolyte is depleted and needs to be replenished, since the liquid injection hole has been welded and sealed and cannot be opened again, the entire lithium battery can only be scrapped as a whole. The cost of lithium batteries is high and the resource waste is very serious.

[0006] In view of the above problems, there is an urgent need for a lithium battery top cover structure that can be sealed repeatedly, which can not only improve the production yield but also extend the service life of the battery core. Summary of the Invention

[0007] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a lithium battery top cover that can be refilled with liquid repeatedly, which can be quickly reworked and repaired when there is a battery core with poor sealing, and the battery core can be disassembled for liquid replenishment after use.

[0008] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0009] A lithium battery top cover that can be refilled with liquid repeatedly, including a top cover sheet, a liquid injection hole, and a pole column. The liquid injection hole is provided on the pole column, and a sealing component that can achieve a sealing effect is detachably installed on the liquid injection hole.

[0010] Further, the sealing component includes a screw; a threaded structure is provided on the inner side wall of the liquid injection hole, and the detachable sealing with the liquid injection hole is achieved through the cooperation of the screw and the threaded structure.

[0011] Furthermore, the liquid injection hole includes a threaded hole at the lower end and a limiting platform above the threaded hole for restricting the fastening position of the screw; the threaded structure is provided on the inner wall of the threaded hole.

[0012] Still further, a sealing platform is provided between the threaded hole and the limiting platform, and the limiting platform and the sealing platform are integrally formed and distributed in a stepped shape; the sealing assembly further includes a sealing ring provided on the sealing platform. The connection surface between the sealing platform and the limiting platform is perpendicular to both of them, which is not only convenient for processing, but also facilitates the sealing ring to enter the sealing platform. At the same time, it can also make the sealing ring completely fit on the side wall of the liquid injection hole to achieve the maximum sealing effect.

[0013] Furthermore, the screw includes a screw rod and a nut connected to the screw rod; a screw counterbore for accommodating the nut and tightly fitting with it is provided at the upper end of the limiting platform.

[0014] Even further, the height of the screw counterbore is at least 1 mm greater than the height of the nut. In this way, after the screw is tightened, the entire screw will completely sink into the pole column, avoiding the screw protruding outside the pole column and affecting the normal use of the lithium battery top cover. At the same time, it also avoids the screw being affected by the external environment during the use of the lithium battery, ensuring the installation stability and sealing effect of the screw on the liquid injection hole.

[0015] Furthermore, the pole column is an anode pole column and / or a cathode pole column.

[0016] Furthermore, when the liquid injection hole is provided on the anode pole column, the material of the screw is aluminum or stainless steel; when the liquid injection hole is provided on the cathode pole column, the material of the screw is copper, stainless steel or nickel-plated copper.

[0017] Furthermore, the fastening end face of the screw is in a "one-shaped", "cross-shaped" or "inner square" structure.

[0018] In the present invention, the size of the nut is completely matched with that of the limiting platform, and the limiting platform can be completely sealed after the nut enters the screw counterbore.

[0019] Design principle of the present invention: To solve the problem that the injection hole cannot be disassembled and thus cannot be refilled, the welding and sealing method has to be changed to other detachable sealing methods. Threaded connection is a very common detachable connection method. However, in the lithium battery top cover, the thickness of the light aluminum sheet (top cover sheet) is less than 1 cm. If threads are forcibly formed on the inner wall of the injection hole, only a very limited number of threads can be formed. Such a small number of threads not only cannot be firmly connected to the light aluminum sheet with screws, but also cannot meet the sealing requirements of the injection hole. The thickness of the anode terminal and the cathode terminal is much greater than that of the light aluminum sheet. If the injection hole is formed on the terminal, enough threads can be formed to ensure the stability of the detachable connection structure. The specific solution of the present invention is designed based on the above technical status and principles.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The present invention moves the position of the injection hole from the light aluminum sheet to the terminal, changing the habitual thinking in the prior art, solving the defect that a stable threaded structure cannot be formed on the top cover sheet where the injection hole is located, and providing a practical technical basis for the detachable sealing of the injection hole. At the same time, there is no need to open an injection hole on the light aluminum sheet, ensuring the integrity of the light aluminum sheet, simplifying the structure of the battery top cover to a certain extent, reducing the cracking probability of the light aluminum sheet, and extending the service life of the light aluminum sheet.

[0022] (2) The present invention uses a screw sealing method to replace the sealing method of the sealing aluminum nail + laser welding in the prior art. While plugging the injection hole, a firm connection between the filling piece and the injection hole is also achieved, not only solving the problem that the injection hole cannot be reused due to non-disassembly after sealing in the prior art, but also ensuring the stability of the lithium battery top cover.

[0023] (3) The present invention enables the terminal to achieve a new function while realizing its own function, that is, the injection function, without changing the size and structural layout of the entire top cover, without increasing the processing cost and processing difficulty, solving the long-existing and unsolvable problem of non-reusability of the injection hole in the prior art. The design is very ingenious and has a high innovation value.

[0024] (4) The present invention eliminates the welding process for the injection hole, not only avoiding defects such as explosion points and welding holes caused by laser welding, reducing the scrap rate of lithium batteries, but also simplifying the processing technology of the lithium battery top cover and reducing the processing cost.

[0025] (5) The present invention forms a space for placing a sealing ring between the limit platform and the sealing platform. The sealing platform provides support for the sealing ring from below, while the limit platform not only provides support for the nut from below but also limits the degree of tightening of the nut, that is, it ensures the compression rate of the sealing ring. Through the mutual cooperation of the sealing platform, the limit platform and the screw, the sealing of the threaded hole is achieved, and the sealing ring can be prevented from being subjected to excessive pressure, resulting in shortened service life or damage. At the same time, it also provides a basis for possible reuse after disassembly in the later stage.

[0026] (6) The present invention changes the conventional cylindrical liquid injection hole into a structure with a larger upper part and a smaller lower part, that is, the screw counterbore in the upper part and the threaded hole in the lower part. And a multi-layer step is arranged at the junction of the screw counterbore and the threaded hole, that is, the sealing platform and the limit platform. Then, a screw with a larger upper part and a smaller lower part is selected to cooperate with the step to form an all-round enclosure for the sealing ring, which not only limits the space of the sealing ring to prevent the sealing ring from being damaged by excessive pressure but also forms a triple sealing effect of the screw, the sealing ring and the nut, so as to effectively ensure the sealing effect without welding sealing.

[0027] (7) Although the technology of the present invention is simple, the design is very ingenious. Without changing the existing structure and function of the top cover, it uses simple existing technologies to solve the long-existing and difficult-to-solve technical problems in the existing technologies. This is a huge breakthrough in the design idea and a thinking innovation, which has great reference significance and learning value and can provide reference ideas for all technological innovations. Description of the Drawings

[0028] Figure 1 Schematic diagram of the battery top cover in the prior art;

[0029] Figure 2 Schematic diagram of the lithium battery top cover provided by the present invention;

[0030] Figure 3 Cross-sectional view of the pole column in Embodiment 1 of the present invention;

[0031] Figure 4 Cross-sectional view of the pole column in Embodiment 2 of the present invention;

[0032] Figure 5 Partial assembly cross-sectional view of Embodiment 2 of the present invention.

[0033] Among them, the names corresponding to the reference numerals are: 1 - top cover sheet, 2 - liquid injection hole, 3 - sealing aluminum nail, 4 - pole column, 5 - threaded hole, 6 - sealing platform, 7 - limit platform, 8 - screw counterbore, 9 - sealing ring, 10 - screw. Detailed Description of the Invention

[0034] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. The implementation manners of the present invention include but are not limited to the following embodiments.

[0035] Embodiment 1

[0036] As Figure 2 、 3 shown, this embodiment provides a lithium battery top cover with repeatable liquid injection, including a top cover sheet. Usually, a cathode pole column and an anode pole column are arranged on the top cover sheet. The liquid injection hole is arranged on any one of the pole columns 4, and a sealing component capable of realizing a sealing function is detachably installed on the liquid injection hole.

[0037] In this embodiment, the sealing component is a screw 10. The screw 10 includes a screw rod with threads on the surface and a nut arranged at the upper end of the screw rod. Since the bottom of the screw 10 will contact the electrolyte inside the battery cell, the material needs to ensure that no electrochemical reaction occurs. In this embodiment, when the liquid injection hole is arranged on the anode pole column, the material of the screw is aluminum or stainless steel; when the liquid injection hole is arranged on the cathode pole column, the material of the screw is copper, stainless steel or nickel-plated copper. In addition, the fastening cross-section is not limited to "one-word", "cross", "inner square", etc.

[0038] The liquid injection hole includes a threaded hole 5 at the lower end and a limiting platform 7 located above the threaded hole 5 for limiting the fastening position of the screw 10. A threaded structure is arranged on the inner side wall of the threaded hole 5, and this threaded structure cooperates with the screw 10 to achieve detachable sealing of the liquid injection hole. In this embodiment, detachable sealing of the sealing component and the liquid injection hole is achieved through the threaded structure. However, in the prior art, there are many detachable structures, and other detachable methods can also be used during actual use. The limiting platform 7 is used to limit the fastening position of the screw, and its size should match that of the nut.

[0039] In addition, in order to ensure that the nut at the upper end of the screw is not interfered by the outside, a screw counterbore 8 is arranged at the upper end of the limiting platform 7. This structure can make the whole screw sink inside the pole column without interfering with the outside. During actual implementation, the diameter of the screw counterbore is at least 5 mm larger than the diameter of the threaded hole, and the height of the screw counterbore is at least 1 mm larger than the height of the nut.

[0040] Embodiment 2

[0041] As Figure 4 、 5As shown, on the basis of Embodiment 1, in order to further enhance the sealing performance between the sealing component and the liquid injection hole, a sealing platform 6 is provided between the threaded hole 5 and the limiting platform 7, and a sealing ring 9 is provided on the sealing platform 6. The cooperation between the sealing ring 9 and the sealing platform 6 plays a sealing role, enabling the sealing between the liquid injection hole and the screw and preventing the leakage of the electrolyte. In this embodiment, the limiting platform 7 and the sealing platform 6 are integrally formed and distributed in a stepped shape. The connection surface between the sealing platform 6 and the limiting platform 7 is perpendicular to both of them. This not only facilitates processing but also allows the sealing ring to enter the sealing platform easily. At the same time, it can make the sealing ring completely fit the side wall of the liquid injection hole, achieving the maximum sealing effect. The sealing platform provided in this embodiment can support the sealing ring, while the limiting platform restricts the tightening degree of the screw. Under the action of the nut, the compression rate of the sealing ring can be guaranteed, avoiding fatigue fracture or permanent deformation of the sealing ring due to excessive deformation. Thus, while ensuring the sealing effect, the service life of the sealing ring can be extended.

[0042] The above embodiments are only one of the preferred embodiments of the present invention and should not be used to limit the protection scope of the present invention. Any modification or polishing that has no substantial meaning made on the main design concept and spirit of the present invention, as long as the technical problems solved are still consistent with those of the present invention, should be included within the protection scope of the present invention.

Claims

1. A lithium battery top cover capable of repeated liquid injection, comprising a top cover sheet, a liquid injection hole, and a pole column (4), characterized in that, The liquid injection hole is arranged on the pole column (4), and a sealing component capable of realizing a sealing function is detachably installed on the liquid injection hole.

2. The top cover of a lithium battery capable of repeated refilling according to claim 1, wherein, The sealing component includes a screw (10); a threaded structure is arranged on the inner side wall of the liquid injection hole, and the detachable sealing with the liquid injection hole is realized through the cooperation of the screw (10) and the threaded structure.

3. The top cover of a lithium battery capable of repeated refilling according to claim 2, wherein The liquid injection hole includes a threaded hole (5) at the lower end and a limiting platform (7) located above the threaded hole (5) for limiting the fastening position of the screw (10); the threaded structure is arranged on the inner wall of the threaded hole (5).

4. A rechargeable lithium battery top cover according to claim 3, characterized in that A sealing platform (6) is arranged between the threaded hole (5) and the limiting platform (7), and the limiting platform (7) and the sealing platform (6) are integrally formed and distributed in a stepped shape; the sealing component further includes a sealing ring (9) arranged on the sealing platform (6).

5. A rechargeable lithium battery top cover according to claim 4, characterized in that, The screw (10) includes a screw rod and a nut connected to the screw rod; a screw counterbore (8) for accommodating the nut and tightly matching with it is arranged at the upper end of the limiting platform (7).

6. A rechargeable lithium battery top cover according to claim 5, characterized in that, The height of the screw counterbore (8) is at least 1 mm greater than the height of the nut.

7. A rechargeable lithium battery top cover according to claim 3 or 4 or 6, characterized in that, The pole column (4) is an anode pole column and / or a cathode pole column.

8. A lithium battery top cover capable of repeated refilling according to claim 7, characterized in that, When the liquid injection hole is arranged on the anode pole column, the material of the screw (10) is aluminum or stainless steel; when the liquid injection hole is arranged on the cathode pole column, the material of the screw (10) is copper, stainless steel or nickel-plated copper.

9. The top cover of a lithium battery capable of repeated refilling according to claim 8, wherein, The fastening end face of the screw (10) is in a "one-shaped", "cross-shaped" or "inner square" structure.

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