Battery cap and lithium battery comprising battery cap

Abstract

The present application discloses a battery cap and a lithium battery comprising the battery cap. The battery cap comprises: a sealing rubber ring, which is provided with an accommodating cavity; an explosion-proof aluminum sheet, which is arranged within the accommodating cavity, the explosion-proof aluminum sheet having a first side surface and a second side surface opposite one another, the first side surface being provided with a limiting flange, and a clamping recess being formed between the first side surface and the limiting flange; a cap body, a peripheral edge of the cap body being clamped in the clamping recess; and a CID element, which is connected to the second side surface. The accommodating cavity has an outer end portion relatively close to the limiting flange, and the outer end portion is provided with an opening. When the outer end portion is not bent toward the first side surface, the opening gradually increases outward along the Y-axis direction; and when the outer end portion is bent toward the first side surface to press against the explosion-proof aluminum sheet, a side wall of the opening abuts against the limiting flange. The shape of the opening facilitates the guidance and mounting of the explosion-proof aluminum sheet, the cap body, and the CID element into correct positions within the accommodating cavity, and can make the sealing connection between the side wall of the opening and the limiting flange easier, closer, and more stable.

Description

Battery cap and lithium battery including the battery cap

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202422490467.0, filed on October 14, 2024, entitled "Battery Cap and Lithium Battery Including the Battery Cap", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of battery safety technology, and in particular to a battery cap and a lithium battery including the battery cap. Background Technology

[0004] With the continuous development of lithium battery technology, its application in portable electronic devices, electric vehicles, and energy storage systems is becoming increasingly widespread. However, lithium batteries may face safety risks such as overheating, short circuits, and overcharging during use. If these risks occur, they may not only damage the battery itself but also pose a threat to the surrounding environment and human safety. Therefore, improving the safety of lithium batteries has become a focus of industry attention. Technical issues

[0005] Traditional battery caps typically consist of key components such as a sealing ring, an explosion-proof aluminum sheet, the cap body, and a CID (Current Interruption Device) element. These components need to be precisely positioned during assembly to ensure the cap's sealing and explosion-proof performance. However, in practice, insufficient fit or poor design between components often leads to low assembly efficiency or even improper assembly, affecting the overall battery quality. Particularly during the installation of the explosion-proof aluminum sheet and the cap body, traditional designs often lack effective guiding and securing mechanisms, making it difficult to accurately and stably place the aluminum sheet within the sealing ring's cavity. This not only increases assembly difficulty but may also cause the aluminum sheet to loosen or detach during battery use, thus jeopardizing battery safety.

[0006] Furthermore, traditional battery caps also have certain shortcomings in terms of sealing. Due to large gaps between components or unreasonable selection and design of sealing materials, the sealing effect of the battery cap is often poor, making it easy for harmful substances such as electrolyte inside the battery to leak out, which can harm the environment and human health. Technical solutions

[0007] To overcome at least one of the defects described in the prior art, this application provides a battery cap and a lithium battery including the battery cap, aiming to make it easier and more accurate to place and fix the components during the assembly process, while ensuring that the battery cap has excellent sealing and explosion-proof performance.

[0008] The technical solution adopted in this application to solve its problem is:

[0009] A battery cap includes: a sealing ring with a receiving cavity; an explosion-proof aluminum sheet disposed within the receiving cavity, the explosion-proof aluminum sheet having a first side and a second side facing away from each other, the first side having a limiting flange, and a snap-fit ​​groove formed between the first side and the limiting flange; a cap body, the periphery of which snaps into the snap-fit ​​groove; and a CID element connected to the second side; wherein the receiving cavity has an outer end relatively close to the limiting flange, the outer end having an opening; when the outer end is not bent toward the first side, the opening gradually increases outward along the Y-axis direction; when the outer end is bent toward the first side to press against the explosion-proof aluminum sheet, the sidewall of the opening abuts against the limiting flange.

[0010] In addition, this application also provides a lithium battery, including the battery cap as described above. Beneficial effects

[0011] In summary, the battery cap and the lithium battery including the battery cap provided in this application have at least the following technical advantages:

[0012] On the one hand, when the outer end is not bent toward the first side, the opening gradually increases outward along the Y-axis, which provides a natural guide path for the installer, making it easier and more accurate for each component to be placed in the correct position in the receiving cavity. This not only improves assembly efficiency but also reduces quality problems caused by improper assembly. On the other hand, when the outer end is bent toward the first side to press against the explosion-proof aluminum sheet, the shape of the opening makes the sealing connection between the side wall of the opening and the limiting flange easier, more snug, and more stable. Attached Figure Description

[0013] Figure 1 is a schematic diagram of the structure of a lithium battery (without sealing) according to an embodiment of this application;

[0014] Figure 2 is a schematic cross-sectional view of the lithium battery (without sealing) according to an embodiment of this application;

[0015] Figure 3 is a structural schematic diagram of the battery cap (without sealing) according to an embodiment of this application;

[0016] Figure 4 is a schematic diagram of the exploded structure of the battery cap (without sealing) according to an embodiment of this application;

[0017] Figure 5 is a schematic cross-sectional view of the battery cap (without sealing) according to an embodiment of this application;

[0018] Figure 6 is a schematic diagram of the structure of the battery cap (already sealed) according to an embodiment of this application;

[0019] Figure 7 is a schematic cross-sectional view of the battery cap (already sealed) according to an embodiment of this application.

[0020] The meanings of the reference numerals in the attached drawings are as follows: 1. Sealing ring; 11. Receiving cavity; 111. Outer end; 112. Opening; 113. Limiting wall; 114. First annular protrusion; 115. Second annular protrusion; 116. First mounting hole; 117. Second mounting hole; 118. Connecting hole; 2. Explosion-proof aluminum sheet; 21. First side; 211. Groove; 22. Second side; 23. Limiting flange; 24. Snap-fit ​​groove; 25. Recess; 3. Cap body; 31. Limiting cavity; 32. Vent hole; 4. CID element; 41. Vent hole; 5. Outer shell. Embodiments of the present invention

[0021] To better understand and implement this application, the technical solutions in this application will be clearly and completely described below with reference to the accompanying drawings.

[0022] Please refer to Figures 1 to 7. This embodiment discloses a battery cap, which includes a sealing ring 1, an explosion-proof aluminum sheet 2, a cap body 3, and a CID element 4. The sealing ring 1 is provided with a receiving cavity 11. The explosion-proof aluminum sheet 2 is disposed in the receiving cavity 11. The explosion-proof aluminum sheet 2 has a first side 21 and a second side 22 facing away from each other. The first side 21 is provided with a limiting flange 23. A snap-fit ​​groove 24 is formed between the first side 21 and the limiting flange 23. The periphery of the cap body 3 is snapped into the snap-fit ​​groove 24. The CID element 4 is connected to the second side 22. The receiving cavity 11 has an outer end 111 that is relatively close to the limiting flange 23. The outer end 111 is provided with an opening 112. When the outer end 111 is not bent toward the first side 21, the opening 112 gradually increases outward along the Y-axis direction. When the outer end 111 is bent toward the first side 21 to press against the explosion-proof aluminum sheet 2, the sidewall of the opening 112 abuts against the limiting flange 23. Specifically, referring to the coordinate system in Figure 5, the Y-axis direction is the axial direction of the cap body 3, the X-axis direction is perpendicular to the Y-axis direction, and the size of the opening 112 in the X-axis direction gradually increases outward along the Y-axis direction; when the opening 112 is circular, the inner diameter of the opening 112 in the X-axis direction gradually increases outward along the Y-axis direction.

[0023] It should be noted that CID element 4 in a lithium battery, short for Current Interrupt Device, is an important safety protection device inside the lithium battery. The main function of CID element 4 is to cut off the current through an internal mechanism when the cell fails (such as overheating, short circuit, overcharging, etc.), thereby preventing further damage or danger to the battery. This is a conventional technical means well known to those skilled in the art and will not be elaborated here.

[0024] This embodiment also provides a lithium battery, which includes the battery cap mentioned above and a housing 5. After the battery cap is welded to the end of the housing 5, the housing 5 needs to be flanged. Then the flange of the housing 5 and the battery cap are pressed together to seal the housing 5 and the battery cap. It can be understood that during the above sealing, the outer end 111 of the receiving cavity 11 is bent toward the first side 21 to press against the explosion-proof aluminum sheet 2, and the side wall of the opening 112 abuts against the limiting flange 23.

[0025] The battery cap provided in this embodiment has the following advantages: on the one hand, when the outer end 111 is not bent toward the first side 21, the shape of the opening 112 facilitates the correct placement of the explosion-proof aluminum sheet 2, the cap body 3, and the CID element 4 within the receiving cavity 11; on the other hand, when the outer end 111 is bent toward the first side 21 to press against the explosion-proof aluminum sheet 2, the shape of the opening 112 makes the sealing connection between the side wall of the opening 112 and the limiting flange 23 easier, more snug, and more stable.

[0026] As shown in Figures 3, 4, 5, 6 and 7, and optionally, in this embodiment, when the outer end 111 is not bent toward the first side 21, the inner wall of the receiving cavity 11 is provided with a first annular protrusion 114, which is adjacent to the opening 112; when sealing, that is, when the outer end 111 is bent toward the first side 21, the first annular protrusion 114 is used to seal and press against the limiting flange 23, thereby improving the sealing performance between the outer end 111 and the limiting flange 23.

[0027] As shown in Figures 4 and 5, optionally, in this embodiment, the inner wall of the receiving cavity 11 is provided with a radially extending limiting wall 113, and the second side 22 is connected to the limiting wall 113. The limiting wall 113 can effectively support the explosion-proof aluminum sheet 2, preventing unnecessary movement or deformation of the explosion-proof aluminum sheet 2 inside the battery. This stable support not only helps maintain the flatness and functionality of the explosion-proof aluminum sheet 2, but also improves the stability and durability of the entire battery cap structure. The limiting wall 113 can provide a positioning effect for the installation of the explosion-proof aluminum sheet 2. When installing the explosion-proof aluminum sheet 2, the limiting wall 113 can serve as a clear reference point or boundary, enabling the explosion-proof aluminum sheet 2 to be accurately and quickly placed in the correct position. This positioning effect not only simplifies the installation process, but also reduces the error rate caused by improper installation, and improves production efficiency and product quality.

[0028] More preferably, in this embodiment, to simplify the overall structure and improve its strength, the limiting wall 113 is integrally formed on the inner wall of the receiving cavity 11. This integral design means that the limiting wall 113 and the inner wall of the receiving cavity 11 are formed simultaneously during manufacturing, eliminating the need for additional assembly steps. This not only reduces the number of parts but also simplifies the production process and lowers production costs. Furthermore, by reducing connection points and potential assembly errors, the compactness and consistency of the overall structure are improved. The integral design also enhances the connection strength between the limiting wall 113 and the inner wall of the receiving cavity 11. Since they are manufactured as a single unit, there are no structural weaknesses caused by weak connections. This enhanced connection strength makes the entire battery cap more stable and reliable when subjected to internal pressure, external impact, or vibration, and less prone to deformation or damage.

[0029] As shown in Figures 4, 5, 6, and 7, more preferably, in this embodiment, when the outer end 111 is not bent toward the first side 21, the limiting wall 113 is provided with a second annular protrusion 115, which contacts the second side 22; during sealing, that is, when the outer end 111 bends toward the first side 21 to press against the explosion-proof aluminum sheet 2, the second annular protrusion 115 and the second side 22 form a sealing and pressing action, thereby improving the sealing performance between the limiting wall 113 and the second side 22.

[0030] As shown in Figures 4 and 5, specifically in this embodiment, the limiting wall 113 divides the receiving cavity 11 into a first mounting hole 116 and a second mounting hole 117. The limiting wall 113 is provided with a connecting hole 118 that connects the first mounting hole 116 and the second mounting hole 117. The cap body 3 is located in the first mounting hole 116, and the CID element 4 is located in the second mounting hole 117. The CID element 4 has a vent hole 41. Optionally, the first side 21 is provided with an annular groove 211, and the limiting wall 113 can prevent the CID element 4 from moving from the second mounting hole 117 to the first mounting hole 116. With this configuration, when the battery experiences a short circuit or other reasons that cause internal battery damage, When a large amount of gas is generated, causing a rapid increase in pressure, the gas enters the space between the explosion-proof aluminum sheet 2 and the CID element 4 through the vent 41 on the CID element 4, generating pressure on the explosion-proof aluminum sheet 2. When the pressure rises to a certain level, the groove 211 deforms, the opening of the groove 211 becomes larger, and the strength of the explosion-proof aluminum sheet 2 at the groove 211 decreases. When the pressure continues to rise to a certain level, the groove 211 is torn open, and the internal pressure is released instantly, preventing the battery from exploding. The cap body 3 can prevent the fragments of the explosion-proof aluminum sheet 2 from flying outwards, and the limiting wall 113 can prevent the CID element 4 from moving from the second mounting hole 117 to the first mounting hole 116.

[0031] As shown in Figures 5 and 7, optionally, in this embodiment, the explosion-proof aluminum sheet 2 is provided with a recessed portion 25 that is recessed from the first side 21 to the second side 22. The recessed portion 25 is located inside the second mounting hole 117. The CID element 4 is connected to the recessed portion 25. Specifically, the CID element 4 is welded to the recessed portion 25. The groove 211 is provided around the periphery of the recessed portion 25. The recessed portion 25 allows the deformation of the explosion-proof aluminum sheet 2 to be mainly concentrated at the groove 211. When the pressure rises to a certain level, it is beneficial for the explosion-proof aluminum sheet 2 to tear from the groove 211, thereby achieving smooth pressure relief.

[0032] As shown in Figures 5 and 7, optionally, in this embodiment, the diameter of the groove 211 is smaller than the diameter of the connecting hole 118. When the pressure rises to a certain level, it is beneficial for the explosion-proof aluminum sheet 2 to tear from the groove 211, thereby achieving smooth pressure relief.

[0033] As shown in Figures 5 and 7, optionally, in this embodiment, a limiting cavity 31 is provided on the side of the cap body 3 facing the first side 21. The limiting cavity 31 can provide space for the flipping of the fragment structure of the explosion-proof aluminum sheet 2.

[0034] As shown in Figures 3, 4 and 6, optionally, in this embodiment, the cap body 3 is provided with a plurality of vent holes 32. Optionally, in this embodiment, the number of vent holes 32 is preferably three. The three vent holes 32 ensure the timely release of the internal air pressure of the battery cell after the explosion-proof aluminum sheet 2 explodes, avoiding the problem of battery cell explosion caused by the inability to effectively release the air pressure.

[0035] Optionally, in this embodiment, the sealing ring 1 is made of PBT material, and the cap body 3 is made of SPCC material.

[0036] In summary, the battery cap and lithium battery including the battery cap disclosed in this application can bring at least the following beneficial technical effects:

[0037] 1) The opening 112 gradually increases outward along the Y-axis, which provides a natural guide path for the installer, making it easier and more accurate for each component to be placed in the correct position in the receiving cavity. This not only improves assembly efficiency but also reduces quality problems caused by improper assembly.

[0038] 2) The shape of the opening 112 makes the sealing connection between the side wall of the opening 112 and the limiting flange 23 easier, more fitting and more stable;

[0039] 3) The limiting wall 113 can effectively support the explosion-proof aluminum sheet 2 and prevent the explosion-proof aluminum sheet 2 from moving or deforming unnecessarily inside the battery. This stable support not only helps to maintain the flatness and functionality of the explosion-proof aluminum sheet 2, but also improves the stability and durability of the entire battery cap structure.

[0040] 4) The limiting wall 113 is integrally formed on the inner side wall of the receiving cavity 11, eliminating the need for additional assembly steps. This not only reduces the number of parts but also simplifies the production process and lowers production costs. At the same time, the compactness and consistency of the overall structure are improved due to the reduction of connection points and potential assembly errors.

Claims

1. A battery cap, characterized in that include: A sealing ring (1) is provided with a receiving cavity (11); An explosion-proof aluminum sheet (2) is disposed in the receiving cavity (11). The explosion-proof aluminum sheet (2) has a first side (21) and a second side (22) facing away from each other. The first side (21) is provided with a limiting flange (23). A snap-fit ​​groove (24) is formed between the first side (21) and the limiting flange (23). The cap body (3) is engaged with the snap-fit ​​groove (24) around its periphery; CID element (4) is connected to the second side (22); The receiving cavity (11) has an outer end (111) that is relatively close to the limiting flange (23), and the outer end (111) is provided with an opening (112); when the outer end (111) is not bent toward the first side (21), the opening (112) gradually increases outward along the Y-axis direction; when the outer end (111) is bent toward the first side (21) to press against the explosion-proof aluminum sheet (2), the sidewall of the opening (112) abuts against the limiting flange (23).

2. The battery cap of claim 1, wherein, The inner wall of the receiving cavity (11) is provided with a limiting wall (113) extending radially, and the second side (22) is connected to the limiting wall (113).

3. The battery cap of claim 2, wherein, When the outer end (111) is not bent toward the first side (21), the limiting wall (113) is provided with a second annular protrusion (115), which contacts the second side (22); when the outer end (111) is bent toward the first side (21) to press against the explosion-proof aluminum sheet (2), the second annular protrusion (115) and the second side (22) form a sealing and pressing action.

4. The battery cap of claim 2, wherein, The limiting wall (113) divides the receiving cavity (11) into a first mounting hole (116) and a second mounting hole (117). The limiting wall (113) is provided with a connecting hole (118) connecting the first mounting hole (116) and the second mounting hole (117). The cap body (3) is located in the first mounting hole (116), and the CID element (4) is located in the second mounting hole (117). The first side (21) is provided with a groove (211). The limiting wall (113) can prevent the CID element (4) from moving from the second mounting hole (117) to the first mounting hole (116).

5. The battery cap of claim 4, wherein, The limiting wall (113) is integrally formed on the inner side wall of the receiving cavity (11).

6. The battery cap of claim 4, wherein, The explosion-proof aluminum sheet (2) is provided with a recessed portion (25) that is recessed from the first side (21) to the second side (22). The recessed portion (25) is located in the second mounting hole (117). The CID element (4) is connected to the recessed portion (25). The groove (211) is provided around the periphery of the recessed portion (25).

7. The battery cap of claim 6, wherein, The diameter of the groove (211) is smaller than the diameter of the connecting hole (118).

8. The battery cap of any one of claims 4-7, wherein, The cap body (3) has a limiting cavity (31) on the side facing the first side (21).

9. The battery cap of any one of claims 1-7, wherein, When the outer end portion (111) is not bent to the first side surface (21), the inner side wall of the accommodating cavity (11) is provided with a first annular protrusion (114) adjacent to the opening (112); when the outer end portion (111) is bent to the first side surface (21), the first annular protrusion (114) is used for sealingly abutting against the limiting flange (23).

10. A lithium battery characterized by A battery cap comprising the battery cap according to any one of claims 1-9.

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