Sealing structure and battery cell

Abstract

The application relates to the technical field of lithium batteries, and provides a sealing structure and a battery cell. The sealing structure of the application is arranged at a liquid injection hole of a battery cell cover plate, and comprises a liquid blocking turn-up edge arranged on the battery cell cover plate, a sealing element and a sealing cover; the liquid blocking turn-up edge surrounds the circumferential direction of the liquid injection hole and extends along the outer side of the battery cell cover plate, and the liquid blocking turn-up edge defines a mounting cavity in communication with the liquid injection hole; the sealing element at least comprises a hole plug in interference fit in the liquid injection hole; the sealing cover is arranged in the mounting cavity and is used for covering the liquid injection hole; the liquid blocking turn-up edge can be folded to the inner side of the mounting cavity, so that the sealing cover is limited in the mounting cavity. The sealing structure of the application utilizes the liquid blocking turn-up edge, not only plays a liquid blocking role, but also provides a mounting and fixing structural basis for the sealing cover; and by means of the cooperation of the liquid blocking turn-up edge and the sealing cover and the cooperation of the hole plug and the liquid injection hole, the sealing effect at the liquid injection hole can be enhanced, and the problem of welding burst points at the liquid injection hole can be avoided.

Description

Technical Field

[0001] The present application relates to the technical field of lithium batteries, in particular to a sealing structure. The present application further relates to a battery cell provided with the above sealing structure. Background Art

[0002] As an important component of a lithium battery, the electrolyte functions to conduct electrons between the positive and negative electrodes in the battery, and is the guarantee for the lithium ion battery to obtain advantages such as high voltage and high specific energy. With the charge-discharge cycles of the battery, the electrolyte continuously reacts with the positive and negative electrodes of the battery, and is consumed and decomposed. As the amount of the electrolyte decreases, the electron conductivity inside the battery is reduced, the electrical performance of the battery will also decrease accordingly, which further leads to a reduction in the service life of the battery.

[0003] In the structure of a lithium battery, after the lithium battery completes the operations of electrolyte injection, formation and possible electrolyte replenishment, the liquid injection hole is usually blocked by a rubber nail in cooperation with welding of a sealing aluminum sheet, so as to prevent electrolyte leakage and intrusion of external impurities, thereby ensuring the safety and performance of the battery. However, the manner of welding the sealing aluminum sheet to the battery cell cover plate has poor sealing problems such as welding spatter points, therefore, the sealing structure at the liquid injection hole needs to be further improved. Contents of the Utility Model

[0004] In view of this, the present application aims to propose a sealing structure, which can ensure the sealing effect at the liquid injection hole while avoiding the problem of poor sealing caused by welding spatter points generated by welding at the liquid injection hole.

[0005] In order to achieve the above purpose, the technical solution of the present application is implemented as follows: A sealing structure is arranged at a liquid injection hole of a battery cell cover plate, and the sealing structure includes a liquid-stop turned edge arranged on the battery cell cover plate, as well as a sealing member and a sealing cover; The liquid-stop turned edge surrounds the circumferential direction of the liquid injection hole, extends in a direction pointing to the outer side of the battery cell cover plate, and defines a mounting cavity communicated with the liquid injection hole; The sealing member at least includes a hole plug that is interference-fitted in the liquid injection hole; The sealing cover is arranged in the mounting cavity and is used for covering the liquid injection hole, and the liquid-stop turned edge can be turned over toward the inner side of the mounting cavity to limit the sealing cover in the mounting cavity.

[0006] Further, on the longitudinal section of the liquid injection hole, the sealing cover is in a shape of "几", and has a cover main body covering the liquid injection hole, and a connecting edge connected to the circumferential direction of the cover main body; the turned-over liquid-stop turned edge can press the connecting edge against the bottom wall of the mounting cavity.

[0007] Further, an insulating patch is disposed on the outer side of the connecting edge; the folded liquid-retaining flange presses the sealing cover against the bottom wall of the mounting cavity through the insulating patch.

[0008] Further, the insulating patch is made of any one of PC, PE, and PET materials; and / or, the thickness of the insulating patch is between 0.05mm and 0.5mm.

[0009] Further, the sealing member further comprises a sealing ring disposed between the sealing cover and the bottom wall of the mounting cavity.

[0010] Further, a mounting groove is provided on the sealing cover and / or the bottom wall of the mounting cavity; the sealing ring is embedded and mounted in the mounting groove.

[0011] Further, the compression ratio β of the sealing ring satisfies: 10%≤β≤45%.

[0012] Further, the plug comprises a sealing portion and a pre-mounting portion connected to each other; the plug is pre-installed into the liquid injection hole through the pre-mounting portion, and the sealing portion is in interference fit with the hole wall of the liquid injection hole.

[0013] Further, the plug comprises a main body portion, and a lapping portion disposed at one end of the main body portion; the lapping portion is lapped on the connecting end surface where the liquid injection hole communicates with the mounting cavity, a plurality of sealing convex rings are disposed in the circumferential direction of the main body portion, the plurality of sealing convex rings are arranged along the axial direction of the main body portion, and at least part of the sealing convex rings are in interference fit with the hole wall of the liquid injection hole.

[0014] Compared with the related art, the present application has the following advantages: (1) In the sealing structure of the present application, by providing the liquid-retaining flange on the cell cover plate, as well as the sealing member and the sealing cover, the liquid-retaining flange surrounds the circumferential direction of the liquid injection hole and extends toward the outer side of the cell cover plate. In this way, during liquid injection of the cell, the liquid retaining effect of the liquid-retaining flange can effectively prevent the electrolyte from overflowing to the outer side of the battery cover plate; the plug in the sealing member is in interference fit with the liquid injection hole, which can effectively prevent the liquid from flowing out of the liquid injection hole, the sealing cover seals the liquid injection hole, and the liquid-retaining flange is folded inward to limit the sealing cover in the mounting cavity, which not only can improve the fixing effect of the sealing cover, enhance the sealing effect at the liquid injection hole, prevent liquid or gas in the external environment from entering the liquid injection hole, but also can avoid the problem of welding spatter points generated by welding at the liquid injection hole, thereby ensuring the sealing performance inside the cell.

[0015] (2) On the longitudinal section of the liquid injection hole, the sealing cover is designed in a shape like the Chinese character "几", by utilizing its own bending portion structure, it is beneficial for the sealing cover to be in interference fit in the mounting cavity, and in cooperation with the pressing effect of the folded liquid-retaining flange, the mounting reliability of the sealing cover can be improved.

[0016] (3) An insulating patch is provided on the outside of the connecting edge so that the folded liquid-blocking flange is pressed on the insulating patch, and the sealing cover is pressed on the bottom wall of the mounting cavity by the insulating patch. This can avoid the problem of short circuit of battery caused by metal wires between the metal liquid-blocking flange and the metal sealing cover after riveting.

[0017] (4) The insulating patch is made of any one of PC, PE, or PET. These materials have good insulation properties, chemical corrosion resistance, and mechanical strength, and can provide reliable insulation protection and performance. Limiting the thickness of the insulating patch can not only ensure that the insulating patch has sufficient insulation properties and mechanical strength, but also avoid the problem that the thickness is too thick and affects the installation and sealing effect of the sealing cap, as well as the problem that the thickness is too thin and the mechanical strength is too low and easily damaged.

[0018] (5) A sealing ring is set between the sealing cap and the bottom wall of the mounting cavity to seal the gap between the sealing cap and the bottom wall of the mounting cavity, thereby improving the sealing performance. Furthermore, the combination of the sealing ring and the plug can further improve the sealing effect at the injection hole.

[0019] (6) The mounting groove is designed so that the sealing ring is embedded in the mounting groove, which can improve the installation effect of the sealing ring, prevent the sealing ring from shifting or deforming during installation and use, and ensure that the sealing ring is evenly compressed, thereby achieving a better sealing effect. At the same time, the mounting groove can also protect the sealing ring to a certain extent, which helps to extend the service life of the sealing ring.

[0020] (7) Limiting the compression ratio of the sealing ring can further improve the sealing performance and avoid the sealing ring being unable to fully seal the gap due to the compression ratio being too small, resulting in poor sealing, and the sealing ring being excessively deformed due to the excessive compression ratio, which affects the long-term sealing performance and service life.

[0021] (8) The plug includes a connected sealing part and a pre-installation part. The pre-installation part can be pre-installed into the injection hole, and then the sealing part can be press-fitted with the wall of the injection hole. This makes the installation of the plug more convenient and quick, ensuring the installation effect of the plug and thus ensuring the sealing performance at the injection hole. In addition, the design of the pre-installation part can also protect the sealing part to a certain extent, preventing the sealing part from being damaged during the installation process, thereby ensuring the sealing effect at the injection hole.

[0022] (9) The plug includes a main body and an overlapping part at one end of the main body. The overlapping part overlaps the connecting end face where the injection hole and the mounting cavity are connected, which can play the role of positioning and fixing the plug, preventing the plug from going too deep into the injection hole or not being installed properly, and ensuring that the sealing part of the plug can accurately fit with the wall of the injection hole. The main body is provided with multiple sealing protrusions in the circumferential direction. The multiple sealing protrusions are arranged at intervals along the axial direction of the main body. At least some of the sealing protrusions are interference-fitted with the wall of the injection hole, so that multiple seals can be formed between the plug and the wall of the injection hole, further improving the sealing performance.

[0023] Another object of this application is to provide a battery cell having a sealing structure as described above.

[0024] The battery cell described in this application, by adopting the above-mentioned sealing structure, not only plays a role in blocking liquid during liquid injection, but also provides a base for installing and fixing the sealing cap. At the same time, by using the cooperation between the liquid-blocking flange and the sealing cap, as well as the cooperation between the plug and the injection hole, the sealing effect at the injection hole can be enhanced, thereby improving the internal sealing performance of the battery cell. Attached Figure Description

[0025] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a first-view structural schematic diagram of the sealing structure in application state according to the embodiments of this application; Figure 2 This is a second-view structural schematic diagram of the sealing structure in application state according to the embodiments of this application; Figure 3 This is a third-view structural schematic diagram of the sealing structure in application state according to an embodiment of this application. Figure 4 for Figure 3 Enlarged view of the middle AA section; Figure 5 This is a schematic diagram of the structure of the liquid-blocking flange after folding according to an embodiment of this application; Figure 6 This is a partial structural schematic diagram of the battery cell cover plate described in an embodiment of this application; Figure 7 This is a schematic diagram of the sealing ring installation state as described in the embodiments of this application; Figure 8 This is a schematic diagram of the sealing cap structure described in an embodiment of this application; Figure 9 This is a schematic diagram of the first structure of the plug described in this application embodiment; Figure 10This is a schematic diagram of a second structure of the plug described in an embodiment of this application; Figure 11 This is a schematic diagram of a third structure of the plug described in an embodiment of this application; Explanation of reference numerals in the attached figures: 1. Cell cover plate; 2. Cell housing; 3. Hole plug; 4. Sealing ring; 5. Sealing cap; 6. Insulating patch; 100. Injection hole; 101. Positive electrode post; 102. Negative electrode post; 103. Explosion-proof valve; 200. Mounting cavity; 300. Mounting groove; 11. Liquid-blocking flange; 301. Sealing part; 302. Pre-installation part; 303. Main body part; 304. Overlap part; 3031 (3031a), sealing convex ring; 30311. Guide end face; 30312. Limiting end face; 501. Cover body; 502. Connecting edge. Detailed Implementation

[0026] To make the technical solution and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0028] Furthermore, it should be noted that in the description of this application, if terms such as "upper," "lower," "inner," or "outer" appear, indicating orientation or positional relationship, these are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, if terms such as "first" or "second" appear, they are also used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0029] Furthermore, in the description of this application, unless otherwise expressly defined, the terms "installation," "connection," "joining," and "connector" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application in light of the specific circumstances.

[0030] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0031] The present application will now be described in detail through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0032] The first aspect of this application provides a sealing structure installed at the liquid injection hole of the cell cover plate, which not only ensures the sealing effect at the liquid injection hole, but also avoids the problem of poor sealing caused by welding explosions at the liquid injection hole.

[0033] Electrolyte, a crucial component of lithium batteries, plays a vital role in conducting electrons between the positive and negative electrodes, ensuring the high voltage and high specific energy of lithium-ion batteries. During charge-discharge cycles, the electrolyte continuously reacts with the electrodes, being consumed and decomposed. As the amount of electrolyte decreases, the battery's internal electronic conductivity declines, leading to a decrease in electrical performance and consequently, a reduction in battery lifespan.

[0034] In related technologies, after the electrolyte injection, formation, and possible replenishment operations are completed, the injection hole of a lithium battery is usually sealed by welding a rubber pin with a sealing aluminum sheet to prevent electrolyte leakage and the intrusion of external impurities, thereby ensuring the safety and performance of the battery. However, the method of welding the sealing aluminum sheet to the cell cover plate has sealing problems such as welding spalls. Therefore, the sealing structure at the injection hole needs further improvement.

[0035] In view of this, in order to overcome the shortcomings of related technologies, the sealing structure of this embodiment combines... Figures 1 to 11 As shown, the overall design includes a liquid-blocking flange 11 on the cell cover plate 1, as well as a sealing element and a sealing cover 5.

[0036] The liquid-retaining flange 11 surrounds the circumference of the injection hole 100 and extends outward toward the cell cover plate 1, defining a mounting cavity 200 communicating with the injection hole 100. The sealing element includes at least a plug 3 that is interference-fitted into the injection hole 100. A sealing cap 5 is disposed in the mounting cavity 200 and used to seal the injection hole 100. The liquid-retaining flange 11 can be folded inward toward the mounting cavity 200, thus confining the sealing cap 5 within the mounting cavity 200.

[0037] Therefore, by providing a liquid-blocking flange 11 on the cell cover 1, the liquid-blocking flange 11 surrounds the circumference of the injection hole 100 and extends outwards towards the cell cover 1. Thus, during cell filling, the liquid-blocking effect of the flange 11 effectively prevents electrolyte from overflowing to the outside of the battery cover. The plug 3 in the sealing component is interference-fitted into the injection hole 100, effectively preventing liquid from flowing out of the injection hole 100.

[0038] The sealing cap 5 is located in the mounting cavity 200 and covers the liquid injection hole 100. The liquid-blocking flange 11 is folded inward to confine the sealing cap 5 within the mounting cavity 200. The liquid-blocking flange 11 not only serves to block liquid but also provides a structural foundation for the installation and fixation of the sealing cap 5, and strengthens the fixing effect of the sealing cap 5. This makes the entire sealing structure more firmly installed on the cell cover plate 1, and it is less likely to loosen or fall off due to external forces or other factors, thereby improving the stability of the sealing structure.

[0039] Meanwhile, the combination of the liquid-blocking flange 11, the sealing element and the sealing cover 5 can also enhance the sealing effect at the liquid injection hole 100, prevent liquid or gas in the external environment from entering the liquid injection hole 100, and also avoid the problem of welding explosion at the liquid injection hole 100 due to welding sealing, thereby ensuring the sealing of the inside of the battery cell.

[0040] Based on the above overview, specifically, firstly, in terms of the overall structure of the battery cell, such as... Figures 1 to 3 As shown, it typically includes a cell housing 2 with a top opening, an electrode assembly housed within the cell housing 2, and a cell cover 1 that seals the top opening. The cell cover 1 has a positive electrode post 101 and a negative electrode post 102 arranged at intervals, as well as an explosion-proof valve 103 and an electrolyte injection port 100. The positive electrode post 101 and the negative electrode post 102 are electrically connected to the corresponding positive and negative tabs of the electrode assembly. The electrolyte injection port 100 is used to inject electrolyte into the cell housing 2.

[0041] The sealing structure of this embodiment is installed at the liquid injection hole 100 of the cell cover plate 1, and the sealing structure includes a liquid-retaining flange 11 formed on the cell cover plate 1, as well as a sealing member and a sealing cover 5. The liquid-retaining flange 11 surrounds the circumferential direction of the liquid injection hole 100, extends along the direction pointing to the outer side of the cell cover plate 1, and encloses an installation cavity 200, which is in communication with the liquid injection hole 100.

[0042] With reference to Figures 3 to 5 , and Figure 8 shown in the figures, in some exemplary implementation forms, on the longitudinal section of the liquid injection hole 100, the sealing cover 5 is, for example, in a shape of "几", and has a cover main body 501 for covering the liquid injection hole 100, and a connecting edge 502 connected to the circumferential direction of the cover main body 501. The folded liquid-retaining flange 11 can press the connecting edge 502 against the bottom wall of the installation cavity 200.

[0043] Here, the sealing cover 5 adopts a structural design of the "几" shape on the longitudinal section of the liquid injection hole 100, which can utilize its own bending part structure, that is, utilize the deformation at the connecting position between the cover main body 501 and the connecting edge 502, to facilitate the interference fit of the sealing cover 5 in the installation cavity 200, and cooperate with the pressing action of the folded liquid-retaining flange 11, so as to improve the installation reliability of the sealing cover 5.

[0044] In addition, in this embodiment, in terms of the structure of the sealing cover 5, the outer peripheral surface thereof is formed with a first conical surface, that is, the outer peripheral surface of the connecting edge 502 is formed with the first conical surface. Correspondingly, the bottom of the installation cavity 200 is also formed with a second conical surface. When the sealing cover 5 is installed in the installation cavity 200, the first conical surface abuts against the second conical surface. In this way, not only the guided installation of the sealing cover 5 is utilized to ensure its installation accuracy, but also the cooperation of the first conical surface and the second conical surface is utilized to facilitate the tight abutment between the sealing cover 5 and the side wall of the installation cavity 200.

[0045] It is worth noting here that, in addition to the above structural form, the sealing cover 5 can also adopt a flat plate structure, so that the folded liquid-retaining flange 11 can also press the sealing cover 5 against the bottom wall of the installation cavity 200.

[0046] With reference to Figures 4 to 7 shown in the figures, in some exemplary implementation forms, for example, an insulating patch 6 is provided on the outer side of the connecting edge 502, and the folded liquid-retaining flange 11 presses the sealing cover 5 against the bottom wall of the installation cavity 200 through the insulating patch 6. At this time, the folded liquid-retaining flange 11 is pressed against the insulating patch 6, and presses the sealing cover 5 against the bottom wall of the installation cavity 200 through the insulating patch 6. In this way, the provided insulating patch 6 can avoid the problem of battery short circuit caused by metal wires generated between the metal liquid-retaining flange 11 after spin riveting and the metal sealing cover 5.

[0047] In practice, the insulating patch 6 is, for example, in the shape of a ring, and a through hole is formed in the middle of the insulating patch 6. When the insulating patch 6 is installed on the connecting edge 502, the cover body 501 of the sealing cover 5 can pass through the through hole to ensure the stability of the insulating patch 6 installation.

[0048] In some exemplary embodiments, the insulating patch 6 is made of any of the materials selected from PC, PE, and PET. These materials have good insulation properties, chemical resistance, and mechanical strength, providing reliable insulation protection and performance.

[0049] Furthermore, in some exemplary embodiments, the thickness of the insulating patch 6 is set, for example, between 0.05mm and 0.5mm. By limiting the thickness of the insulating patch 6, not only can sufficient insulation performance and mechanical strength be ensured, but also the problems of excessive thickness affecting the installation and sealing effect of the sealing cap 5, and insufficient thickness leading to low mechanical strength and easy damage can be avoided.

[0050] Furthermore, in specific implementations, the thickness of the insulating patch 6 can be set to, for example, 0.05mm, 0.10mm, 0.15mm, 0.20mm, 0.25mm, 0.30mm, 0.35mm, 0.40mm, 0.45mm, or 0.50mm.

[0051] Based on the sealing element including the plug 3 that is interference-fitted into the injection hole 100, combined with Figures 4 to 7 As shown, in some exemplary embodiments, the seal further includes a sealing ring 4 disposed between the sealing cap 5 and the bottom wall of the mounting cavity 200. In this case, the sealing ring 4 between the sealing cap 5 and the bottom wall of the mounting cavity 200 seals the gap between them, improving sealing performance. Furthermore, the cooperation between the sealing ring 4 and the plug 3 further enhances the sealing effect at the injection hole 100.

[0052] It should be noted that the sealing ring 4 mentioned above is preferably made of fluororubber or other rubber materials, which have good corrosion resistance and excellent sealing performance.

[0053] Continue to combine Figures 4 to 7As shown, in some exemplary embodiments, a mounting groove 300 is provided on the bottom wall of the mounting cavity 200, i.e., on the cell cover plate 1, and the sealing ring 4 is embedded in the mounting groove 300. The mounting groove 300 ensures that the sealing ring 4 is properly fitted, improving the installation effect of the sealing ring 4, preventing displacement or deformation during installation and use, and ensuring that the sealing ring 4 is evenly compressed, thus achieving a better sealing effect. At the same time, the mounting groove 300 also protects the sealing ring 4 to a certain extent, helping to extend its service life.

[0054] It can be understood that, in addition to setting the mounting groove 300 on the bottom wall of the mounting cavity 200, the mounting groove 300 can also be set on the lower surface of the sealing cover 5, or the mounting groove 300 can be set on both the lower surface of the sealing cover 5 and the bottom wall of the mounting cavity 200, so as to ensure the reliable installation of the sealing ring 4 and the sealing effect between the sealing cover 5 and the bottom wall of the mounting cavity 200.

[0055] Reference Figure 7 As shown, in some exemplary embodiments, the compression ratio β of the sealing ring 4 satisfies: β = m / M, and 10% ≤ β ≤ 45%. Where M is the thickness of the sealing ring 4 in its free state, and m is the compressed thickness of the sealing ring 4.

[0056] At this point, by limiting the compression ratio of the sealing ring 4, the sealing performance can be further improved. This also avoids the sealing ring 4 failing to fully seal the gap due to an insufficient compression ratio, resulting in poor sealing, and avoids the sealing ring 4 being excessively deformed due to an excessively high compression ratio, which would affect the long-term sealing performance and service life.

[0057] In practical implementation, the compression ratio β of the sealing ring 4 can be set to, for example, 10%, 15%, 20%, 25%, 30%, 35%, 40%, or 45%. Within this compression ratio range, the sealing ring 4 can maintain a certain elastic recovery ability while ensuring the sealing effect, thus achieving better sealing performance.

[0058] Reference Figure 4 , Figure 5 and combined Figure 9As shown, in some exemplary embodiments, the plug 3 includes, for example, a connected sealing portion 301 and a pre-installation portion 302. The plug 3 is pre-installed into the injection hole 100 via the pre-installation portion 302, and the sealing portion 301 is press-fitted with the wall of the injection hole 100. This arrangement allows the plug 3 to be pre-installed into the injection hole 100 via the pre-installation portion 302, and then the sealing portion 301 is press-fitted with the wall of the injection hole 100. This makes the installation of the plug 3 more convenient and quick, ensuring the installation effect of the plug 3 and thus guaranteeing the sealing performance at the injection hole 100. Furthermore, the design of the pre-installation portion 302 can also protect the sealing portion 301 to a certain extent, preventing damage to the sealing portion 301 during installation, thereby ensuring the sealing effect at the injection hole 100.

[0059] In addition, in this embodiment, the plug 3 can also adopt the above-described structural form. Figure 10 and Figure 11 The structure shown, for example, the plug 3, includes a main body 303 and an overlapping portion 304 at one end of the main body 303. The overlapping portion 304 overlaps the connecting end face where the injection hole 100 connects to the mounting cavity 200. The main body 303 is provided with a plurality of sealing protrusions 3031 in the circumferential direction. The plurality of sealing protrusions 3031 are arranged at intervals along the axial direction of the main body 303, and at least some of the sealing protrusions 3031 are interference-fitted with the hole wall of the injection hole 100.

[0060] In this structure, the overlapping portion 304 overlaps with the connecting end face connecting the injection hole 100 and the mounting cavity 200, which can play a role in positioning and fixing the plug 3, preventing the plug 3 from being inserted too deeply into the injection hole 100 or not installed properly, and ensuring that the sealing portion 301 of the plug 3 can accurately fit with the wall of the injection hole 100. Furthermore, the multiple sealing protrusions 3031 arranged circumferentially along the axial direction of the main body 303 ensure that at least some of the sealing protrusions 3031 are interference-fitted with the wall of the injection hole 100. This forms multiple seals between the plug 3 and the wall of the injection hole 100, further improving the sealing performance.

[0061] Specifically, the overlapping portion 304 is formed at one end of the main body portion 303, and the radial dimension of the overlapping portion 304 is larger than the radial dimension of the main body. The main body portion 303 can be configured as follows: Figure 9 It can be cylindrical as shown, or it can be set as... Figure 10 As shown, the radial dimension of the main body 303 gradually decreases along the injection direction, that is, the radial dimension of the end away from the overlap 304 is smaller than the radial dimension of the end near the overlap 304. This facilitates guiding the main body 303 into the injection hole 100.

[0062] The sealing ring 3031, in terms of structure, can be like... Figure 9As shown in the figure, on the longitudinal section of the liquid injection hole 100, the sealing convex rings 3031 have a rectangular cross-section, and a plurality of the sealing convex rings 3031 are arranged at intervals along the axial direction of the main body portion 303. It is also possible to Figure 10 As shown in the figure, the sealing convex rings 3031a have a tooth-shaped cross-section, a plurality of the sealing convex rings 3031a are continuously arranged along the axial direction of the main body portion 303, and each of the sealing convex rings 3031a has a guiding end surface 30311 and a limiting end surface 30312. The guiding end surface 30311 is used to guide the main body portion 303 to be inserted into the liquid injection hole 100, and the limiting end surface 30312 located outside the liquid injection hole 100 can be engaged with the lower surface of the cell cover plate 1 to prevent the main body portion 303 from slipping out of the liquid injection hole 100. In addition, part of the sealing convex rings 3031a is in interference fit with the wall of the liquid injection hole 100, so as to ensure the sealing performance of the liquid injection hole 100.

[0063] It should be noted that, for the sealing structure of this embodiment, based on the above exemplary implementation forms, in specific implementation, as a preferred embodiment, it is still Figures 1 to 11 As shown in the figure, it may for example include a liquid-retaining flange 11 formed on the cell cover plate 1, as well as a sealing member and a sealing cover 5. The liquid-retaining flange 11 surrounds the circumferential direction of the liquid injection hole 100 and extends toward the outer side of the cell cover plate 1, and the liquid-retaining flange 11 defines a mounting cavity 200 communicating with the liquid injection hole 100. The sealing member includes a plug 3 in interference fit in the liquid injection hole 100, and a sealing ring 4 disposed between the sealing cover 5 and the bottom wall of the mounting cavity 200. The sealing cover 5 is installed in the mounting cavity 200 and is used to cover the liquid injection hole 100, and the liquid-retaining flange 11 can be folded toward the inner side of the mounting cavity 200 to limit the sealing cover 5 within the mounting cavity 200.

[0064] Wherein, on the longitudinal section of the liquid injection hole 100, the sealing cover 5 is in a shape of "几", and has a cover main body 501 for covering the liquid injection hole 100, and a connecting edge 502 connected to the circumference of the cover main body 501. The folded liquid-retaining flange 11 can press the connecting edge 502 against the bottom wall of the mounting cavity 200. Also, preferably, an insulating patch 6 is disposed on the outer side of the connecting edge 502, and the folded liquid-retaining flange 11 presses the sealing cover 5 against the bottom wall of the mounting cavity 200 through the insulating patch 6.

[0065] Wherein, the insulating patch 6 is made of any one of PC, PE, and PET materials; and / or, the thickness of the insulating patch 6 is between 0.05mm and 0.5mm.

[0066] Wherein, a mounting groove 300 is provided on the bottom wall of the mounting cavity 200, and the sealing ring 4 is embedded and installed in the mounting groove 300. In addition, the compression ratio β of the sealing ring 4 satisfies: 10%≤β≤45%.

[0067] The plug 3 includes a sealing part 301 and a pre-installation part 302 connected together; the plug 3 is pre-installed into the injection hole 100 through the pre-installation part 302, and the sealing part 301 is interference-fitted with the hole wall of the injection hole 100.

[0068] The plug 3 includes a main body 303 and an overlapping part 304 at one end of the main body 303. The overlapping part 304 overlaps the connecting end face of the injection hole 100 and the mounting cavity 200. The main body 303 is provided with a plurality of sealing protrusions 3031 in the circumferential direction. The plurality of sealing protrusions 3031 are arranged at intervals along the axial direction of the main body 303. At least some of the sealing protrusions 3031 are interference fit with the hole wall of the injection hole 100.

[0069] In the preferred embodiments described above, the specific configuration and arrangement of the liquid-blocking flange 11, the sealing element and the sealing cover 5, as well as the mating structure between the liquid-blocking flange 11 and the sealing cover 5, and the mating structure between the sealing cover 5 and the cell cover plate 1, can still be referred to the descriptions in the above exemplary embodiments. Furthermore, in this preferred embodiment, the beneficial effects brought about by the design of the liquid-blocking flange 11, the sealing element and the sealing cover 5, as well as the mating structure between the liquid-blocking flange 11 and the sealing cover 5, and the mating structure between the sealing cover 5 and the cell cover plate 1, can also be referred to the descriptions in the above exemplary embodiments.

[0070] The sealing structure of this embodiment, using the above-described design, effectively prevents electrolyte from overflowing to the outside of the battery cover during cell filling by utilizing the liquid-blocking flange 11. Furthermore, the sealing cap 5 covers the filling hole 100 via the interference fit between the plug 3 and the filling hole 100. The liquid-blocking flange 11 folds inward to confine the sealing cap 5 within the mounting cavity 200. This not only improves the fixing effect of the sealing cap 5 and enhances the sealing effect at the filling hole 100, preventing liquids or gases from the external environment from entering the filling hole 100, but also avoids welding spatter issues at the filling hole 100, thus ensuring the internal sealing of the cell.

[0071] An embodiment of the second aspect of this application provides a battery cell, such as Figures 1 to 3 As shown, the battery cell has a sealing structure as described above.

[0072] The battery cell in this embodiment, by adopting the above-mentioned sealing structure, can not only play a role in blocking liquid during liquid injection, but also provide a base for the installation and fixation of the sealing cover 5. At the same time, with the cooperation of the liquid-blocking flange 11 and the sealing cover 5, and the cooperation of the plug 3 and the liquid injection hole 100, the sealing effect at the liquid injection hole 100 can be enhanced, thereby improving the internal sealing performance of the battery cell.

[0073] The above descriptions are merely some embodiments of this application and are not intended to limit this application. The technical features or structures in the foregoing different embodiments can be arbitrarily combined to form other specific technical solutions as needed. For those skilled in the art, this application can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the protection scope of the claims of this application.

Claims

1. A sealing structure, disposed at a liquid injection hole of a cell cover plate, characterized in that: The sealing structure comprises a liquid-retaining flange disposed on the cell cover plate, as well as a sealing member and a sealing cover; The liquid-retaining flange surrounds the circumference of the liquid injection hole, extends in a direction pointing to the outer side of the cell cover plate, and defines a mounting cavity communicating with the liquid injection hole; The sealing member at least comprises a plug that is in interference fit with the liquid injection hole; The sealing cover is disposed in the mounting cavity and is used for covering the liquid injection hole, and the liquid-retaining flange can be folded towards the inner side of the mounting cavity to limit the sealing cover within the mounting cavity.

2. The sealing structure according to claim 1, characterized in that: On the longitudinal section of the liquid injection hole, the sealing cover is in a shape of "几" and has a cover body for covering the liquid injection hole, and a connecting edge connected to the circumference of the cover body; The folded liquid-retaining flange can press the connecting edge against the bottom wall of the mounting cavity.

3. The sealing structure according to claim 2, characterized in that: An insulating patch is disposed on the outer side of the connecting edge; The folded liquid-retaining flange presses the sealing cover against the bottom wall of the mounting cavity through the insulating patch.

4. The sealing structure according to claim 3, characterized in that: The insulating patch is made of any one of PC, PE and PET materials; and / or, The thickness of the insulating patch is between 0.05mm and 0.5mm.

5. The sealing structure according to claim 1, characterized in that: The sealing member further comprises a sealing ring disposed between the sealing cover and the bottom wall of the mounting cavity.

6. The sealing structure according to claim 5, characterized in that: A mounting groove is provided on the sealing cover and / or the bottom wall of the mounting cavity; The sealing ring is embedded and mounted in the mounting groove.

7. The sealing structure according to claim 5, characterized in that: The compression ratio β of the sealing ring satisfies: 10%≤β≤45%.

8. The sealing structure according to any one of claims 1 to 7, characterized in that: The plug comprises a sealing portion and a pre-mounting portion connected to each other; The plug is pre-installed into the liquid injection hole through the pre-mounting portion, and the sealing portion is in interference fit with the hole wall of the liquid injection hole.

9. The sealing structure according to any one of claims 1 to 7, characterized in that: The plug comprises a main body portion, and a lapping portion disposed at one end of the main body portion; The lapping portion is lapped on the joint end surface where the liquid injection hole communicates with the mounting cavity, a plurality of sealing convex rings are circumferentially disposed on the main body portion, the plurality of sealing convex rings are arranged along the axial direction of the main body portion, and at least part of the sealing convex rings are in interference fit with the hole wall of the liquid injection hole.

10. A cell, characterized in that: The cell is provided with the sealing structure according to any one of claims 1 to 9.

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