Cover plate assembly and battery cell

Abstract

The application relates to the technical field of lithium batteries, and provides a cover plate assembly and a battery cell. The cover plate assembly comprises a cover plate body provided with a liquid injection hole and a sealing element arranged at the liquid injection hole; the liquid injection hole is a stepped hole and has a first hole, a second hole and a third hole which are connected in sequence along a liquid injection direction; the first hole, the second hole and the third hole are arranged in a gradually decreasing manner, and a first step surface is formed between the first hole and the second hole, and a second step surface is formed between the second hole and the third hole; the sealing element has a hole cover part and a hole plug part which are connected in sequence; the hole cover part is in abutment with the first step surface and the second step surface, and the hole cover part is welded to the cover plate body; and the hole plug part is in interference fit in the third hole. The cover plate assembly is used for cooperation of the hole cover part and the two step surfaces on the cover plate body, which is beneficial to improving assembly precision, facilitating welding between the hole cover part and the cover plate body, improving welding quality, and improving the sealing performance of the liquid injection hole.

Description

Technical Field

[0001] This application relates to the field of lithium battery technology, and in particular to a cover plate assembly. This application also relates to a battery cell equipped with the aforementioned cover plate assembly. Background Technology

[0002] The cover assembly of a battery cell typically includes a cover body, a lower plastic core, positive / negative terminals, and an explosion-proof valve. The cover body usually has an injection hole; after electrolyte is injected, this hole needs to be sealed to prevent electrolyte leakage.

[0003] In existing technologies, the electrolyte injection hole is typically sealed using rubber studs and welded aluminum sealing sheets to prevent electrolyte leakage and the intrusion of external impurities, thereby ensuring battery safety and performance. However, in this structure, the positional accuracy of the aluminum sealing sheet at the injection hole is difficult to guarantee, which can easily affect the welding yield of the aluminum sealing sheet, thus impacting the sealing efficiency and the overall sealing performance of the injection hole. Utility Model Content

[0004] In view of this, this application aims to provide a cover plate assembly to improve the assembly accuracy of the seal.

[0005] To achieve the above objectives, the technical solution of this application is implemented as follows: A cover plate assembly includes a cover plate body having an injection hole, and a seal disposed at the injection hole; The injection hole is a stepped hole, and has a first hole, a second hole and a third hole that are connected along the injection direction. The diameters of the first hole, the second hole and the third hole are gradually reduced, and a first step surface is formed between the first hole and the second hole, and a second step surface is formed between the second hole and the third hole. The seal has a connected cap portion and a plug portion. The cap portion abuts against both the first step surface and the second step surface, and the cap portion is welded to the cover plate body. The plug portion is interference-fitted into the third hole.

[0006] Furthermore, the hole cover portion and the hole plug portion are integrally formed.

[0007] Furthermore, one end of the hole cover portion is provided with an insert groove, and a limiting edge is formed on a portion of the side wall of the insert groove, the limiting edge extending radially inward toward the hole cover portion; the hole plug portion is provided with a retaining groove, one end of the hole plug portion is disposed in the insert groove, and the limiting edge is engaged in the retaining groove.

[0008] Furthermore, one end of the hole cover portion is provided with a protrusion, and the hole plug portion is provided with a groove corresponding to the protrusion, and the protrusion is engaged in the groove.

[0009] Furthermore, the plug portion has a connected insertion section and a sealing section; the diameter of the insertion section is smaller than the diameter of the sealing section, and the sealing section is interference-fitted into the third hole.

[0010] Furthermore, the extension section is provided with a guide portion, which is used to guide the plug portion to be inserted into the injection hole.

[0011] Furthermore, the axial dimension L1 of the extension section in the plug portion satisfies: 0.5mm≤L1≤1.5mm.

[0012] Furthermore, in the axial direction of the plug portion, the dimension L2 of the sealing section is greater than the dimension H of the third hole.

[0013] Furthermore, the plug portion is provided with an anti-detachment part, which is used to prevent the plug portion from detaching from the injection hole.

[0014] Compared with related technologies, this application has the following advantages: (1) The cover plate assembly described in this application, through the sealing element provided at the injection hole, makes the hole cover part of the sealing element abut against the first step surface and the second step surface in the injection hole, and the hole cover part is welded to the cover plate body. The hole plug part of the sealing element is interference-fitted in the third hole in the injection hole. This structure, by using the hole cover part to cooperate with the two step surfaces on the cover plate body, can increase the contact area between the hole cover part and the cover plate body, prevent the hole cover part from being skewed, which is conducive to improving the assembly accuracy, facilitating the subsequent welding between the hole cover part and the cover plate body, improving the welding quality, enhancing the sealing performance of the injection hole, and having a very good use effect.

[0015] (2) The hole cover and the hole plug are integrally formed to form an integral sealing nail structure. Compared with the traditional structure that uses separate hole cover and hole plug, the number of parts can be reduced, which is conducive to improving assembly efficiency.

[0016] (3) An insert groove and a limiting edge are provided at one end of the hole cover part. When the hole plug part and the hole cover part are integrally formed, one end of the hole plug part is embedded in the insert groove, and the limiting edge is locked in the slot on the hole plug part. This ensures the reliability of the connection between the hole cover part and the hole plug part and ensures that the hole plug part will not fall off.

[0017] (4) A protrusion is provided at one end of the hole cover part. When the hole plug part and the hole cover part are integrally formed, the protrusion part can be engaged with the groove on the hole plug to form a concave-convex fit structure. This structure can also ensure the reliability of the connection between the hole cover part and the hole plug part and ensure that the hole plug part will not fall off.

[0018] (5) The plug part has a connected extension section and a sealing section, so that the diameter of the extension section is smaller than the diameter of the sealing section. In this way, the extension section can play a better guiding role. Before and during the pre-pressing of the seal, it is convenient to assemble the seal with the injection hole, ensure the positioning accuracy of the seal, and improve the subsequent preparation yield. The sealing section is interference-fitted in the third hole, which can provide a better sealing effect for the injection hole.

[0019] (6) The guide part set on the extension section is conducive to guiding the insertion of the plug part into the injection hole, making the assembly of the seal more convenient.

[0020] (7) Limiting the axial dimension of the extension section in the plug part can further improve the guiding effect and will not affect the assembly of the lower plastic in the cover plate assembly due to excessive length.

[0021] (8) Set the axial dimension of the sealing section in the plug part to be greater than the depth of the third hole. This can accommodate the small distance caused by the plug part being pushed by the increased internal air pressure of the battery, and ensure that the sealing section can always seal the third hole well.

[0022] (9) The anti-detachment part provided on the plug part can effectively prevent the plug part from falling out of the injection hole and improve the reliability of use.

[0023] This application also proposes a battery cell having a cover plate assembly as described above.

[0024] The battery cell described in this application, by adopting the aforementioned cover plate assembly, is beneficial to improving assembly accuracy, facilitating subsequent welding between the hole cover portion and the cover plate body, improving welding quality, and thus enhancing the manufacturing quality and service life 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 perspective view of the cover plate assembly in the application state according to the embodiments of this application; Figure 2 This is a front view of the cover plate assembly application status as described in the embodiments of this application; Figure 3 for Figure 2A sectional view along the AA direction; Figure 4 This is a schematic diagram of the injection hole structure described in an embodiment of this application; Figure 5 This is a cross-sectional view of the seal described in the embodiments of this application; Figure 6 This is a perspective view of the sealing element described in the embodiments of this application; Figure 7 This is a schematic diagram of the structure of the hole cover portion as described in an embodiment of this application; Figure 8 This is a schematic diagram of the structure of the plug portion described in an embodiment of this application; Figure 9 This is another structural schematic diagram of the connection structure between the hole cover portion and the hole plug portion described in the embodiments of this application; Figure 10 This is another structural schematic diagram of the plug portion described in the embodiments of this application; Explanation of reference numerals in the attached figures: 1. Cover plate body; 2. Cell housing; 3. Sealing components; 11. Positive terminal; 12. Negative terminal; 13. Explosion-proof valve; 31. Hole cover portion; 32. Hole plug portion; 310. Protrusion; 311. Insertion groove; 312. Limiting edge; 320. Slot; 321. Sealing section; 322. Extension section; 323. Anti-detachment part; 3220. Guide part; 101, Injection Hole; 1011, First Hole; 1012, Second Hole; 1013, Third Hole. 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] An embodiment of the first aspect of this application provides a cover plate assembly that improves the assembly accuracy of the seal and enhances the welding quality of the seal, thereby improving the sealing performance of the injection hole.

[0033] In related technologies, the cover plate assembly of a battery cell typically includes a cover plate body, a lower plastic layer, positive / negative terminals, and an explosion-proof valve. The cover plate body usually has an injection hole; after the electrolyte is injected, this injection hole needs to be sealed to prevent electrolyte leakage.

[0034] In traditional structures, the electrolyte injection hole is typically sealed using rubber studs and welded aluminum sealing sheets to prevent electrolyte leakage and the intrusion of external impurities, thereby ensuring battery safety and performance. However, in this structure, the positional accuracy of the aluminum sealing sheet at the injection hole is difficult to guarantee, which can easily affect the welding yield of the aluminum sealing sheet, impacting the sealing efficiency and the overall sealing performance of the injection hole.

[0035] In view of this, in order to overcome the shortcomings of the related technology, the cover plate assembly of this embodiment combines... Figures 1 to 10 As shown, the overall design includes a cover body 1 with an injection hole 101 and a sealing element 3 located at the injection hole 101.

[0036] The injection hole 101 is a stepped hole with a first hole 1011, a second hole 1012, and a third hole 1013 connected along the injection direction. The diameters of the first hole 1011, the second hole 1012, and the third hole 1013 are progressively smaller. A first stepped surface is formed between the first hole 1011 and the second hole 1012, and a second stepped surface is formed between the second hole 1012 and the third hole 1013. The sealing member 3 has a connected hole cover portion 31 and a hole plug portion 32. The hole cover portion 31 abuts against both the first and second stepped surfaces and is welded to the cover plate body 1. The hole plug portion 32 is interference-fitted into the third hole 1013.

[0037] At this time, the sealing element 3 provided at the injection hole 101 makes the hole cover portion 31 of the sealing element 3 abut against the first step surface and the second step surface in the injection hole 101, and the hole cover portion 31 is welded to the cover plate body 1. The hole plug portion 32 of the sealing element 3 is interference-fitted in the third hole 1013 in the injection hole 101. This structure, by using the hole cover portion 31 to cooperate with the two step surfaces on the cover plate body 1, can increase the contact area between the hole cover portion 31 and the cover plate body 1, prevent the hole cover portion 31 from being skewed, improve the assembly accuracy, facilitate the subsequent welding between the hole cover portion 31 and the cover plate body 1, improve the welding quality, and thus improve the sealing performance of the injection hole 101.

[0038] Based on the above overall introduction, specifically, combined with Figure 1 and Figure 2 As shown, the cover plate assembly is located at the opening of the cell housing 2, forming an internally sealed structure with the cell housing 2. The cover plate assembly typically includes a cover plate body 1, a lower plastic part, a positive terminal 11, a negative terminal 12, an explosion-proof valve 13, etc. The cover plate body 1 has a liquid injection hole 101, and the aforementioned sealing element 3 is located at the liquid injection hole 101.

[0039] In this embodiment, it should be noted that the material of the hole cover portion 31 is consistent with the material of the cover plate body 1. For example, the material of the hole cover portion 31 can be aluminum, aluminum alloy, etc., to ensure the weldability between the hole cover portion 31 and the cover plate body 1. The material of the hole plug portion 32 can be fluororubber, silicone rubber, or other materials with sealing and elastic effects.

[0040] Combined Figures 3 to 6 As shown, in some exemplary embodiments, the orifice cap portion 31 and the orifice plug portion 32 are integrally formed. In this case, the orifice cap portion 31 and the orifice plug portion 32 form an integral sealing pin structure. Compared with the conventional structure that uses separate orifice caps and orifice plugs, the number of parts can be reduced, which is conducive to improving assembly efficiency and improving the sealing efficiency of the injection hole 101.

[0041] Continue to combine Figures 3 to 6 As shown, in some exemplary embodiments, one end of the hole cover portion 31 is provided with an insert groove 311, and a limiting edge 312 is formed on a portion of the sidewall of the insert groove 311, the limiting edge 312 extending radially inward toward the hole cover portion 31. The hole plug portion 32 is provided with a retaining groove 320, one end of the hole plug portion 32 is disposed in the insert groove 311, and the limiting edge 312 is engaged in the retaining groove 320.

[0042] In this structure, by providing an insert groove 311 and a limiting edge 312 at one end of the hole cover portion 31, when the hole plug portion 32 and the hole cover portion 31 are integrally formed, one end of the hole plug portion 32 is embedded in the insert groove 311, and the limiting edge 312 is engaged in the slot 320 on the hole plug portion 32. This ensures the reliability of the connection between the hole cover portion 31 and the hole plug portion 32 and prevents the hole plug portion 32 from falling off.

[0043] It should be noted that, in addition to the aforementioned structure of the insert groove 311 and the limiting edge 312, other structural forms can also be adopted, such as... Figure 9 As shown, a protrusion 310 is provided at one end of the hole cover portion 31, and a groove corresponding to the protrusion 310 is provided on the hole plug portion 32, with the protrusion 310 being engaged in the groove. At this time, by utilizing the provided protrusion 310, when the hole plug portion 32 and the hole cover portion 31 are integrally formed, the protrusion 310 can engage with the groove on the hole plug, forming a concave-convex fit structure. This structure also ensures the reliability of the connection between the hole cover portion 31 and the hole plug portion 32, preventing the hole plug portion 32 from falling off.

[0044] Specifically, the protrusion 310 has a connecting section and a protruding section connected together, and the protrusion 310 is integrally connected to the lower end face of the hole cover portion 31 through the connecting section. The connecting section and the protruding section are, for example, both columnar structures, and the diameter of the connecting section is smaller than the diameter of the protruding section. This allows the protruding section to form a concave-convex interlocking structure with the hole plug portion 32, further ensuring the reliability of the connection between the hole cover portion 31 and the hole plug portion 32, and effectively preventing the hole plug portion 32 from falling off.

[0045] Combination Figure 3 , Figure 5 and Figure 8As shown, in some exemplary embodiments, the plug portion 32 has a connected extension section 322 and a sealing section 321. The diameter of the extension section 322 is smaller than the diameter of the sealing section 321, and the sealing section 321 is interference-fitted into the third hole 1013. By setting the diameter of the extension section 322 to be smaller than the diameter of the sealing section 321, the extension section 322 can provide better guidance, facilitating the assembly of the seal 3 with the injection hole 101 before and during pre-pressurization, ensuring the positioning accuracy of the seal 3, and improving the subsequent manufacturing yield. Furthermore, the interference fit of the sealing section 321 into the third hole 1013 provides a better seal for the injection hole 101.

[0046] Continue to combine Figure 3 , Figure 5 and Figure 8 As shown, in some exemplary embodiments, the insertion section 322 is provided with a guide portion 3220 for guiding the plug portion 32 into the injection hole 101. In this case, the guide portion 3220 provided on the insertion section 322 facilitates the insertion of the plug portion 32 into the injection hole 101, making the assembly of the seal 3 more convenient.

[0047] In a specific implementation, the guide portion 3220 may be, for example, a chamfer formed at the end of the plug portion 32. This structure is simple, easy to manufacture and process, and can better guide the assembly of the plug portion 32 in the injection hole 101.

[0048] In addition, refer to Figure 3 As shown, in some exemplary embodiments, the axial dimension L1 of the extension section 322 in the plug portion 32 satisfies: 0.5mm ≤ L1 ≤ 1.5mm. By limiting the axial dimension of the extension section 322 in the plug portion 32, a better guiding effect can be achieved, and the excessive length will not affect the assembly of the lower plastic in the cover assembly.

[0049] In specific implementation, the dimension L1 of the extension section 322 in the axial direction of the plug portion 32 can be set to, for example, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, or 1.5mm.

[0050] During battery cell use, normal gas generation increases the internal pressure. Under this pressure, the plug portion 32 is pushed upwards by a small distance. To ensure the sealing performance of the injection port 101, combined with... Figure 3As shown, in some exemplary embodiments, for example in the axial direction of the plug portion 32, the dimension L2 of the sealing section 321 is larger than the dimension H of the third hole 1013. That is, in the plug-assembled state, the sealing section 321 can partially extend out of the third hole 1013. This arrangement can accommodate the small distance caused by the plug portion 32 being pushed up by the increased internal air pressure of the battery, ensuring that the sealing section 321 can always seal the third hole 1013 well.

[0051] In specific implementation, in the axial direction of the plug portion 32, the dimension L2 of the sealing section 321 is 0.1mm-0.5mm larger than the dimension H of the third hole 1013. For example, it can be 0.1mm, 0.2mm, 0.3mm, 0.4mm, or 0.5mm larger. This further ensures that the sealing section 321 always has an interference fit with the third hole 1013, guaranteeing the sealing effect of the injection hole 101.

[0052] In some exemplary embodiments, the plug portion 32 may also be provided with an anti-detachment portion 323, which prevents the plug portion 32 from detaching from the injection hole 101. This configuration effectively prevents the plug portion 32 from detaching from the injection hole 101, improving reliability in use.

[0053] For example Figure 10 As shown, the plug portion 32 is provided with only a sealing section 321, the dimension of which in the axial direction is larger than that of the third hole 1013. An anti-detachment portion 323 is provided at the end of the sealing section 321. The anti-detachment portion 323 includes, for example, an anti-detachment protrusion formed at the end of the sealing section 321. The anti-detachment protrusion extends radially outward along the sealing section 321. When the sealing section 321 is installed into the third hole 1013, the anti-detachment protrusion elastically deforms under the constraint of the third hole 1013. After the anti-detachment portion 323 protrudes from the third hole 1013, the anti-detachment protrusion elastically returns to its original position and can be locked onto one side of the cover plate body 1.

[0054] It is worth noting that, regarding the cover plate assembly of this embodiment, based on the above exemplary embodiments, in specific implementation, as a preferred embodiment, it is still composed of... Figures 1 to 10 As shown in the figure, it includes a cover plate body 1 and a sealing element 3. The injection hole 101 on the cover plate body 1 is a stepped hole, and has a first hole 1011, a second hole 1012 and a third hole 1013 that are connected along the injection direction. The diameters of the first hole 1011, the second hole 1012 and the third hole 1013 are gradually reduced, and a first stepped surface is formed between the first hole 1011 and the second hole 1012, and a second stepped surface is formed between the second hole 1012 and the third hole 1013.

[0055] The sealing element 3 is provided at the injection hole 101 and has a connected hole cover portion 31 and hole plug portion 32. The hole cover portion 31 and the hole plug portion 32 are integrally formed. The hole cover portion 31 abuts against both the first step surface and the second step surface, and the hole cover portion 31 is welded to the cover plate body 1. The hole plug portion 32 is interference-fitted into the third hole 1013.

[0056] The hole cover portion 31 has an insertion groove 311 at one end, and a limiting edge 312 is formed on a portion of the side wall of the insertion groove 311, extending radially inward towards the hole cover portion 31. The hole plug portion 32 has a retaining groove 320. When the hole plug portion 32 and the hole cover portion 31 are integrally formed, one end of the hole plug portion 32 is located in the insertion groove 311, and the limiting edge 312 is engaged in the retaining groove 320.

[0057] The plug portion 32 has a connected insertion section 322 and a sealing section 321. The diameter of the insertion section 322 is smaller than the diameter of the sealing section 321, and the sealing section 321 is interference-fitted into the third hole 1013. Furthermore, the insertion section 322 is provided with a guide portion 3220, which is used to guide the plug portion 32 into the injection hole 101.

[0058] Specifically, the dimension L1 of the extension section 322 in the axial direction of the plug portion 32 satisfies: 0.5mm ≤ L1 ≤ 1.5mm. Furthermore, in the axial direction of the plug portion 32, the dimension L2 of the sealing section 321 is greater than the dimension H of the third hole 1013.

[0059] During assembly, the sealing element 3 is aligned with the injection hole 101, that is, the insertion section 322 is aligned with the third hole 1013. First, pre-pressing is applied to press the sealing section 321 of the plug portion 32 into the third hole 1013, ensuring the positional accuracy of the cover portion 31 and the plug portion 32. Then, final pressing is performed to press the sealing section 321 into the third hole 1013, with the cover portion 31 abutting against both the first and second step surfaces. Finally, the cover portion 31 is welded to the cover plate body 1.

[0060] In the above preferred embodiments, the specific settings and arrangements of the hole cover portion 31, the hole plug portion 32, the mating structure between the hole cover portion 31 and the hole plug portion 32, the size of the hole plug portion 32, etc., 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 hole cover portion 31, the hole plug portion 32, the mating structure between the hole cover portion 31 and the hole plug portion 32, the size of the hole plug portion 32, etc., can also be referred to the descriptions in the above exemplary embodiments.

[0061] The cover plate assembly of this embodiment adopts the above design. Through the matching structure of the hole cover part 31 and the two stepped surfaces on the cover plate body 1, the contact area between the hole cover part 31 and the cover plate body 1 can be increased, preventing the hole cover part 31 from being skewed. This is beneficial to improving the assembly accuracy, facilitating the subsequent welding between the hole cover part 31 and the cover plate body 1, improving the welding quality, and having a good performance.

[0062] An embodiment of the second aspect of this application provides a battery cell having a cover plate assembly as described above.

[0063] In this embodiment, the battery cell, by adopting the aforementioned cover plate assembly, is beneficial to improving assembly accuracy, facilitating subsequent welding between the hole cover portion 31 and the cover plate body 1, improving welding quality, and thus enhancing the manufacturing quality and service life of the battery cell.

[0064] 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 principles of this application should be included within the scope of protection of the claims of this application.

Claims

1. A cover plate assembly, characterized in that: It includes a cover plate body with an injection hole, and a sealing element disposed at the injection hole; The injection hole is a stepped hole, and has a first hole, a second hole and a third hole that are connected along the injection direction. The diameters of the first hole, the second hole and the third hole are gradually reduced, and a first step surface is formed between the first hole and the second hole, and a second step surface is formed between the second hole and the third hole. The seal has a connected cap portion and a plug portion. The cap portion abuts against both the first step surface and the second step surface, and the cap portion is welded to the cover plate body. The plug portion is interference-fitted into the third hole.

2. The cover plate assembly according to claim 1, characterized in that: The hole cover portion and the hole plug portion are integrally formed.

3. The cover plate assembly according to claim 2, characterized in that: One end of the hole cover portion is provided with an insert groove, and a limiting edge is formed on a portion of the sidewall of the insert groove, the limiting edge extending radially inward toward the hole cover portion; The plug portion is provided with a slot, one end of the plug portion is disposed in the mounting groove, and the limiting edge is engaged in the slot.

4. The cover plate assembly according to claim 2, characterized in that: One end of the hole cover portion is provided with a protrusion, and the hole plug portion is provided with a groove corresponding to the protrusion, and the protrusion is engaged in the groove.

5. The cover plate assembly according to claim 1, characterized in that: The plug portion has a connected extension section and a sealing section; The diameter of the inserted section is smaller than the diameter of the sealing section, and the sealing section is interference-fitted into the third hole.

6. The cover plate assembly according to claim 5, characterized in that: The extension section is provided with a guide portion, which is used to guide the plug portion to be inserted into the injection hole.

7. The cover plate assembly according to claim 5, characterized in that: The axial dimension L1 of the extension section in the plug portion satisfies: 0.5mm≤L1≤1.5mm.

8. The cover plate assembly according to claim 5, characterized in that: In the axial direction of the plug portion, the dimension L2 of the sealing section is greater than the dimension H of the third hole.

9. The cover plate assembly according to claim 1, characterized in that: The plug portion is provided with an anti-detachment part, which is used to prevent the plug portion from falling out of the injection hole.

10. A battery cell, characterized in that: The battery cell is provided with a cover plate assembly as described in any one of claims 1 to 9.

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