Cover plate assembly and battery cell

Abstract

The application relates to the technical field of power 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, a sealing plug and a sealing cover; the liquid injection hole is a stepped hole and is provided with a first hole, a second hole and a third hole which are sequentially communicated along a liquid injection direction, a first step surface is formed between the first hole and the second hole, and a second step surface is arranged between the second hole and the third hole; the sealing plug is provided with a main body portion which is in interference fit in the third hole, one end of the main body portion is formed with a limiting portion in a stepped shape, and the limiting portion is in abutting fit with the first step surface and the second step surface; the sealing cover is arranged in the first hole and covers at least the upper portion of the sealing plug, and the sealing cover is fixedly connected with the cover plate body. The cover plate assembly can not only increase the contact area and the fit tightness between the sealing plug and the liquid injection hole, but also prevent the sealing plug from excessively entering the liquid injection hole, so that the sealing plug can be effectively limited, and the sealing effect of the liquid injection hole is guaranteed.

Description

Technical Field

[0001] This application relates to the field of power 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] In the manufacturing process of lithium batteries, after the secondary electrolyte filling of the cell, the electrolyte filling hole of the cell casing needs to be sealed to prevent subsequent leakage. In traditional structures, a sealing pin (i.e., a sealing plug) is usually used in conjunction with a sealing cap to achieve a seal at the electrolyte filling hole. The sealing pin is inserted into the electrolyte filling hole and makes an interference fit with the inner wall of the hole, and the sealing cap is welded to the cell cover plate to achieve a seal.

[0003] To improve the sealing performance at the injection hole, the radial dimension of the sealing plug is usually increased. However, as the radial dimension of the sealing plug increases, the nailing force of the nailing equipment also increases. At this time, the sealing plug may over-enter the injection hole, causing poor sealing of the injection hole. Therefore, it is urgent to improve the sealing structure at the injection hole. Utility Model Content

[0004] In view of this, this application aims to provide a cover plate assembly that can prevent the sealing plug from excessively entering the injection hole and affecting the sealing performance at the injection hole.

[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 sealing plug and a sealing cap disposed at the injection hole; The injection hole is a stepped hole, and has a first hole, a second hole and a third hole connected in sequence along the injection direction. A first step surface is formed between the first hole and the second hole, and a second step surface is provided between the second hole and the third hole. The sealing plug has a main body portion that is interference-fitted into the third hole. One end of the main body portion forms a limiting portion, which is stepped and abuts against the first stepped surface and the second stepped surface. The sealing cap is disposed in the first hole and covers at least the top of the sealing plug, and the sealing cap is fixedly connected to the cover plate body.

[0006] Furthermore, relative to the end with the limiting part, the other end of the main body is provided with an anti-detachment part, which is used to prevent the sealing plug from coming out of the third hole in a direction opposite to the injection direction.

[0007] Furthermore, the anti-detachment part is provided with a guide end face, which is used to guide the sealing plug into the third hole.

[0008] Further, the anti-dropping part comprises an anti-dropping convex ring formed on the main body part, and the anti-dropping convex ring can be clamped on the inner side of the cover plate body.

[0009] Further, in the longitudinal section of the liquid injection hole, the sealing cover is in an "Ω" shape, and has a cover main body covering the sealing plug, and a connecting edge arranged circumferentially on the cover main body; the connecting edge abuts against the first stepped surface, and the connecting edge is welded to the cover plate body.

[0010] Further, a limiting protrusion is provided on a side of the sealing cover facing the sealing plug, and the limiting protrusion can limit the axial displacement of the sealing plug.

[0011] Further, a groove corresponding to the limiting protrusion is provided on an end surface of the sealing plug, and the limiting protrusion can be inserted into the groove.

[0012] Compared with the related art, the present application has the following advantages: (1) In the cover plate assembly described in the present application, the liquid injection hole is provided as a stepped hole, which includes a first hole, a second hole and a third hole. The first hole can provide an installation foundation for the sealing cover and is beneficial to ensuring the position accuracy of the sealing cover on the cover plate body; the main body part of the sealing plug is in interference fit with the third hole of the liquid injection hole, which can achieve a good sealing effect on the liquid injection hole. Moreover, the stepped limiting part formed at one end of the main body part abuts and cooperates with the first stepped surface and the second stepped surface of the liquid injection hole, so that the cooperation between the sealing plug and the liquid injection hole forms a multi-layer limiting effect, which can well limit the sealing plug along the liquid injection direction, prevent the problem of poor sealing of the liquid injection hole caused by the sealing plug excessively entering the liquid injection hole, and ensure the sealing effect of the liquid injection hole.

[0013] (2) The provided anti-dropping part can prevent the sealing plug from falling out of the third hole in the direction opposite to the liquid injection direction, which is beneficial to ensuring that the sealing plug always maintains a good sealing effect during the use of the battery cell, and avoids problems such as electrolyte leakage caused by the falling out of the sealing plug, thereby facilitating improving the use reliability and service life of the battery cell.

[0014] (3) The guide end surface provided on the anti-dropping part can guide the sealing plug to be smoothly loaded into the third hole by means of the guide end surface when installing the sealing plug, which reduces installation difficulty and improves assembly efficiency and assembly quality.

[0015] (4) The anti-dropping part adopts an anti-dropping convex ring formed on the main body part, which has a simple structure, is convenient for preparation and molding, and can well prevent the sealing plug from falling out.

[0016] (5) In the longitudinal section of the electrolyte injection hole, the sealing cover has an Ω-shaped ("ji"-shaped) structure, which can effectively cover the upper part of the sealing plug, further improving the sealing performance at the electrolyte injection hole, and meanwhile playing a protective role for the sealing plug to prevent external foreign matters from entering the electrolyte injection hole. In addition, after the Ω-shaped sealing cover is welded to the cover plate body, the overall structural stability of the cover plate assembly can be enhanced, so that the cover plate is not prone to deformation or damage when subjected to external forces such as internal pressure of the battery, which ensures the safety and reliability of the battery.

[0017] (6) A limit protrusion is provided on a side of the sealing cover facing the sealing plug, which can limit the axial displacement of the sealing plug. On the basis of the limit portion, the position of the sealing plug can be further accurately limited, ensuring that the sealing plug is always in the optimal sealing position.

[0018] (7) A groove corresponding to the limit protrusion is provided on the end face of the sealing plug, so that the limit protrusion can be inserted into the groove. By means of the cooperation between the limit protrusion and the groove, when the internal gas production pressure of the electric core pushes the hole plug, the hole plug can be effectively prevented from moving reversely along the injection direction, which ensures the position reliability and sealing performance of the sealing plug.

[0019] Another object of the present application is to provide an electric core, which is provided with the cover plate assembly described above.

[0020] The electric core described in the present application adopts the above cover plate assembly, and through the limit cooperation between the stepped limit portion provided on the sealing plug and the first step surface and the second step surface of the electrolyte injection hole, it can prevent the sealing plug from excessively entering the electrolyte injection hole to affect the sealing performance, and can play a good limiting role for the sealing plug, ensuring the sealing effect of the electrolyte injection hole, thereby being beneficial to improving the use reliability and service life of the electric core. Description of Drawings

[0021] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The schematic embodiments and descriptions thereof in the present application are used to explain the present application, and do not constitute an improper limitation on the present application. In the drawings: Figure 1 it is a structural schematic diagram of the cover plate assembly according to the embodiment of the present application in an application state from a first viewing angle; Figure 2 it is a structural schematic diagram of the cover plate assembly according to the embodiment of the present application in an application state from a second viewing angle; Figure 3 it is a structural schematic diagram of the cover plate assembly according to the embodiment of the present application in an application state from a third viewing angle; Figure 4 is Figure 3 an enlarged view taken along line A-A in; Figure 5 it is another structural schematic diagram of the cover plate assembly according to the embodiment of the present application; Figure 6 This is a schematic diagram of the injection hole structure described in an embodiment of this application; Figure 7 This is a schematic diagram of the sealing plug described in an embodiment of this application; Figure 8 This is a schematic diagram of the sealing cap structure described in an embodiment of this application; Explanation of reference numerals in the attached figures: 1. Cover plate body; 2. Cell housing; 3. Sealing plug; 4. Sealing cover; 10. Injection hole; 101. First hole; 102. Second hole; 103. Third hole; 104. First stepped surface; 105. Second stepped surface; 11. Positive terminal; 12. Negative terminal; 13. Explosion-proof valve; 14. Lower plastic part; 30. Main body; 30a. Limiting part; 31. First limiting flange; 32. Second limiting flange; 33. Anti-detachment part; 331. Guide end face; 41. Cover body; 42. Connecting edge; 43. Limiting protrusion. Detailed Implementation

[0022] 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.

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] An embodiment of the first aspect of this application provides a cover plate assembly that can effectively prevent the sealing plug from excessively entering the injection hole and affecting the sealing performance at the injection hole.

[0029] In related technologies, during the production of lithium batteries, after the secondary electrolyte filling of the cell, the electrolyte filling hole of the cell casing needs to be sealed to prevent subsequent leakage. In traditional structures, a sealing pin (i.e., a sealing plug) is usually used in conjunction with a sealing cap to achieve a seal at the electrolyte filling hole. The sealing pin is inserted into the electrolyte filling hole and makes an interference fit with the inner wall of the hole, and the sealing cap is welded to the cell cover plate to achieve a seal.

[0030] To improve the sealing performance at the injection hole, the radial dimension of the sealing plug is usually increased. However, as the radial dimension of the sealing plug increases, the nailing force of the nailing equipment also increases. At this time, the sealing plug may over-enter the injection hole, causing poor sealing of the injection hole. Therefore, it is urgent to improve the sealing structure at the injection hole.

[0031] 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 8 As shown, the overall design includes a cover plate body 1 with an injection hole 10, and a sealing plug 3 and a sealing cap 4 located at the injection hole 10.

[0032] The injection hole 10 is a stepped hole, having a first hole 101, a second hole 102, and a third hole 103 connected sequentially along the injection direction. A first stepped surface 104 is formed between the first hole 101 and the second hole 102, and a second stepped surface 105 is provided between the second hole 102 and the third hole 103. The sealing plug 3 has a main body 30 that is interference-fitted into the third hole 103. One end of the main body 30 has a limiting part 30a, which is stepped and abuts against the first stepped surface 104 and the second stepped surface 105. The sealing cap 4 is disposed in the first hole 101 and at least covers the top of the sealing plug 3, and the sealing cap 4 is fixedly connected to the cap plate body 1.

[0033] Therefore, by making the injection hole 10 a stepped hole, including a first hole 101, a second hole 102, and a third hole 103, the first hole 101 can provide an installation base for the sealing cap 4 and help ensure the positional accuracy of the sealing cap 4 on the cover plate body 1. The main body 30 of the sealing plug 3 is interference-fitted with the third hole 103 of the injection hole 10, which can provide a good sealing effect for the injection hole 10. Furthermore, the stepped limiting part 30a formed at one end of the main body 30 abuts against the first stepped surface 104 and the second stepped surface 105 of the injection hole 10, so that the fit between the sealing plug 3 and the injection hole 10 forms a multiple limiting effect, which can better limit the sealing plug 3 along the injection direction, prevent the sealing plug 3 from excessively entering the injection hole 10 and causing poor sealing of the injection hole 10, and ensure the sealing effect of the injection hole 10.

[0034] Based on the above overall introduction, specifically, combined with Figures 1 to 3 As shown, the battery cell, in its overall structure, mainly includes a battery cell housing 2 with an opening, an electrode assembly housed within the battery cell housing 2, and a cover plate assembly that seals the opening. The cover plate assembly includes a cover plate body 1, a lower plastic part 14, a positive electrode post 11, a negative electrode post 12, and an explosion-proof valve 13, etc. An injection hole 10 is formed on the cover plate body 1, which is used to inject electrolyte into the battery cell housing 2.

[0035] Reference Figures 4 to 6 As shown, in this embodiment, the injection hole 10 on the cover plate body 1 is a stepped hole, and has a first hole 101, a second hole 102 and a third hole 103 connected in sequence along the injection direction. The diameter of the first hole 101 is larger than the diameter of the second hole 102, and a first step surface 104 is formed between the first hole 101 and the second hole 102. The diameter of the second hole 102 is larger than the diameter of the third hole 103, and a second step surface 105 is formed between the second hole 102 and the third hole 103.

[0036] In terms of structure, the sealing plug 3, such as Figure 7As shown, it has a main body 30 that is interference-fitted into the third hole 103. One end of the main body 30 forms a limiting portion 30a, which is stepped and abuts against the first stepped surface 104 and the second stepped surface 105. Specifically, the limiting portion 30a includes a first limiting flange 31 and a second limiting flange 32 formed on the main body 30. The radial dimension of the first limiting flange 31 is larger than the radial dimension of the second limiting flange 32, and the radial dimension of the second limiting flange 32 is larger than the radial dimension of the main body 30.

[0037] When the sealing plug 3 is inserted into the third hole 103, the first limiting protrusion 31 can abut against the first step surface 104, and the second limiting protrusion 32 can abut against the second step surface 105. In this way, a limiting structure is formed between the first limiting protrusion 31 and the first step surface 104, and a limiting structure is also formed between the second limiting protrusion 32 and the second step surface 105. That is, a double limiting structure is formed between the sealing plug 3 and the injection hole 10, which can effectively prevent the sealing plug 3 from excessively entering the injection hole 10.

[0038] It should be noted that the sealing plug 3 is made of, for example, fluororubber, and the sealing cap 4 is made of the same material as the cap body 1, for example, aluminum.

[0039] In addition, the radial dimension of the first limiting flange 31 is larger than the radial dimension of the second limiting flange 32. This can also increase the contact area between the sealing plug 3 and the nailing device, making the sealing plug 3 more evenly stressed. This prevents the sealing plug 3 from being damaged due to uneven stress and tilting into the third hole 103, thus ensuring the structural integrity and sealing performance of the sealing plug 3.

[0040] During actual operation of the battery cell, a corresponding air pressure will be generated inside, which can reach up to about 0.3 MPa in actual tests. This pressure can push the sealing plug 3 outward, and the sealing effect at the injection hole 10 is easily reduced after the sealing plug 3 moves.

[0041] Therefore, in this embodiment, combined with Figure 4 , Figure 5 and Figure 7 As shown, in some exemplary embodiments, for example, an anti-detachment portion 33 is provided at the other end of the main body 30 relative to the end where the limiting portion 30a is provided. This anti-detachment portion 33 is used to prevent the sealing plug 3 from detaching from the third hole 103 in a direction opposite to the liquid injection direction. This arrangement helps to ensure that the sealing plug 3 maintains a good sealing effect during battery use, avoiding problems such as electrolyte leakage caused by the sealing plug 3 detaching, thereby improving the reliability and service life of the battery cell.

[0042] Specifically, as an exemplary structure, the anti-drop portion 33 includes, for example, an anti-drop convex ring formed on the outer peripheral surface of the main body portion 30 and protruding radially outward of the main body portion 30, and the anti-drop convex ring can be clamped on the inner side of the cover plate body 1. In this case, by providing the anti-drop portion 33 as the anti-drop convex ring formed on the main body portion 30, the structure is simple, facilitates preparation and molding, and can well prevent the sealing plug 3 from dropping out.

[0043] In specific implementation, after the sealing plug 3 is installed into the third hole 103, when the sealing plug 3 moves outward under the internal pressure of the battery cell, the anti-drop convex ring can be clamped on the inner side surface of the cover plate main body, thereby preventing the sealing plug 3 from dropping out.

[0044] Continuing with reference to Figure 4 , Figure 5 and Figure 7 shown in, in some exemplary embodiments, a guide end surface 331 may be provided on the anti-drop portion 33, and the guide end surface 331 is used to guide the sealing plug 3 to be installed into the third hole 103. In this case, the arrangement of the guide end surface 331 can guide the sealing plug 3 to be smoothly installed into the third hole 103 by means of the guide end surface 331 when installing the sealing plug 3, thereby reducing the installation difficulty and improving the assembly efficiency and assembly quality.

[0045] In specific implementation, the guide end surface 331 can be, for example, a rounded corner or a chamfer formed on the anti-drop portion 33, that is, a rounded corner or a chamfer formed on the anti-drop protrusion, which has a simple structure and is convenient for preparation and molding.

[0046] With reference to Figure 4 , Figure 5 and Figure 8 shown in, in some exemplary embodiments, for example, on the longitudinal section of the electrolyte injection hole 10, the sealing cover 4 is in an I-shaped structure, and has a cover main body 41 enclosing the sealing plug 3, and a connecting edge 42 arranged in the circumferential direction of the cover main body 41. Wherein, the connecting edge 42 abuts against the first step surface 104, and the connecting edge 42 is welded connected to the cover plate body 1.

[0047] In this case, the I-shaped structure of the sealing cover 4 can effectively enclose above the sealing plug 3, further improve the sealing performance at the electrolyte injection hole 10, and meanwhile play a protective role for the sealing plug 3 to prevent foreign matters from entering the electrolyte injection hole 10. Moreover, after the sealing cover 4 with an I-shaped longitudinal section is welded connected to the cover plate body 1, the overall structural stability of the cover plate assembly can be enhanced, so that the cover plate is not prone to deformation or damage when bearing external forces such as the internal pressure of the battery, and the safety and reliability of the battery are ensured.

[0048] Referring to Figure 5As shown, in some exemplary embodiments, for example, a limiting protrusion 43 is provided on the side of the sealing cap 4 facing the sealing plug 3, which can limit the axial displacement of the sealing plug 3. In specific implementations, the limiting protrusion 43 is provided corresponding to the sealing plug 3, and the axial direction of the limiting protrusion 43 is consistent with the axial direction of the sealing plug 3. When the sealing plug 3 moves in the opposite direction along the injection direction, the limiting protrusion 43 can abut against the end of the sealing plug 3, which can better limit the axial displacement of the sealing plug 3.

[0049] Furthermore, it is worth noting that the cooperation between the limiting protrusion 43 and the limiting part 30a on the sealing plug 3 can further precisely limit the position of the sealing plug 3, ensuring that the sealing plug 3 is always in the optimal sealing position.

[0050] In some exemplary embodiments, the cross-section of the aforementioned limiting protrusion 43 is circular, rectangular, cross-shaped, or triangular. Its structure is simple and easy to manufacture. It is understood that the cross-section of the limiting protrusion 43 may also take other shapes besides those described above, such as elliptical or irregular polygonal shapes.

[0051] Furthermore, based on the provision of a limiting protrusion 43 on the sealing cover 4, in this embodiment, referring to... Figure 5 As shown, as an exemplary structural form, for example, a groove corresponding to the limiting protrusion 43 is provided on the end face of the sealing plug 3, and when the sealing cover 4 is assembled onto the cover plate body 1, the limiting protrusion 43 can be at least partially inserted into the groove.

[0052] A groove corresponding to the limiting protrusion 43 is provided on the end face of the sealing plug 3, so that the limiting protrusion 43 can be inserted into the groove. In this way, by utilizing the cooperation between the limiting protrusion 43 and the groove, when the gas pressure generated inside the battery cell pushes the plug, it can effectively prevent the plug from moving in the opposite direction to the liquid injection direction, thus ensuring the positional reliability and sealing performance of the sealing plug 3.

[0053] It should be noted that, in the direction of liquid injection, the limiting protrusion 43 and the groove can be spaced apart or have a certain interference fit, for example, the interference fit is between 0.1-0.5mm. In this case, the certain interference fit makes the first limiting protrusion 31 and the second limiting protrusion 32 abut against the first step surface 104 and the second step surface 105 respectively, and cooperate with the interference fit between the main body 30 and the third hole 103. This makes the sealing plug 3 and the liquid injection hole 10 form a three-seal structure, which can better improve the sealing performance of the liquid injection hole 10.

[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 8As shown, the present invention may, for example, comprise a cover plate body 1, a sealing plug 3 and a sealing cover 4. The electrolyte injection hole 10 on the cover plate body 1 is a stepped hole, and is provided with a first hole 101, a second hole 102 and a third hole 103 which are sequentially communicated along the electrolyte injection direction. A first step surface 104 is formed between the first hole 101 and the second hole 102, and a second step surface 105 is provided between the second hole 102 and the third hole 103.

[0055] The sealing plug 3 has a main body portion 30 interference-fitted in the third hole 103, a limiting portion 30a is formed at one end of the main body portion 30, the limiting portion 30a is stepped, and the limiting portion 30a is in abutting fit with the first step surface 104 and the second step surface 105. The sealing cover 4 is arranged in the first hole 101, at least covers above the sealing plug 3, and the sealing cover 4 is welded and fixedly connected with the cover plate body 1.

[0056] Wherein, relative to the end provided with the limiting portion 30a, the other end of the main body portion 30 is provided with an anti-drop portion 33, and the anti-drop portion 33 is configured to prevent the sealing plug 3 from coming out of the third hole 103 in a direction opposite to the electrolyte injection direction. As a further preferred embodiment, the anti-drop portion 33 is provided with a guide end surface 331, and the guide end surface 331 is configured to guide the sealing plug 3 into the third hole 103.

[0057] Wherein, on the longitudinal section of the electrolyte injection hole 10, the sealing cover 4 is in an inverted U shape, and has a cover main body 41 covering the sealing plug 3, and a connecting edge 42 arranged on the circumference of the cover main body 41; the connecting edge 42 abuts against the first step surface 104, and the connecting edge 42 is welded to the cover plate body 1.

[0058] Wherein, a side of the sealing cover 4 facing the sealing plug 3 is provided with a limiting protrusion 43, and the limiting protrusion 43 can limit the axial displacement of the sealing plug 3. Moreover, an end surface of the sealing plug 3 is provided with a groove corresponding to the limiting protrusion 43, and the limiting protrusion 43 can be inserted into the groove.

[0059] In the above preferred embodiments of the cover plate assembly, for the specific arrangement and deployment of the sealing plug 3, the sealing cover 4, the limiting portion 30a, the anti-drop portion 33, the fitting structure of the sealing plug 3 and the electrolyte injection hole 10, and the fitting structure of the sealing cover 4 and the electrolyte injection hole 10, reference may still be made to the records in the above exemplary embodiments, and in this preferred embodiment, for the beneficial effects brought by the design of the sealing plug 3, the sealing cover 4, the limiting portion 30a, the anti-drop portion 33, the fitting structure of the sealing plug 3 and the electrolyte injection hole 10, and the fitting structure of the sealing cover 4 and the electrolyte injection hole 10, reference may also be made to the records in the above exemplary embodiments.

[0060] The cover plate assembly of this embodiment adopts the above design. By optimizing the structure of the sealing plug 3 and the sealing cap 4, as well as the matching structure of the sealing plug 3 and the sealing cap 4 with the injection hole 10, and by utilizing the step-shaped limiting part 30a provided on the sealing plug 3 to limit the matching with the first step surface 104 and the second step surface 105, it can not only increase the contact area and the tightness of the matching between the sealing plug 3 and the injection hole 10, which is beneficial to improving the sealing performance, but also prevent the sealing plug 3 from excessively entering the injection hole 10 and causing the injection hole 10 to be poorly sealed. Thus, it can effectively limit the sealing plug 3 and ensure the sealing effect of the injection hole 10.

[0061] An embodiment of the second aspect of this application provides a battery cell, such as Figures 1 to 4 As shown, the battery cell has a cover plate assembly as described above.

[0062] In this embodiment, the battery cell uses the cover plate assembly described above. By utilizing the step-shaped limiting part 30a provided on the sealing plug 3 and the limiting cooperation between the first step surface 104 and the second step surface 105 of the injection hole 10, the sealing plug 3 can be prevented from excessively entering the injection hole 10 and affecting the sealing performance. It can also play a good limiting role for the sealing plug 3, ensuring the sealing effect of the injection hole 10, thereby improving the reliability and service life of the battery cell.

[0063] 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: comprises a cover plate body with an electrolyte injection hole, and a sealing plug and a sealing cover arranged at the electrolyte injection hole; the electrolyte injection hole is a stepped hole and has a first hole, a second hole and a third hole which are sequentially communicated along the electrolyte injection direction, a first step surface is formed between the first hole and the second hole, and a second step surface is arranged between the second hole and the third hole; the sealing plug has a main body portion that is interference-fitted in the third hole, a limiting portion is formed at one end of the main body portion, the limiting portion is step-shaped, and the limiting portion is in abutting fit with the first step surface and the second step surface; the sealing cover is arranged in the first hole, at least covers the upper part of the sealing plug, and is fixedly connected with the cover plate body.

2. The cover plate assembly according to claim 1, characterized in that: relative to the end provided with the limiting portion, the other end of the main body portion is provided with an anti-drop portion, and the anti-drop portion is configured to prevent the sealing plug from falling out of the third hole in a direction opposite to the electrolyte injection direction.

3. The cover plate assembly according to claim 2, characterized in that: the anti-drop portion is provided with a guide end surface, and the guide end surface is configured to guide the sealing plug to be installed into the third hole.

4. The cover plate assembly according to claim 2, characterized in that: the anti-drop portion comprises an anti-drop convex ring formed on the main body portion, and the anti-drop convex ring can be clamped on the inner side of the cover plate body.

5. The cover plate assembly according to claim 1, characterized in that: on the longitudinal cross-section of the electrolyte injection hole, the sealing cover is in an "Ω" shape, and has a cover main body covering the sealing plug, and a connecting edge arranged on the circumference of the cover main body; the connecting edge abuts against the first step surface, and the connecting edge is welded to the cover plate body.

6. The cover plate assembly according to claim 5, characterized in that: a side of the sealing cover facing the sealing plug is provided with a limiting protrusion, and the limiting protrusion can limit the axial displacement of the sealing plug.

7. The cover plate assembly according to claim 6, characterized in that: an end surface of the sealing plug is provided with a groove corresponding to the limiting protrusion, and the limiting protrusion can be inserted into the groove.

8. A battery cell, characterized in that: the battery cell is provided with the cover plate assembly according to any one of claims 1 to 7.

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