Sealing cover and battery cover plate assembly

Abstract

This application relates to the field of power battery technology and provides a sealing cap and a battery cover assembly. The sealing cap of this application is disposed at the liquid injection hole of the battery cover and is welded to the battery cover to seal the liquid injection hole. The sealing cap includes a main body, a buffer portion disposed circumferentially on the main body, and a sealing portion. The sealing portion is disposed circumferentially on the buffer portion and welded to the wall of the liquid injection hole. The sealing portion has a connected cylindrical portion and a conical portion. In the thickness direction of the sealing cap, the relationship between the dimension L of the cylindrical portion and the thickness H of the sealing cap satisfies: 10% ≤ L / H ≤ 100%. The sealing cap of this application not only improves its molding yield but also effectively ensures the welding quality between the sealing cap and the battery cover, guaranteeing the sealing effect at the liquid injection hole, thereby improving the manufacturing quality and safety of the battery.

Description

Technical Field

[0001] This application relates to the field of power battery technology, and in particular to a sealing cover and battery cover assembly. Background Technology

[0002] In battery structures, the battery cover typically has an injection hole for injecting or replenishing electrolyte. To prevent leakage later, the injection hole needs to be sealed.

[0003] In the prior art, a sealing plug and a sealing cap are usually installed at the injection hole. The sealing hole is achieved by the sealing plug being press-fitted into part of the inner wall of the injection hole, and the sealing cap covering the sealing plug being welded to the cover plate.

[0004] However, the traditional sealing cap has unreasonable structural design, resulting in poor weld formation and cracks between the sealing cap and the cover plate. This directly leads to the failure of the filling hole seal, causing the electrolyte inside the battery casing to leak. This not only affects the electrochemical performance and service life of the battery, but also poses safety hazards such as thermal runaway and fire. Summary of the Invention

[0005] In view of this, this application aims to provide a sealing cover to improve the welding quality between it and the battery cover.

[0006] To achieve the above objectives, the technical solution of this application is implemented as follows:

[0007] A sealing cap is disposed at the liquid injection hole of a battery cover plate for welding to the battery cover plate to seal the liquid injection hole. The sealing cap includes a main body, a buffer portion disposed in the circumferential direction of the main body, and a sealing portion.

[0008] The sealing part is located circumferentially in the buffer part and is welded to the wall of the injection hole. The sealing part has a connected cylindrical part and a conical part. In the thickness direction of the sealing cap, the relationship between the dimension L of the cylindrical part and the thickness H of the sealing cap satisfies: 10%≤L / H≤100%.

[0009] Furthermore, the thickness H of the sealing cap is between 0.8mm and 1.5mm, and the dimension L of the cylindrical part is between 0.09mm and 0.9mm.

[0010] Furthermore, the buffer portion includes a buffer groove recessed from the upper surface of the sealing cap to the lower surface of the sealing cap, the buffer groove surrounding the circumference of the main body portion.

[0011] Furthermore, the thickness of the main body is Z; the bottom of the buffer groove is formed with a rounded corner, and the radius R of the rounded corner satisfies: 0.2mm≤R≤Z.

[0012] Furthermore, in the thickness direction of the sealing cover, the relationship between the depth Z1 of the buffer groove and the thickness Z of the main body satisfies: 20%≤Z1 / Z≤200%, and in the direction perpendicular to the axial direction of the sealing cover, the relationship between the width Z2 of the buffer groove and the thickness Z of the main body satisfies: 50%≤Z2 / Z≤500%.

[0013] Furthermore, the thickness Z of the main body is between 0.4mm and 1.2mm, the depth Z1 of the buffer groove is between 0.08mm and 0.8mm, and the width Z2 of the buffer groove is between 0.2mm and 2mm.

[0014] Furthermore, the injection hole is a stepped hole, and has a first hole and a second hole that are connected to each other, with a stepped surface formed between the first hole and the second hole; the sealing cap is located in the first hole and abuts against the stepped surface, and the area S1 of the part of the sealing cap that abuts against the stepped surface and the area S2 of the stepped surface are related by the following condition: 20%≤S1 / S2≤90%.

[0015] Furthermore, the area S1 of the portion where the sealing cap abuts against the stepped surface is 5.6 mm. 2 ≤S1≤30mm 2 The area S2 of the stepped surface is 20 mm. 2 ≤S1≤50mm 2 .

[0016] Furthermore, a sealing nail is provided in the second hole, and the sealing nail is interference-fitted with the hole wall of the second hole; the distance between the side of the main body near the sealing nail and the step surface is D, the end face of the sealing nail near the sealing cap is higher than the step surface, the distance between the end face and the step surface is D1, and satisfies: 0%≤D1 / D2≤80%.

[0017] Compared with related technologies, this application has the following advantages:

[0018] (1) The sealing cap described in this application, by setting a main body, a buffer part and a sealing part, and defining the relationship between the cylindrical part of the sealing part and the thickness of the sealing cap, can not only block the liquid injection hole well, but also the sealing part can be well adapted to the hole wall of the liquid injection hole, avoiding the generation of metal wires or burrs due to the small size of the cylindrical part, which would affect the molding yield and welding yield of the sealing cap. At the same time, the buffer part can also effectively relieve welding stress, and the cooperation between the sealing part and the buffer part can well ensure the welding quality of the sealing cap and the battery cover plate, and ensure the sealing effect at the liquid injection hole, thereby improving the manufacturing quality and safety of the battery.

[0019] (2) By limiting the thickness H of the sealing cap and the size L of the cylindrical part, the molding yield and welding yield of the sealing cap can be further guaranteed.

[0020] (3) The buffer part adopts a buffer groove around the circumference of the main body. It has a simple structure, is easy to manufacture and mold, and can play a good buffering role. It can effectively buffer the welding stress between the sealing cover and the battery cover plate, avoid weld cracking, and thus improve the sealing effect at the injection hole.

[0021] (4) By limiting the radius of the rounded corner at the bottom of the buffer groove, it is possible to prevent problems such as difficulty in forming due to the small rounded corner size and cracking of the sealing cap due to stress concentration. It is also possible to prevent the structural strength of the sealing cap from being affected by the large rounded corner size.

[0022] (5) By limiting the relationship between the depth of the buffer groove and the thickness of the main body, and limiting the relationship between the width of the buffer groove and the thickness of the main body, on the one hand, it can avoid the shallow depth of the buffer groove, which cannot buffer the welding stress between the sealing cap and the battery cover, resulting in welding cracks or other quality problems. On the other hand, it can avoid the narrow width of the buffer groove, which makes it difficult to form the sealing cap. At the same time, it is also conducive to ensuring the assembly quality of the sealing cap and avoiding affecting the design of the liquid injection port and the battery cover. Thus, it can ensure the forming yield and assembly yield of the sealing cap and improve the welding yield between the sealing cap and the battery cover.

[0023] (6) By limiting the thickness of the main body, the depth of the buffer groove and the width of the buffer groove, the molding yield and assembly yield of the sealing cover can be further guaranteed, and the welding yield of the sealing cover and the battery cover plate can be improved.

[0024] (7) By limiting the relationship between the area of ​​the sealing cover and the step surface that abuts, and the area of ​​the step surface, the sealing cover can be prevented from being easily moved during assembly due to its small contact area, which would affect the welding quality. It can also prevent interference with the sealing nail in the second hole after assembly, thereby ensuring the assembly stability and welding quality of the sealing cover.

[0025] (8) By limiting the area of ​​the contact part between the sealing cover and the step surface, as well as the area of ​​the step surface, the assembly stability and welding quality of the sealing cover can be further guaranteed.

[0026] (9) The sealing nail set in the second hole, together with the sealing cap, can further improve the sealing effect at the injection hole. Furthermore, by limiting the relationship between the lower surface of the main body and the step surface and the upper end surface of the sealing nail and the step surface, it can not only prevent the sealing nail from falling into the battery, but also ensure the assembly yield of the sealing cap and improve the welding quality of the sealing cap.

[0027] Another object of this application is to provide a battery cover assembly, including a battery cover having an injection hole and a sealing cap as described above, the sealing cap being disposed at the injection hole.

[0028] The battery cover assembly described in this application, by adopting the aforementioned sealing cover, can fit well with the wall of the injection hole, ensuring the molding yield of the sealing cover and also ensuring the welding quality between the sealing cover and the battery cover, thus guaranteeing the sealing effect at the injection hole, thereby improving the manufacturing quality and safety of the battery. Attached Figure Description

[0029] 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:

[0030] Figure 1 This is a first-view structural schematic diagram of the sealing cap according to an embodiment of this application;

[0031] Figure 2 This is a second-view structural schematic diagram of the sealing cap described in an embodiment of this application;

[0032] Figure 3 This is a third-view structural schematic diagram of the sealing cap described in an embodiment of this application;

[0033] Figure 4 This is a schematic diagram of the sealing cover described in this application applied to the battery cover assembly;

[0034] Figure 5 for Figure 4 AA-view sectional view;

[0035] Figure 6 This is a schematic diagram of the structure of the battery cover injection hole as described in an embodiment of this application;

[0036] Explanation of reference numerals in the attached figures:

[0037] 10. Sealing cap;

[0038] 100. Operating hole; 101. Main body; 102. Buffer groove; 103. Sealing part; 1031. Cylindrical part; 1032. Conical part;

[0039] 11. Battery cover; 22. Lower plastic part; 33. Terminal post; 44. Sealing nail; 110. Injection hole; 110a. First hole; 110b. Second hole; 110c. Stepped surface. Detailed Implementation

[0040] 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.

[0041] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] An embodiment of the first aspect of this application provides a sealing cap disposed at the liquid injection hole of a battery cover plate for welding connection with the battery cover plate to seal the liquid injection hole. The sealing cap of this embodiment, through its optimized structure, improves the molding quality of the sealing cap and also improves the welding quality between the sealing cap and the battery cover plate.

[0047] In related technologies, battery covers typically have electrolyte injection holes for injecting or replenishing electrolyte into the battery. To prevent leakage later, the injection holes need to be sealed.

[0048] In the prior art, a sealing plug and a sealing cap are usually installed at the injection hole. The sealing hole is achieved by the sealing plug being press-fitted into part of the inner wall of the injection hole, and the sealing cap covering the sealing plug being welded to the cover plate.

[0049] However, the traditional sealing cap has unreasonable structural design, resulting in poor weld formation and cracks between the sealing cap and the cover plate. This directly leads to the failure of the filling hole seal, causing the electrolyte inside the battery casing to leak. This not only affects the electrochemical performance and service life of the battery, but also poses safety hazards such as thermal runaway and fire.

[0050] In view of this, in order to overcome the shortcomings of the related technology, the sealing cover of this embodiment combines... Figures 1 to 6 As shown, the overall design includes a main body 101, a buffer portion disposed in the circumferential direction of the main body 101, and a sealing portion 103 disposed in the circumferential direction of the buffer portion, which is welded to the wall of the injection hole 110.

[0051] The sealing cap 10 is disposed at the liquid injection hole 110 of the battery cover plate 11 and is welded to the battery cover plate 11 to seal the liquid injection hole 110. Furthermore, the sealing portion 103 has a connected cylindrical portion 1031 and a conical portion 1032. In the thickness direction of the sealing cap 10, the relationship between the dimension L of the cylindrical portion 1031 and the thickness H of the sealing cap 10 satisfies: 10% ≤ L / H ≤ 100%.

[0052] At this time, in the above structure, by setting the main body 101, buffer part and sealing part 103, and defining the relationship between the cylindrical part 1031 of the sealing part 103 and the thickness of the sealing cap 10, this structural form not only allows the sealing cap 10 to be well placed at the injection hole 110, but also allows the sealing part 103 to be well adapted to the hole wall of the injection hole 110, avoiding the generation of metal wires or burrs due to the small size of the cylindrical part 1031, which would affect the molding yield and welding yield of the sealing cap 10.

[0053] At the same time, the buffer section can effectively relieve welding stress, and the cooperation between the sealing section 103 and the buffer section can ensure the welding quality of the sealing cover 10 and the battery cover 11, and ensure the sealing effect at the injection hole 110, thereby improving the manufacturing quality and safety of the battery.

[0054] Based on the above overview, specifically, let's continue to combine... Figures 1 to 6 As shown, the sealing cap 10 includes a main body 101, a buffer portion, and a sealing portion 103. The main body 101 is flat, the buffer portion is disposed circumferentially on the main body 101, and the sealing portion 103 is disposed circumferentially on the buffer portion and welded to the wall of the injection hole 110. Furthermore, the sealing portion 103 has a cylindrical portion 1031 and a conical portion 1032 connected together.

[0055] In specific implementation, the relationship between the dimension L of the cylindrical portion 1031 in the thickness direction of the sealing cover 10 and the thickness H of the sealing cover 10 can be set, for example, to any one of 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100% or a range between any two values.

[0056] Reference Figure 3 As shown, in some exemplary embodiments, for example, the thickness H of the sealing cap 10 is between 0.8 mm and 1.5 mm, and the dimension L of the cylindrical portion 1031 is between 0.09 mm and 0.9 mm. In this case, by defining the dimension H of the conical portion 1032 and the dimension L of the cylindrical portion 1031 respectively, the molding yield and welding yield of the sealing cap 10 can be further guaranteed.

[0057] In specific implementation, the thickness H of the sealing cover 10 can be set to any one of 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, or 1.5mm, or a range between any two values.

[0058] Combination Figures 1 to 3As shown, in some exemplary embodiments, for example, the buffer portion includes a buffer groove 102 recessed from the upper surface of the sealing cap 10 to the lower surface of the sealing cap 10, the buffer groove 102 surrounding the circumference of the main body portion 101. Here, the buffer portion adopts the structure of the buffer groove 102, which is not only simple in structure and easy to manufacture, but also can play a better buffering role, effectively buffering the welding stress between the sealing cap 10 and the battery cover plate 11, avoiding weld cracking, thereby improving the sealing effect at the injection hole 110.

[0059] It should be noted that the buffer groove 102 can be a complete circle arranged around the main body 101 in the circumference, or it can be a plurality of grooves arranged at intervals around the main body 101 in the circumference. Preferably, in this embodiment, the buffer groove 102 is a complete circle arranged around the main body 101 in the circumference.

[0060] Continue to combine Figures 1 to 3 As shown, in some exemplary embodiments, the thickness of the main body 101 is Z. The bottom of the buffer groove 102 has a rounded corner, the radius R of which satisfies: 0.2mm ≤ R ≤ Z.

[0061] In the above embodiment, by limiting the radius of the rounded corner at the bottom of the buffer groove 102, it is possible to prevent problems such as molding difficulties caused by excessively small rounded corner size and cracking of the sealing cover 10 due to stress concentration. It is also possible to prevent the structural strength of the sealing cover 10 from being affected by excessively large rounded corner size.

[0062] In a specific implementation, for example, if the thickness of the main body 101 is 0.4mm, then the radius R of the rounded corner can be set to, for example, 0.2mm, 0.3mm or 0.4mm.

[0063] Reference Figure 3 As shown, in some exemplary embodiments, for example, in the thickness direction of the sealing cap 10, the relationship between the depth Z1 of the buffer groove 102 and the thickness Z of the main body 101 satisfies: 20% ≤ Z1 / Z ≤ 200%, and in the direction perpendicular to the axial direction of the sealing cap 10, the relationship between the groove width Z2 of the buffer groove 102 and the thickness Z of the main body 101 satisfies: 50% ≤ Z2 / Z ≤ 500%.

[0064] In practice, the value of Z1 / Z can be set to any one of the following values ​​or a range between any two values: 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 110%, 120%, 130%, 140%, 150%, 160%, 170%, 180%, 190%, and 200%.

[0065] The value of Z2 / Z can be set to any one of the following values ​​or a range between any two values: 50%, 80%, 100%, 120%, 150%, 180%, 200%, 220%, 250%, 270%, 300%, 330%, 350%, 370%, 400%, 420%, 450%, 180%, and 500%.

[0066] Here, by limiting the relationship between the depth of the buffer groove 102 and the thickness of the main body 101, and limiting the relationship between the width of the buffer groove 102 and the thickness of the main body 101, on the one hand, it can avoid the buffer groove 102 being too shallow, which would not be able to buffer the welding stress between the sealing cover 10 and the battery cover plate 11, thus avoiding quality problems such as welding cracks or cracks. On the other hand, it can avoid the buffer groove 102 being too narrow, which would make it difficult to form the sealing cover 10. At the same time, it is also conducive to ensuring the assembly quality of the sealing cover 10 and avoiding affecting the design of the liquid injection port and the battery cover plate 11. Thus, it can ensure the forming yield and assembly yield of the sealing cover 10 and improve the welding yield between the sealing cover 10 and the battery cover plate 11.

[0067] Continue to refer to Figure 3 As shown, in some exemplary embodiments, for example, the thickness Z of the main body 101 is between 0.4 mm and 1.2 mm, the depth Z1 of the buffer groove 102 is between 0.08 mm and 0.8 mm, and the width Z2 of the buffer groove 102 is between 0.2 mm and 2 mm. In this case, by limiting the thickness of the main body 101, the depth of the buffer groove 102, and the width of the buffer groove 102, the molding yield and assembly yield of the sealing cover 10 can be further guaranteed, and the welding yield between the sealing cover 10 and the battery cover 11 can be improved.

[0068] In specific implementation, the thickness Z of the main body 101 can be set to any one of 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, or 1.2mm, or a range between any two values.

[0069] Depend on Figures 4 to 6 and combined Figures 1 to 3 As shown, in some exemplary embodiments, for example, the injection hole 110 is a stepped hole and has a first hole 110a and a second hole 110b that are connected. The diameter of the first hole 110a is larger than the diameter of the second hole 110b, and the hole wall of the first hole 110a is inclined. A stepped surface 110c is formed between the first hole 110a and the second hole 110b.

[0070] The aforementioned sealing cap 10 is located in the first hole 110a. The conical portion 1032 abuts against the wall of the first hole 110a, and the cylindrical portion 1031 forms a receiving area for accommodating the weld between itself and the wall of the first hole 110a. The outer wall of the buffer groove 102 on the sealing cap 10 abuts against the stepped surface 110c. The area S1 of the outer wall of the sealing cap 10 (i.e., the buffer groove 102) abuts against the stepped surface 110c, and the area S2 of the stepped surface 110c, satisfy the following relationship: 20% ≤ S1 / S2 ≤ 90%. Moreover, in specific implementations, the value of S1 / S2 can be set to any one of 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or a range between any two values.

[0071] In the above embodiment, by limiting the relationship between the area of ​​the contact portion between the sealing cover 10 and the step surface 110c and the area of ​​the step surface 110c, the sealing cover 10 can be prevented from being easily moved during assembly due to its small contact area, which would affect the welding quality. In addition, it can also prevent interference with the sealing nail 44 in the second hole 110b after assembly, thereby ensuring the assembly stability and welding quality of the sealing cover 10.

[0072] Furthermore, in some exemplary embodiments, the area S1 of the portion where the sealing cap 10 abuts against the step surface 110c is 5.6 mm² ≤ S1 ≤ 30 mm², and the area S2 of the step surface 110c is 20 mm² ≤ S1 ≤ 50 mm². By limiting the area of ​​the portion where the sealing cap 10 abuts against the step surface 110c, and the area of ​​the step surface 110c, the assembly stability and welding quality of the sealing cap 10 can be further guaranteed.

[0073] In specific implementations, the area S1 mentioned above can be set to any one of the following values, or a range between any two values: 5.6 mm², 8 mm², 10 mm², 12 mm², 15 mm², 18 mm², 20 mm², 22 mm², 25 mm², 28 mm², and 30 mm². Similarly, the area S2 mentioned above can be set to any one of the following values, or a range between any two values: 20 mm², 22 mm², 25 mm², 28 mm², 30 mm², 33 mm², 35 mm², 37 mm², 40 mm², 42 mm², 45 mm², 48 mm², and 50 mm².

[0074] Reference Figure 5As shown, in some exemplary embodiments, for example, a sealing pin 44 is provided in the second hole 110b, and the sealing pin 44 is interference-fitted with the hole wall of the second hole 110b. Furthermore, the distance between the side of the main body 101 near the sealing pin 44 and the stepped surface 110c is D, that is, the distance between the lower surface of the main body 101 and the stepped surface 110c is D. The end face of the sealing pin 44 near the sealing cap 10 is higher than the stepped surface 110c, and the distance between this end face, that is, the upper end face of the sealing pin 44, and the stepped surface 110c is D1. The relationship between the two satisfies: 0% ≤ D1 / D2 ≤ 80%.

[0075] In the above configuration, the sealing nail 44, which is provided in the second hole 110b, works in conjunction with the sealing cover 10 to further improve the sealing effect at the injection hole 110. Furthermore, by limiting the relationship between the lower surface of the main body 101 and the step surface 110c, and the upper end surface of the sealing nail 44 and the step surface 110c, it is possible not only to prevent the sealing nail 44 from falling into the battery, but also to ensure the assembly yield of the sealing cover 10 and improve the welding quality of the sealing cover 10.

[0076] In practice, the values ​​of D1 / D2 mentioned above can be set to any one of 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or a range between any two values.

[0077] In addition, in this embodiment, the top surface of the sealing cover 10 is also provided with an operation hole 100 to facilitate the removal, installation and positioning of the sealing cover 10.

[0078] In some embodiments, sealing caps 10 of different sizes L and H are provided, and each sealing cap 10 is welded to a cover plate of the same specification. The welding quality between the sealing cap 10 and the cover plate is tested, and the verification results are shown in Table 1.

[0079] Table 1

[0080]

[0081] Referring to Examples 1 to 13, when the dimension L of the cylindrical portion 1031 and the dimension H of the conical portion 1032 satisfy 10% ≤ L / H ≤ 100% in the thickness direction of the sealing cap 10, the molding yield of the sealing cap 10 and the welding yield with the injection hole 110 both meet the design requirements. Referring to Comparative Examples 1 and 2, sealing caps 10 with L / H values ​​exceeding the above range have lower molding yields and are prone to generating metal wires or burrs during the manufacturing process, affecting the welding quality of the sealing cap 10, and thus do not meet the design requirements.

[0082] In some embodiments, sealing caps 10 of different sizes Z, Z1, and Z2 are provided, and the sealing caps 10 are welded to cover plates of the same specifications. After welding, the welding quality between the sealing caps 10 and the cover plates is tested, and the verification results are shown in Table 2.

[0083] Table 2

[0084]

[0085] Based on the test results of Examples 1 to 9, it can be seen that when the depth Z1 of the buffer groove 102 and the thickness Z of the main body 101 satisfy 20% ≤ Z1 / Z ≤ 200%, and the groove width Z2 of the buffer groove 102 and the thickness Z of the main body 101 satisfy 50% ≤ Z2 / Z ≤ 500%, the molding yield of the sealing cap 10 and the welding yield with the injection hole 110 both meet the design requirements. However, according to Comparative Examples 1 to 4, sealing caps 10 with Z1 / Z and Z2 / Z values ​​exceeding the above ranges have low molding yields, or the diameter of the sealing cap 10 is too large, affecting the design of the injection hole 110 of the cover plate, or the height of the sealing cap 10 is too large, affecting the design of the cover plate thickness; all of these do not meet the design requirements.

[0086] In some embodiments, by setting different sizes of S1 and S2, the assembly quality of the sealing cap 10 and the welding quality between the sealing cap 10 and the cover plate are detected during the process of installing the sealing cap 10 onto the stepped surface 110c of the injection hole 110. The verification results are shown in Table 3.

[0087] Table 3

[0088]

[0089] The results from Examples 1 to 11 show that when the area S1 of the part where the sealing cap 10 abuts against the step surface 110c and the area S2 of the step surface 110c satisfy 20% ≤ S1 / S2 ≤ 90%, the sealing cap 10 does not exhibit problems such as movement, lifting, or tilting during assembly, and both the assembly yield and welding yield meet the design requirements. Comparative Examples 1 and 2 show that when the value of S1 / S2 exceeds the above range, problems such as a small contact area between the sealing cap 10 and the step surface 110c, poor stability of the sealing cap 10 after assembly, easy movement, or interference between the sealing cap 10 and the sealing nail 44 during assembly occur, and both the assembly yield and welding quality do not meet the design requirements.

[0090] In some embodiments, by setting different D and D1 values ​​and welding the sealing cover 10 to a cover plate of the same specification, the assembly quality and welding quality of the sealing cover 10 are tested, and the verification results are shown in Table 4.

[0091] Table 4

[0092]

[0093] As can be seen from Examples 1 to 8, when the distance D between the lower surface of the main body 101 and the step surface 110c and the distance D2 between the top end face of the sealing nail 44 and the step surface 110c satisfy 0% ≤ D1 / D2 ≤ 80%, the assembly yield and welding yield of the sealing cover 10 both meet the design requirements. As can be seen from Comparative Examples 1 and 2, when the value of D1 / D2 exceeds the above range, there is a high risk that the sealing nail 44 will fall into the battery, or it may affect the assembly and welding of the sealing cover 10, thus failing to meet the design requirements.

[0094] The sealing cap 10 in this embodiment adopts the above design. By optimizing its own structure, it can not only improve its molding yield, but also ensure the welding quality of the sealing cap 10 and the battery cover plate 11, and ensure the sealing effect at the injection hole 110, thereby improving the manufacturing quality and safety of the battery.

[0095] An embodiment of the second aspect of this application provides a battery cover 11 assembly, referring to... Figures 4 to 6 As shown, the battery cover 11 assembly includes a battery cover 11 with an injection hole 110, a lower plastic part 22 disposed on one side of the battery cover 11, an electrode post 33 passing through the battery cover 11 and the lower plastic part 22, and a sealing cap 10 disposed at the injection hole 110 as described above.

[0096] The injection hole 110 is a stepped hole with a first hole 110a and a second hole 110b that are connected. The diameter of the first hole 110a is larger than that of the second hole 110b, and a stepped surface 110c is formed between the first hole 110a and the second hole 110b. The sealing cap 10 is located in the first hole 110a and is welded to the battery cover plate 11 through the sealing part 103. A sealing plug 44 is provided in the second hole 110b, and the sealing plug 44 is interference-fitted with the hole wall of the second hole 110b. In this way, the sealing of the injection hole 110 is achieved by the cooperation of the sealing plug and the sealing cap 10.

[0097] The battery cover plate 11 assembly of this embodiment, by adopting the above-mentioned sealing cover 10, can fit well with the hole wall of the injection hole 110, ensuring the molding yield of the sealing cover 10, while also ensuring the welding quality of the sealing cover 10 and the battery cover plate 11, ensuring the sealing effect at the injection hole 110, thereby helping to improve the manufacturing quality and safety of the battery.

[0098] 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 sealing cap, disposed at the liquid injection hole of a battery cover plate, for welding to the battery cover plate to seal the liquid injection hole, characterized in that: The sealing cover includes a main body, a buffer portion disposed in the circumferential direction of the main body, and a sealing portion; The sealing part is located circumferentially in the buffer part and is welded to the wall of the injection hole. The sealing part has a connected cylindrical part and a conical part. In the thickness direction of the sealing cap, the relationship between the dimension L of the cylindrical part and the thickness H of the sealing cap satisfies: 10%≤L / H≤100%.

2. The sealing cap according to claim 1, characterized in that: The thickness H of the sealing cap is between 0.8mm and 1.5mm, and the dimension L of the cylindrical part is between 0.09mm and 0.9mm.

3. The sealing cap according to claim 1, characterized in that: The buffer portion includes a buffer groove recessed from the upper surface of the sealing cap to the lower surface of the sealing cap, the buffer groove surrounding the circumference of the main body portion.

4. The sealing cap according to claim 3, characterized in that: The thickness of the main body is Z; The bottom of the buffer groove has a rounded corner, and the radius R of the rounded corner satisfies: 0.2mm≤R≤Z.

5. The sealing cap according to claim 3, characterized in that: In the thickness direction of the sealing cover, the relationship between the depth Z1 of the buffer groove and the thickness Z of the main body satisfies: 20%≤Z1 / Z≤200%, and in the direction perpendicular to the axial direction of the sealing cover, the relationship between the width Z2 of the buffer groove and the thickness Z of the main body satisfies: 50%≤Z2 / Z≤500%.

6. The sealing cap according to claim 5, characterized in that: The thickness Z of the main body is between 0.4mm and 1.2mm, the depth Z1 of the buffer groove is between 0.08mm and 0.8mm, and the width Z2 of the buffer groove is between 0.2mm and 2mm.

7. The sealing cap according to any one of claims 1 to 6, characterized in that: The injection hole is a stepped hole, and has a first hole and a second hole that are connected to each other, with a stepped surface formed between the first hole and the second hole; The sealing cap is located in the first hole and abuts against the step surface. The area S1 of the part of the sealing cap that abuts against the step surface and the area S2 of the step surface are related by the following condition: 20% ≤ S1 / S2 ≤ 90%.

8. The sealing cap according to claim 7, characterized in that: The area S1 of the part where the sealing cover abuts against the step surface is 5.6 mm2 ≤ S1 ≤ 30 mm2, and the area S2 of the step surface is 20 mm2 ≤ S1 ≤ 50 mm2.

9. The sealing cap according to claim 7, characterized in that: The second hole is provided with a sealing nail, and the sealing nail is interference-fitted with the hole wall of the second hole; The distance between the side of the main body near the sealing nail and the step surface is D. The end face of the sealing nail near the sealing cap is higher than the step surface. The distance between the end face and the step surface is D1, and satisfies: 0%≤D1 / D2≤80%.

10. A battery cover assembly, characterized in that: The battery includes a battery cover with an injection hole, and a sealing cap as described in any one of claims 1 to 9, the sealing cap being disposed at the injection hole.

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