Battery liquid injection hole sealing structure and battery pack

Abstract

The utility model provides a kind of battery liquid injection hole sealing structure and battery package.The battery liquid injection hole sealing structure includes: top cover component, top cover component is equipped with liquid injection hole, liquid injection hole includes welding hole section, threaded hole section and sealing hole section sequentially connected in the thickness direction of top cover component;Sealing component includes sealing nail piece and sealing cover piece, sealing cover piece includes welding cover body and the threaded cover body connected with welding cover body, welding cover body is connected with welding hole section, threaded cover body is matched with threaded hole section, sealing nail piece and sealing hole section sealing cooperation.The technical scheme of the utility model's battery liquid injection hole sealing structure can effectively prevent sealing cover piece from warping in assembly process, thereby avoiding the welding sealing defects caused thereby.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and more specifically, to a battery filling hole sealing structure and a battery pack. Background Technology

[0002] In existing technology, secondary batteries generally have a liquid injection hole on the top cover, and the liquid injection hole is generally designed with three sections, such as... Figure 1 As shown, one section is a ramp section 1 that mates with the aluminum sealing nail 4, another section is a straight section 2 that mates with the sealing nail 5 and extends in the thickness direction of the top cover, and a connecting section 3 is used to connect the ramp section 1 and the straight section 2. Thus, after the battery cell has completed its electrolyte filling, as shown... Figure 2 Insert the sealing nail 5, which forms an interference fit seal with the straight section 2, and then... Figure 3 Assemble aluminum sealing nails 4 to the corresponding positions of the ramp section 1, and weld the top cover and aluminum sealing nails 4 to achieve a seal.

[0003] Although the sealing method of the above-mentioned sealing nail 5 and straight section 2 can prevent the electrolyte and other substances from overflowing and contaminating the slope section 1, thus avoiding welding abnormalities such as welding explosions, the aluminum sealing nail 4 is prone to warping during the assembly process with the injection hole, which can also lead to welding defects. Utility Model Content

[0004] The main objective of this invention is to provide a battery filling hole sealing structure and a battery pack. The battery filling hole sealing structure can effectively prevent the sealing cover from lifting up during assembly, thereby avoiding welding sealing defects caused by it.

[0005] To achieve the above objectives, this utility model provides a battery filling hole sealing structure, comprising: a top cover component, a filling hole provided on the top cover component, the filling hole including a welded hole segment, a threaded hole segment and a sealing hole segment connected sequentially along the thickness direction of the top cover component; a sealing component, including a sealing pin and a sealing cover, the sealing cover including a welded cover body and a threaded cover body connected to the welded cover body, the welded cover body being welded to the welded hole segment, the threaded cover body being threadedly engaged with the threaded hole segment, and the sealing pin being sealedly engaged with the sealing hole segment.

[0006] Furthermore, the cross-sectional area of ​​the welded hole section is larger than that of the threaded hole section.

[0007] Furthermore, the cross-sectional area of ​​the welded cover is less than or equal to the cross-sectional area of ​​the welded hole segment.

[0008] Furthermore, the cross-sectional area of ​​the threaded hole section is larger than that of the sealing hole section. The bottom wall of the threaded hole section is provided with an annular groove, which surrounds the sealing hole section. The sealing component also includes an annular seal provided in the annular groove. The threaded cover body is sealed to the bottom wall of the threaded hole section through the annular seal.

[0009] Furthermore, the annular seal is a sealing ring, and the compression of the sealing ring is 20%~40%.

[0010] Furthermore, the annular groove has a groove depth h in the thickness direction, and the top cover component has a thickness H, with the groove depth h being 0.05 to 0.5 times the thickness H.

[0011] Furthermore, the outer periphery of the threaded cover is provided with a convex thread, and the inner wall of the threaded hole section is provided with a concave thread, with the convex thread and the concave thread engaging.

[0012] Furthermore, the outer diameter D of the threaded cover is less than or equal to the inner diameter d of the threaded hole section.

[0013] Furthermore, the welded cover is provided with a screwing groove, which is located on the side of the welded cover opposite to the threaded cover.

[0014] According to another aspect of the present invention, the present invention provides a battery pack, including a battery housing, the aforementioned battery filling hole sealing structure, and a cell module, wherein the cell module is located inside the battery housing, and a top cover component is provided on the battery housing.

[0015] By applying the technical solution of this utility model, when the welding cover is welded to the welding hole section, the threaded cover and the threaded hole section form a threaded fit. The pre-tightening force generated by the threaded connection can effectively prevent the sealing cover from lifting up during the assembly process, thereby avoiding welding sealing defects caused by this, such as uneven weld or incomplete sealing. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0017] Figure 1 A schematic diagram of a prior art battery fluid injection port is shown;

[0018] Figure 2 It shows Figure 1 A schematic diagram of the assembly structure of the battery filling hole and the adhesive pin;

[0019] Figure 3 It shows Figure 1 A schematic diagram of the assembly structure of the battery filling hole, adhesive pins, and aluminum pins;

[0020] Figure 4 A schematic diagram of an embodiment of the battery filling hole sealing structure of this utility model is shown;

[0021] Figure 5 It shows Figure 4 A sectional view of the battery filling hole sealing structure along line AA;

[0022] Figure 6 It shows Figure 5 A partially enlarged view of the battery filling hole sealing structure;

[0023] Figure 7 It shows Figure 5 Another enlarged view of the battery filling hole sealing structure;

[0024] Figure 8 It shows Figure 5 Another enlarged view of the battery filling hole sealing structure;

[0025] Figure 9 It shows Figure 5 Another enlarged view of the battery filling hole sealing structure;

[0026] Figure 10 It shows Figure 5 A schematic diagram of the filling hole structure of the battery filling hole sealing structure;

[0027] Figure 11 It shows Figure 5 A schematic diagram of the sealing cover of the battery filling hole sealing structure;

[0028] Figure 12 It shows Figure 11 BB-direction sectional view of the sealing cover.

[0029] The above figures include the following reference numerals:

[0030] 10. Top cover component; 11. Welded hole section; 12. Threaded hole section; 121. Concave thread; 13. Sealing hole section; 14. Annular groove; 20. Sealing component; 21. Welded cover body; 211. Twisting groove; 22. Threaded cover body; 221. Convex thread; 23. Sealing pin; 24. Annular seal. Detailed Implementation

[0031] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0032] like Figures 4 to 12As shown, an embodiment of this utility model provides a battery filling hole sealing structure, including: a top cover component 10, a filling hole provided on the top cover component 10, the filling hole including a welded hole segment 11, a threaded hole segment 12 and a sealing hole segment 13 connected sequentially along the thickness direction of the top cover component 10; a sealing component 20, including a sealing pin 23 and a sealing cover, the sealing cover including a welded cover body 21 and a threaded cover body 22 connected to the welded cover body 21, the welded cover body 21 is welded to the welded hole segment 11, the threaded cover body 22 is threadedly engaged with the threaded hole segment 12, and the sealing pin 23 is sealed to the sealing hole segment 13.

[0033] In the above technical solution, when the welding cover 21 is welded to the welding hole section 11, the threaded cover 22 and the threaded hole section 12 form a threaded fit. The pre-tightening force generated by the threaded connection can effectively prevent the sealing cover from lifting during the assembly process, thereby avoiding welding sealing defects such as uneven weld or incomplete sealing.

[0034] In some embodiments, the injection hole is a cylindrical stepped hole, such that the welding hole section 11, the threaded hole section 12 and the sealing hole section 13 all have an inner diameter; the sealing pin 23, the welding cap 21 and the threaded cap 22 are all cylindrical.

[0035] In some embodiments, the sealing nail 23 is a sealing adhesive nail, and the sealing cover is an aluminum nail.

[0036] It should be noted that the length, width and thickness of the top cover component 10 are arranged perpendicularly to each other.

[0037] Because the thread crest is a stress concentration area, if the inner diameter of the welded hole section 11 and the threaded hole section 12 are the same or similar, the high-temperature heat-affected zone during laser welding will directly act on the thread tip, potentially leading to changes in the microstructure and uneven stress release in the threaded area, thereby inducing microcracks at the weld edge or in the heat-affected zone. Therefore, if... Figure 10 As shown, in an embodiment of this utility model, the cross-sectional area of ​​the welding hole segment 11 is larger than the cross-sectional area of ​​the threaded hole segment 12.

[0038] Through the above setup, on the one hand, a welding protection zone can be established to avoid thermal stress interference; on the other hand, the larger welding hole segment 11 provides a wide, flat, and thread-free annular welding surface to provide a smooth weld bead. This ensures that the laser beam can act uniformly, forming a wide and deep penetration, thereby improving the density and strength of the weld and avoiding welding defects caused by structural abrupt changes. Therefore, this dimensional relationship is a key prerequisite for ensuring the reliability of welding as the final sealing method. It is not a simple enlargement of dimensions, but rather a functional decoupling of welding quality and thread assembly reliability.

[0039] It should be noted that the cross-sectional area of ​​the welded hole segment 11 refers to the orthographic projection of the welded hole segment 11 onto a plane perpendicular to the thickness direction of the top cover member 10; the cross-sectional area of ​​the threaded hole segment 12 refers to the orthographic projection of the threaded hole segment 12 onto a plane perpendicular to the thickness direction of the top cover member 10; where, for example Figure 5 The vertical direction is the thickness direction of the top cover component 10.

[0040] like Figures 4 to 12 As shown, in an embodiment of this utility model, the cross-sectional area of ​​the welding cover 21 is less than or equal to the cross-sectional area of ​​the welding hole segment 11.

[0041] In the above technical solution, by adjusting the size of the welding cover 21 to match or not exceed the size of the welding hole section 11, it is convenient to install the sealing cover on the injection hole for subsequent welding.

[0042] It should be noted that the cross-sectional area of ​​the welded cover 21 refers to the orthographic projection of the welded cover 21 onto a plane perpendicular to the thickness direction of the top cover component 10.

[0043] In existing technologies, aluminum sealing nails are prone to pinholes and microcracks, which are difficult to detect, during the welding process. This can lead to battery leakage after a period of use. Therefore, if... Figures 4 to 12 As shown in the embodiment of the present invention, the cross-sectional area of ​​the threaded hole section 12 is larger than the cross-sectional area of ​​the sealing hole section 13. An annular groove 14 is provided on the bottom wall of the threaded hole section 12. The annular groove 14 surrounds the sealing hole section 13. The sealing member 20 also includes an annular sealing member 24 disposed in the annular groove 14. The threaded cover 22 is sealed and fitted with the bottom wall of the threaded hole section 12 through the annular sealing member 24.

[0044] In the above technical solution, by adding an annular seal 24 between the sealing nail 23 and the sealing cover, compared with the sealing of the rubber nail and the weld in the prior art, this application can form a four-fold sealing structure from the inside out, including the sealing rubber nail, the annular seal 24, the thread and the weld. Even if the weld is defective, it can still meet the high sealing performance (the helium leak detection rate is less than 10 to the power of -7) and has high long-term reliability.

[0045] It should be noted that the cross-sectional area of ​​the sealing hole section 13 refers to the orthographic projection of the sealing hole section 13 onto a plane perpendicular to the thickness direction of the top cover member 10.

[0046] like Figure 7 and Figure 8 As shown in the embodiment of this utility model, the annular seal 24 is a sealing ring, and the compression amount of the sealing ring is 20%~40%.

[0047] In the above technical solution, by adjusting the compression of the sealing ring, an effective seal can be formed between the sealing cap and the injection hole. The compression of the sealing ring not only ensures sufficient sealing force to maintain the airtightness of the structure, but also, because the compression is controlled within a reasonable range, avoids problems such as seal ring damage or excessive stress concentration that could lead to excessive compression and thus affect long-term sealing performance. Furthermore, it allows the sealing state at the injection hole to remain stable; even if there are minor defects in the weld, the elastic recovery ability of the sealing ring can compensate for the sealing gap, improving the overall sealing reliability and durability of the structure.

[0048] In some embodiments, the sealing ring is an O-ring.

[0049] like Figures 4 to 12 As shown, in an embodiment of the present invention, the annular groove 14 has a groove depth h in the thickness direction, and the top cover component 10 has a thickness H, with the groove depth h being 0.05 to 0.5 times the thickness H.

[0050] By setting the groove depth as described above, the compression ratio of the annular seal 24 can be precisely controlled, maintaining the structural strength of the top cover component 10. On one hand, if the groove depth is too shallow, the seal ring will not compress sufficiently, resulting in poor sealing and easy shearing damage during assembly. On the other hand, if the groove depth is too deep, the seal ring will be over-compressed, leading to a surge in assembly force and potentially generating significant radial stress, interfering with subsequent thread tightening torque, and even causing knocking. Therefore, setting the groove depth within the aforementioned range optimizes sealing and prevents loosening. On the other hand, welding is a process of rapid localized heating and cooling, requiring stable substrate support. If the groove depth is too deep, it will severely weaken the local stiffness and heat capacity of the top cover component 10 in the welding area, leading to uneven heat conduction during welding, increasing the risk of deformation, and affecting weld formation. The range of 0.05 to 0.5 times the thickness of the substrate of the top cover component 10 is a balance point verified through extensive simulation and experimentation, ensuring sealing while providing a rigid "anvil" for welding to maintain the stiffness of the welding substrate. In summary, the selection of this specific depth range is a structural guarantee that both the sealing ring seal and the weld seal can achieve the best results.

[0051] like Figures 4 to 12 As shown in the embodiment of this utility model, the outer periphery of the threaded cover 22 is provided with a convex thread 221, and the inner wall of the threaded hole section 12 is provided with a concave thread 121, with the convex thread 221 and the concave thread 121 engaging. This facilitates the screwing of the threaded cover 22 into the threaded hole section 12; and the threaded engagement enables a sealed connection between the threaded cover 22 and the threaded hole section 12.

[0052] like Figures 4 to 12 As shown in the embodiment of this utility model, the outer diameter D of the threaded cover 22 is less than or equal to the inner diameter d of the threaded hole section 12.

[0053] The above settings ensure smooth assembly and precise pre-tightening sealing. Firstly, if the outer diameter D of the threaded cap 22 is larger than the inner diameter d of the threaded hole 12, the threaded pair will be difficult to fit during assembly, easily leading to seizing or misalignment, and even knocking. Therefore, the above dimensional relationship ensures that the sealing cap receives good guidance during the initial screwing-in process, avoiding misalignment and achieving guiding and centering functions. Secondly, if the outer diameter D of the threaded cap 22 is less than or equal to the inner diameter d of the threaded hole 12, the major diameter of the thread of the threaded cap 22 will be aligned with the major diameter of the thread of the top cover component 10 when the threaded cap 22 is fully tightened. There is a small gap or interference fit option between the threaded sections 12, which allows the operator to precisely control the tightening torque to generate a certain preload between the end face of the sealing cover and the bottom of the annular groove 14, forming a stable and reliable seal, without causing uncontrollable assembly stress due to excessive interference. The outer diameter D of the threaded cover 22, the inner diameter d of the threaded section 12, and the thickness of the annular groove 14 work together to ensure the stability of the assembly process and lay the foundation for high-quality welding in the future.

[0054] It should be noted that the outer diameter D of the threaded cover 22 refers to the outer diameter of the threaded cover 22 when the protruding thread 221 is not provided.

[0055] like Figures 4 to 12 As shown in the embodiment of this utility model, the welding cover 21 is provided with a screwing groove 211, which is located on the side of the welding cover 21 opposite to the threaded cover 22.

[0056] With the above setup, the operator can use a tool to rotate the welding cover 21 through the screw groove 211, thereby achieving a tight connection between the welding cover 21 and the threaded cover 22 for easy assembly.

[0057] In some embodiments, the screw groove 211 is a hexagonal or cross-shaped groove that facilitates rotation and locking.

[0058] In this application, after the cell is filled with electrolyte, the sealing pin 23 is inserted into the sealing hole section 13 of the electrolyte filling hole, see... Figure 6 Place the O-ring into the corresponding annular groove 14 of the injection hole. The O-ring can also be installed before installing the sealing pin 23, see [link to installation instructions]. Figure 7 The rotating sealing cap and the injection hole are threaded together to compress the O-ring (compression amount 20%~40%). See [link / details]. Figure 8 The welded cover body 21 and the welded hole section 11 of the sealing cover are welded together to seal the gap, see Figure 9 This forms the battery filling hole sealing structure of this application.

[0059] In summary, the technical solution of this application further solves the problem of achieving high-quality welded seals based on threaded connections. While using threaded assembly to improve the initial seal and prevent pin warping, it ensures the quality and long-term reliability of the final welded seal. The above-mentioned dimensional relationship can also prevent and eliminate derivative problems such as reduced welding quality and long-term seal reliability that may be caused by the introduction of threads.

[0060] An embodiment of this utility model provides a battery pack, including a battery housing, the aforementioned battery filling hole sealing structure, and a cell module. The cell module is located inside the battery housing, and a top cover component 10 covers the battery housing.

[0061] The battery filling hole sealing structure described above has all the advantages of the battery packs mentioned above, and will not be repeated here.

[0062] As can be seen from the above description, the above embodiments of this utility model achieve the following technical effects: when the welding cover is welded to the welding hole section, the threaded cover and the threaded hole section form a threaded fit. The pre-tightening force generated by the threaded connection can effectively prevent the sealing cover from lifting up during the assembly process, thereby avoiding welding sealing defects caused by this, such as uneven weld or incomplete sealing.

[0063] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A battery electrolyte filling hole sealing structure, characterized in that, include: Top cover component (10), the top cover component (10) is provided with a liquid injection hole, the liquid injection hole includes a welding hole section (11), a threaded hole section (12) and a sealing hole section (13) that are connected sequentially along the thickness direction of the top cover component (10). The sealing component (20) includes a sealing pin (23) and a sealing cover. The sealing cover includes a welded cover (21) and a threaded cover (22) connected to the welded cover (21). The welded cover (21) is welded to the welded hole section (11), the threaded cover (22) is threaded to the threaded hole section (12), and the sealing pin (23) is sealed to the sealing hole section (13).

2. The battery filling hole sealing structure according to claim 1, characterized in that, The cross-sectional area of ​​the welded hole section (11) is greater than the cross-sectional area of ​​the threaded hole section (12).

3. The battery filling hole sealing structure according to claim 1, characterized in that, The cross-sectional area of ​​the welded cover (21) is less than or equal to the cross-sectional area of ​​the welded hole segment (11).

4. The battery filling hole sealing structure according to claim 1, characterized in that, The cross-sectional area of ​​the threaded hole section (12) is larger than the cross-sectional area of ​​the sealing hole section (13). The bottom wall of the threaded hole section (12) is provided with an annular groove (14), which surrounds the sealing hole section (13). The sealing member (20) also includes an annular seal (24) disposed in the annular groove (14). The threaded cover (22) is sealed to the bottom wall of the threaded hole section (12) through the annular seal (24).

5. The battery filling hole sealing structure according to claim 4, characterized in that, The annular seal (24) is a sealing ring, and the compression of the sealing ring is 20%~40%.

6. The battery filling hole sealing structure according to claim 4, characterized in that, The annular groove (14) has a groove depth h in the thickness direction, and the top cover member (10) has a thickness H, wherein the groove depth h is 0.05 to 0.5 times the thickness H.

7. The battery filling hole sealing structure according to any one of claims 1 to 6, characterized in that, The outer periphery of the threaded cap (22) is provided with a convex thread (221), and the inner wall of the threaded hole section (12) is provided with a concave thread (121). The convex thread (221) and the concave thread (121) are engaged.

8. The battery filling hole sealing structure according to claim 7, characterized in that, The outer diameter D of the threaded cap (22) is less than or equal to the inner diameter d of the threaded hole section (12).

9. The battery filling hole sealing structure according to any one of claims 1 to 6, characterized in that, The welded cover (21) is provided with a screw groove (211), which is located on the side of the welded cover (21) opposite to the threaded cover (22).

10. A battery pack, characterized in that, The battery includes a battery housing, a battery filling hole sealing structure according to any one of claims 1 to 9, and a battery cell module, wherein the battery cell module is located inside the battery housing, and the top cover member (10) covers the battery housing.

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