Structure for connecting top cover and connecting sheet of lithium battery

Abstract

The utility model discloses a structure for connecting a top cover and a connecting piece of a lithium battery. The structure comprises a cover plate, the connecting piece and a bolt, threaded holes are formed in the cover plate, through holes are formed in the connecting pieces, bolts penetrate through the through holes and are in threaded connection with the threaded holes, and the connecting pieces are mechanically fixed to the cover plate. After mechanical fixation, the cover plate and the connecting sheet are connected through laser welding. The diameter of the through hole of the connecting piece is larger than that of the threaded hole but smaller than that of the bolt top cap, the connecting piece comprises an arc-shaped notch, and the welding area is located outside the edge of the bolt top cap. Through the combination of mechanical locking and welding, the fitting property of the connecting piece and the cover plate is improved, the cold solder joint risk is reduced, and the connecting piece is suitable for the fields of energy storage lithium batteries and the like.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery connection technology, and in particular to a structure for connecting the top cover of a lithium battery to a connecting piece. Background Technology

[0002] Currently, square aluminum-cased lithium-ion batteries are widely used in energy storage systems and electric vehicles, and their performance and safety are crucial to the stable operation of the entire system. In lithium battery manufacturing, the welding method between the connecting tabs and the cover plate is one of the key steps in connecting the internal electrodes of the battery to the external circuitry. However, the current technology typically uses a tooling to press the connecting tabs onto the cover plate, causing their welding areas to contact each other before laser welding to achieve mechanical and electrical connections. While this process has certain conveniences, it is limited by the precision of the tooling and the availability of testing methods, and therefore carries certain risks during the welding process.

[0003] Specifically, in practice, the press-fitting method commonly used in existing technologies is prone to poor adhesion between the connecting piece and the cover plate due to processing errors or insufficient inspection accuracy. For example, the height detection device used to check the adhesion has limited accuracy, or the CCD vision inspection system has limitations in judging the integrity of the solder joint, making it difficult to accurately identify hidden cold solder joints. Poor adhesion between the connecting piece and the welding area of ​​the cover plate leads to unstable welding quality, which in turn causes cold solder joint problems. Such cold solder joints not only increase the contact resistance of the battery and cause heat accumulation, but may also cause battery safety accidents, such as overheating or even fire, due to high internal resistance during long-term use.

[0004] To address the aforementioned issues, an improved connection method combining mechanical locking and welding has become a research focus. By designing threaded holes on the cover plate and through holes on the connecting piece, and mechanically locking the two together with bolts, reliable adhesion between the connecting piece and the cover plate can be ensured before welding, significantly reducing the incidence of incomplete welds. This structure not only solves the problem of poor adhesion through mechanical fixing, but also further enhances the connection strength and electrical performance through subsequent laser welding, ensuring the safety and stability of the battery under high-load conditions.

[0005] In summary, the problem of poor soldering in existing technologies poses a significant challenge to the safety and performance of lithium batteries. The "structure for connecting the top cover and connecting piece of a lithium battery" provided by this utility model, with its innovative design combining mechanical locking and welding, effectively solves the above-mentioned problems and possesses significant technical advantages and practical application value. Utility Model Content

[0006] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a structure for connecting the top cover and the connecting piece of a lithium battery. By combining mechanical locking with laser welding, the tight fit between the connecting piece and the top cover is ensured, effectively reducing the incidence of poor welding, improving the stability and reliability of the connection, thereby enhancing the safety and performance of the lithium battery.

[0007] The technical solution adopted by this utility model to solve its technical problem is: a structure for connecting a lithium battery top cover and a connecting piece, including a cover plate, a connecting piece and a bolt, wherein the cover plate is provided with a threaded hole; the connecting piece is provided with a through hole for fitting the bolt, and the connecting piece is mechanically fixed to the cover plate by the bolt; the cover plate and the connecting piece are connected by laser welding after being mechanically fixed.

[0008] Furthermore, the diameter of the through hole of the connecting piece is larger than the diameter of the threaded hole of the cover plate but smaller than the diameter of the bolt cap, so as to achieve a precise fit between the bolt and the through hole.

[0009] Furthermore, the connecting piece has an arc-shaped cut and a welding area located outside the edge of the bolt cap to avoid direct contact with the cap.

[0010] The beneficial effects of this utility model are:

[0011] This invention ensures a tight fit between the connecting piece and the cover plate before welding by setting threaded holes on the cover plate, through holes on the connecting piece, and using bolts for mechanical fixing, thus significantly reducing the risk of incomplete welding.

[0012] The diameter of the connecting plate through hole of this utility model is larger than the diameter of the threaded hole of the cover plate but smaller than the diameter of the bolt cap. Through reasonable size design, the bolt can be precisely matched with the connecting plate and the cover plate, thereby improving the stability and reliability of the structural connection.

[0013] This invention uses laser welding to further connect the connecting piece and the cover plate on the basis of mechanical fixation, which improves the connection strength while ensuring a tight fit and avoiding the occurrence of incomplete welding.

[0014] The connecting piece of this utility model has an arc-shaped cut and a welding area. The welding area is located outside the edge of the bolt cap. By reasonably designing the position of the welding area, the influence on the bolt cap during the welding process is avoided, thereby improving the welding quality.

[0015] This invention combines mechanical locking with laser welding, which not only ensures a tight fit between the connecting piece and the cover plate, but also optimizes the distribution of the welding area, thereby improving the safety and reliability of the overall structure. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall assembly of this utility model;

[0017] Figure 2 This is a top view of the present invention;

[0018] Figure 3 This is a schematic diagram of the cover plate of this utility model;

[0019] Figure 4 This is a schematic diagram of the connecting piece of this utility model.

[0020] In the diagram, 1-cover plate; 11-threaded hole; 2-connecting piece; 21-through hole; 3-bolt. Detailed Implementation

[0021] The present invention will now be further described with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the present invention, and therefore only show the components relevant to the present invention.

[0022] like Figure 1 As shown, this utility model relates to a structure for connecting a lithium battery top cover and a connecting piece, including a cover plate 1, a connecting piece 2, and a bolt 3. The cover plate 1 has a threaded hole 11, and the connecting piece 2 has a through hole 21. The bolt 3 passes through the through hole 21 of the connecting piece 2 and is threadedly connected to the threaded hole 11 of the cover plate 1, mechanically fixing the connecting piece 2 to the cover plate 1. After mechanical fixing, the connecting piece 2 and the cover plate 1 are connected by laser welding, thereby ensuring a tight fit between them.

[0023] like Figure 1 and Figure 2 As shown, the connecting pieces 2 are fixed to the cover plate 1 in a symmetrical arrangement on both sides. The threaded holes 11 on the cover plate 1 correspond one-to-one with the through holes 21 of the connecting pieces 2. Each bolt 3 is mechanically fixed through its corresponding through hole 21 and threaded hole 11, ensuring a stable connection between the connecting pieces 2 and the cover plate 1. The top cap of the bolt 3 is located on the surface of the connecting piece 2 to provide fixing force while preventing direct contact between the bolt and the welding area. Figure 2 It can be further seen that the threaded hole 11 of the cover plate 1 and the through hole 21 of the connecting piece 2 are arranged in pairs along the length of the cover plate 1 to meet the connection requirements of multi-module lithium batteries, ensuring the tightness of the connection and the symmetry of the structure.

[0024] like Figure 3 As shown, the cover plate 1 is the top cover of the lithium battery, with two evenly distributed threaded holes 11 for engaging with bolts 3 to mechanically fix the connecting piece 2 to the cover plate 1. The diameter and depth of the threaded holes 11 are designed to match the specifications of the bolts 3 to ensure the stability of the mechanical connection.

[0025] like Figure 4 As shown, the connecting piece 2 features an arc-shaped cut to accommodate different lithium battery module shapes. A through hole 21 is provided on the connecting piece 2. The diameter of the through hole 21 is larger than the diameter of the threaded hole 11 in the cover plate 1 but smaller than the diameter of the top cap of the bolt 3, allowing the bolt 3 to pass through the through hole 21 and achieve mechanical locking. The connecting piece 2 also has a welding area located outside the edge of the top cap of the bolt 3, avoiding direct contact with the top cap, thereby reducing the impact of the welding process on the bolt and improving welding quality.

[0026] The installation layout is as follows:

[0027] Marking and dividing: According to the design requirements, mark lines on the surface of the cover plate 1 to determine the position of the threaded hole 11, which is used to accurately position the through hole 21 of the connecting piece 2.

[0028] Install the connecting piece: Place the connecting piece 2 on the cover plate 1, so that the through hole 21 of the connecting piece 2 is aligned with the threaded hole 11 of the cover plate 1.

[0029] Installation bolts: Pass the bolts 3 through the through holes 21 of the connecting piece 2 and screw them into the threaded holes 11 of the cover plate 1 in sequence. The connecting piece 2 is mechanically fixed to the cover plate 1 by the threaded connection.

[0030] Welding operation: After mechanical fixing is completed, laser welding is performed on the welding area of ​​the connecting piece 2 to firmly connect the connecting piece 2 with the cover plate 1, while ensuring that the welding area avoids the top edge of the bolt 3.

[0031] Check the fixing effect: Check the tightening of bolt 3 and the welding quality of the welding area to ensure the tight fit and firm connection between connecting piece 2 and cover plate 1.

[0032] The above embodiments are only for illustrating the technical concept and features of this utility model. Their purpose is to enable those skilled in the art to understand the content of this utility model and implement it. They should not be used to limit the protection scope of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be covered within the protection scope of this utility model.

Claims

1. A structure for connecting a lithium battery top cover with a connecting piece, comprising a cover plate (1), a connecting piece (2) and a bolt (3), characterized in that: The cover plate (1) is provided with a threaded hole (11); the connecting plate (2) is provided with a through hole (21) for matching a bolt (3), and the connecting plate (2) is mechanically fixed to the cover plate (1) through the bolt (3); and the cover plate (1) and the connecting plate (2) are connected through laser welding after mechanical fixation.

2. The structure for connecting the top cover of a lithium battery with the connecting piece according to claim 1, characterized in that: The diameter of the through hole (21) of the connecting plate (2) is greater than the diameter of the threaded hole (11) of the cover plate (1) but less than the diameter of the top cap of the bolt (3).

3. The structure for connecting the top cover of a lithium battery with the connecting piece according to claim 1, characterized in that: The shape of the connecting plate (2) comprises an arc-shaped cutout, and a welding area is arranged outside the edge of the top cap of the bolt (3) to avoid direct contact with the top cap.

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