Connecting piece structure for lithium battery

Abstract

The utility model belongs to the technical field of lithium batteries, and particularly discloses a connecting piece structure for a lithium battery, which comprises two connecting piece bodies arranged in mirror symmetry, each connecting piece body comprises a connecting part used for being connected with a cover plate, a bending part used for bending after the connecting piece body is welded and a plane part used for being welded with a tab, the bending part is located between the plane part and the connecting part, and a semicircular boss is arranged in the middle of the end, away from the bending part, of the connecting part; according to the utility model, the two connecting sheet bodies which are in mirror symmetry are respectively connected with the positive plate and the negative plate through the matching of the two connecting sheet bodies which are in mirror symmetry, the two connecting sheet bodies are symmetrically paired after being welded, and are bent by less than 180 degrees through the bending parts during bending, so that the aim of combining multiple roll cores is fulfilled; and through the arrangement of the boss, the positioning precision can be effectively improved, the height of the tab is shortened, and the process yield of processes such as coating, rolling and laser cutting is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium batteries, in particular to a connecting piece structure for lithium batteries. Background Art

[0002] Rectangular lithium power batteries are a shape variation of lithium-ion batteries. They usually adopt a square design with an aluminum shell or a steel shell. This type of battery is widely used in electric vehicles, electric bicycles, energy storage equipment and other fields due to its high voltage, light weight, long life, wide operating temperature range and no memory effect.

[0003] In the production of lithium-ion batteries, most square aluminum shells adopt a winding butterfly welding structure, and a connecting sheet is required to connect the positive electrode sheet and the negative electrode sheet, and the positive electrode sheet, the negative electrode sheet and the isolation film are rolled together. For example, the patent document application number is 202123040097.3, which discloses a laminated battery cell connection structure and a laminated lithium power battery. The laminated battery cell connection structure includes a connecting sheet structure and a cover plate structure. The connecting sheet structure is arranged in a split type and can be fixed and electrically connected to at least two laminated battery cells; a positive terminal and a negative terminal are arranged on the cover plate structure, and the connecting sheet structure can be fixedly connected to the cover plate structure, and the positive terminal and the negative terminal are both electrically connected to the connecting sheet structure. The connecting sheet structure can be folded so that the laminated battery cells connected to it are folded and the cover plate structure can be buckled on the ends of each laminated battery cell. The utility model effectively reduces the length of the tabs of the laminated battery cell without affecting the assembly and welding of the battery, improves the energy density of the laminated battery cell, increases the current carrying capacity of the laminated battery cell, and improves the safety of the battery and the production qualification rate.

[0004] However, most of the current connecting plate structures are planar structures, which are prone to displacement and sliding, resulting in poor welding in subsequent processes, and have high requirements for the height of the tabs, especially in large-sized and thick battery cells, where the tab height may even exceed 30 mm. Too high a tab height may cause wrinkling, flanging, folding, and breakage in coating, rolling and other process steps, resulting in a significant increase in product defective rate and increased battery cell process cost. Therefore, we need to propose a connecting plate structure for lithium batteries to solve the above-mentioned problems, so that it can achieve the purpose of low tab height and improved process excellence. Utility Model Content

[0005] The purpose of the utility model is to provide a connecting plate structure for lithium batteries, which realizes the purpose of multi-core winding through the cooperation of two mirror-symmetrical connecting plate bodies. Through the setting of the boss, the positioning accuracy can be effectively improved, the height of the pole ear can be shortened, and the yield rate of the coating, rolling, laser cutting and other processes can be improved to solve the problems raised in the background technology.

[0006] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a connecting piece structure for a lithium battery, comprising two connecting piece bodies arranged in a mirror-symmetrical manner, each of the connecting piece bodies comprising a connecting portion for connecting to a cover plate, a bending portion for bending the connecting piece body after welding, and a planar portion for welding to a pole ear, wherein the bending portion is located between the planar portion and the connecting portion, and the bending portion is partially hollowed out.

[0007] Preferably, a semicircular boss is provided in the middle of one end of the connecting portion away from the bending portion, and the bosses on the two connecting piece bodies are spliced ​​to form a complete circular structure.

[0008] Preferably, the interior of the boss is hollow, and a plurality of embossed convex points are arranged on the inner side of the boss.

[0009] Preferably, the embossed convex points are arranged in a square or rectangular shape, and the depth of the embossed convex points is set to 0.1-0.15 mm.

[0010] Preferably, after the two connecting piece body cores are welded, the bending angle of the bent portion is less than 180°.

[0011] Preferably, a protrusion is integrally formed on one side of the connecting portion adjacent to the boss portion, and a positioning hole is formed on the protrusion.

[0012] Preferably, the length of the planar portion is greater than the width of the connecting portion, and one end of the planar portion is flush with a side of the connecting portion having the protrusion.

[0013] Preferably, a corner of one side of the planar portion away from the bending portion is set to be an oblique angle, and the oblique angle of the planar portion and the protrusion are located on the same horizontal plane.

[0014] Compared with the prior art, the beneficial effects of the utility model are:

[0015] 1. The utility model mainly connects the two connecting sheet bodies to the positive electrode sheet and the negative electrode sheet respectively through the cooperation of two mirror-symmetrical connecting sheet bodies, and performs symmetrical pairing after welding. When bending, the bending portion is used to perform a bending of less than 180°, thereby achieving the purpose of combining multiple winding cores.

[0016] 2. The utility model adopts the hollow setting of the bending part, which is designed as fuse protection. When a short circuit occurs in the battery cell, the local instantaneous current here exceeds the upper limit of the current carrying capacity of this position and can be fused to achieve current circuit breaking and improve the safety performance of the battery cell product.

[0017] 3. The utility model can effectively improve the positioning accuracy, shorten the height of the tab, and improve the process yield of coating, rolling, laser cutting and other processes through the setting of the boss. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a three-dimensional structural schematic diagram of the utility model;

[0019] Figure 2 This is a schematic diagram of the three-dimensional structure of the connecting piece body of the utility model;

[0020] Figure 3 This is a schematic diagram of the side view of the connecting piece body of the utility model;

[0021] Figure 4 This is a schematic diagram of the structure of the connecting piece body of the utility model when it is not bent;

[0022] Figure 5 This is a schematic diagram of the top view structure of the utility model;

[0023] Figure 6 This is a side view of the structure of the utility model;

[0024] Figure 7 It is a schematic diagram of the structure of the connecting piece body of the utility model when it is bent.

[0025] In the figure: 1, connecting piece body; 11, flat portion; 12, bending portion; 13, connecting portion; 2, boss; 3, protrusion; 4, positioning hole; 5, embossed convex point. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0027] See also Figure 1-7 The utility model provides a technical solution: a connecting piece structure for a lithium battery, comprising two connecting piece bodies 1 arranged in mirror symmetry, each of the connecting piece bodies 1 comprising a connecting portion 13 for connecting to a cover plate, a bending portion 12 for bending the connecting piece body 1 after welding, and a plane portion 11 for welding to a pole ear, the bending portion 12 is located between the plane portion 11 and the connecting portion 13, the bending portion 12 is partially hollowed out, and this design is a fuse protection. When a short circuit occurs in a battery cell, the local instantaneous current here exceeds the upper limit of the current carrying capacity of this position, and can be fused to achieve current disconnection, thereby improving the safety performance of the battery cell product.

[0028] A semicircular boss 2 is provided in the middle of one end of the connecting portion 13 away from the bending portion 12. The bosses 2 on the two connecting plate bodies 1 are spliced ​​together to form a complete circular structure. After the two connecting plate bodies 1 are core-rolled and welded, the bending angle of the bending portion 12 is less than 180°.

[0029] The interior of the boss 2 is hollow, and a plurality of embossed convex points 5 are arranged on the inner side of the boss 2. The embossed convex points 5 are arranged in a square or rectangular shape, and the depth of the embossed convex points 5 is set to 0.1-0.15mm, filling the entire inner side of the boss 2. This design can effectively prevent laser high reflection phenomenon.

[0030] A protrusion 3 is integrally formed on one side of the connecting portion 13 adjacent to the boss 2, and a positioning hole 4 is opened on the protrusion 3. The positioning hole 4 is used to position the connecting piece body 1 to prevent the connecting piece body 1 from shifting and improve the positioning accuracy of the connection between the connecting piece body 1 and the battery cell.

[0031] The length of the plane portion 11 is greater than the width of the connecting portion 13 , and one end of the plane portion 11 is flush with the side of the connecting portion 13 having the protrusion 3 , so that the plane portion 11 increases the area for ultrasonic welding with the tab.

[0032] The corner of the plane portion 11 away from the bending portion 12 is set to be an oblique angle, and the oblique angle of the plane portion 11 is located on the same horizontal plane as the protrusion 3. Through the setting of the oblique angle and the setting of the embossed convex point 5, the connection piece body 1 can be fool-proof during installation, which makes it easy to distinguish the connection piece body 1 and prevent the connection piece body 1 from being misplaced.

[0033] Before welding, the connecting piece body 1 is in a flat state. Figure 4 As shown, the bending portion 12 is first bent at a right angle so that the plane portion 11 is perpendicular to the connecting portion 13. Figure 2 In the state shown, the plane parts 11 of the two mirror-symmetrical connecting sheet bodies 1 are welded to the pole ears of the positive and negative electrodes respectively. After the positive and negative electrodes are welded, the positive, negative and diaphragm sheets are symmetrically matched. The two symmetrical bosses 2 form a complete circular structure that conforms to the outer shape of the cover sheet. The adapter sheet and the positive and negative poles of the cover plate are laser welded inside the bosses 2. Then the bending part 12 is bent less than 180 degrees to make the bending shape of the connecting sheet body 1 as shown. Figure 7 As shown (the bending angle is close to 180°), the purpose of combining multiple cores is achieved, and the two symmetrical bosses 2 form a complete circular structure that matches the shape of the cover sheet, which can effectively improve the positioning accuracy, shorten the ear height, and improve the process yield of coating, rolling, laser cutting and other processes.

[0034] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A connecting sheet structure for a lithium battery, characterized in that: The invention comprises two connecting piece bodies (1) arranged in a mirror-symmetrical manner, each of the connecting piece bodies (1) comprising a connecting portion (13) for connecting to a cover plate, a bending portion (12) for bending the connecting piece body (1) after welding, and a plane portion (11) for welding to a tab, the bending portion (12) being located between the plane portion (11) and the connecting portion (13), and the bending portion (12) being partially hollowed out.

2. A connecting piece structure for a lithium battery according to claim 1, characterized in that: A semicircular boss (2) is provided in the middle of one end of the connecting portion (13) away from the bending portion (12); the bosses (2) on the two connecting piece bodies (1) are spliced ​​together to form a complete circular structure.

3. A connecting piece structure for a lithium battery according to claim 2, characterized in that: The interior of the boss (2) is hollow, and a plurality of embossed convex points (5) are arranged on the inner side of the boss (2).

4. A connecting piece structure for a lithium battery according to claim 3, characterized in that: The embossed convex points (5) are arranged in a square or rectangular shape, and the depth of the embossed convex points (5) is set to 0.1-0.15 mm.

5. A connecting sheet structure for a lithium battery according to claim 4, characterized in that: After the core welding of the two connecting piece bodies (1) is completed, the bending angle of the bending portion (12) is less than 180°.

6. A connecting piece structure for a lithium battery according to claim 5, characterized in that: A protrusion (3) is integrally formed on one side of the connecting portion (13) adjacent to the boss (2), and a positioning hole (4) is provided on the protrusion (3).

7. A connecting piece structure for a lithium battery according to claim 6, characterized in that: The length of the plane portion (11) is greater than the width of the connecting portion (13), and one end of the plane portion (11) is flush with a side of the connecting portion (13) containing the protrusion (3).

8. A connecting piece structure for a lithium battery according to claim 7, characterized in that: A corner of one side of the plane portion (11) away from the bending portion (12) is set to be an oblique angle, and the oblique angle of the plane portion (11) and the protrusion (3) are located on the same horizontal plane.

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