Fixing cover connecting structure of secondary battery

Abstract

The present application relates to a fixing cover connection structure of a secondary battery, comprising: a top cover plate having a first pole via hole penetrating in the thickness direction, the upper surface of the top cover plate protruding upward at the periphery of the first pole via hole to form a welding boss; and the fixed cover is made of a metal material, the fixed cover is provided with a second pole through hole penetrating along the thickness direction, and the fixed cover covers the welding boss and is welded with the welding boss. By arranging the welding boss on the top cover plate and improving the structure of the fixing cover, welding and fixing can be conducted from the top when the fixing cover is assembled, welding operation is more convenient, the production efficiency of products can be improved, the reject ratio can be reduced, in addition, the influence of high temperature in the welding process on the sealing piece can be reduced or avoided, and the sealing quality is improved. And the air tightness of the product is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of processing of secondary battery cover plate structure, and particularly relates to a fixed cover connecting structure of a secondary battery. BACKGROUND

[0002] In the existing power battery structure, such as the common square aluminum shell battery, generally includes a shell, a battery cell and a top cover assembly, the battery cell is arranged in the shell, and the top cover assembly is used for closing the shell, and the top cover assembly usually includes a lower support, a top cover plate, a sealing ring and positive and negative bipolar posts. In addition, in order to strengthen the fixing effect of the pole, reduce the displacement and dislocation of the pole during use, a support is arranged outside the pole, the support usually has a frame structure matched with the pole, is sleeved outside the pole, and is fixed with the pole by cooperating with the injection molding of the pole cap. The support is usually made of metal material, and is fixed with the top cover plate by welding during assembly.

[0003] For example, the inventor previously proposed a Chinese patent application with the application number CN202222348142.X and the name of a top cover assembly of a secondary battery and a secondary battery, which discloses a top cover assembly of a secondary battery and a secondary battery, the top cover assembly comprises: a top cover plate having a first pole through hole penetrating in the thickness direction, and an upper surface of the top cover plate is formed with a penetration welding groove surrounding the first pole through hole outside the first pole through hole; a pole; a support matched with the pole, the pole is embedded in the support; a pole cap surrounding the outside of the pole, and respectively connected with the pole and the support, the lower end edge of the support is extended to form a welding part exposed outside the pole cap and matched with the penetration welding groove, and the welding part is arranged in the penetration welding groove and penetration welded with the bottom surface of the penetration welding groove. In the above technical solution, the support is installed on the top cover plate by the bottom penetration welding method, and the inventor found the following defects during actual application of the above structure for production:

[0004] Firstly, since the assembly of each component before injection molding is in a loose state, the product cannot be turned over as a whole at this time, and the welding gun can only be moved from the lower direction of the top cover plate to the penetration welding groove during actual welding. There are many difficulties in bottom welding, such as inconvenient operation of the welder, difficulty in accurately finding the welding position, etc., which leads to low overall production efficiency, and high product failure rate caused by inaccurate welding position and non-standard welding operation;

[0005] Secondly, the welding position of the bottom welding method is close to the sealing member made of rubber, and the high temperature generated during the welding process may cause the sealing member to melt, which will affect the overall air tightness of the product and further affect the product quality.

[0006] In summary, the prior art support and top cover plate using the bottom welding mode, there is a low production efficiency, affecting the product gas tightness defects, need to be improved. Practical new type content

[0007] In order to solve the above problems existing in the prior art, the application aims to provide a fixed cover connection structure of secondary battery. The application sets a welding boss on the top cover plate and improves the structure of the fixed cover, so that welding and fixing can be carried out from the top when assembling the fixed cover, which is more convenient for welding operation, which is conducive to improving the production efficiency of the product and reducing the defective rate, in addition, it can also reduce or avoid the influence of high temperature in the welding process on the sealing element, and ensure the air tightness of the product.

[0008] The fixed cover connection structure of secondary battery provided by the application comprises:

[0009] The top cover plate has a first pole through hole penetrating in the thickness direction, and the upper surface of the top cover plate is upwardly protruded to form a welding boss around the first pole through hole;

[0010] The fixed cover is made of metal material, and has a second pole through hole penetrating in the thickness direction, and the fixed cover is arranged on the welding boss and welded with the welding boss.

[0011] Preferably, the fixed cover comprises a welding part and an outer edge part perpendicular to the welding part, a welding groove adapted to the welding boss is formed between the welding part and the outer edge part, the welding part is welded with the welding boss, and the outer edge part abuts against the outer sidewall of the welding boss.

[0012] Preferably, the width of the welding part is greater than the width of the welding boss, so that the inner side edge of the welding part extends above the first pole through hole.

[0013] Preferably, the thickness of the welding part is 0.5mm-2.5mm.

[0014] Preferably, the inner edge of the fixed cover is inwardly recessed to form a glue injection groove.

[0015] Preferably, the number of glue injection grooves is four, which are distributed at equal angles around the center of the fixed cover.

[0016] The fixed cover connection structure of secondary battery provided by the application has the following advantages:

[0017] 1. The application forms a welding boss by extending upwards on the periphery of the first pole via hole of the top cover plate, improves the structure of the support, forms a fixed cover with a cover structure, the upper part of the cover structure is thin, cooperates with the welding boss structure of the top cover plate, so that the fixed cover and the top cover plate can adopt the top welding mode, compared with the bottom welding mode in the prior art, the welding personnel is more convenient to operate, and the welding position is also easy to determine, which can improve the overall production efficiency of the product, improve the product quality, and reduce the defective rate;

[0018] 2. Since the top welding mode is adopted, the welding position is far away from the bottom sealing ring, which can effectively reduce or avoid the influence of high temperature in the welding process on the sealing element, reduce the probability of thermal melting of the sealing element, effectively guarantee the sealing effect of the sealing element, and further guarantee the air tightness of the product;

[0019] 3. The application further designs the structure of the fixed cover, so that it includes a perpendicular welding part and an outer edge part, a welding groove adapted to the welding boss and capable of being arranged above the welding boss is formed between the welding part and the outer edge part, when the fixed cover is assembled to the top cover plate, quick positioning can be realized through the cooperation of the welding groove and the welding boss, which can further improve the welding efficiency of the fixed cover, and also can enhance the connection stability between the fixed cover and the welding boss. In addition, after the fixed cover is welded to the welding boss, a step structure is formed outside the welding boss, and the fixed cover and the top cover plate form an integral whole after welding, which will help to enhance the stability of the integral connection of the pole cap formed by injection molding and the top cover plate, effectively reducing the upwarping dislocation phenomenon of the edge of the pole cap, and improving the quality of the product. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a structure diagram of a fixed cover connection structure of a secondary battery according to the application (only showing the fixed cover and the top cover plate);

[0021] Figure 2 is an exploded view of Figure 1 ;

[0022] Figure 3 is a sectional view of Figure 1 ;

[0023] Figure 4 is one of the structure diagrams of the fixed cover according to the application;

[0024] Figure 5 is the second structure diagram of the fixed cover according to the application;

[0025] Figure 6 is an exploded view of the secondary battery cover plate product according to the embodiment;

[0026] Figure 7is a structure diagram of the top cover plate of the explosion-proof valve in the embodiment;

[0027] Figure 8 is Figure 7 a structure diagram of the lower support;

[0028] Figure 9 is Figure 8 a structure diagram of the sealing ring;

[0029] Figure 10 is Figure 9 a structure diagram of the pole column;

[0030] Figure 11 is Figure 10 a structure diagram of the fixed cover;

[0031] Figure 12 is Figure 11 a structure diagram of the pole cap formed by injection molding;

[0032] Figure 13 is Figure 12 a structure diagram of the connecting piece.

[0033] Explanation of reference numerals: 1-top cover plate, 11-first pole column through hole, 12-welding boss, 13-explosion-proof valve mounting hole, 14-liquid injection hole, 2-fixed cover, 21-welding part, 22-outer edge part, 23-welding groove, 24-gel injection groove, 3-lower support, 4-pole column, 5-pole cap, 6-sealing ring, 7-connecting piece, 8-explosion-proof valve, 9-protection film, 10-sealing nail, A-welding point position. DETAILED DESCRIPTION

[0034] As Figures 1-5 shown, the fixed cover connecting structure of the secondary battery in the application comprises:

[0035] a top cover plate 1, as shown in detail, Figure 2 the top cover plate 1 is generally in the form of a square plate structure, which has a first pole column through hole 11 penetrating in the thickness direction, for the pole column to pass through, so that the pole column can be electrically connected with the battery cell inside the battery shell. In the double-pole column structure, the number of first pole column through holes 11 is usually two, which are respectively distributed at both ends of the length direction of the top cover plate 1, to correspond to the positive pole column and the negative pole column respectively. The top cover plate 1 is also provided with an explosion-proof valve mounting hole 13 and a liquid injection hole 14, the explosion-proof valve mounting hole 13 is used for mounting the explosion-proof valve, and the liquid injection hole 14 is used for injecting electrolyte.

[0036] In this embodiment, please refer to Figures 3-5In order to change the way of welding the support from the bottom of the top cover plate 1 in the prior art, the structure of the top cover plate 1 is improved, specifically, the upper surface of the top cover plate 1 is upwardly protruded to form a welding boss 12 around the first pole post through hole 11, for example, corresponding to the circular first pole post through hole 11, the welding boss 12 is annular.

[0037] Corresponding to the structure of the welding boss 12, the support is changed to a hollow cover-shaped fixing cover 2, the fixing cover 2 is made of metal material and is hollow and circular cover-shaped, has a second pole post through hole penetrating in the thickness direction in the middle for accommodating the pole post, and is cover-set on the welding boss 12 and is welded and fixed with the welding boss 12 by the way of top surface welding, that is, the welding gun position is located on the upper surface of the fixing cover 2 and penetrates downwardly from the top to weld

[0038] Further, in the embodiment, please refer to 4、 Figure 5 The fixing cover 2 includes a welding part 21 and a peripheral part 22 perpendicular to the welding part 21, the welding part 21 is annular plate structure, the peripheral part 22 is hollow annular structure, and the welding groove 23 adapted to the welding boss 12 is formed by the welding part 21 and the peripheral part 22, specifically, corresponding to the annular welding boss 12, the welding groove 23 is circular groove body, so that the fixing cover 2 can be cover-set above the welding boss 12 to realize quick and accurate positioning during welding and to ensure that the welding process is not easy to shift.

[0039] Further, in the embodiment, please refer to Figure 3 The width of the welding part 21 is greater than the width of the welding boss 12, so that the inner side edge of the welding part extends above the first pole post through hole. After the fixing cover 2 is installed above the welding boss 12, the inner side edge of the welding part 21 extends above the pole post. The advantage of this structure is that when the pole cap is formed by subsequent injection molding, the glue will flow into the space between the welding part 21 and the pole post, and through this structure, the movement freedom degree of the pole post upward displacement can be effectively limited, thereby realizing the limitation of the upward dislocation of the pole post and reducing the possibility of upward dislocation.

[0040] Further, in the embodiment, the thickness of the welding part 21 is 0.5mm-2.5mm, the thickness of the welding part 21 is moderate, which can cooperate with the welding boss 12 to effectively limit the pole post and also can obtain good welding effect when penetrating from the top to the bottom.

[0041] Further, in the embodiment, the inner edge of the fixed cover 2 is inwardly recessed to form glue injection grooves 24, which will be injected with glue during subsequent injection molding of the pole cap. After molding, the fixed cover 2 and the pole cap can be relatively fixed in the circumferential direction, avoiding circumferential dislocation of the fixed cover. Further, the number of glue injection grooves 24 is four, which are distributed at equal angles around the center of the fixed cover 2, so that the tightening effect of the glue injection grooves 24 is evenly distributed.

[0042] As shown in the structure of the secondary battery cover plate product Figure 6 , the fixed cover connecting structure of the embodiment is applied, and the specific processing steps are as follows:

[0043] The top cover plate 1, the pole 4, the lower support 3 and the fixed cover 2 are made for use. Specifically, the top cover plate 1, the fixed cover 2 and the pole 4 are punched from metal materials, and the lower support 3 is formed by injection molding.

[0044] In assembly, as shown in Figure 7 , the explosion-proof valve 8 is first installed into the explosion-proof valve mounting hole 13 of the top cover plate 1.

[0045] As shown in Figure 8 , the lower support 3 is connected with the top cover plate 1, as shown in Figure 9 , the sealing ring 6 is installed into the first pole through hole 11 of the top cover plate 1.

[0046] As shown in Figure 10 , the pole 4 is installed into the first pole through hole 11, as shown in Figure 11 , and then the fixed cover 2 is installed onto the top cover plate 1, so that the fixed cover 2 covers the welding boss 12 of the top cover plate 1. The fixed cover 2 is welded and fixed with the top cover plate 1 by welding from the position corresponding to the welding boss 12 on the upper surface of the fixed cover 2.

[0047] As shown in Figure 12 , the integrated structure of the top cover plate 1, the sealing ring 6, the pole 4 and the fixed cover 2 is placed in a mold, and the pole cap 5 is formed by injection molding outside the pole 4. As shown in Figure 13 , the connecting piece 7 is connected to the lower surface of the lower support 3, the lower support 3 is connected with the pole 4, and the stability of the pole 4 is enhanced.

[0048] The obtained top cover assembly is marked, and a protective film is attached at the explosion-proof valve. Then, helium inspection and insulation voltage detection are performed, and the secondary battery cover plate product is obtained after the test is passed.

[0049] The application sets the welding boss 12 on the top cover plate 1 and improves the structure of the fixed cover 2, so that the welding fixing can be carried out from the top when assembling the fixed cover 2, which is more convenient for welding operation, is beneficial to improve the production efficiency of the product and reduce the defective rate, in addition, can reduce or avoid the influence of high temperature in the welding process on the sealing element, and guarantee the air tightness of the product.

[0050] In the description of the application, it should be understood that the orientation words such as "front, back, up, down, left, right", "transverse, vertical, horizontal" and "top, bottom" and the like indicate the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the application and simplifying the description, and do not indicate and imply that the devices or elements referred to must have a specific orientation or be constructed and operated in a specific orientation, therefore cannot be understood as a limitation on the scope of protection of the application.

[0051] For those skilled in the art, according to the above described technical solutions and concepts, other various corresponding changes and deformations can be made, and all these changes and deformations should belong to the protection scope of the claims of the application.

Claims

1. A fixing cover connection structure for a secondary battery, characterized in that, The application relates to a top cover plate with a first pole post through hole penetrating through in the thickness direction, and an upper surface of the top cover plate is upwardly protruded to form a welding boss at the periphery of the first pole post through hole. A fixing cover made of a metal material has a second pole post through hole penetrating through in the thickness direction, and the fixing cover is arranged on and welded with the welding boss; the fixing cover comprises a welding part and a peripheral part perpendicular to the welding part, a welding groove adapted to the welding boss is formed between the welding part and the peripheral part, the welding part is welded with the welding boss, and the peripheral part is abutted to the outer side wall of the welding boss; the thickness of the welding part is 0.5-2.5 mm. The width of the welding part is greater than the width of the welding boss, so that the inner side edge of the welding part extends to the upper side of the first pole post through hole.

2. The secondary battery fixing cover connecting structure according to claim 1, wherein The inner edge of the fixing cover is inwardly recessed to form glue injection grooves.

3. The secondary battery fixing cover connecting structure according to claim 1, wherein The number of the glue injection grooves is four, and the glue injection grooves are equiangularly distributed around the center of the fixing cover.

4. The secondary battery fixing cover connecting structure according to claim 3, wherein ​

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