Liquid injection hole sealing structure, power battery top cover and assembly mode of power battery top cover

Abstract

The invention provides a liquid injection hole sealing structure, a power battery top cover and an assembly mode of the power battery top cover. The liquid injection hole sealing structure comprises a sealing cavity and a sealing ball, and the sealing cavity is sealed and fixed to the liquid injection hole. The sealing cavity comprises a peripheral wall and a bottom wall, and a cavity is defined by the peripheral wall and the bottom wall. The sealing bead is contained in the cavity and at least abuts against the peripheral wall, and at least part of the peripheral wall wraps the sealing bead. By adopting the structure, metal chips generated when the sealing bead applies pressure to seal can fall into the cavity, and can be prevented from falling into the battery to influence the performance of the battery. The sealing bead at least abuts against the peripheral wall, at least part of the peripheral wall wraps the sealing bead, the peripheral wall exerts abutting pressure on the sealing bead, and therefore the sealing bead, the peripheral wall and the inner wall of the liquid injection hole are tightly combined, connection is firm, and sealing performance is high. The sealing beads are adopted for sealing, the outer wall of the sealing bead is arc-shaped without edges and corners, the strength is high, the sealing bead can be easily inserted into the cavity, and the abutting force with the peripheral wall is balanced.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy storage devices, and in particular to a liquid injection hole of a power battery, and more particularly to a liquid injection hole sealing structure, a power battery top cover and an assembly method thereof. Background Art

[0002] At present, lithium-ion batteries have been widely used in consumer electronic products, automotive lithium-ion products and large energy storage equipment. According to the capacity of the battery, lithium-ion batteries are divided into consumer batteries and power batteries. Consumer batteries are usually packaged in aluminum-plastic film, and the injection is completed by inserting the injection needle into the aluminum-plastic film. Power batteries usually have an injection hole on the top cover sheet, and the battery is injected through the injection hole. After the injection, the injection hole can be sealed with a steel ball and cured by dispensing glue, or laser welded with a sealing sheet or sealing nail.

[0003] Steel ball sealing is generally done manually or mechanically, and there is usually a problem of insufficient precision between the injection port and the steel ball. In addition, the amount of glue used during glue curing and the shape after glue dispensing are difficult to control, resulting in poor consistency in the appearance of battery glue dispensing. Laser welding of sealing sheets or sealing nails is generally due to differences in welding materials, a small amount of moisture and oil in the assembly gap, and residual electrolyte at the injection hole. Impurities and gases are generated during the welding process. The welding area inevitably has defects such as explosion points, pinholes, pits, and cracks, resulting in insufficient welding strength and poor welding morphology, which ultimately leads to battery sealing failure and battery scrapping. More importantly, whether it is a steel ball seal, a sealing sheet or a sealing needle, it is usually made of metal such as steel or aluminum. When sealing the injection hole, it will produce friction with the inner wall of the metal injection hole to produce metal chips. Once the metal chips fall into the battery, unnecessary side reactions will occur and there may be a risk of internal short circuits.

[0004] Therefore, the current conventional steel ball sealing combined with glue curing, sealing sheet or sealing pin combined with laser welding all have certain shortcomings, and a new injection hole sealing structure is urgently needed to solve the above problems. Summary of the invention

[0005] Based on the above problems, the purpose of the present invention is to provide a liquid injection hole sealing structure, a power battery top cover and an assembly method thereof. This liquid injection hole sealing structure can not only achieve effective sealing of the liquid injection hole, but also avoid the influence of metal chips on the interior of the battery.

[0006] To achieve the above-mentioned objectives, on one hand, the present invention provides a liquid injection hole sealing structure for sealing the liquid injection hole on a power battery, comprising a sealing cavity and a sealing bead, wherein the sealing cavity seals and is fixed to the liquid injection hole, the sealing cavity comprises a peripheral wall and a bottom wall, the peripheral wall and the bottom wall together form a cavity, the sealing bead is accommodated in the cavity and at least abuts against the peripheral wall, and at least a portion of the peripheral wall wraps the sealing bead.

[0007] In the technical solution adopted by the present invention, the sealing cavity includes a peripheral wall and a bottom wall, and the sealing bead is accommodated in the cavity formed by the peripheral wall and the bottom wall. Therefore, the metal chips generated when the sealing bead is pressed to seal will fall into the cavity, which can prevent them from falling into the battery and affecting the battery performance. The sealing bead not only at least abuts against the peripheral wall, but also at least part of the peripheral wall wraps the sealing bead. The peripheral wall exerts a pressure on the sealing bead, so the sealing bead, the peripheral wall and the inner wall of the injection hole are tightly combined, and the connection is firm and the sealing is strong. When the sealing bead is used for sealing, its outer wall is an arc without edges and corners. It is not only high in strength and easy to insert into the cavity, but also has a balanced pressure with the peripheral wall.

[0008] As a technical solution of the present invention, the sealing cavity is riveted and fixed to the liquid injection hole.

[0009] As a technical solution of the present invention, the side of the peripheral wall away from the bottom wall extends outward to form a convex portion, and the convex portion overlaps the liquid injection hole.

[0010] As a technical solution of the present invention, the side of the peripheral wall away from the bottom wall extends outward to form a convex portion, and the convex portion is welded and fixed to the liquid injection hole.

[0011] As a technical solution of the present invention, the sealing bead also abuts against the bottom wall.

[0012] As a technical solution of the present invention, an opening is provided at one end of the cavity away from the bottom wall, and the cavity includes a first cavity and a second cavity, the first cavity is close to the opening, and the second cavity is close to the bottom wall, and the lateral dimension of the first cavity gradually decreases along the direction from the opening to the bottom wall until it is flush with the second cavity, and the sealing bead is accommodated in the first cavity and the second cavity at the same time.

[0013] As a technical solution of the present invention, the minimum transverse dimension of the first cavity is a, the diameter of the sealing bead is b, and a / b is greater than or equal to 0.7 and less than 1.0.

[0014] As a technical solution of the present invention, the peripheral wall and / or the bottom wall are provided with notches.

[0015] As a technical solution of the present invention, the sealing cavity is made of aluminum, and the sealing bead is made of aluminum or steel.

[0016] The second aspect of the present invention provides a power battery top cover, comprising a top cover sheet, a liquid injection hole provided on the top cover sheet, and the aforementioned liquid injection hole sealing structure for sealing the liquid injection hole. The liquid injection hole sealing structure is firmly connected to the liquid injection hole, has good sealing performance, and can store metal chips to prevent them from falling into the battery.

[0017] As a technical solution of the present invention, the injection hole includes a first injection hole and a second injection hole which pass through the upper and lower holes in sequence, the minimum aperture of the first injection hole is larger than the maximum aperture of the second injection hole, and the injection hole sealing structure is sealed and fixed to the second injection hole.

[0018] A third aspect of the present invention provides a method for assembling a power battery top cover, comprising the steps of:

[0019] (1) preparing the top cover sheet, the sealing cavity and the sealing bead provided with the injection hole, wherein the maximum transverse dimension of the peripheral outer wall of the sealing cavity is less than or equal to the minimum hole diameter of the injection hole;

[0020] (2) inserting the sealing cavity into the liquid injection hole;

[0021] (3) Inserting the sealing bead into the cavity and applying downward pressure until the sealing bead at least abuts against the peripheral wall and the peripheral wall is deformed to at least partially wrap the sealing bead.

[0022] This assembly method is simple. First, insert the sealing cavity into the liquid injection hole, then insert the sealing bead and apply pressure to complete the assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a partial cross-sectional view of the power battery top cover of the present invention before the liquid injection hole is sealed.

[0024] Figure 2 It is a partial cross-sectional view of the power battery top cover after the liquid injection hole is sealed according to the present invention.

[0025] Figure 3 yes Figure 1 A change diagram of .

[0026] Figure 4 yes Figure 1 Another variation of .

[0027] Figure 5 It is a cross-sectional view of the sealed cavity of the present invention.

[0028] Figure 6 It is a partial cross-sectional view of the top cover sheet of the present invention.

[0029] Figure 7 for Figure 3 Enlarged view of the circled area.

[0030] Figure 8 for Figure 4 Enlarged view of the circled area.

[0031] Components comply with the description

[0032] 100-power battery top cover; 10-top cover sheet; 11-liquid injection hole; 111-first liquid injection hole; 113-second liquid injection hole; 30-liquid injection hole sealing structure; 31-sealing bead; 33-sealed cavity; 331-peripheral wall; 333-bottom wall; 335-convex part; 50-notch; S-cavity; S1-first cavity; S2-second cavity; d1-lateral dimension of the first cavity; d2-lateral dimension of the peripheral outer wall of the sealed cavity; d3-aperture of the liquid injection hole DETAILED DESCRIPTION

[0033] In order to better illustrate the purpose, technical solution and beneficial effects of the present invention, the present invention will be further described below in conjunction with specific drawings. It should be noted that the following drawings are further explanations of the present invention and should not be used as limitations of the present invention.

[0034] like Figures 1 to 4 As shown, the power battery top cover 100 of the present invention includes a top cover sheet 10, a liquid injection hole 11 provided on the top cover sheet 10, and a liquid injection hole sealing structure 30 for sealing the liquid injection hole 11. Figure 6 As shown, the injection hole 11 includes a first injection hole 111 and a second injection hole 113 which are sequentially connected from top to bottom, the minimum aperture of the first injection hole 111 is larger than the maximum aperture of the second injection hole 113, and the injection hole sealing structure 30 is sealed and fixed to the second injection hole 113. Therefore, the injection hole 11 is a stepped hole, and further, the inner peripheral wall of the first injection hole 111 is a slope, and the aperture of the first injection hole 111 is larger than the aperture of the second injection hole 113, so when the injection hole sealing structure 30 is sealed, the stepped injection hole 11 can also play a positioning role. In addition, the injection hole 11 is set as a stepped hole and the aperture of the first injection hole 111 is larger, which is also conducive to the sealing operation of the injection hole sealing structure 30. Of course, in addition to the injection hole 11, the top cover sheet 1 may also include structures such as a positive electrode sheet, a negative electrode column, and an explosion-proof valve. Because it is not the focus of the present invention and can be a conventional structure, it is not repeated here.

[0035] Continue as Figures 1 to 4 As shown, the injection hole sealing structure 30 includes a sealing cavity 33 and a sealing bead 31, and the sealing cavity 33 is sealed and fixed to the injection hole 11. Figure 5As shown, the sealing cavity 33 includes a peripheral wall 331 and a bottom wall 333, and the peripheral wall 331 and the bottom wall 333 enclose a cavity S. When the sealing bead 31 is pressurized and sealed, the metal chips generated will fall into the cavity S, which can prevent them from falling into the battery and affecting the battery performance. The sealing bead 31 is accommodated in the cavity S and at least abuts against the peripheral wall 331. At least a portion of the peripheral wall 331 wraps the sealing bead 31 (such as Figure 2 As shown, the surrounding wall 331 is squeezed and transformed, and the sealing bead 31 is embedded in the deformed area and wrapped). The surrounding wall 331 has a resisting pressure on the sealing bead 31, so the sealing bead 31, the surrounding wall 331 and the inner wall of the injection hole 11 are tightly combined, and the connection is firm and the sealing is strong.

[0036] Furthermore, the sealing cavity 33 is fixed to the injection hole 11 by riveting, or the side of the peripheral wall 331 away from the bottom wall 333 extends outward to form a convex portion 335, and the convex portion 335 overlaps the injection hole 11, or the convex portion 335 is welded and fixed to the injection hole 11. Whether it is riveting, overlapping or welding, the connection reliability between the sealing cavity 33 and the injection hole 11 can be further strengthened. The material of the sealing cavity 33 is aluminum, and the aluminum material can ensure that when the sealing bead 31 is pressurized, the peripheral wall 331 of the sealing cavity 33 is easily deformed to wrap the sealing bead 31. Of course, the sealing cavity 33 is preferably riveted, overlapped or welded to the second injection hole 113.

[0037] In addition to abutting against the peripheral wall 331, the sealing bead 31 further Figure 2 As shown, the sealing bead 31 also abuts against the bottom wall 333. The sealing bead 31 is made of aluminum or steel. The sealing bead 31 is used for sealing. Its outer wall is an arc without edges and corners. It is not only strong but also easy to insert into the cavity S, and the abutting pressure with the peripheral wall 331 is balanced.

[0038] Continuing as shown in Figure 5, an opening is provided at one end of the cavity S away from the bottom wall 333 (not shown in the figure), and the cavity S includes a first cavity S1 and a second cavity S2. The first cavity S1 is close to the opening, and the second cavity S2 is close to the bottom wall 333. The transverse dimension d1 of the first cavity S1 gradually decreases along the direction from the opening to the bottom wall 333 until it is flush with the second cavity S2, and the sealing bead 31 is accommodated in the first cavity S1 and the second cavity S2 at the same time. Since the transverse dimension d1 of the first cavity S1 gradually decreases, when the sealing bead 31 is inserted into the first cavity S1, the sealing bead 31 can easily roll and enter the second cavity S2. In order to maximize the connection reliability, the sealing bead 31 is at least pressed to roll between the first cavity S1 and the second cavity S2, and abuts against the peripheral wall 331 and the bottom wall 333 at the same time. However, in order to avoid the bottom wall 333 from being damaged and affecting the sealing performance, the sealing bead 31 and the bottom wall 333 only need to be in point contact. The minimum value of the lateral dimension d1 of the first cavity S1 is a, the diameter of the sealing bead 31 is b, and a / b is greater than or equal to 0.7 and less than 1.0. Within this parameter, the connection reliability between the sealing bead 31 and the sealing cavity 33 is guaranteed, and the peripheral wall 331 of the sealing cavity 33 is prevented from being excessively squeezed and severely reduced in strength, which affects long-term use.

[0039] Further, such as Figures 3-4 and Figures 7-8 It can be seen that the score 50 is provided on the peripheral wall 331 or the bottom wall 333, that is, the score 50 is provided on the sealed cavity 33. Therefore, when the internal air pressure of the power battery is relatively high, it exerts pressure on the sealed cavity 33, causing the peripheral wall 331 or the bottom wall 333 to be damaged at the score 50, thereby exhausting air at the injection hole 11 to avoid the risk of power battery explosion. Therefore, the sealed cavity 33 integrates the injection hole sealing and the battery explosion-proof effect, and the structural integration can make the structure of the power battery top cover 100 more compact.

[0040] The assembly method of the power battery top cover 100 of the present invention may include the following steps.

[0041] (1) Prepare the top cover sheet 10 provided with the injection hole 11, the sealing cavity 33 and the sealing bead 31. The maximum value of the transverse dimension d2 of the peripheral wall of the sealing cavity 33 is less than or equal to the minimum value of the hole diameter d3 of the injection hole 11.

[0042] (2) The sealing cavity 33 is inserted into the liquid injection hole 11 .

[0043] (3) The sealing bead 31 is inserted into the cavity S and pressed downward until the sealing bead 31 at least abuts against the peripheral wall 331 and the peripheral wall 331 is deformed to at least partially wrap the sealing bead 31 .

[0044] The power battery top cover 100 of the present invention is simple to assemble. First, the sealing cavity 33 is inserted into the liquid injection hole 11, and then the sealing bead 31 is inserted and pressure is applied to complete the assembly.

[0045] In addition, in step (1), it is necessary to strictly control the lateral dimension d2 of the outer wall of the sealing cavity 33 and the aperture d3 of the injection hole 11. The maximum value of the lateral dimension d2 of the outer wall of the sealing cavity 33 must be less than or equal to the minimum value of the aperture d3 of the injection hole 11. Only when these parameters are met can the sealing cavity 33 be inserted into the injection hole 11 without friction between them and without the generation of metal chips.

[0046] In step (2), if the transverse dimension d2 of the peripheral wall of the sealing cavity 33 is large, it will not fall off after being inserted into the injection hole 11. If the transverse dimension d2 of the peripheral wall of the sealing cavity 33 is small, the sealing cavity 33 needs to be riveted, overlapped or welded to the injection hole 11 before inserting the sealing bead 31, so as to avoid the sealing cavity 33 passing through the injection hole 11 and falling into the battery due to downward pressure when the sealing bead 31 is subsequently inserted into the cavity S, resulting in sealing failure. From a process perspective, the sealing cavity 33 is preferably overlapped on the injection hole 11.

[0047] In step (3), when the sealing bead 31 is inserted into the cavity S and pressure is applied downward, the pressure applied needs to be controlled and cannot be too large, so as to avoid excessive squeezing of the peripheral wall 331 of the sealing cavity 33 and serious reduction in strength, which affects long-term use, and to prevent the bottom wall 333 from being squeezed thin or damaged, which affects the sealing performance. Of course, the applied pressure cannot be too small either, and it is necessary to ensure that the sealing bead 31 at least abuts against the peripheral wall 331 after entering the cavity S, and at least part of the peripheral wall 331 is squeezed and deformed to wrap the sealing bead 31. In other words, part of the outer wall of the sealing bead 31 is embedded in the deformed peripheral wall 331.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention is described in detail with reference to the preferred embodiments, it is not limited to those listed in the embodiments. Those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A liquid injection hole sealing structure, used for sealing the liquid injection hole on a power battery, characterized in that: It includes a sealing cavity and a sealing bead, the sealing cavity is sealed and fixed to the injection hole, the sealing cavity includes a peripheral wall and a bottom wall, the peripheral wall and the bottom wall are enclosed to form a cavity, the sealing bead is accommodated in the cavity and at least abuts against the peripheral wall, and at least a portion of the peripheral wall wraps the sealing bead.

2. The sealing structure of the injection hole according to claim 1, characterized in that: The sealing cavity is riveted and fixed to the liquid injection hole.

3. The sealing structure of the injection hole according to claim 1, characterized in that: The side of the peripheral wall away from the bottom wall extends outward to form a convex portion, and the convex portion overlaps the liquid injection hole.

4. The sealing structure of the injection hole according to claim 1, characterized in that: The side of the peripheral wall away from the bottom wall extends outward to form a convex portion, and the convex portion is welded and fixed to the liquid injection hole.

5. The sealing structure of the injection hole according to claim 1, characterized in that: The sealing bead also abuts against the bottom wall.

6. The sealing structure of the injection hole according to claim 1, characterized in that: An opening is provided at one end of the cavity away from the bottom wall, and the cavity includes a first cavity and a second cavity, the first cavity is close to the opening, and the second cavity is close to the bottom wall, and the lateral dimension of the first cavity gradually decreases along the direction from the opening to the bottom wall until it is flush with the second cavity, and the sealing bead is accommodated in the first cavity and the second cavity at the same time.

7. The sealing structure of the injection hole according to claim 6, characterized in that: The minimum transverse dimension of the first cavity is a, the diameter of the sealing bead is b, and a / b is greater than or equal to 0.7 and less than 1.

0.

8. The sealing structure of the injection hole according to claim 1, characterized in that: The peripheral wall and / or the bottom wall are provided with notches.

9. A power battery top cover, characterized in that: The invention comprises a top cover sheet, a liquid injection hole arranged on the top cover sheet, and a liquid injection hole sealing structure according to any one of claims 1 to 8 for sealing the liquid injection hole.

10. The assembly method of the power battery top cover according to claim 9, characterized in that: Includes steps: (1) preparing the top cover sheet, the sealing cavity and the sealing bead provided with the injection hole, wherein the maximum transverse dimension of the peripheral outer wall of the sealing cavity is less than or equal to the minimum hole diameter of the injection hole; (2) inserting the sealing cavity into the liquid injection hole; (3) Inserting the sealing bead into the cavity and applying downward pressure until the sealing bead at least abuts against the peripheral wall and the peripheral wall is deformed to at least partially wrap the sealing bead.

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