TWI743961B - Curved surface shell of button type lithium secondary battery - Google Patents

Abstract

The present invention is a cambered shell of button type lithium secondary battery. Surrounding the ring wall connecting the outer convex arc surface and an accommodation space between the ring wall, the one-sided opening and the outer convex arc surface, the outer surface of the ring wall is covered with an insulating rubber ring, and the lower shell The body has a cover that shields the accommodating space and a cap ring that connects the cover and separates the insulating rubber ring and closes the accommodating space; accordingly, the accommodating space will be due to the contour of the convex arc An outer convex space is formed at the center. The increased structural thickness of an inner cell component and the upper shell and the lower shell can be accommodated in the outer convex space, reducing the internal cell component’s thickness. The central area causes electrical and safety risks due to oppression.

Description

Curved surface shell of button type lithium secondary battery

The present invention relates to lithium ion batteries, in particular to the structure of a composite case for button-type lithium secondary batteries.

Lithium-ion battery is a kind of rechargeable battery. It mainly relies on the movement of lithium ions between the positive electrode and the negative electrode to convert chemical energy into electrical energy to work. It has the advantages of high energy density, no memory effect, etc., and a large number of Used in 3C products, such as smart phones and tablet computers, etc.

Generally, a button-type lithium secondary battery is composed of an outer casing part and an inner cell part, and the outer casing part includes a lower casing and an upper casing (including an insulating rubber ring). The internal cell component includes a first electrode, a second electrode, and a diaphragm arranged between the first electrode and the second electrode; the internal cell component is connected to the lower casing and the upper casing. After the electrical connection, it will be assembled again. After the internal battery core component is inserted between the lower casing and the upper casing, an electrolyte is injected and the riveting and sealing assembly process is carried out so that the lower casing and the upper casing are assembled. The upper casing is closed, and finally charging is performed to complete the production of the button-type lithium secondary battery. The detailed structure and manufacturing steps are described later.

The inner cell component and the outer shell component are usually welded to achieve electrical connection. Therefore, the first electrode, the second electrode, the upper shell, and the lower shell derived from the inner cell component are connected to each other. The end surface area is bonded and welded, and insulating tape will be attached to the end surface area as protection to avoid short circuit; the semi-finished product that completes the electrical connection of the first electrode, the second electrode and the upper shell and the lower shell will be assembled , The assembly procedure is to insert the internal cell component between the lower casing and the upper casing. At this time, the end surface of the internal cell component and the end surfaces of the lower casing and the upper casing are parallel to each other. The central area of the end face area will be squeezed and deformed due to the increased structural thickness of the end face area due to the bonding welding. A slight squeezing situation will cause the internal battery core components to appear imprinting, which is severely squeezed In this case, the structure of the central area of the internal battery cell component is damaged, leading to related undesirable phenomena after the subsequent assembly of the button-type lithium battery, such as abnormal charging and discharging, and safety risks caused by internal short circuits.

The main purpose of the present invention is to solve the problem that the conventional case will compress the central area of the inner battery cell component after assembly, which causes electrical and safety risks.

In order to achieve the above objective, the present invention provides a button-type lithium secondary battery arc shell. The structure of the present invention includes an upper shell and a lower shell, wherein the upper shell has a single side opening and a convex arc surface. , A ring wall and an accommodating space, the outer convex arc surface is far away from the single-sided opening, the ring wall surrounds and connects the outer convex arc surface, the accommodating space is located on the ring wall, the single-sided opening and the outer convex arc surface And the outer surface of the ring wall is covered with an insulating rubber ring. The lower shell has a cover and a cap ring, the cover shields the accommodating space, the cap ring is connected to the cover and spaced apart from the insulating rubber ring and closes the accommodating space.

The accommodating space can accommodate an internal cell component, the internal cell component having a first electrode, a second electrode electrically connected to the upper casing, the lower casing, and a separation between the first electrode and the The diaphragm of the second electrode. And after the upper shell and the lower shell are respectively attached and welded to the first electrode and the second electrode and assembled and injected with an electrolyte, the upper shell and the lower shell can be riveted and sealed.

Accordingly, the accommodating space will form a convex space at the center due to the contour of the convex arc surface. The convex space can be used as a placement space, and the placement space can accommodate the upper shell and the lower shell. The thickness of the structure increased by the bonding and welding of the first electrode and the second electrode, and after the riveting and sealing, can prevent the central area of the inner cell component from being excessively squeezed, thereby reducing defects. Moreover, the contour of the convex arc surface can provide a better injection space in the mold, help the molten polymer flow and control, thereby improving the yield of the polymer injection process, and can provide riveting and sealing during the assembly process. Dimensional margin of sizing improves the yield rate of the riveting and sealing process.

The detailed description and technical content of the present invention are described as follows in conjunction with the drawings:

Please refer to "FIG. 1", "FIG. 2", "FIG. 3" and "FIG. 4". The structure of the present invention provides a button-type lithium secondary battery composite casing structure, including an upper casing 10 and a lower casing 20. The upper housing 10 has a single-sided opening 11, an outer convex arc surface 12, a ring wall 13 and an accommodating space 14. The outer convex arc surface 12 is away from the single-sided opening 11, and the outer convex arc surface The center height h is 0.1~1 millimeter (mm), the ring wall 13 surrounds and connects the convex arc surface 12, and the accommodating space 14 is located between the ring wall 13, the one-sided opening 11 and the convex arc surface 12 And the outer surface of the ring wall 13 is covered with an insulating rubber ring 30, and the manufacturing method of the insulating rubber ring 30 is formed by polymer injection molding and covering the outer surface of the ring wall, which can make insulating polymer materials The ring wall 13 is covered by in-mold injection through high temperature melting (as shown in FIG. 2), and the material of the insulating rubber ring can be selected from polypropylene, polyethylene terephthalate, rubber, and the like. The lower housing 20 has a cover 21 and a cap ring 22, the cover 21 shields the accommodating space 14, the cap ring 22 is connected to the cover 21 and separated from the insulating rubber ring 30 and closes the accommodating space 14 to form a good sealing structure. The upper housing 10 and the lower housing 20 can be made of polymer, composite material, etc. besides being metal. The insulating rubber ring 30 is made of polypropylene, polyethylene terephthalate, rubber, etc. Other materials, the material of the insulating rubber ring 30 is elastic and can be squeezed and deformed to close the gap, and has an airtight effect.

Please also refer to "FIG. 5". The accommodating space 14 can accommodate an internal battery component 40. The internal battery component 40 can be formed by winding or stacking. The internal battery component 40 has A first electrode 41 and a second electrode 42 of the upper casing 10 and the lower casing 20 are electrically connected to a diaphragm 45 separating the first electrode 41 and the second electrode 42.

The accommodating space 14 will form a convex space 141 at the center due to the contour of the convex arc surface 12 (as shown in FIG. 4). The convex space 141 can be used as a placement space, and the placement space can be accommodated. The structural thickness of the upper casing 10, the lower casing 20, the first electrode 41 and the second electrode 42 is increased by the bonding and welding. In more detail, the first electrode 41 is bonded and welded to the inner surface of the convex arc surface 12 of the upper housing 10, and the second electrode 42 is bonded and welded to the seal of the lower housing 20. After the inner surface of the cover 21 is attached and welded, the inner cell component 40 is placed between the upper casing 10 and the lower casing 20 and the upper casing 10 and the lower casing 20 are assembled Insulating tape (not shown in the figure) is attached to the end surface area as protection to avoid short circuits. The central part of the internal battery core component 40 has soldering materials, insulating tape, etc., and has an increased structural thickness, and the convex The space 141 can accommodate the increased structural thickness.

In summary, the present invention has the following characteristics:

1. The convex space is formed by the convex arc surface being arranged in the accommodating space. The convex space can be used as a placement space, and the placement space can accommodate the upper shell, the lower shell and the second shell. The thickness of the structure is increased by the bonding and welding of an electrode and the second electrode, and the central area of the internal battery core component is prevented from being excessively squeezed during assembly, thereby reducing defects.

2. Utilizing the characteristic that the contour of the convex arc surface is a curved surface, the insulating polymer material can be melted in high temperature for in-mold injection, and the outer surface of the ring wall is covered with the insulating rubber ring, which can provide a better mold The inner injection molding space helps the molten polymer flow and control, thereby improving the yield of the polymer injection molding process.

3. The convex arc surface of the upper shell can provide the dimensional margin of the riveting and sealing during the assembly process, and improve the yield of the riveting and sealing process.

h: center height 10: Upper shell 11: Single side opening 12: Convex curved surface 13: Ring wall 14: accommodating space 141: Convex Space 20: Lower shell 21: capping 22: cap ring 30: Insulating rubber ring 40: Internal battery components 41: first electrode 42: second electrode 45: Diaphragm

Figure 1 is a schematic cross-sectional view of the upper casing of the present invention. 2 is a schematic cross-sectional view of the insulating rubber ring formed on the upper casing of the present invention. Fig. 3 is a schematic cross-sectional structure view of the lower casing of the present invention before sealing. Figure 4 is a schematic view of the overall cross-sectional structure of the present invention after sealing. Fig. 5 is a schematic diagram of the structure of the internal battery core components of the present invention.

h: center height

10: Upper shell

12: Convex curved surface

13: Ring wall

14: accommodating space

141: Convex Space

20: Lower shell

21: capping

22: cap ring

30: Insulating rubber ring

Claims (4)

A cambered shell of a button-type lithium secondary battery, comprising: An upper housing, the upper housing having a single-sided opening, an outer convex arc surface away from the single-sided opening, a ring wall and an accommodating space, the ring wall surrounds and connects the outer convex arc surface, the accommodating space Located between the ring wall, the one-sided opening and the convex arc surface, and the outer surface of the ring wall is covered with an insulating rubber ring; and A lower shell, the lower shell has a cover and a cap ring, the cover shields the accommodating space, the cap ring is connected to the cover and is spaced from the insulating rubber ring and closes the accommodating space. According to claim 1, the curved surface of the button-type lithium secondary battery, wherein the center height of the convex curved surface is 0.1 to 1 millimeter (mm). The arc-surfaced shell of the button-type lithium secondary battery according to claim 1, wherein the insulating rubber ring is formed by polymer injection molding and covers the outer surface of the ring wall. According to claim 1, the cambered shell of a button type lithium secondary battery, wherein the material of the insulating rubber ring is selected from the group consisting of polypropylene, polyethylene terephthalate and rubber.

Images