KR200262297Y1 - Cap assembly in secondary battery - Google Patents

Abstract

The present invention provides a cap assembly of a secondary battery. Cap assembly of the present invention is a cap plate of a conductive material having an assembly hole; An electrode pin of a conductive material having a body portion inserted into the assembly hole of the cap plate, and a disc-shaped head portion formed at the top of the body portion, and assembled to the cap plate by caulking or spinning the bottom portion of the body portion; A gasket disposed around the electrode pin to insulate the electrode pin and the cap plate, the gasket having a receiving hole for accommodating the body portion of the electrode pin and a circular expansion part for accommodating the head of the electrode pin; An insulating plate disposed around the lower end of the electrode pin to insulate the electrode pin and the cap plate; It is characterized in that it comprises an adhesive applied between the gasket and the cap plate, and between the gasket and the electrode pin to increase the insulation and airtightness between the cap plate and the electrode pin. In particular, the gasket is composed of fluororesin, and the surface of the fluororesin gasket is etched to increase the adhesion between the electrode pin and the cap plate. The present invention is made of a fluorine resin and the gasket is etched to improve the adhesion to prevent the rotation of the electrode pin without forming the head of the electrode pin and the expansion portion of the gasket in a polygon. In particular, by applying an adhesive between the upper end of the gasket and the cap plate, and between the insulating plate and the cap plate, it is possible to increase the insulation between the electrode pin and the cap plate, increase the sealability of the can and prevent the rotation of the electrode pin.

Description

CAP ASSEMBLY IN SECONDARY BATTERY}

The present invention relates to a cap assembly of a secondary battery, and more particularly, it is possible to secure the airtightness and insulation between the electrode pin and the cap plate, and to prevent the rotation of the electrode pin, as well as to extrude or inject or compress the gasket. The present invention relates to a cap assembly of a secondary battery capable of reducing manufacturing costs by manufacturing by the method.

Secondary batteries are rechargeable and can be repeatedly used, such as nickel cadmium (Ni-Cd) batteries, nickel hydrogen (Ni-MH) batteries, and lithium ion (Li-ion) batteries. In particular, lithium ion batteries have been in the spotlight in recent years because of their high energy density, which enables small-capacity large-capacity, long life, and does not use pollutants such as cadmium, lead, or mercury.

Lithium-ion batteries are cylindrical and square depending on their appearance. Among them, rectangular lithium-ion batteries are frequently used because of their advantages in installation. Such a rectangular lithium ion battery (hereinafter, abbreviated as "secondary battery") includes an aluminum can having a storage compartment, and thereafter accommodates a positive electrode sheet and a negative electrode sheet wound with a separator therebetween in the storage compartment of the can. The open top of the seal is closed by a cap assembly, and the electrolyte is injected into the storage compartment of the can and sealed.

On the other hand, the cap assembly is provided with a positive electrode terminal, a negative electrode terminal, an inlet for injecting the electrolyte and a safety vent for releasing the internal pressure of the can. 1 is a cross-sectional view showing the configuration of the cap assembly. According to this, the cap assembly 1 has a cap plate 3. The cap plate 3 is aluminum, which is a conductive material, and is welded to the opening of the storage chamber R. The cap plate 3 is configured to be connected to the positive electrode sheet (not shown) to perform the role of the positive electrode terminal. Here, the cap plate 3 may be directly connected to the positive electrode sheet, but is usually indirectly connected through the can (C).

An assembly hole 3a is formed in the center of the cap plate 3, and the electrode pin 5 is provided through the gasket 7 in the assembly hole 3a. That is, a gasket 7 may be formed by forming a body portion 5a and a head portion 5b of the electrode pin 5, and then assembled by inserting the electrode pin 5 into the gasket 7. The assembled electrode pin 5 and the gasket 7 are press-fitted into the assembly hole 3a of the cap plate 3, and the ends of the electrode pin 5 protruding downward are insulated from the insulating plate 9a and the terminal plate 9b. Caulking or spinning through). The electrode pins 5 installed in this way are connected to the negative electrode sheet (not shown) through the terminal plate 9b in the state of being insulated from the cap plate 3 by the gasket 7 and the insulating plate 9, and thus, serve as the negative electrode terminal. It is configured to perform. Here, the gasket 7 serves to insulate the electrode pin 5 and the cap plate 3 but also to maintain the airtightness between the electrode pin 5 and the assembly hole 3a.

On the other hand, the body portion 5a of the electrode pin 5 is composed of a cylinder, there is a fear that it is rotated in the state assembled to the cap plate (3). This causes a decrease in the airtightness between the electrode pins 5 and the assembly holes 3a, and causes the shorts by bringing the electrode pins 5 into contact with the cap plate 3. Therefore, the electrode pin 5 is configured to prevent rotation in the assembled state on the cap plate 3, for this purpose, the head portion 5b of the electrode pin 5 is configured in a polygon such as a triangle or a square, and the gasket ( 7 is formed a polygonal expansion portion (7a) that can be fitted into the polygonal head portion 5b of the electrode pin (5), the cap plate 3 is a polygonal expansion portion (7a) of the gasket (7) ) Is provided with a seating groove (3b) that can be seated. As the electrode pin 5 and the gasket 7 are prevented from rotating relative to each other and the gasket 7 and the cap plate 3 are prevented from rotating relative to each other, the electrode pin 5 is formed by the cap plate 3. ) Is prevented from rotating.

In addition, the cap plate 3 is provided with an injection hole 3c for injecting an electrolyte into the storage chamber R of the can C, and a safety valve 3d for releasing the internal pressure of the can C. In particular, although the safety valve 3d is normally clogged, when the pressure in the storage chamber R of the can C rises, the safety valve 3d is ruptured and configured to release the gas therein.

However, the conventional cap assembly as described above forms a seating groove 3b in the cap plate 3 to prevent the rotation of the electrode pin 5, so that the thickness of the cap plate 3 becomes thin and the strength of the cap plate 3 is reduced. Disadvantages are pointed out. In particular, the cap plate 3, which is vulnerable in the process of caulking or spinning the end of the electrode pin 5, is easily deformed and has difficulty in assembling to the can C. On the other hand, the thickness of the cap plate 3 can be increased by increasing the thickness of the cap plate 3, but this causes various problems such as increasing the weight of the product and reducing workability.

In addition, the conventional cap assembly had to process the head 5b of the electrode pin 5 into a polygon in order to prevent the rotation of the electrode pin 5, and also to the gasket 7 to which the electrode pin 5 is fitted. The disadvantage of having to form the polygonal expansion portion 7a into which the head 5b of the electrode pin 5 is fitted is pointed out. In particular, the gasket 7 has a disadvantage in that it must be manufactured only by injection molding in order to form the polygonal expanding portion 7a. Such a disadvantage causes a rise in manufacturing cost.

Therefore, the present invention has been made to solve the above-mentioned problems, the purpose of the rotation of the electrode pin without forming the head portion of the electrode pin and the expansion portion of the gasket in the polygon, without forming a mounting groove in the cap plate It is to provide a cap assembly of a secondary battery that can prevent.

Another object of the present invention is to provide a cap assembly of a secondary battery that can ensure the airtightness and insulation between the electrode pin and the cap plate.

Another object of the present invention is to increase the strength of the cap plate by not forming a seating groove in the cap plate, and also by extrusion molding method or compression molding by not forming a polygonal expansion portion in the gasket It is also possible to manufacture a gasket by the method to provide a secondary battery cap assembly that can reduce the manufacturing cost.

1 is a cross-sectional view showing the configuration of a cap assembly of a general secondary battery,

Figure 2 is an exploded perspective view showing the configuration of the cap assembly of the secondary battery according to the present invention,

3 is a cross-sectional view showing a coupling state of FIG.

4 and 5 are an exploded perspective view and a cross-sectional view showing a configuration of a modification of the cap assembly of the secondary battery according to the present invention.

♣ Explanation of symbols for the main parts of the drawing ♣

10: cap assembly 20: cap plate

22: assembly hole 24: electrolyte injection hole

26: safety valve 30: electrode pin

32: torso 34: head

40: gasket 42: receiving hole

44: expansion pipe 50: insulating plate

60: terminal plate 70: adhesive

The cap assembly of the secondary battery according to the present invention for achieving the above object in the cap assembly of the secondary battery for sealing the compartment of the can containing the positive electrode sheet and the negative electrode sheet and the electrolyte, the positive electrode sheet and the negative electrode sheet and the electrolyte A cap assembly of a secondary battery for sealing a storage chamber of cans to be accommodated, the cap assembly comprising: a cap plate of a conductive material having an assembly hole; An electrode pin of a conductive material assembled to the cap plate by having a body portion inserted into the assembly hole of the cap plate and a disc shaped head portion formed at an upper end of the body portion, and coking or spinning the lower end of the body portion; A gasket disposed around the electrode pin to insulate the electrode pin from the cap plate, the gasket having a receiving hole for accommodating the body of the electrode pin and a circular expansion part for accommodating the head of the electrode pin; and; An insulating plate disposed around the lower end of the electrode pin to insulate the electrode pin and the cap plate; And an adhesive applied between the gasket and the cap plate and between the gasket and the electrode pin to increase insulation and airtightness between the cap plate and the electrode pin.

Preferably, the electrode pin is made of aluminum alloy or forged steel, the surface is nickel plated with a thickness of 1㎛ to 10㎛, and additionally forming a knurled portion in contact with the gasket, the gasket is fluorine It is made of a resin, the fluororesin gasket is characterized in that the surface is etched so that the adhesion between the electrode pin and the cap plate can be increased.

Hereinafter, a preferred embodiment of the cap assembly of the secondary battery according to the present invention will be described in detail with reference to the accompanying drawings.

First, as shown in FIGS. 2 and 3, the cap assembly 10 of the secondary battery according to the present invention has a cap plate 20. The cap plate 20 is made of a conductive material, an assembly hole 22 is formed at the center thereof, an electrolyte injection hole 24 is formed at one end thereof, and a safety valve 26 is formed at the other end thereof. The cap plate 20 is connected to a positive electrode sheet in a can (not shown) to serve as a positive electrode terminal.

On the other hand, the electrode pin 30 is fitted into the assembly hole 22 of the cap plate 20 via the gasket 40. Electrode pin 30 is composed of a body portion 32 and the head 34, the body portion 32 is configured to be inserted through the assembly hole 22 of the cap plate 20, the head 34 Is configured to protrude to the top surface of the cap plate 20. In particular, unlike the conventional head 34 is configured in a disc shape, the bottom surface is formed with a knurling (knurling: 34a) as shown in FIG. The reason why the knurled portion 34a is formed on the bottom surface of the head 34 is to increase the contact area with the gasket 40 as wide as possible to improve the coupling force with the gasket 40. Of course, as the coupling force with the gasket 40 is improved, rotation about the gasket 40 is prevented.

The electrode pin 30 is composed of aluminum alloy or forged steel, such as conductive material. In addition, the surface of the electrode pin 30 is preferably nickel plated with a thickness of 1㎛ ~ 10㎛, which enhances the corrosion resistance of the electrode pin 30, improves the surface roughness of the electrode pin 30, weldability To improve. This electrode pin 30 is connected to the negative electrode sheet in the can not shown through the terminal plate 60 to be described later serves as a negative electrode terminal.

The gasket 40 is disposed around the electrode pin 30 to insulate the cap plate 20 and the electrode pin 30, and accommodates the body 32 of the electrode pin 30. 42 is provided, and the expansion part 44 which can accommodate the head part 34 of the electrode pin 30 is formed in the upper end. The dilator 44 is circularly expanded to accommodate the discoid head 34. The gasket 40 is made of a fluorine resin material having good corrosion resistance, chemical resistance, impact resistance and heat resistance, and is manufactured by injection molding or extrusion molding or compression molding.

On the other hand, such a fluorine resin gasket 40 is fitted into the assembly hole 22 of the cap plate 20 through the adhesive 70 so that the electrode pin 30 is fitted into the receiving hole 42 in the assembled state. In this case, the gasket 40 has to be fluorine resin etched to improve the adhesion between the electrode pin 30 and the cap plate 20. That is, the fluorine resin has good corrosion resistance, chemical resistance and heat resistance, but can not be adhered with an adhesive because it is poor in adhesion, thereby improving the adhesion by modifying the surface by etching it, and thus the fluorine resin gasket according to the present invention (40). ) Is also etched to modify the surface to improve adhesion to the electrode pin 30 and the cap plate 20. Examples of the fluororesin etching method include a chemical etching process using an etching solution, an electrical etching process using a corona, a prisma etching process, or an excimer laser etching process. In the present invention, a chemical etching treatment method using an etching solution in which metal sodium is mixed with 1 to 2% by weight of liquid ammonia is used. The etching solution in which metal sodium is mixed with liquid ammonia has good etching efficiency, particularly fluorine resin. This is because the efficiency is high for etching. Since the chemical etching treatment method using the etching solution is a known technique, a detailed description thereof will be omitted.

As a result, the etched gasket 40 has good adhesion, so that it is firmly coupled to the electrode pin 30 in a state of being fitted around the electrode pin 30, and also to the assembly hole 22 of the cap plate 20. It can be firmly coupled with the cap plate 20 in the fitted state. In particular, the electrode pin 30 is pressed in the receiving hole 42 of the gasket 40, the knurled portion 34a formed in the head 34 is in close contact with the expansion portion 44 of the gasket 40 Accordingly, the gasket 40 is more firmly coupled.

On the other hand, the end of the electrode pin 30 protruding through the assembly hole 22 to the bottom of the cap plate 20 extends radially outward by caulking or spinning as shown in FIG. Therefore, the electrode pin 30 is firmly coupled to the cap plate 20. Here, an insulating plate 50 and a terminal plate 60 are interposed between the cap plate 20 and the end of the electrode pin 30, and the insulating plate 50 has an end portion of the electrode pin 30 and the cap plate 20. The terminal plate 60 is in contact with the end of the electrode pin 30 and is connected to the negative electrode sheet in the can not shown at the same time to allow the electrode pin 30 to serve as a negative electrode terminal. Let's do it.

And the present invention is the adhesive between the cap plate 20 and the top of the gasket 40 and the insulating plate 50 and the cap plate 20 in the state that the assembly of the electrode pin 30 to the cap plate 20 is completed 70 is applied to increase the insulation between the cap plate 20 and the electrode pins 30 and to increase the sealing property of the can, and to prevent the rotation of the electrode pins 30. Of course, the adhesive 70 is also applied between the gasket 40 and the cap plate 20, and also between the gasket 40 and the electrode pin 30. As the adhesive used at this time, it is preferable to use an adhesive having good heat resistance and good chemical resistance, for example, an acrylic anaerobic adhesive.

As described above, the cap assembly of the present invention etches the fluororesin gasket 40 to improve the adhesion between the electrode pin 30 and the cap plate 20, and thus the head and the gasket 40 of the electrode pin as in the prior art. It is possible to prevent the rotation of the electrode pin 30 without forming the expansion portion 44 of the polygon. In particular, as the adhesive 70 is applied between the upper end of the gasket 40 and the cap plate 20, and between the insulating plate 50 and the cap plate 20, the electrode pin 30 and the cap plate 20 are separated from each other. Increasing the insulation and can increase the sealability of the can and can prevent the rotation of the electrode pin (30).

Next, Figures 4 and 5 is a view showing a modification of the secondary battery cap assembly according to the present invention. According to this, the cap assembly of a modification has the structure which formed the gasket 40 by the cylindrical tube body. The cylindrical gasket 40 is press-fitted into the assembly hole 22 of the cap plate 20 in a state of being fitted around the electrode pin 30, in which the electrode pin 30 as shown in FIG. Pressed by the head 34 of the folded to the inner surface is enlarged or enlarged as it is configured to surround the head 34 of the electrode pin 30 while forming the expansion portion 44.

The cap assembly of this modification does not form a separate expansion portion 44 for accommodating the head portion 34 of the electrode pin 30 in the gasket 40, thereby preforming the gasket 40 to extrusion molding. It can be produced by the method. In particular, such advantages provide various effects, such as simplifying the manufacturing process and reducing manufacturing costs. Of course, the gasket 40 thus manufactured is made of fluorine resin, and must be etched to modify its surface.

In the above described a preferred embodiment of the present invention by way of example, the scope of the present invention is not limited only to this specific embodiment, it can be appropriately changed within the scope described in the utility model registration claims.

As described above, the cap assembly of the secondary battery according to the present invention comprises a gasket for insulating the electrode pin and the cap plate with a fluorine resin, and is etched to improve adhesiveness, thereby improving the adhesion between the head and the gasket of the electrode pin. It has the advantage of preventing the rotation of the electrode pin without forming the expansion portion of the polygon. In particular, the adhesive is applied between the top of the gasket and the cap plate, and between the insulating plate and the cap plate to increase the insulation between the electrode pin and the cap plate, increase the sealability of the can, and prevent rotation of the electrode pin. Has In addition, by manufacturing the gasket by the extrusion molding method, the manufacturing process can be simplified and the manufacturing cost can be reduced.

Claims (3)

In the cap assembly of the secondary battery for sealing the storage compartment of the can containing the positive electrode sheet and negative electrode sheet and the electrolyte, A cap plate of conductive material having an assembly hole; An electrode pin of a conductive material assembled to the cap plate by having a body portion inserted into the assembly hole of the cap plate and a disc shaped head portion formed at an upper end of the body portion, and coking or spinning the lower end of the body portion; A gasket disposed around the electrode pin to insulate the electrode pin from the cap plate, the gasket having a receiving hole for accommodating the body of the electrode pin and a circular expansion part for accommodating the head of the electrode pin; and; An insulating plate disposed around the lower end of the electrode pin to insulate the electrode pin and the cap plate; And an adhesive applied between the gasket and the cap plate and between the gasket and the electrode pin to increase insulation and airtightness between the cap plate and the electrode pins. The method of claim 1, wherein the electrode pin is made of aluminum alloy or forged steel, the surface is nickel plated with a thickness of 1㎛ 10㎛, characterized in that the knurled portion is further formed in contact with the gasket. Cap assembly of the secondary battery. The cap assembly of claim 1, wherein the gasket is formed of a fluorine resin, and the surface of the fluorine resin gasket is etched to increase adhesion to the electrode pin and the cap plate.