KR20040110335A - Secondary battery and methode for sealing thereof - Google Patents

Abstract

PURPOSE: A secondary battery whose electrolyte inlet is sealed with pillar wires is provided to solve the problems caused by complicated sealing processes, welding impurities remaining after welding and defects in a cap plate. CONSTITUTION: The secondary battery comprises: an electrode assembly(20) comprising a cathode plate(22), anode plate(24) and a separator(26) interposed between both electrode plates; a can(10) for housing the electrode assembly(20); a cap plate(32) for sealing the opening of the can; an electrolyte inlet(32') formed on the can or cap plate; and a sealing member(40) for sealing the electrolyte inlet, wherein the sealing member comprises molten solution(42) of pillar wires.

Description

Secondary battery and its sealing method {SECONDARY BATTERY AND METHODE FOR SEALING THEREOF}

The present invention relates to a secondary battery, and more particularly, to a method for sealing an electrolyte injection hole using a filler wire.

Rechargeable batteries can be recharged, miniaturized, and large-capacity. Representative examples include nickel-hydrogen (Ni-MH) batteries, lithium (Li) batteries, and lithium-ion (Li-ion) batteries. Separated by.

Typically, the secondary battery includes a power generation element consisting of a positive electrode plate, a negative electrode plate, and a separator, that is, an electrode assembly, a metal can containing the electrode assembly and the electrolyte, and a cap assembly sealing the opening of the can.

Here, the cap assembly includes a cap plate welded directly to the opening of the can to seal the can, a terminal pin installed through the cap plate, and a gasket for insulating the terminal pin from the cap plate. The negative electrode tab drawn out from the negative electrode plate is welded so that the terminal pin functions as a negative electrode terminal portion.

The positive electrode tab drawn from the positive electrode plate is directly connected to the lower surface of the cap plate or the inner surface of the can so that the entire outside of the battery except the terminal pin functions as a positive electrode terminal portion.

A secondary battery having such a configuration accommodates an electrode assembly in a can, welds a cap plate to an opening, and injects electrolyte through an electrolyte injection hole formed in the cap plate as a final step of the assembling process. The same plug is press-fitted to close the injection hole, followed by laser welding, and then the UV-curable resin layer is coated and cured to enhance the sealing property, thereby sealing the electrolyte injection hole.

However, the conventional method of sealing the electrolyte inlet using the above-described method is complicated in the sealing process, there is a problem that a defect such as a welding foreign matter on the cap plate or a hole is perforated in the cap plate after sealing. .

Accordingly, an object of the present invention is to provide a secondary battery and a sealing method thereof, which solve the above problems by sealing an electrolyte injection hole using a filler wire.

1 is a cross-sectional view showing the configuration of a secondary battery according to an embodiment of the present invention.

FIG. 2 is a view showing a sealing method of an electrolyte injection hole shown in FIG. 1. FIG.

3 is an enlarged view of a circle in FIG. 1 showing the configuration of an electrolyte injection hole sealing member according to another embodiment of the present invention;

The present invention to achieve the above object,

An electrode assembly having a positive electrode plate and a negative electrode plate, and a separator interposed between the positive electrode plates;

A can in which the electrode assembly is received;

A cap plate for sealing an opening of the can;

An electrolyte injection hole provided in the can or the cap plate;

A sealing member for sealing the electrolyte injection hole;

The sealing member is achieved by a secondary battery comprising a filler wire melt.

According to a preferred embodiment of the present invention, the sealing member may further include a plug such as a ball or a pin.

The method of sealing a secondary battery in which the electrolyte injection hole of the secondary battery seals the electrolyte injection hole with the molten filler wire by melting the filler wire using a laser beam while supplying a filler wire to the electrolyte injection hole at a constant speed. It can seal by.

According to a preferred embodiment of the present invention, the sealing process using the filler wire may be carried out after pressing a plug such as a ball or a pin into the electrolyte injection hole.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view of a rectangular secondary battery according to an embodiment of the present invention, Figure 2 shows a process diagram showing the electrolyte injection hole sealing process of FIG.

Referring to the drawings, a secondary battery according to an embodiment of the present invention, the can 10 is provided with an opening on one surface, the electrode assembly 20 accommodated in the can 10 through the opening, and the can 10 Cap assembly 30 to seal the opening of the < RTI ID = 0.0 >

The electrode assembly 20 is formed of the positive electrode plate 22 and the negative electrode plate 24 via the separator 26. According to an exemplary embodiment of the present invention, the positive electrode plate 22 and the negative electrode plate 24 may be formed of the separator 26. The electrode assembly 20 of the jelly roll-type wound after being laminated through a) may be used.

At this time, the negative electrode plate 24 includes a negative electrode current collector made of a strip-shaped metal thin plate, and a copper thin plate may be used as the negative electrode current collector. A negative electrode coating part coated with a negative electrode mixture including a negative electrode active material is formed on at least one surface of the negative electrode current collector, and a carbon material is used as the negative electrode active material, and may contain a binder, a plasticizer, a conductive material, and the like to form a negative electrode mixture. have.

In addition, the positive electrode plate 22 includes a positive electrode current collector made of a strip-shaped metal thin plate, and an aluminum thin plate may be used as the positive electrode current collector. At least one surface of the positive electrode current collector is formed with a positive electrode coating portion coated with a positive electrode mixture including a positive electrode active material, the lithium active material is used as the positive electrode active material, containing a binder, a plasticizer, a conductive material, etc. Can be achieved.

A positive electrode tab (not shown) and a negative electrode tab 28, which are electrically connected to the positive electrode plate 22 and the negative electrode plate 24, respectively, are drawn out from the upper side of the electrode assembly 20. Nickel thin film may be used as the negative electrode tab 28, and aluminum thin film may be used as the positive electrode tab, but is not limited thereto. Positions of the positive electrode tab and the negative electrode tab 28 may be provided as opposed to FIG. 1.

On the other hand, the can 10 may be made of a metal material having a substantially rectangular parallelepiped shape, and thus can itself serve as a terminal. According to the present embodiment, the can 10 may be formed of Al or an Al alloy, which is a lightweight conductive metal.

The can 10 may be provided in an angled square of the side edge portion thereof, and although not shown in the drawing, the can 10 may be provided in a round shape in which the edge portion is rounded.

A cap assembly 30 is installed and sealed at the opening of the can 10, and the cap assembly 30 has a cap plate 32 welded directly to the opening to seal the can 10. . The can 10 and the cap plate 32 may be provided with the same metal material for ease of welding.

In addition, the cap assembly 30 is provided with a terminal pin 36 formed to be insulated from the cap plate 32 through the gasket 34, and the lower portion of the cap assembly 30 is withdrawn from the negative electrode plate 24. The negative electrode tab 28 is welded so that the terminal pin 36 functions as a negative electrode terminal portion.

On the other hand, the positive electrode tab drawn out from the positive electrode plate 22 is electrically directly on the lower surface of the cap plate 32 or the inner surface of the can 10 so that the entire outside of the battery except the terminal pin 36 functions as a positive electrode terminal portion. Connected.

However, the structures of the positive electrode terminal and the negative electrode terminal are not necessarily limited thereto, and the structure of the positive electrode terminal portion may be formed through a separate terminal pin like the structure of the negative electrode terminal portion, and any other structure may be applied. have.

Meanwhile, an insulating protective case 38 may be installed between the electrode assembly 20 and the cap assembly 30 to fix the electrode assembly 20 more firmly.

In addition, the electrolyte injection hole 32 ′ formed in the cap plate 32 is sealed by the sealing member 40 of the present embodiment. In this embodiment, the filler wire in which the sealing member 40 is melted by a laser beam is used. It consists of the melt 42.

In the sealing process of the electrolyte injection hole 32 ', the diameter R, the supply speed V, and the output of the laser beam B, etc., of the wire W forming the filler wire melt 42 are capped. Various modifications can be made depending on the material of the plate 32 and the filler wire W. However, in the case of using the aluminum or aluminum alloy-based filler wire W having easy meltability and adhesion to the cap plate, the diameter Electrolyte injection hole 32 'by using laser beam B having an output of 0.2 to 1.5 kW while supplying filler wire W having a (R) of 0.5 to 2.0 mm at a speed V of 1 to 3 mm / sec. ) Can be sealed.

Of course, it is also possible to melt the filler wire of another material, for example lead filler wire with a heating rod to seal the electrolyte injection hole (32 ').

FIG. 3 is an enlarged view of a circle in FIG. 1 showing a sealing member according to another embodiment of the present invention. The secondary battery of the present embodiment may further improve the sealing property of the electrolyte injection hole 32 '. After inserting a plug 44 such as a ball or a pin into '), the electrolyte injection hole 32' is sealed using the filler wire W and the laser welding method of FIG. Therefore, in the present embodiment, since the sealing member 40 'is made of the plug 44 and the filler wire melt 42, the sealing property is further improved as compared with the above-described embodiment of Figs.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it is within the scope of the present invention.

As described above, in the present invention, by sealing the electrolyte injection port by the laser welding method using a filler wire, the sealing process can be simplified than before, and the foreign matters or welded holes on the cap plate after the sealing process are perforated. There is an effect that can remove the defects such as being.

Claims (9)

An electrode assembly having a positive electrode plate and a negative electrode plate, and a separator interposed between the positive electrode plates; A can in which the electrode assembly is received; A cap plate for sealing an opening of the can; An electrolyte injection hole provided in the can or the cap plate; A sealing member for sealing the electrolyte injection hole; The secondary battery of claim 2, wherein the sealing member comprises a filler wire melt. The secondary battery of claim 1, wherein the sealing member further comprises a plug such as a ball or a pin. The secondary battery of claim 1 or 2, wherein the filler wire melt is made of any one material selected from aluminum, aluminum alloy, and lead. The secondary battery of claim 3, wherein the filler wire melt is made of, in particular, aluminum or an aluminum alloy-based material. In the sealing method of the secondary battery for injecting the electrolyte into the can through the electrolyte injection hole provided in the can or cap plate, the electrolyte injection hole, A method of sealing a secondary battery in which an electrolyte inlet is sealed by the molten filler wire by melting the filler wire using a laser beam while supplying a filler wire to the electrolyte inlet at a constant speed. The method for sealing a secondary battery according to claim 5, wherein a sealing step using the filler wire is performed after press-fitting a plug such as a ball or a pin into the electrolyte injection hole. The secondary battery according to any one of claims 5 and 6, wherein a filler wire made of any material selected from aluminum, aluminum alloy, or lead is used. The method of sealing a secondary battery according to claim 7, wherein the filler wire uses aluminum or an aluminum-based alloy. The laser beam according to claim 8, wherein the laser beam having an output of 0.2 to 1.5 kW is supplied while supplying a filler wire of aluminum or an aluminum alloy material having a diameter R of 0.5 to 2.0 mm at a speed V of 1 to 3 mm / sec. The sealing method of the secondary battery which seals the electrolyte injection opening using the.