KR100440935B1 - Prismatic type sealed battery - Google Patents

Abstract

Disclosed is a rectangular sealed battery. According to the present invention, a battery unit wound in the order of a positive electrode plate, a separator, and a negative electrode plate; and a can in which the battery unit is accommodated and an insulating film is formed on an inner wall thereof; a cap plate installed on the can and coupled to the can; and a cap plate. An electrode terminal penetrating into the can through a terminal through hole formed in the can and having a gasket interposed therebetween on an outer surface thereof to be insulated from the cap plate; and a lead drawn from one of the electrode plates of the battery unit and electrically connected to the electrode terminal. And a second electrode tab drawn from the other electrode plate of the battery unit and electrically connected to the cap plate or the can. The electrode tab drawn from the battery unit has a different polarity. Even if the inner wall of the can is not in constant contact with the inner wall of the can, the inner wall of the can is formed with an insulating film made of polymer resin, thereby preventing short circuits. have. Thereby, the safety of a battery can be improved.

Description

Square type sealed battery

The present invention relates to a rectangular sealed battery, and more particularly, to a rectangular sealed battery having an improved structure to prevent a short circuit between an electrode tab and a can connecting the battery unit and the electrode terminal.

Secondary batteries (secondary battery) is a battery that can be charged and discharged, unlike a primary battery that can not be charged, and is widely used in the field of advanced electronic devices such as cellular phones, notebook computers, camcorders. In particular, lithium secondary batteries have a working voltage of 3.6V, which is three times higher than nickel-cadmium batteries or nickel-hydrogen batteries, which are widely used as electronic equipment power sources, and is rapidly increasing in terms of high energy density per unit weight. .

Such lithium secondary batteries mainly use lithium-based oxides as positive electrode active materials and carbon materials as negative electrode active materials. In general, a battery is classified into a liquid electrolyte battery and a polymer electrolyte battery according to the type of electrolyte. A battery using a liquid electrolyte is called a lithium ion battery, and a battery using a polymer electrolyte is called a lithium polymer battery. Moreover, although lithium secondary batteries are manufactured in various shapes, typical shapes include cylindrical shape, square shape, and pouch type.

1 illustrates a conventional rectangular secondary battery 10.

Referring to the drawings, the rectangular secondary battery 10 may include a can 11, a cap plate 12 coupled to the can 11, and a battery unit 13 accommodated in the can 11. And an electrode tab 14 drawn out from the battery unit 13 and an electrode terminal 15 electrically connected to the electrode tab 14.

The battery unit 13 is installed in the order of the positive electrode plate, the separator, and the negative electrode plate, and is wound and installed in the can 11. The electrode tabs 14 are plural from each of the electrode plates of the battery unit 13. The electrode tabs of one of the electrode plates are connected to the electrode terminals 15, and the electrode tabs of the other electrode plates are of the can 11 or the cap plate. It is connected to (12) and insulated from each other. At this time, the can 11 is made of a metal material having excellent conductivity such as aluminum or steel, and the electrode tab 14 also uses a metal thin plate having excellent electrical conductivity, such as aluminum or nickel.

The electrode terminal 15 is surrounded by a gasket 16 on the outer surface for electrical insulation with the cap plate 12, the lower end of the electrode terminal 15 is drawn into the can 11 to the terminal plate ( It is fixed to 17). An insulating plate 18 is interposed between the lower surface of the cap plate 12 and the upper surface of the terminal plate 17.

In the rectangular sealed battery 10 having the above-described structure, after welding and fixing the electrode tab 14 and the electrode terminal 15 during the assembly process, the cap plate 12 is coupled to the can 11. At this time, the electrode tab 14 is bent in a meandering direction to the short side portion of the can 11 in the process that the cap plate 12 is seated on the upper portion of the can (11). .

However, when the short side width of the can 11 is narrow, it is not easy to secure the gap G between the inner wall of the can 11 and the electrode tab 14. Accordingly, when the position change of the battery unit 11, the rotation of the electrode terminal 15, or the length of the protective tape (not shown) covering a part of the electrode tab 14 is short, the electrode tab 14 is short. ) Is likely to contact the inner wall of the can 11.

In this case, as described above, a short circuit occurs between the can 11 having a different polarity and the electrode tab 14. When a short circuit occurs, the internal temperature of the battery 10 rises rapidly, and there is a problem in safety such as heat generation.

The present invention is to solve the above problems, to improve the stability of the battery by preventing an electrical short between the electrode tab for electrically connecting the battery unit and the electrode terminal, and the can accommodates the battery unit having a different polarity. It is an object of the present invention to provide a rectangular sealed battery whose structure is improved.

1 is a cross-sectional view showing a conventional rectangular sealed battery,

Figure 2 is an exploded perspective view showing a rectangular sealed battery according to an embodiment of the present invention,

3 to 7 sequentially illustrate the process of manufacturing the rectangular sealed battery of FIG.

3 is a perspective view illustrating a state in which a battery unit is manufactured;

4 is a partial ablation perspective view showing a state in which the can is manufactured;

5 is a perspective view showing a state in which the battery unit can be accommodated;

Figure 6 is an exploded perspective view showing a state in which the cap assembly is coupled to the can,

Figure 7 is a perspective view showing a state in which the cap assembly is coupled to the can.

<Brief description of symbols for the main parts of the drawings>

20 ... battery 21 ... can

22 Battery compartment 23 Anode tab

24.Negative tap 26.Insulated case

27 Cap plate 28 Insulation plate

29.Terminal plate 200 ... Negative terminal

210 ... gasket 220 ... ball

230 Insulation

Square sealed battery according to an aspect of the present invention to achieve the above object,

A battery unit wound in the order of a positive electrode plate, a separator, and a negative electrode plate;

A can accommodating the battery part and having an insulating film formed on an inner wall thereof;

A cap plate installed on an upper portion of the can and coupled to the can;

An electrode terminal penetrating into the can through a terminal through hole formed in the cap plate and having a gasket interposed therebetween for insulating the cap plate; And

A first electrode tab drawn from one of the electrode plates of the battery unit and electrically connected to the electrode terminal; And

And a second electrode tab drawn out from the other electrode plate of the battery unit and electrically connected to the cap plate or the can.

The insulating layer may be formed on an inner wall of the can larger than an area in which the first electrode tab is in contact with the inner wall of the can to prevent a short circuit between the first electrode tab and the can having a different polarity.

In addition, the insulating film is made of a polymer resin having insulation and heat resistance and not reacting with the organic electrolyte injected into the can.

Further, the insulating film is characterized in that the polyethylene.

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

2 illustrates a rectangular sealed battery 20 according to an embodiment of the present invention.

Referring to the drawing, a can 21 is provided in the square battery 20. An insulating film 230 is formed on an inner wall of the can 21. The battery unit 22 is accommodated in the can 21. Positive and negative electrode tabs 23 and 24 are respectively drawn out from the battery unit 22. A portion of the positive and negative electrode tabs 23 and 24 is covered with a protective tape 25.

An insulating case 26 is provided above the battery unit 22. The cap assembly coupled to the can 21 is positioned above the insulating case 26.

The cap assembly includes a cap plate 27, an insulating plate 28 located on the bottom surface of the cap plate 27, and a terminal plate 29 located on the bottom surface of the insulating plate 28. The negative electrode terminal 200 is inserted through the terminal through hole 27a formed at the center of the cap plate 27. The outer surface of the negative electrode terminal 200 is provided with a gasket 210 for electrical insulation with the cap plate 27. In addition, a ball 220 is disposed in the electrolyte injection hole 27b formed at one side of the cap plate 27 to seal the electrolyte solution after the electrolyte is injected.

When the rectangular sealed battery 20 according to the present invention having the above-described configuration classified by manufacturing process as follows.

Referring to FIG. 3, the battery unit 22 includes a positive electrode plate 22a of a positive electrode current collector coated with a positive electrode active material layer, a negative electrode plate 22b of a negative electrode current collector coated with a negative electrode active material layer, the positive electrode and The separator 22c interposed between the negative electrode plates 22a and 22b is included. The battery unit 22 is wound and compressed in a state where the battery unit 22 is arranged in the order of the positive electrode plate 22a, the separator 22c, and the negative electrode plate 22b.

At this time, the positive electrode tab 23 and the negative electrode tab 24 are welded and fixed to the positive and negative electrode plates 22a and 22b, respectively, and are drawn out to the outside of the battery unit 22. In the case of a lithium secondary battery, aluminum metal is used as the positive electrode tab 23 and nickel metal is used as the negative electrode tab 24. Protective tapes 25 are respectively wrapped in portions where the positive and negative electrode tabs 23 and 24 are drawn out from the battery unit 22 to prevent short circuits. An adhesive tape 30 is attached to the lower part of the battery part 22 to maintain the shape of the wound positive electrode plate 22a, separator 22c, and negative electrode plate 22b.

4 illustrates a can 21 in which the battery part 22 is accommodated.

Referring to the drawings, the can 21 is made of a metal having excellent conductivity, such as steel or aluminum. The can 21 has a rectangular shape, and a space portion 21a in which the battery part 22 is accommodated is formed in the center thereof.

An insulating film 230 is formed on an inner wall of the can 21. The insulating film 230 is formed along the longitudinal direction of the can 21 from the upper end portion 21b of the can 21. In this case, the minimum region where the insulating layer 230 is formed should be larger than the region where the negative electrode tab 24 bent when the battery unit 22 is accommodated can contact the inner wall of the can 21. In addition, the insulating layer 230 is formed on the inner wall of the short side and the long side of the can 21 when formed on the inner wall of the can 21.

The insulating layer 230 is made of a polymer resin for insulation between the can 21 made of the metal material 21 and the negative electrode tab 24. At this time, the characteristics required for the insulating film 230 should have heat resistance, and at the same time should have physical properties that do not dissolve in the organic electrolyte injected into the can 21. As the insulating film 230, it is preferable to use polyethylene (PE), polypropylene (PP), a copolymer of polyethylene and polyflopropylene, polyimide (PI), or the like. The insulating layer 230 is formed by coating the aforementioned polymer resin on the inner wall of the can 21.

As illustrated in FIG. 5, the battery unit 22 may be accommodated in the can 21 in which the insulating layer 230 completed as described above is formed. After the battery unit 22 is inserted into the can 21, the insulating case 26 is seated on the upper part of the battery unit 22. The negative electrode tab 24 may be pulled out through the through hole 26a of the insulating case 26.

FIG. 6 illustrates a state in which the cap assembly is coupled to the can 21 in which the battery unit 22 is accommodated.

Referring to the drawing, in the can 21, the positive electrode tab 23 and the negative electrode tab 24 protrude from the battery unit 22 through the insulating case 26 to the upper portion of the can 21. An end portion of the negative electrode terminal 200 via the gasket 210 is introduced into the cap plate 27 into the can 21 to be fixed to the terminal plate 29. In this case, an insulating plate 28 is interposed between the cap plate 27 and the terminal plate 29.

The positive electrode tab 23 is directly welded to the bottom surface of the cap plate 27. Accordingly, the positive electrode plate 22a of the battery unit 22 is electrically connected to the positive electrode tab 23 drawn out therefrom and the cap plate 27 to which the positive electrode tab 23 is welded. The cap plate 27 is then welded to the can 21 to form one pole.

The negative electrode tab 24 is welded to the bottom surface of the negative electrode terminal 200 riveted to the terminal plate 29. Accordingly, the negative electrode plate 22b of the battery unit 22 is electrically connected to the negative electrode terminal 200 through the negative electrode tab 24 drawn therefrom and the terminal plate 29 to which the negative electrode tab 24 is welded. It is connected. In this case, in order to electrically insulate the cathode terminal 200 from the cap plate 27, the cap plate 27 is provided with an insulating plate 28 and a gasket 210.

Alternatively, the positive electrode and the negative electrode may be configured with different polarities. That is, the terminal portion which is insulated from the cap plate 27 and protrudes to the outside may be designed as an anode, and the portion connected to the can 21 may be designed as a cathode. In addition, an electrode tab directly welded to the cap plate 27 may be welded to a can 21 electrically connected to the cap plate 27.

After the positive and negative electrode tabs 23 and 24 are welded to the lower surface of the cap plate 27 and the lower portion of the terminal plate 29, the cap plate 27 is coupled to the can 21. Done.

In this case, the negative electrode tab 24 protruding to the upper portion of the can 21 is bent in the direction of the short side of the can 21 to be positioned inside the can 21. Accordingly, there is a possibility that the negative electrode tab 24 contacts the inner wall of the can 21 having different polarities. To prevent this, an insulating film 230 made of a polymer resin is formed on an inner wall of the can 21 including a region where the negative electrode tab 24 is in contact with the can 21 from an upper end of the can 21. Accordingly, even if the negative electrode tab 24 is deformed, the negative electrode tab 24 does not directly contact the can 21 made of metal, but contacts the insulating film 230 formed on the inner wall of the can 21 to short-circuit it. Can be prevented in advance. As described above, the insulating film 230 is completed by coating polyethylene, polypropylene, a copolymer of polyethylene and polypropylene, polyimide, or the like on the inner wall of the can 21.

When the cap plate 27 is coupled to the can 21 as described above, laser welding or the like is performed at the boundary between the can 21 and the cap plate 27 to seal the inside of the battery. Subsequently, the electrolyte is injected through the electrolyte injection hole 27b formed in the cap plate 27, and the ball 220 is press-welded to the electrolyte injection hole 27b to seal it.

Accordingly, as shown in FIG. 7, the cap plate 27 is coupled to the can 21 to complete the rectangular sealed battery 20.

As described above, in the rectangular sealed battery of the present invention, the electrode tab drawn out from the battery unit electrically connected to the electrode terminal is used to change the position of the battery unit during the assembly process of the battery, to rotate the electrode terminal, or to surround the electrode tab. Even if the protective tape is not sufficiently wrapped, the inner wall of the can with different polarity can be directly contacted without maintaining a constant distance. However, an insulating film made of a polymer resin is formed on the inner wall of the can, thereby preventing short circuits. . Thereby, the safety of a battery can be improved.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (7)

A battery unit wound in the order of a positive electrode plate, a separator, and a negative electrode plate; A can containing the battery unit; And, A cap plate installed on an upper portion of the can and coupled to the can; An electrode terminal penetrating into the can through a terminal through hole formed in the cap plate and having a gasket interposed therebetween for insulating the cap plate; A first electrode tab drawn out of one electrode plate of the battery unit and electrically connected to the electrode terminal; And a second electrode tab drawn out from another electrode plate of the battery unit and electrically connected to the cap plate or the can. In order to prevent a short circuit between the first electrode tab and the can having a different polarity, an inner wall of the can is formed larger than an area in which the first electrode tab is in contact with the inner wall of the can, And an insulating film formed by coating a polymer resin on an inner wall of the can so as not to react with an electrolyte solution. delete delete The method of claim 1, The insulating film is a rectangular sealed battery, characterized in that the polyethylene. The method of claim 1, The rectangular sealed battery, characterized in that the insulating film is polypropylene. The method of claim 1, The insulating film is a rectangular sealed battery, characterized in that the copolymer of polyethylene and polypropylene. The method of claim 1, The insulating film is a rectangular sealed battery, characterized in that the polyimide.