KR20060027275A - Secondary battery - Google Patents

Abstract

The secondary battery includes an electrode assembly in which a first electrode, a second electrode, and a separator are wound, a container-shaped can open at one side to accommodate the electrode assembly and the electrolyte, and a cap plate covering the opening of the can to close the can. In the secondary battery having the cap assembly, the can is provided with a stopper for guiding the position of the cap plate coupled to the top of the can, the can is provided with a stopper to stably combine the can and the cap plate, Since the boundary where the cap plate is coupled is formed on the upper side of the can, there is an effect that welding can be performed on the upper side of the can.

Cans, Cap Plates, Welding

Description

Secondary Battery {SECONDARY BATTERY}

1 is a cross-sectional view showing a conventional secondary battery,

2 is a cross-sectional view showing a can and a cap plate according to an embodiment of a secondary battery according to the present invention;

3A, 3B, 3C, and 3D are top views illustrating various embodiments of positions where stoppers are installed.

4 is a cross-sectional view showing a can and a cap plate according to another embodiment of a secondary battery according to the present invention;

5 is a cross-sectional view showing a can and a cap plate according to another embodiment of a secondary battery according to the present invention.

<Brief description of the main symbols in the drawings>

510,610,710: Cap plate 511,611,711: Can

513: stopper 515: terminal hole

517: electrolyte injection hole 520: gasket

530: electrode terminal 570: welding part

613: slope

The present invention relates to a secondary battery, and more particularly, to a secondary battery having a stopper for guiding the coupling position when the can and the cap plate of the secondary battery are coupled.

Recently, compact and lightweight electric / electronic devices such as cellular phones, notebook computers, camcorders, etc. have been actively developed and produced. These portable electric / electronic devices have a battery pack that can be operated in a place where no separate power source is provided. The built-in battery pack includes at least one battery therein for outputting a predetermined level of voltage for driving the portable electric / electronic device for a period of time.

In consideration of economical aspects, battery packs employ secondary batteries that can be charged and discharged in recent years. Typical secondary batteries include nickel secondary batteries such as nickel-cadmium (Ni-Cd) batteries, nickel-hydrogen (Ni-MH) batteries, lithium (Li) batteries, and lithium ion (Li-ion) batteries.

In particular, the lithium secondary battery has an operating voltage of 3.6 V, which is three times higher than that of a nickel-cadmium battery or a nickel-hydrogen battery, which is widely used as a power source for portable electronic equipment, and is rapidly expanding in terms of high energy density per unit weight. to be.

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, and 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 a lithium secondary battery is manufactured in various shapes, typical shapes include cylindrical shape, square shape, and pouch type.

Typically, a rectangular lithium secondary battery is composed of a can for a secondary battery, a jelly-roll electrode assembly accommodated in the can, and a cap assembly coupled to the top of the can.

Here, the can is opened at the top to accommodate the electrode assembly therein, and the opening of the can containing the electrode assembly is sealed with the cap assembly. In order to increase the sealing reliability, the cap assembly and the periphery of the electrolyte injection port sealed by the indentation of the cap are sealed by welding.

In particular, the electrolyte injected into the can uses a non-aqueous electrolyte because the active material is a strong active material of lithium, and the electrode assembly is prevented from reacting with moisture or air to cause various problems. And shut off from air.

Welding must have a certain level of mechanical strength, satisfy the reliability that there must be no leakage through the welding area, and at the same time economical or efficient to minimize the cost and time required for welding. Factors affecting the efficiency of welding include welding method, welding equipment and material to be welded, accuracy and reliability required for welding. Together with these, the shape and position of the welded object are also important factors related to the efficiency of welding.

1 is a cross-sectional view showing a conventional secondary battery. However, the size of the weld or the gap is exaggerated for clarity.

Referring to this figure, the can 111 is a metal container having an upper end opening in a substantially rectangular box shape, and the first electrode 161, the separator 165, and the second electrode 163 through the opening 111a. The wound electrode assembly 160 and the electrolyte are received and sealed by the cap assembly.

The cap assembly is provided with a flat cap plate 110 having a size and shape corresponding to the opening 111a of the can 111. A terminal through hole 113 is formed in the center portion of the cap plate 110 so that the electrode terminal 130 is drawn out, and an electrode terminal 130 and a cap plate (on the outer surface of the electrode terminal 130 penetrating through the terminal through hole 113). A tubular gasket 120 is installed for electrical insulation with the 110. An insulating plate 140 is installed on the lower surface of the cap plate 110, and a terminal plate 160 is installed on the lower surface of the insulating plate 140 to be electrically connected to the electrode terminal 130.

Here, when the cap plate 110 is formed in the same size as the opening 111a of the can 111, the cap 111 is not provided with a separate stopper for supporting the cap plate 110. When the cap plate 110 is formed to be the same as the upper surface of the can 111, the lower surface of the cap plate 110 is seated on the upper surface of the can 111 because the cap plate 110 is inserted through the opening 111a of the can 111. When the welding operation, there is a problem that a separate fixing device for fixing the position so that the cap plate 110 does not move.

Accordingly, the cap plate 110 in contact with the opening 111a of the can 111 has a step formed on its lower surface, and the cap plate 110 is coupled in such a manner as to cover the opening 111a of the can 111. That is, the lower surface of the cap plate 110 is inserted into the opening 111a of the cap plate 110, and the lower surface of the edge of the cap plate 110 is formed on the upper surface of the can 111 by the step of the cap plate 110. It is seated. Therefore, the cap plate 110 may be inserted into the opening 111a of the can 111 or may not be welded by using a separate fixing device.

In this case, since the boundary between the can 111 and the cap plate 110 is located at the side of the cap plate 110, the weld part 170 is formed at the side. Therefore, when welding the welding unit 170 with a laser welder, the laser welder irradiates a laser beam to the boundary between the can 111 and the cap plate 110 while rotating the can 111 with the can 111 lying on its side. Welding while the laser welder rotates the can 111 at the same time as the laser welder irradiates the laser beam from the side of the can 111 or the laser welder rotates the beam at the boundary between the can 111 and the cap plate 110. Should be investigated and welded.

However, since the shape of the can 111 is a rectangular box, such a conventional secondary battery is not easily rotated. Therefore, there is a problem that the welding work efficiency is lowered.

In addition, as the welding work efficiency is lowered, there is a problem in that a welding defect is caused and the production yield is lowered.

The present invention has been made to solve the above problems, an object of the present invention is to guide the coupling position of the cap plate when the cap plate is coupled to the can to increase the secondary battery to increase the coupling force of the can and the cap plate to provide.

The present invention for achieving the above object covers an electrode assembly in which a first electrode, a second electrode, a separator is wound, a container-shaped can open at one side to accommodate the electrode assembly and the electrolyte, and an opening of the can. A secondary battery having a cap assembly provided with a cap plate to close the can, wherein the can is provided with a stopper for guiding a coupling position of the cap plate coupled to an upper portion of the can. to provide.

The stopper may form a step so that the thickness of the top of the sidewall of the can is formed to be thinner than the thickness of the bottom thereof, and thus the bottom of the stepper may be formed at the inside of the opening of the can, and the height of the stopper may be the same as that of the cap plate. desirable.

When the can is formed in a rectangular shape, the stopper may be formed only at the short side of the can, or may be formed only at the long side of the can, and may be formed only at an edge portion of the can.

The thickness of the top sidewall of the can is preferably formed to a thickness of about 35 to 50% of the thickness of the bottom sidewall.

In addition, the upper side of the can has an inclined surface tapered to increase the inclination angle from the outside to the inside, the inclination angle of the inclined surface is preferably formed smaller than 90 °.

In addition, the height of the inclined surface formed on the side wall of the can is formed to be the same as the thickness of the cap plate, or the height of the inclined surface formed on the side wall of the can may be formed about 30 to 90% of the thickness of the cap plate.

At this time, the side of the cap plate has an inclined surface corresponding to the inclined surface of the can as the height of the inclined surface of the can, the lower side is preferably formed corresponding to the inner surface of the can.

On the other hand, the edge portion of the cap plate is preferably formed to correspond to the inner surface of the can.

Hereinafter, with reference to the drawings will be described the present invention in more detail.

2 is a cross-sectional view showing a can and a cap plate according to an embodiment of a secondary battery according to the present invention. Referring to this figure, the can 511 is formed in a substantially rectangular box shape, one side is opened, and is formed of a metal material, so the can 511 itself may serve as a terminal. The material constituting the can 511 may be made of iron, such as stainless steel, but is preferably a light conductive metal and has excellent corrosion resistance so as to cope with corrosion. However, the material is not limited to this embodiment.

The opening 511a of the can 511 is sealed by a cap assembly provided with a cap plate 510.

The can 511 is formed to face the side of the cap plate 510 by providing a stopper 513 supporting the lower surface of the cap plate 510 therein.

The stopper 513 has a thickness d of the upper end of the sidewall of the can 511 that is thinner than the thickness D of the lower end thereof to form a step inside the opening 511a of the can 511, and the lower end of the step is formed of a stopper ( 513). The step height of the stopper 513 is formed to be equal to the thickness of the cap plate 510 to be seated on the stopper 513. When the cap plate 510 is seated on the bottom end 513 of the can 511, the can 511 is mounted. The upper surface of the side wall and the upper surface of the cap plate 510 forms the same surface.

Meanwhile, the step of the can 511 forming the stopper 513 may use a method of forming a thin end in the process of deep drawing the can 511, and in the initial stage, the can 511 may be formed to the same thickness. Partial hot or cold rolling of the rear end is also possible. In this case, the thickness d of the upper sidewall of the can 511, that is, the sidewall of the can 511 facing the side surface of the cap plate 510 may be at least 35 to 50% of the thickness of the lower sidewall D of the can 511. It may be formed to be a stopper 513 supporting the cap plate 510.

3A, 3B, 3C, and 3D, when the can 511 is formed in an approximately rectangular box shape, the stopper 513 may be formed on all inner surfaces of the can 511 as shown in FIG. 3A. However, as shown in FIGS. 3B and 3C, it may be formed only on the long side or the short side of the can 511. In addition, as shown in FIG. 3D, it may be formed only at the corner of the can 511 to support only the corner of the cap plate 510.

In this case, the cap plate 510 has a terminal through-hole 515 into which the electrode terminal 530 inserted into the gasket 520 is inserted, and an electrolyte injection hole 517 into which the electrolyte is injected is formed at one side thereof. In addition, the cap plate 510 is preferably formed of the same material as the can 511 to improve the weldability when combined with the can 511, the lower surface of the cap plate 510 is in the shape of the stopper 513. Of course, it should be formed correspondingly.

Accordingly, when the bottom edge portion of the cap plate 510 is seated on the stopper 513, the boundary between the cap plate 510 and the can 511 is formed above the can 511, and the operator uses a laser beam. The welding operation 570 is formed on the upper side of the can 511 by performing a welding operation.

Figure 4 is a cross-sectional view showing a can and a cap plate according to another embodiment of a secondary battery according to the present invention, referring to this view, the top of the can 611 is formed to be tapered so as to increase the inclination angle from the outside to the inside. That is, the upper inner surface of the can 611 is an inclined surface 613 having a constant inclination angle. At this time, the inclination angle is formed to be smaller than 90 ° cap plate 610 is not inserted into the can 611.

That is, since the inclined surface 613 of the can 611 becomes narrower toward the inside thereof, it is prevented from being inserted into the can 611 when the cap plate 610 is seated. Therefore, the inclined surface 613 of the can 611 itself becomes a stopper.

Therefore, the side of the cap plate 610 is preferably formed to have an inclined surface corresponding to the inclined surface 613 of the can 611, the height of the inclined surface 613 formed on the side wall of the can 611 is the height of the cap plate 610 When the cap plate 610 is formed to have the same thickness and is seated on the inclined surface 613 of the can 611, the upper surface of the can 611 and the upper surface of the cap plate 610 may form the same surface.

Thus, the weld 670 in which the can 611 and the cap plate 610 are coupled is formed on the upper side of the can 611.

5 is a cross-sectional view showing a can and a cap plate according to another embodiment of a secondary battery according to the present invention. Referring to this figure, the upper inner surface of the can 711 is tapered as in the inclined surface of Figure 4, the height of the inclined surface is formed to about 30 ~ 90% of the thickness of the cap plate 710.

Therefore, the side surface of the cap plate 710 is formed so as to correspond to the inclined surface 713a of the can 711 by the height of the inclined surface 713a of the can 711, and the lower side of the cap plate 710, that is, the vertical surface of the can 711. It is formed to form a vertical plane corresponding to (713b).

Accordingly, when the cap plate 710 is seated on the can 711, the vertical surface 713b of the can 711 faces the lower vertical surface of the cap plate 710, and the inclined surface 713a of the can 711 is the cap plate. It faces the inclined surface of 710.

That is, the inclined surface 713a of the can 711 serves as a stopper for supporting the seating of the cap plate 710, and the vertical surface 713b of the can 711 allows the cap plate 710 to be accurately coupled to the can 711. It becomes a guide part which guides the engagement.

Accordingly, the weld 770 in which the can 711 and the cap plate 710 are coupled is formed on the upper side of the can 711.

Therefore, according to the present invention, the can is provided with a stopper, the coupling position of the can and the cap plate is guided so that the coupling is made stable, and the boundary between the can and the cap plate is formed on the upper side of the can. There is an effect that welding can be performed from the upper side.                     

Therefore, there is an effect that the welding efficiency and production yield are increased.

As described above, the present invention is not limited to the specific preferred embodiments described above, and those skilled in the art without departing from the gist of the present invention as claimed in the following claims. Anyone may implement various modifications, and such changes are within the scope of the claims.

Claims (13)

An electrode assembly on which the first electrode, the second electrode, and the separator are wound, a container-shaped can open at one side to accommodate the electrode assembly and the electrolyte, and a cap plate covering the opening of the can to close the can. In a secondary battery having a cap assembly, The can is provided with a stopper for guiding the coupling position of the cap plate coupled to the upper portion of the can. The method of claim 1, The stopper is a secondary battery, characterized in that the step of forming a step so that the thickness of the top of the side wall of the can is formed thinner than the thickness of the lower end of the step is formed on the inside of the opening of the can. The method of claim 2, The stepped height of the stopper is a secondary battery, characterized in that formed the same as the thickness of the cap plate. The method of claim 2, And the stopper is formed only on a short side of the can when the can is formed in a square shape. The method of claim 2, And the stopper is formed only on the long side of the can when the can is formed in a square shape. The method of claim 2, And the stopper is formed only at an edge portion of the can when the can is formed in a square shape. The method of claim 2, The thickness of the upper sidewall of the can is a secondary battery, characterized in that formed to a thickness of about 35 to 50% of the thickness of the lower sidewall. The method of claim 1, Secondary battery, characterized in that the upper inner surface of the can has an inclined surface tapered so as to increase the inclination angle from the outside to the inside. The method of claim 8, Secondary battery, characterized in that the inclination angle of the inclined surface is formed smaller than 90 °. The method of claim 8, The height of the inclined surface formed on the inner surface of the upper end of the can is the same as the thickness of the cap plate, the secondary battery. The method of claim 8, The height of the inclined surface formed on the upper inner surface of the can is a secondary battery, characterized in that about 30 ~ 90% of the thickness of the cap plate. The method of claim 11, A side surface of the cap plate has a secondary battery, characterized in that the upper side has an inclined surface corresponding to the inclined surface of the can by the height of the inclined surface of the can, the lower side corresponding to the inner surface of the can. The method of claim 2 or 8, The edge portion of the cap plate, characterized in that formed to correspond to the inner surface of the can.

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