KR100659877B1 - Secondary battery and the method of preparing the same - Google Patents

Abstract

The present invention relates to a secondary battery and a method of manufacturing the same, and more particularly, an electrode assembly and an electrolyte are coupled to each other through a gasket at an upper opening of the can, and include at least two lamination members. The present invention relates to a secondary battery and a method of manufacturing the same, by employing a cap assembly welded by a contact means by welding means, thereby reducing contact resistance between the red members.

Description

Secondary Battery and Manufacturing Method Thereof {Secondary battery and the method of preparing the same}

1 is a front sectional view showing the structure of a conventional secondary battery;

2 is an exploded perspective view showing the structure of a conventional secondary battery;

Figure 3 is a partial front cross-sectional view showing a conventional cap assembly structure of a secondary battery,

4 is a partial front cross-sectional view showing the structure of a secondary battery according to an embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings *

10: cans

13a and 13b: insulating plate 20: electrode assembly

21: Separator 23: Anode

25: cathode 27, 29: electrode tab

30: gasket 40: safety vent

42: recess of the vent 50: current breaker (CID)

60: current controller 70: cap up

80: cap assembly 90: welding rod

101: weld

The present invention relates to a secondary battery and a method of manufacturing the same, and more particularly, an electrode assembly and an electrolyte are coupled to each other through a gasket at an upper opening of the can, and include at least two lamination members. The present invention relates to a secondary battery and a method of manufacturing the same, by employing a cap assembly welded by a contact means by welding means, thereby reducing contact resistance between the red members.

Secondary batteries have been rapidly developed and used in recent years due to the advantages of being rechargeable and capable of miniaturization and large capacity. Secondary batteries may be divided into nickel-hydrogen (Ni-MH) batteries, lithium-ion (Li-ion) batteries, and the like according to electrode active materials.

Lithium secondary batteries can also be divided into cans and pouches according to the type of container in which the electrode assembly is accommodated.

Can type secondary batteries can be divided into rectangular and cylindrical batteries according to the shape. A square shape is formed by thinly forming a container in a cuboid shape or by giving a curvature to the sidewall edge of the cube. Cylindrical is used in a relatively large amount of electronic and electrical equipment, a plurality is used in the form of a combination to form a battery pack.

1 is a front sectional view showing the structure of a conventional secondary battery, Figure 2 is an exploded perspective view showing the structure of a conventional secondary battery, Figure 3 is a partial front sectional view showing a cap assembly structure of a conventional secondary battery. .

Hereinafter, a method of forming a conventional cylindrical secondary battery will be described with reference to FIGS. 1 to 3.

First, it is formed in a rectangular plate shape, the positive electrode 22 and the negative electrode 25 with the separators 21 and 23 interposed therebetween, and are wound in a spiral to form an electrode assembly 20 collectively referred to as a jelly roll. Each electrode plate is formed by coating an active material slurry on a current collector made of a metal foil.

Next, after placing the lower insulating plate 13b on the bottom of the can 10 through the opening of the can 10, the electrode assembly 20 is placed on the lower insulating plate 13b. Inside the can 10, beads (not shown) are provided in advance to prevent the electrode assembly 20 from flowing inside the can. Thereafter, after the electrolyte is injected, the upper portion of the electrode assembly 20 is covered with the upper insulating plate 13a.

In addition, the inner wall of the opening of the can is provided with an insulating gasket 30 that insulates the can 10 and a cap assembly 80 that increases the airtightness between the inside of the can 10 and the outside air and functions as a lid of the can.

As shown in FIG. 3, the cap assembly 80 includes a cap up 70, a current controller 60, a current interrupter (CID) 50, and a vent 40 sequentially disposed from the top. It is composed. The current breaker 50 located above the vent 40 is to be broken when the recess 42 of the vent 40 is convexly deformed upward by the internal pressure of the battery. The current controller 60 is installed on the current breaker 50 to block the flow of current in the battery due to overheating of the battery, and the current controller 60 blocks the flow of current in the battery by overheating the battery. It is composed of a PTC (Positive Thermal Coefficient) device, or a PTC protection device or a separate protective circuit board on the PTC. A PTC device is a kind of conductive semiconductor, which is electrically conductive at a normal operating temperature, but when overheated above a certain temperature, resistance rapidly increases due to a change in the arrangement of molecules, thereby preventing electricity from flowing through the insulator. Has

Next, as shown in FIG. 3, crimping to seal the can by applying pressure inward and downward to the opening wall of the cylindrical can 10 with a cap up 70 coupled to the gasket 30, etc. And a tubing operation in which an exterior material is coated on the outside of the battery to complete the secondary battery.

However, according to the conventional secondary battery forming method described above, even when the battery is sealed by crimping the can, fine gaps are often generated. Therefore, in the conventional cap assembly, contact resistance is generated by surface contact between the stacking members. This has a large resistance value compared to the welded. Therefore, even if the internal resistance of the battery is increased, there is a problem that the charge and discharge efficiency is lowered.

The first object of the present invention is to solve the above-described secondary battery problems, to provide a secondary battery that can close the cap-up and its lower parts in close contact, to increase the sealing and to reduce the contact resistance. will be.

A second object of the present invention is to provide a secondary battery manufacturing method which can improve the life performance by reducing the contact resistance.

The present invention for the first purpose,

A secondary battery having an electrode assembly, a can in which the electrode assembly is housed, and a cap assembly closing an opening of the can,

The cap assembly is coupled to the upper opening of the can containing the electrode assembly and the electrolyte via a gasket, the cap assembly includes at least two stacking members, and the contact portion of any two stacking members positioned above and below the stacking member is connected to the welding means. It provides a secondary battery including a welded portion welded by.

The cap assembly includes at least one welded portion.

The welds may be formed on each or both of the laminated members stacked in the cap assembly. The stacking members may include a cap up, a current controller, a current breaker, or a vent.

It is preferable that the said weld part is 0.6 mm or more in diameter. It is possible to carry enough current through a size of just 0.6 mm, to form a number of places, and to weld the entire surface.

The cap-up upper portion is provided with a groove for preventing shaking of the electrode.

For the second purpose of the present invention,

Receiving the electrode assembly inside the can; Injecting an electrolyte; And installing a gasket; Assembling the cap assembly; In the secondary battery manufacturing method comprising the step of sealing the can by fixing the assembled cap assembly,

The cap assembly assembly step provides a secondary battery manufacturing method comprising the step of welding the contact portion of the laminated member laminated in the gasket by the welding means.

The cap assembly may be assembled before or after the gasket is installed in the opening of the can.

The stacking member used to assemble the cap assembly may include a cap up, a current controller, a current breaker, or a vent.

The cap assembly assembling step may further include forming a groove for preventing shaking of the electrode when welding the upper portion of the cap up.

The welding means may be any method commonly available in the art to which the present invention belongs, and laser welding and resistance welding are particularly preferable.

In the case of resistance welding, the welding means is preferably surface-treated so that the resistance between the electrode and the cap-up surface is not greater than the resistance between the cap-up and the lower parts. For this purpose, the contact between the cap-up and the lower parts is embossed, punched or scratched. It is preferable to form the protruding portion. In this way, the amount of heat generated between the cap-up and the lower parts to be welded can be greater than that between the electrode and the cap-up, thereby reducing the welding failure due to the difference in the amount of heat generated.

Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG. 4. In the description of the embodiments, the same reference numerals are used for the same parts as the conventional components, and detailed description thereof will be omitted to avoid duplicate description.

4 is a partial front cross-sectional view illustrating a cap assembly structure of a secondary battery according to an embodiment of the present invention.

The secondary battery houses the electrode assembly in which the positive electrode 22 and the negative electrode 25 are wound, with the separator 21 interposed inside the can 10, injects an electrolyte therein, and inserts the inside of the opening of the cap. The cap assembly 80, which is connected to the anode 22 in an insulated state through the gasket 30, is coupled to the can 10. To install the cap assembly, the upper electrode tab 27 is welded to the downwardly protruding recess 42 of the vent 40 after the gasket is first installed.

As shown in FIG. 4, the cap assembly 80 according to an embodiment of the present invention is insulated from the can through the gasket 30, the cap up 70, the current limiter 60, and the current breaker ( 50) and vent 40 are sequentially stacked and then sealed by crimping the openings of the can. At this time, the welding between the cap up 70 and the current limiter 60 by using the electrode 90 in the upper portion of the cap up 70. The cap-up upper portion forms a groove 100 to prevent shaking of the electrode. The current flows through the welding rod to perform welding between the cap-up and the current limiter to form a welding portion 101. The said welding may make a welding part in many places centering on a capup, or may weld all the front surfaces.

Thus, the welding allows the battery to be more firmly sealed, thereby increasing the sealing pressure and preventing the leakage of the electrolyte, and at the same time reducing the contact resistance between the cap-up and the current limiter.

The embodiments of the present invention have been described above with reference to the accompanying drawings, which are merely exemplary, and those skilled in the art may make modifications and changes through the above embodiments, and such modifications are within the scope of the present invention. Of course it belongs.

According to the secondary battery according to the present invention having the configuration as described above, since the coupling between the components constituting the cap assembly is more firm and tight, the effect of improving the battery life by reducing the contact resistance between the cap assembly components have.

Claims (12)

A secondary battery having an electrode assembly, a can in which the electrode assembly is housed, and a cap assembly closing an opening of the can, The cap assembly is coupled to the upper opening of the can containing the electrode assembly and the electrolyte via a gasket, the cap assembly includes at least two stacking members, and the contact portion of any two stacking members positioned above and below the stacking member is connected to the welding means. A welded part welded by Secondary battery, characterized in that the stacking member includes a cap-up including an anti-shake groove of the welding rod on the top. The method of claim 1, Secondary battery, characterized in that the weld portion is 0.6mm or more in diameter. The method of claim 1, And the cap assembly includes at least one welded portion. The method of claim 1, Secondary battery, characterized in that the welding portion is formed in each or all between the laminated members stacked in the cap assembly. The method of claim 1, Secondary battery, characterized in that the laminated member comprises a current controller, a current circuit breaker or a vent. delete Receiving the electrode assembly inside the can; Injecting an electrolyte; And installing a gasket; Assembling the cap assembly; In the secondary battery manufacturing method comprising the step of sealing the can by fixing the assembled cap assembly, The cap assembly assembling step of forming a groove for preventing the shake of the electrode on the upper surface of the cap up; And welding the laminated members stacked in the gasket with welding means through the welding rod shake preventing groove. The method of claim 7, wherein And the cap assembly assembling step is before or after the gasket is installed in the opening of the can. delete The method of claim 7, wherein Secondary battery manufacturing method characterized in that the welding means is laser welding or resistance welding. The method of claim 7, wherein The cap assembly assembly step further comprises the surface treatment step of the laminated member manufacturing method. The method of claim 11, The surface treatment step of the secondary battery manufacturing method comprising the step of forming a protrusion by embossing, punching or scratching the contact portion of the laminated member.

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