METHOD FOR MANUFACTURING RECHARGEABLE BATTERY AND RECHARGEABLE BATTERY MANUFACTURED USING THE SAME

Disclosed is a method for manufacturing a rechargeable battery, including: stacking electrode assemblies; welding lead tabs formed in the electrode assemblies; cutting end portions of the welded lead tabs; and welding lead terminals to the cut lead tabs.

RELATED APPLICATIONS

This application claims priority to and the benefit of Korean Patent Application No. 10-2015-0125840 filed in the Korean Intellectual Property Office on Sep. 4, 2015, the entire contents of which are incorporated herein by reference.

BACKGROUND

Field

The described technology relates generally to a method for manufacturing a rechargeable battery and a rechargeable battery manufactured using the same, and more particularly, to a method that can be used to manufacture a rechargeable battery and a rechargeable battery manufactured using the same.

Description of the Related Art

Rechargeable batteries have been applied to various industry-wide technical fields due to their merits. They are widely used as an energy source of mobile devices such as digital cameras, cellular phones, laptop computers, and the like. They are also used as an energy source of hybrid electric vehicles that are recommended as a solution for solving air pollution and the like of existing gasoline and diesel internal combustion engines using fossil fuels.

Recently, mobile devices have been released in various forms, so the rechargeable battery mounted on the mobile devices are also required to have various forms. Accordingly, in response to demands associated with shapes of the mobile devices, a new type of electrode assembly, which allows the rechargeable battery to be easily deformed to various shapes in accordance with a shape of the device including the rechargeable battery, has been required.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

An exemplary embodiment has been made in an effort to provide a method for manufacturing a rechargeable battery that is easily mountable on various devices, and a rechargeable battery manufactured using the same.

In addition, an exemplary embodiment has been made in an effort to provide a method for manufacturing a rechargeable battery that can manufacture a high quality rechargeable battery regardless of a worker's level of proficiency, and a rechargeable battery manufactured using the same.

An exemplary embodiment provides a method for manufacturing a rechargeable battery, including: stacking electrode assemblies; welding lead tabs formed in the electrode assemblies; cutting end portions of the welded lead tabs; and welding lead terminals to the cut lead tabs.

In welding the lead tabs formed in the electrode assemblies, the plurality of lead tabs may be welded while being vertically positioned to be parallel to each other.

In welding the lead tabs formed in the electrode assemblies, ultrasonic welding may be performed.

In cutting the welded lead tabs, a cutting blade may be vertically moved to cut end portions of the plurality of lead tabs.

The method may include sealing the end portions of the lead terminals in which an insulating layer is formed using a sealing member.

In sealing the end portions of the lead terminals in which the insulating layer is formed using the sealing member, two sealing members may be thermo-bonded after being closely attached to each other.

In stacking the electrode assemblies, one of ends of the electrode assemblies having different planar sizes may be positioned to be vertically parallel to each other.

In stacking the electrode assemblies, the electrode assembly may be any one selected from a wound type and a stacked type.

A rechargeable battery according to an exemplary embodiment includes: at least two electrode assemblies to be stacked; and a plurality of lead tabs drawn out from each of the electrode assemblies. End portions of the plurality of lead tabs are combined to overlap each other.

The electrode assemblies may include a stacked type of electrode assembly and a wound type of electrode assembly, and a plurality of lead tabs may be drawn out from each electrode of the wound type of electrode assembly.

The end portions of the plurality of lead tabs may all be formed to be vertically parallel to each other such that none of them are protruded or depressed.

In the method for manufacturing a rechargeable battery according to the exemplary embodiment, after the lead tabs are welded, parts thereof are cut off. Accordingly, since respective lengths of the lead tabs of the rechargeable having different shapes according to devices do not have to be designed each time, a time for designing the rechargeable battery can be significantly reduced.

In addition, in the method for manufacturing a rechargeable battery according to the exemplary embodiment, the lead tabs can be designed to have sufficient lengths and then be welded. Accordingly, even if a level of proficiency of the worker performing the welding operation is not high, the welding can be performed to connect all the lead tabs.

In addition, the end portions of the lead tabs manufactured by the manufacturing method of the rechargeable battery according to the exemplary embodiment may be aligned in up/down directions. Accordingly, since interference caused by the lead tab protruded while placing the electrode assemblies inside the case, a size of the case can be minimized. Therefore, it can be advantageous in making the size of the rechargeable battery smaller.

DETAILED DESCRIPTION OF CERTAIN INVENTIVE EMBODIMENTS

Further, in exemplary embodiments, for components having the same configuration, like reference numerals are used and described only in a representative embodiment, and in other exemplary embodiments, only different configurations from the representative embodiment will be described.

Prior to describing a manufacturing method of a rechargeable battery according to an exemplary embodiment, a structure of a rechargeable battery that can be manufactured by a manufacturing method of a rechargeable battery according to an exemplary embodiment will now be described.

FIG. 1is a perspective view of a rechargeable battery that can be manufactured by a manufacturing method of a rechargeable battery according to an exemplary embodiment,FIG. 2is a perspective view of the rechargeable battery illustrated inFIG. 1from which a case is removed,FIG. 3is a cross-sectional view of the rechargeable battery illustrated inFIG. 1taken along the line andFIG. 4is a cross-sectional view of the rechargeable battery illustrated inFIG. 1taken along the line IV-IV.

Referring toFIGS. 1 to 4, the rechargeable battery100that can be manufactured by the manufacturing method of a rechargeable battery according to the exemplary embodiment may include electrode assemblies130and140, lead tabs150, a case110, a lead terminal160, and a sealing member120.

At least a pair of electrode assemblies130and140may be stacked. The plurality of electrode assemblies130and140may be stacked while having different planar sizes with respect to each other.

The plurality of lead tabs150are drawn out from each of the electrode assemblies130and140. For example, a plurality of positive electrode lead tabs150aand a plurality of negative electrode lead tabs150bmay be formed in each of the electrode assemblies130and140. Alternatively, one positive electrode lead tab150aand one negative electrode lead tab150bmay be formed in each of the electrode assemblies130and140.

In the rechargeable battery100that can be manufactured by the manufacturing method of a rechargeable battery according to the exemplary embodiment, the plurality of lead tabs150are coupled such that their end portions are aligned with respect to each other. That is, end portions of the plurality of lead tabs150may be formed such that none of them is protruded or is indented to be vertically parallel with respect to each other.

Meanwhile, the electrode assemblies130and140described above may be a stacked type of electrode assembly130or a wound type of electrode assembly140. For example, one of the electrode assemblies130and140may be a wound type of electrode assembly130, while the other thereof may be a stacked type of electrode assembly140.

In this case, as described above, the plurality of lead tabs150may be draw out from each electrode of the wound type of electrode assembly130.

The two electrode assemblies130and140may be stacked to form the rechargeable battery100. For example, the wound type of electrode assembly130having a relatively larger planar size may be positioned under the stacked type of electrode assembly140. Alternatively, the opposite case may also be possible.

In addition, the plurality of electrode assemblies130and140are stacked while they have different planar sizes with respect to each other, and the wound type of electrode assembly130(in a z-axis direction of the drawing) may be formed thicker than the stacked type of electrode assembly140. However, they are not limited thereto, and the opposite case may also be possible.

The wound type of electrode assembly130and the stacked type of electrode assembly140are illustrated in the drawing such that they have the same lengths in a y-axis direction, but they are not limited thereto. Alternatively, the wound type of electrode assembly130and the stacked type of electrode assembly140may have different lengths in the y-axis direction. For example, the length of the wound type of electrode assembly130in the y-axis direction may be longer than that of the stacked type of electrode assembly140in the y-axis direction.

The electrode assemblies130and140may have, for example, a structure in which a positive electrode (not shown) and a negative electrode (not shown) are positioned while interposing a separator (not shown) therebetween. For example, the separator may be formed as a solid electrolyte film through which lithium ions can pass.

The positive electrode may include a coated region where an active material is coated on a current collector of a thin metal film (e.g., an aluminum sheet), and an uncoated region (not shown) which is formed as an exposed current collector since an active material is not coated thereon. The first lead tab150a(referred to as a “positive electrode lead tab”) may be extended while being connected to the uncoated region of the positive electrode.

The negative electrode may include a coated region where a different active material than the active material of the positive electrode is coated on a current collector of a thin metal film (e.g., a copper sheet), and an uncoated region which is formed as an exposed current collector since an active material is not coated thereon. The second lead tab150b(referred to as a “negative electrode lead tab”) may be extended while being separated from the positive electrode lead tab and connected to the uncoated region the positive electrode lead tab150a.

The case110may include an internal space that is formed in accordance with the electrode assemblies130and140. Since the plurality of electrode assemblies130and140are stacked to have a step therebetween while having the different planar sizes, the case110may also be formed to have a step.

The lead terminal160may be connected to the lead tab150. An insulating layer161may be formed at an external surface of the lead terminal160. The insulating layer161may be a polymer layer, for example.

One end of the lead terminal160is connected to the lead tab150, while the other end thereof may be exposed. That is, the insulating layer161may not be formed at the exposed end of the lead terminal160. The exposed end of the lead terminal160may be mechanically and electrically coupled to the lead tab150.

The sealing member120may be formed to partially enclose the lead terminal160. The sealing member120electrically insulates the lead terminal160from the case110.

In the rechargeable battery100having the structure as described above, since the electrode assemblies130and140are formed to have a stepped structure, a mounting space inside a device on which the rechargeable battery100is mounted may be used in various ways. In addition, an empty space inside the device may be used to maximize spatial utility. Further, the high-capacity electrode assemblies130and140may be used in the device, which can be advantageous in making the device smaller.

On the other hand, devices in which the rechargeable battery can be installed may be, for example, mobile phones, laptops, tablets, smartphones, electronic picture frames, light electronic vehicles (LEVs), electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, and power storage devices.

A method for manufacturing a rechargeable battery according to an exemplary embodiment, which can be used to manufacture the rechargeable battery as described above, will now be described.

FIG. 5is a flowchart sequentially illustrating the manufacturing method of a rechargeable battery according to the exemplary embodiment.

Referring toFIG. 5, the manufacturing method of a rechargeable battery according to the exemplary embodiment includes stacking electrode assemblies (S210), welding lead tabs formed in the electrode assemblies (S220), cutting end portions of the welded lead tabs (S230), and welding lead terminals to the cut lead tabs (S240).

Each step of the manufacturing method of a rechargeable battery according to the exemplary embodiment will now be described in detail with reference to the drawings.

FIGS. 6 to 10are drawings that sequentially illustrate each step of the method for manufacturing a rechargeable battery.

FIG. 6illustrates a state in which electrode assemblies are stacked.

Referring toFIG. 6, in stacking the electrode assemblies (S210, refer toFIG. 5), one of ends of electrode assemblies130and140having different planar sizes are positioned to be vertically parallel with respect to each other. More specifically, end portions of the electrode assemblies130and140formed with the lead tabs are formed to be parallel to each other. In stacking the electrode assemblies (S210, refer toFIG. 5), the electrode assemblies130and140may be any type selected from the wound type and the stacked type.

FIG. 7illustrates a state in which the plurality of lead tabs are welded.

Referring toFIG. 7, in welding the lead tabs formed in the electrode assemblies (S220), the plurality of lead tabs150may be welded while being vertically positioned to be parallel to each other. In welding the lead tabs formed in the electrode assemblies (S220, refer toFIG. 5), ultrasonic welding may be performed. Accordingly, the lead tabs150may be electrically coupled to each other since they are welded together.

Referring back toFIG. 2, in welding the lead tabs formed in the electrode assemblies (S220, refer toFIG. 5), the positive electrode lead tabs150amay be connected to each other, and the negative electrode lead tabs150bmay be connected to each other.

FIG. 8illustrates a state in which the lead tabs are partially cut off

Referring toFIG. 8, in cutting the welded lead tabs (S230, refer toFIG. 5), as an example of cutting the lead tabs150, a cutting blade B may be vertically moved to cut the end portions T of the plurality of lead tabs150to a predetermined length. Due to cutting the welded lead tabs (S230, refer toFIG. 5), the lead tabs150are all positioned to be parallel to each other while none of them has protruded portion.

In this case, cutting the welded lead tabs150is not necessarily limited to the use of the cutting blade B, and a laser may also be used.

Alternatively, as opposed to the above description, when welding is performed after cutting each of the lead tabs, welding should be performed after the lead tabs are respectively designed to have different lengths in consideration of bending of the lead tabs. Accordingly, since the length of the lead tabs should be designed and manufactured for every rechargeable battery of a different shape, a design time may take longer.

In addition, depending on a level of proficiency of a worker who performs welding work, an end portion of any one lead tab may not be normally welded to the other lead tabs.

Particularly, the lead tabs respectively formed in the stacked type of electrode assembly and in the wound type of electrode assembly may have different lengths. That is, since the lead tabs of the different types of the electrode assemblies may respectively have different lengths, it may be difficult to align and weld the end portions of all the lead tabs.

In addition, when welding is performed after cutting each of the lead tabs, some of the lead tabs may protrude further to the outside than the other lead tabs. Accordingly, since some of the protruded lead tabs may cause interference while installing the electrode assemblies in the case, the case may be designed to have a corresponding size by taking protruded lengths of some of the lead tabs into account. Therefore, it may be disadvantageous in making the size of the rechargeable battery smaller.

However, in the manufacturing method of a rechargeable battery according to the current exemplary embodiment, the lead tabs are welded and are then partially cut off. Accordingly, since lead tabs of the rechargeable batteries of the different shapes do not need to be respectively designed to have a different length, a time for designing the rechargeable battery can be significantly reduced.

In the manufacturing method of a rechargeable battery according to the current exemplary embodiment, the lead tabs are welded after they are designed to have sufficient lengths. Accordingly, even if a level of proficiency of the worker performing the welding work is not so high, the welding can be performed such that all the lead tabs are connected.

In addition, the end portions of the lead tabs manufactured by the manufacturing method of the rechargeable battery according to the exemplary embodiment may all be aligned in a vertical direction. Accordingly, since interference caused by the protruded lead tabs while placing the electrode assemblies in the case is reduced, the size of the case can be minimized. Therefore, it may be advantageous in making the size of the rechargeable battery smaller.

FIG. 9illustrates a state in which the lead tabs and the lead terminal are connected.

Referring toFIG. 9, in welding the lead terminals to the cut lead tabs (S240, refer toFIG. 5), the lead tab150and the lead terminal160are closely attached to each other and are then welded. In this case, a top surface of the end portion of the lead terminal160may be closely attached to a bottom surface of the end portion of the lead tab150, and a bottom surface of the end portion of the lead terminal160may be closely attached to a top surface of the end portion of the lead tab150.

In this case, as shown inFIG. 2, the positive electrode lead tab150amay be welded to a positive electrode lead terminal160a, and the negative electrode lead tab150bmay be welded to a negative electrode lead terminal160b.

In welding the lead terminal to the cut lead tabs (S240), an ultrasonic welding method may be used, for example, but it is not limited thereto.

FIG. 10illustrates a process of thermally sealing the lead terminal with a sealing member.

Referring toFIG. 10, the manufacturing method of a rechargeable battery according to the current exemplary embodiment may include sealing the end portions of the lead terminals160in which the insulating layer161is formed using the sealing member120. Sealing the end portions of the lead terminals160in which the insulating layer161is formed using the sealing member120may be performed after welding the lead terminal to the cut lead tabs.

In sealing the end portions of the lead terminals160in which the insulating layer161is formed using the sealing member120, two sealing members120may be closely attached to each other such that they are thermo-bonded. By the process as described above, an empty space can be prevented from being created between the sealing member120and the lead terminal160as the sealing member120and the insulating layer161are partially melted. Accordingly, since the sealing member120is more closely attached to the lead terminal160, the lead terminal may provide better sealing reliability.

While this disclosure has been described in connection with what is presently considered to be practical exemplary embodiments, the drawings and the detailed description of the present invention which are described above are merely illustrative, are just used for the purpose of describing the present invention, and are not used for qualifying the meaning or limiting the scope of the present invention, which is disclosed in the appended claims. Therefore, it will be understood by those skilled in the art that various modifications and other equivalent exemplary embodiments may be made from the present invention. Accordingly, an actual technical protection scope of the present invention is to be defined by the claims.