KR20140109280A - Battery Cell Having Electrode Assembly of Stair-like Structure - Google Patents

Abstract

The present invention provides an electrode assembly comprising: an assembly electrode sheet; an electrode assembly including a first electrode roll and a second electrode roll of a structure winding each one end and the other end of the assembly electrode sheet, wherein the height of the first electrode roll is higher than the height of the second electrode; and a battery cell case consisting of a shape corresponding to the outer surface of the electrode assembly. The assembly electrode sheet consists of: a positive electrode sheet; a negative electrode sheet; a first separating sheet intervening between the positive electrode sheet and the negative electrode sheet; and a second separating sheet faced with the first separating sheet in-between the positive electrode sheet and the negative electrode sheet.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a battery cell Having Electrode Assembly of Stair-like Structure,

The present invention relates to a battery cell including a stepped electrode assembly, and more particularly to a battery cell including a positive electrode sheet, a negative electrode sheet, a first separator interposed between the negative electrode sheet and the positive electrode sheet, And a second separating sheet facing the first separating sheet with a sheet interposed therebetween, wherein the first electrode roll and the second electrode roll have a structure in which one end and the other end of the assembled electrode sheet are wound, Wherein the first electrode roll has a height greater than a height of the second electrode roll, and a battery cell case having a shape corresponding to an outer surface of the electrode assembly. .

As information technology (IT) technology has developed remarkably, various portable information and communication devices have been spreading, so that the 21st century is being developed into a "ubiquitous society" capable of providing high quality information services regardless of time and place.

In the development base for such a ubiquitous society, a secondary battery occupies an important position. Specifically, the rechargeable secondary cell is widely used as an energy source for wireless mobile devices, and is proposed as a solution for air pollution in existing gasoline vehicles and diesel vehicles using fossil fuels Electric vehicles, hybrid electric vehicles, and the like.

As described above, as the devices to which the secondary battery is applied are diversified, the lithium secondary battery has been diversified to provide an appropriate output and capacity for the applied device. In addition, miniaturization and miniaturization are strongly demanded.

Such a secondary battery is classified into a cylindrical battery and a prismatic battery in which an electrode assembly is embedded in a cylindrical or rectangular metal can according to the shape of the battery case, and a pouch type battery in which an electrode assembly is embedded in a pouch-shaped case of an aluminum laminate sheet do.

In addition, the electrode assembly incorporated in the battery case is a chargeable / dischargeable power generation device formed of a lamination structure of a positive electrode / separator / negative electrode. The electrode assembly is a jelly-roll type electrode assembly in which a separator is interposed between a positive electrode and a negative electrode coated with an active material, And a stacked type in which a plurality of positive electrodes and negative electrodes of a predetermined size are sequentially stacked in a state interposed in the separator.

The general structure of a prismatic battery among these is shown in Fig.

1, the prismatic battery 50 includes a jelly-roll type electrode assembly 10 housed in a rectangular metal case 20 and having a protruding electrode terminal (for example, And a top cap 30 on which a cap 32 is formed.

The negative electrode of the electrode assembly 10 is electrically connected to the lower end of the negative electrode terminal 32 on the top cap 30 through the negative electrode tab 12. The negative electrode terminal 32 is electrically connected to the top cap 30 by the insulating member 34, (30). On the other hand, another electrode (for example, an anode) of the electrode assembly 10 is electrically connected to the top cap 30 whose anode tab 14 is made of a conductive material such as aluminum, stainless steel, And forms a bipolar terminal by itself.

In order to ensure the electrical insulation between the electrode assembly 10 and the top cap 30 except for the electrode tabs 12 and 14, a sheet-like insulating member 40 The top cap 30 and the case 20 are joined together by welding along the contact surface between the top cap 30 and the case 20. Then, an electrolyte is injected through the electrolyte injection port 43, and then the battery is sealed by welding and applying a welding portion with epoxy or the like to manufacture a battery.

However, in recent years, a new type of battery cell is required due to a slim type or various design trends. Specifically, in accordance with the miniaturization and thinning of the device, there is a need for a battery cell that can be mounted with an efficient structure even when the storage space of the battery does not have a sufficient margin.

Conventional devices have been manufactured in a substantially rectangular parallelepiped shape, but recently, devices having various external shapes have been developed. Generally, in the case of a battery cell having a rectangular parallelepiped shape or a cylindrical shape, It is difficult to be mounted to the vehicle.

For example, in the case of a smart phone, the side can be curved in order to improve the grip feeling. In the case of a device designed to have such a curved portion, there is a problem that the battery cell or the battery pack having a rectangular parallelepiped shape has a limited space utilization inside the device.

That is, a dead space is formed in the curved portion where the battery cell can not be mounted, and such a dead space causes a problem of lowering the capacity per device volume.

Therefore, there is a high need for a battery cell having a structure capable of increasing the installation efficiency by reducing the dead space and maximizing the capacity in devices having various structures.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-described problems of the prior art and the technical problems required from the past.

More specifically, it is an object of the present invention to design a battery cell to be mounted in various spaces of a device to maximize the utilization of the internal space of the device, and to deviate from the external structure of a device having a generally rectangular structure, And to provide a battery cell that can be efficiently mounted even in a device having an external shape.

According to an aspect of the present invention, there is provided a battery cell including an electrode assembly having a stepped structure,

An assembly electrode sheet comprising a positive electrode sheet, a negative electrode sheet, a first separating sheet interposed between the negative electrode sheet and the positive electrode sheet, and a second separating sheet facing the first separating sheet sandwiching the negative electrode sheet or the positive electrode sheet therebetween. And a first electrode roll and a second electrode roll having a structure in which one end and the other end of the assembled electrode sheet are wound, respectively, and the height of the first electrode roll is larger than the height of the second electrode roll An electrode assembly; And

A battery cell case having a shape corresponding to an outer surface of the electrode assembly;

As shown in FIG.

Therefore, the battery cell according to the present invention can be manufactured as a battery cell having various capacities and sizes based on the specific structure as described above. In the manufacture of the device for mounting the battery cell, It is possible to maximize the utilization of the space inside the device.

In addition, since the battery cell case has a shape corresponding to the outer surface of the electrode assembly, the battery capacity can be increased and the utilization of the surplus space can be improved with a compact structure.

In one specific example, the second electrode roll in the electrode assembly may be arranged in the lateral direction of the first electrode roll. Therefore, when the first electrode roll and the second electrode roll are arranged to form an electrode assembly, the electrode assembly may have a stepped structure by a height difference between the first electrode roll and the second electrode roll.

In addition, the second electrode roll in the electrode assembly may be a structure in which the first electrode roll is stacked in the vertical direction. In this case, the second electrode roll may be formed in a different shape in plan view as compared with the first electrode roll. For example, when at least one of the length and the width on the plane of the second electrode roll is formed to be smaller than the length or the width of the first electrode roll, when the second electrode roll is vertically stacked on the first electrode roll , And a structure for forming a stepped structure.

As described above, the height of the first electrode roll may be larger than the height of the second electrode roll. For example, the width of the first electrode roll may be greater than the width of the second electrode roll Width of the first electrode layer. As a specific example, the height of the first electrode roll may be in the range of 20% to 95% of the height of the second electrode roll, preferably in the range of 30% to 90%. The winding width of the first electrode roll may be in the range of 20% to 95%, preferably in the range of 30% to 90% of the winding width of the second electrode roll.

As described above, the structure in which the winding width of the first electrode roll is larger than the winding width of the second electrode roll can be achieved, for example, by forming the structure in which the number of windings of the first electrode roll is larger than the number of windings of the second electrode roll It is possible.

The first electrode roll and the second electrode roll may be respectively wound in a circular or elliptical shape in a vertical section. The electrode rolls wound in the elliptical shape as described above may be manufactured by winding the assembled electrode sheet in a circular shape in a vertical section and then pressing it.

In the first example of this structure, the first electrode roll and the second electrode roll may each be elliptical in vertical section, and the minor axis length of the first electrode roll may be larger than the minor axis length of the second electrode roll . In this case, the minor axis length of the first electrode roll may be in the range of 20% to 95%, preferably 30 to 90% of the minor axis length of the second electrode roll.

In the second example, the first electrode roll and the second electrode roll may each be circular in a vertical section, and the radius of the first electrode roll may be larger than the radius of the second electrode roll. At this time, the radius of the first electrode roll may be in the range of 20% to 95%, preferably in the range of 30% to 90% of the radius of the second electrode roll.

In the third example, the first electrode roll is circular, the second electrode roll is elliptical, and the diameter of the first electrode roll is larger than the short axis length of the second electrode roll. In this case, the diameter of the first electrode roll may be in the range of 20% to 95%, preferably 30 to 90% of the minor axis length of the second electrode roll.

In one specific example, the lower end of the first electrode roll and the lower end of the second electrode roll may be arranged in a straight line on a plane. When the electrode assembly having such a structure is housed in the battery cell case, the step structure may be formed only on the upper portion of the battery cell case according to the height difference between the first electrode roll and the second electrode roll.

Meanwhile, the first electrode roll and the second electrode roll may be formed by winding the assembled electrode sheet in a clockwise or counterclockwise direction, respectively. That is, the first electrode roll and the second electrode roll may be formed by winding the assembled electrode sheets in the same direction, but may also be wound in different directions. Concretely, both the first electrode roll and the second electrode roll can be wound in a clockwise direction or both in a counterclockwise direction. In addition, one of the electrode rolls of the first electrode roll and the second electrode roll is wound clockwise, and the other electrode roll may be wound in a counterclockwise direction.

The assembled electrode sheet according to the present invention is characterized in that the second separator sheet, the negative electrode sheet, the first separator sheet and the positive electrode sheet are stacked in order in the height direction with respect to the plane, or the second separator sheet, A sheet and a negative electrode sheet may be stacked in this order. The first electrode roll and the second electrode roll can be manufactured by winding one end and the other end of the assembled electrode sheet, respectively.

At this time, at least one of the first electrode roll and the second electrode roll may be wound such that the second separator sheet faces outward. The electrode roll having such a structure may be formed with a structure in which the second separation sheet is located at the outermost periphery, and thus the positive electrode sheet or the negative electrode sheet positioned inside by the second separation sheet is protected from the outside of the electrode roll.

The active material may be applied only to the surface of the positive electrode sheet or negative electrode sheet at the outermost side of the electrode roll wound with the second separator sheet facing outwardly, only on the surface facing the first separator sheet.

At least one of the first electrode roll and the second electrode roll may be wound such that the second separator sheet faces inward. In this case, the active material may be applied only to the surface of the positive electrode sheet or the negative electrode sheet of the outermost electrode roll wound so that the second separator sheet faces inward, on the surface facing the first separator sheet in contact with the inside thereof.

The battery cell case may be a battery case of a laminate sheet including a resin layer and a metal layer, or may be a metal can used for a prismatic battery.

The battery case and the metal can of the laminate sheet may be formed with a housing portion in which the electrode assembly having the stepped structure according to the present invention is embedded. The housing portion may have a width corresponding to the shape of the electrode assembly of the step structure according to the present invention It may have a shape of a stepped structure having a height.

The battery cell may be a lithium ion battery cell or a lithium ion polymer battery cell, but is not limited thereto.

The present invention also provides a device comprising the battery cell as a power source, wherein the device is used in a mobile phone, a portable computer, a smart phone, a tablet PC, a smart pad, a netbook, a LEV (Light Electronic Vehicle) A hybrid electric vehicle, a plug-in hybrid electric vehicle, and a power storage device.

The structure of these devices and their fabrication methods are well known in the art, and a detailed description thereof will be omitted herein.

As described above, since the battery cell according to the present invention has a stepped structure, it is possible to easily secure the mounting space of the battery cell, maximize the space utilization by utilizing the dead space inside the device, It is possible to use a high-capacity battery cell, and it is possible to further miniaturize the device.

1 is an exploded perspective view of a typical conventional prismatic battery;
2 is a vertical cross-sectional view of a battery cell according to one embodiment of the present invention;
3 is a vertical cross-sectional view of a battery cell according to another embodiment of the present invention;
Fig. 4 is an enlarged view of part A in Fig. 2; Fig.
5 is an enlarged view of the region B in Fig. 3; Fig.
6 to 9 are vertical sectional views of a battery cell according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited by the scope of the present invention.

In this specification, for convenience of explanation, the electrode terminals and the protection circuit included in the battery cell are omitted.

2 is a vertical sectional view of a battery cell according to an embodiment of the present invention.

2, the battery cell 100 includes an electrode assembly including a first electrode roll 110 and a second electrode roll 120, and a battery cell case 130 housing the electrode assembly. Consists of.

The first electrode roll 110 and the second electrode roll 120 are manufactured by winding one end and the other end of the assembled electrode sheet 150 in which the positive electrode sheet, the first separator sheet, the negative electrode sheet, And the first electrode roll 110 and the second electrode roll 120 are arranged in the lateral direction from each other and the height H ₁ of the first electrode roll 110 is greater than the height H ₁ of the second electrode roll 120 (H ₂ ) of the substrate W ₁ . Accordingly, a stepped structure is formed by the height difference between the first electrode roll 110 and the second electrode roll 120.

The lower end of the first electrode roll 110 and the lower end of the second electrode roll 120 are positioned in a straight line in a plan view so that the height difference between the first electrode roll 110 and the second electrode roll 120 The structure is formed only on the upper portion of the battery cell 100. [

The first electrode roll 110 and the second electrode roll 120 have a structure in which the first electrode roll 110 and the second electrode roll 120 are wound in a substantially elliptical shape in a vertical cross section, And the second electrode roll is formed in a structure in which the other end of the assembled electrode sheet 150 is wound in a clockwise direction.

The battery cell case 130 includes a stepped structure corresponding to the shape of the electrode assembly so that the first electrode roll 110 and the second electrode roll 120 are efficiently mounted.

3 is a vertical cross-sectional view of a battery cell according to another embodiment of the present invention.

3, the battery cell 200 includes a first electrode roll 210, a second electrode roll 220, and a battery cell case 230. Unlike the battery cell 100 of FIG. 1, The first electrode roll 210 and the second electrode roll 220 are all formed in a structure in which the assembled electrode sheet 250 is wound in a counterclockwise direction.

The lower end of the outermost portion of the assembled electrode sheet 250 constituting the first electrode roll 210 is formed by the structure in which the winding directions of the first electrode roll 210 and the second electrode roll 220 are opposite to each other, And is connected to the upper end of the outermost portion of the assembled electrode sheet 250 constituting the two-electrode roll 220.

Referring to Fig. 4 and Fig. 2, an assembled electrode sheet 150 constituting the first electrode roll 110 is formed in the height direction with respect to the plane, A first separator sheet 152, a first separator sheet 154, a negative electrode sheet 156, and a second separator sheet 158 are laminated in this order. The second separating sheet 158 positioned at the outermost portion is formed in a structure that protects the positive electrode sheet 152 or the negative electrode sheet 156 located on the inner side from the outside of the electrode roll. The active material is applied only to the surface of the negative electrode sheet 156 adjacent to the second separating sheet 158 facing the first separating sheet 154.

5, the assembled electrode sheet 250 constituting the second electrode roll 220 includes the second separator sheet 258, the positive electrode sheet 250, and the second separator sheet 250. As shown in FIG. 5, The outermost negative electrode sheet 252 is laminated on the positive electrode sheet 256 with the first separator sheet 256 sandwiched therebetween. The first separator sheet 256, the first separator sheet 254 and the negative electrode sheet 252 are laminated in this order. And the active material is applied only to the side facing the surface.

6 to 9 are vertical sectional views of a battery cell according to another embodiment of the present invention.

Referring first to FIGS. 6 and 7, the second electrode rolls 320 and 320 'form a stacked structure in the vertical direction of the first electrode rolls 310 and 310'. The length L ₁ of the second electrode rolls 320 and 320 'is smaller than the length L ₂ of the first electrode rolls 320 and 320' so that the first electrode rolls 310 and 310 ' The second electrode rolls 320 and 320 'are stacked in the vertical direction to form a stepped structure. FIG. 6 shows a battery cell 300 with a stepped structure on the right side, and FIG. 7 shows a battery cell 300 'with a stepped structure on both sides. Although not shown in the drawings, it goes without saying that the step structure may be formed on the left side according to the position of the second electrode roll.

Referring to FIG. 8, the first electrode roll 410 and the second electrode roll 420 of the battery cell 400 are each formed in a circular shape in a vertical cross section, and the radius r ₁ of the first electrode roll 410, Is larger than the radius (r ₂ ) of the second electrode roll 420 and has a stepped structure.

9, the battery cell 500 has a vertical cross section, and the first electrode roll 510 has a circular structure. The second electrode roll 520 has an elliptical structure. The first electrode roll The diameter R of the second electrode roll 510 is larger than the minor axis W of the second electrode roll 520 to form a stepped structure.

Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims (21)

An assembly electrode sheet comprising a positive electrode sheet, a negative electrode sheet, a first separating sheet interposed between the negative electrode sheet and the positive electrode sheet, and a second separating sheet facing the first separating sheet sandwiching the negative electrode sheet or the positive electrode sheet therebetween. And a first electrode roll and a second electrode roll having a structure in which one end and the other end of the assembled electrode sheet are wound, respectively, and the height of the first electrode roll is larger than the height of the second electrode roll An electrode assembly; And
A battery cell case having a shape corresponding to an outer surface of the electrode assembly;
The battery cell comprising: The battery cell according to claim 1, wherein the second electrode rolls in the electrode assembly are arranged in the lateral direction of the first electrode roll. The battery cell according to claim 1, wherein the second electrode rolls in the electrode assembly are stacked in the vertical direction of the first electrode roll. The battery cell according to claim 1, wherein the first electrode roll has a larger winding width than the second electrode roll. The battery cell according to claim 4, wherein the first electrode roll has a greater number of turns than the second electrode roll. The battery cell according to claim 1, wherein the first electrode roll and the second electrode roll are elliptical in vertical section, respectively, and the minor axis length of the first electrode roll is greater than the minor axis length of the second electrode roll. The battery cell according to claim 1, wherein the first electrode roll and the second electrode roll are circular in a vertical section, respectively, and the radius of the first electrode roll is larger than the radius of the second electrode roll. The battery cell according to claim 1, wherein the first electrode roll is circular, the second electrode roll is elliptical, and the diameter of the first electrode roll is larger than the short axis length of the second electrode roll, . The battery cell according to claim 1, wherein a lower end of the first electrode roll and a lower end of the second electrode roll are positioned in a straight line on a plane. The battery cell according to claim 1, wherein the first electrode roll and the second electrode roll each have a structure in which an assembled electrode sheet is wound clockwise or counterclockwise. The battery cell according to claim 1, characterized in that one of the electrode rolls of the first electrode roll and the second electrode roll is wound in a clockwise direction and the other electrode roll is wound in a counterclockwise direction . The assembly electrode sheet according to claim 1, wherein the assembled electrode sheet has a second separator sheet, a negative electrode sheet, a first separator sheet, and a positive electrode sheet stacked in this order in a height direction with respect to a plane, 1 < / RTI > separator sheet and a negative electrode sheet laminated in this order. 13. The battery cell according to claim 12, wherein at least one of the first electrode roll and the second electrode roll is wound so that the second separator sheet faces outward. 14. The battery according to claim 13, characterized in that an active material is applied only to a surface of the positive electrode sheet or the negative electrode sheet at the outermost side of the electrode roll wound with the second separator sheet facing outward, Cell. The battery cell according to claim 12, wherein at least one of the first electrode roll and the second electrode roll is wound such that the second separator sheet faces inward. The battery according to claim 15, characterized in that an active material is applied only to the surface of the positive electrode sheet or negative electrode sheet at the outermost side of the electrode roll wound with the second separator sheet facing inward Cell. The battery cell according to claim 1, wherein the battery cell case is a battery case of a laminate sheet including a resin layer and a metal layer, or a metal can used for a prismatic battery. The battery cell according to claim 17, wherein the battery case or the metal can of the laminate sheet is formed with a stepped structure having a width and a height. The battery cell according to claim 1, wherein the battery cell is a lithium ion battery cell or a lithium ion polymer battery cell. A device comprising a battery cell according to any one of claims 1 to 19 as a power source. 21. The method of claim 20, wherein the device is selected from the group consisting of a mobile phone, a portable computer, a smart phone, a tablet PC, a smart pad, a netbook, a LEV (Light Electronic Vehicle), an electric vehicle, a hybrid electric vehicle, ≪ / RTI > device.

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