KR20150029544A - Electrode assembly and secondary battery including the same - Google Patents

Abstract

Disclosed are an electrode assembly and a secondary battery comprising the same, wherein the electrode assembly can enhance energy density and can configure the shape of a battery more freely. The disclosed electrode assembly comprises: a square-shaped electrode jelly-roll formed by winding a first electrode plate, a second electrode plate, and a separation membrane inserted into the first electrode plate and the second electrode plate together; a first electrode tab connected to the first electrode plate and withdrawn in the direction of the winding axis of the electrode jelly-roll; and a second electrode tab connected to the second electrode tab and withdrawn in the direction of the winding axis thereof, wherein either or both of the first electrode and the second electrode tab are bent in a direction opposite to a withdrawing direction to be arranged on the exterior surface of the electrode jelly-roll in order to face each other.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an electrode assembly,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode assembly and a secondary battery having the electrode assembly, and more particularly, to an electrode assembly and an secondary battery having the electrode assembly.

A secondary battery is a battery capable of charging and discharging unlike a primary battery which can not be charged, and is widely used in high-tech electronic devices such as a cellular phone, a notebook computer, and a camcorder.

Particularly, lithium secondary batteries have higher voltage and higher energy density per unit weight than nickel-cadmium batteries and nickel-hydrogen batteries, which are widely used as power sources for portable electronic equipment, and their demand is increasing. Such a lithium secondary battery mainly uses a lithium-based oxide as a positive electrode active material and a carbonaceous material as a negative electrode active material. Generally, a battery using a liquid electrolyte is referred to as a lithium ion battery, and a battery using a polymer electrolyte is referred to as a lithium polymer battery, depending on the kind of electrolyte, classified into a liquid electrolyte cell and a polymer electrolyte cell. In addition, the lithium secondary battery is manufactured in various shapes. Typical shapes include a cylindrical shape, a square shape, and a pouch shape.

Typically, a laminated type electrode assembly formed by laminating a plurality of positive electrode plates and negative electrode plates with a separator interposed therebetween, in which a separation membrane is inserted between a positive electrode plate and a negative electrode plate and wound together in a spiral shape, . For example, a cylindrical battery includes a cylindrical can accommodated in a cylindrical can, and an electrolyte is injected and sealed. The prismatic type cell is formed by pressing a wound electrode assembly or a stacked electrode assembly to flatten and flatten it, . The pouch-type battery is formed by wrapping a wound electrode assembly or a stacked electrode assembly together with an electrolyte in a pouch-type sheathing material. In such an electrode assembly, the positive electrode tab and the negative electrode tab may be respectively drawn out from the positive electrode plate and the negative electrode plate to the outside of the electrode assembly and connected to the positive electrode and the negative electrode of the secondary battery.

A rewound type electrode assembly capable of improving energy density and freely configuring a shape of a battery, and a secondary battery having the same.

The electrode assembly according to one embodiment includes a first electrode plate, a second electrode plate, and a separator interposed between the first electrode plate and the second electrode plate. The electrode assembly includes an outer surface parallel to the winding axis, An angular electrode jellyroll having two mutually opposing sides perpendicular to the axis of rotation; A first electrode tab electrically connected to the first electrode plate and extending in a winding axis direction of the electrode jelly roll; And a second electrode tab electrically connected to the second electrode plate and extending in a winding axis direction of the electrode jelly roll, wherein at least one end of the first electrode tab and the second electrode tab extends And may be disposed to face the outer surface of the electrode jelly roll.

Wherein the first electrode plate includes a first electrode current collector and a first active material coated on the first electrode current collector, the second electrode plate includes a second electrode current collector and a second electrode current collector coated on the second electrode current collector, Wherein the first electrode tab is fixed to the electrode uncoated portion of the first electrode current collector to which the first active material is not applied and the second electrode tab is fixed to the second electrode tab, And can be fixed to the electrode non-conductive portion of the electrode current collector.

Wherein the first electrode plate includes a first electrode current collector and a first active material coated on the first electrode current collector, the second electrode plate includes a second electrode current collector and a second electrode current collector coated on the second electrode current collector, Wherein the first electrode tab is a part of the electrode uncoated portion of the first electrode current collector protruding in a direction perpendicular to the longitudinal direction of the first electrode current collector, And may be a part of the electrode uncoated portion of the second electrode current collector protruding in a direction perpendicular to the longitudinal direction of the second electrode current collector.

The first electrode tab and the second electrode tab may be configured to serve as lead tabs, respectively.

The outer surface parallel to the winding axis of the electrode jelly roll includes a flat upper surface and a lower surface opposite to each other, and the electrode jelly roll may further include two curved surfaces between the upper surface and the lower surface.

The first electrode tab and the second electrode tab may be drawn from the same one side surface.

The first electrode tab and the second electrode tab may be respectively drawn out from two opposite sides.

In one embodiment, a line extending in the winding axis direction of the first electrode tab and a line extending in the winding axis direction of the second electrode tab may coincide with each other.

In another embodiment, the line extending the first electrode tab in the winding axis direction and the line extending in the winding axis direction of the second electrode tab may not coincide with each other.

The position of the portion where the first electrode plate and the first electrode tab are connected and the portion where the second electrode plate and the second electrode tab are connected may be different from each other in the height direction of the electrode jelly roll.

The first electrode tab may be bent to face the upper surface, and the second electrode tab may be bent to face the lower surface.

Wherein at least one of the first electrode tab and the second electrode tab includes a first tab portion embedded in the electrode jellyroll roll, a second tab portion opposed to one of the side surfaces, and a third tab portion opposed to the upper surface or the lower surface, Wherein the first tab portion and the third tab portion extend in the winding axis direction and the second tab portion may extend in a direction perpendicular to the winding axis so that the first tab portion and the third tab portion do not overlap with each other .

At least one of the first electrode tab and the second electrode tab may further include a fourth tab portion extending in a direction perpendicular to the winding axis from the third tab portion.

Wherein the first electrode plate includes a first electrode current collector and a first active material coated on the first electrode current collector, the second electrode plate includes a second electrode current collector and a second electrode current collector coated on the second electrode current collector Wherein the first electrode tab is formed with the end of the electrode uncoated portion of the first electrode current collector exposed to the outside of the electrode jelly roll without the first active material coated thereon, And the end of the electrode non-coated portion of the second electrode current collector exposed to the outside of the electrode jelly roll may form the second electrode tab.

At least one of an end portion of the electrode non-coated portion of the first electrode current collector exposed to the outside of the electrode jelly roll and an end portion of the electrode non-coated portion of the second electrode current collector exposed to the outside of the electrode jellyroll roll, As shown in FIG.

A part of the end of the first electrode current collector folded to be pulled out in the winding axis direction or the electrode uncoated portion of the second electrode current collector may be bent in the opposite direction from the pulling direction.

Wherein the first electrode plate includes a first electrode current collector and a first active material coated on the first electrode current collector, the second electrode plate includes a second electrode current collector and a second electrode current collector coated on the second electrode current collector 2 active material and the end of the electrode non-coated portion of the first electrode current collector to which the first active material is not applied may form the outer surface of the electrode jellyroll.

Wherein a portion of the second electrode tab is embedded in the electrode jelly roll and is drawn out from the inside of the electrode jelly roll, and the first electrode tab is formed on an end portion of the electrode non-coated portion of the first electrode current collector exposed to the outside .

A plurality of first electrode tabs and a plurality of second electrode tabs may be disposed for one electrode jelly roll.

Wherein at least one of the first electrode tab and the second electrode tab opposite the outer surface of the electrode jelly roll has a first portion parallel to the winding axis and a first portion parallel to the winding axis and parallel to the outer surface of the electrode jelly roll And a second portion extending from the first portion in one direction.

Wherein at least one of the first electrode tab and the second electrode tab opposing the outer surface of the electrode jellyroll roll extends from the second portion in a direction perpendicular to the winding axis and perpendicular to the outer surface of the electrode jellyroll And a second portion of the second portion.

The lengths of the first and second electrode tabs may be different.

The electrode assembly may further include a first lead electrically connected to the first electrode tab, and a second lead electrically connected to the second electrode tab.

The electrode assembly may further include a first lead tab electrically connected to the first lead and a second lead tab electrically connected to the second lead.

The first and second conductive lines may be formed in a sheet shape, and the widths of the first and second conductive lines may be, for example, 10 to 10000 times the thickness.

The first and second conductors may include at least one of aluminum, copper, stainless steel, and nickel, for example.

The electrode assembly may further include a first lead tab electrically connected to the first electrode tab, and a second lead tab electrically connected to the second electrode tab.

The electrode assembly includes a plurality of electrode jelly rolls and a plurality of first and second electrode tabs respectively disposed on the plurality of electrode jelly rolls, and the plurality of electrode jelly rolls may be electrically connected in series.

Wherein the electrode jelly roll further comprises two curved surfaces between the upper surface and the lower surface, wherein the upper surface and the lower surface are opposite to each other, The distance between the lower surfaces is constant and the upper surface and the lower surface can be curved.

The gap between the outer surface of the electrode jelly roll and at least one of the first electrode tab and the second electrode tab disposed to face the outer surface of the electrode jelly roll may be within 1 mm.

The minimum radius of curvature in the bent portion of at least one of the first electrode tab and the second electrode tab disposed to face the outer surface of the electrode jelly roll may range from 0.006 to 5 mm.

According to another embodiment of the present invention, there is provided an electrode assembly comprising: the first electrode plate, the second electrode plate, and the separator film stacked so that a separation membrane is positioned between the first electrode plate and the second electrode plate; An electrode stacked body having two side surfaces parallel to the surface and the stacking direction and facing each other; A first electrode tab electrically connected to the first electrode plate and extended to one of two sides of the electrode stack body; And

And a second electrode tab electrically connected to the second electrode plate and extended to one of the two sides of the electrode stack body, wherein at least one of the first electrode tab and the second electrode tab May be bent in the opposite direction from the drawing direction and arranged to face the outer surface of the electrode stack body.

The electrode assembly includes a first conductor electrically connected to the first electrode tab and opposed to an outer surface of the electrode stack, and a second conductor electrically connected to the second electrode tab and opposed to the outer surface of the electrode stack And may further include a second lead.

The electrode assembly includes a plurality of first electrode plates and a plurality of second electrode plates, and a plurality of first electrode tabs electrically connected to the plurality of first electrode plates are bonded to each other, And a plurality of second electrode tabs electrically connected to the plurality of second electrode plates are bonded to each other to be folded together to the outer surface of the electrode stacked body.

Wherein the first electrode tab has a first portion drawn out to one side of the electrode stack and a second portion bent at an angle of about 90 degrees so as to face the outer surface of the electrode stacked body at the same time And a first portion and a second portion of the first electrode tab may be joined to each other at any one side of the electrode stack.

The first portion of the first electrode tab may be bent about 180 degrees so as to surround the opposite two surfaces of the end region of the second portion.

According to another aspect of the present invention, there is provided a secondary battery comprising: the electrode assembly described above; A casing covering the electrode assembly; And an electrolyte included together with the electrode assembly in the viscoelastic material.

At least a part of the first electrode tab or the second electrode tab of the electrode assembly or at least a part of the first lead tab or the second lead tab connected to the first electrode tab or the second electrode tab protrudes outside the casing .

The electronic device according to another embodiment may include the above-described secondary battery.

According to the disclosed embodiments, the shape of the secondary battery including the electrode assembly can be freely configured by disposing the electrode tabs on the outer surface of the electrode assembly to restrict the protrusion of the electrode tabs in the lateral direction of the electrode assembly. Therefore, the electronic equipment employing the secondary battery according to the disclosed embodiment can have a more free shape. In particular, a secondary battery having a shape suitable for a portable electronic device requiring a morphological diversity can be constructed. Further, the energy density of the secondary battery according to the disclosed embodiment can be further improved.

In addition, according to the disclosed embodiments, since reliability of electrical connection between a plurality of electrode jelly rolls is high, it is possible to realize a flexible battery having high reliability and durability. The flexible battery thus constructed can be bendable and have a high energy density. In addition, since the electrical connection process between a plurality of electrode jelly rolls is simple, the production process of a large-capacity battery can be simplified and the manufacturing cost can be reduced.

1 is a perspective view schematically showing a configuration of an electrode assembly according to an embodiment.
FIG. 2 is a plan view schematically showing a part of a positive electrode plate used in the electrode assembly shown in FIG. 1. FIG.
3 is a plan view schematically showing a part of a negative electrode plate used in the electrode assembly shown in FIG.
Figs. 4 to 17 are perspective views schematically illustrating the configuration of an electrode assembly according to various embodiments. Fig.
18 to 20 are plan views schematically showing a part of the positive electrode plate and the negative electrode plate used in the electrode assembly shown in FIG.
21 to 25 are perspective views schematically showing the configuration of an electrode assembly according to still another embodiment.
26A and 26B are perspective views schematically showing an electrode assembly according to another embodiment in which a plurality of electrode jelly rolls are connected in parallel.
27 is a perspective view schematically showing an electrode assembly according to another embodiment in which a plurality of electrode jelly rolls are connected in series.
28 is a perspective view schematically showing an electrode assembly according to another embodiment in which a plurality of electrode jelly rolls are stacked and connected in parallel.
29 to 31 are perspective views schematically showing an electrode assembly according to yet another embodiment.
32 is a perspective view schematically showing an electrode assembly according to another embodiment having a curved electrode jelly roll;
33 is a perspective view schematically showing an electrode assembly according to another embodiment in which a plurality of curved electrode jelly rolls shown in Fig. 32 are connected in parallel.
34 schematically shows a configuration of a secondary battery according to an embodiment.
35 and 36 schematically show the configuration of a secondary battery according to a comparative example.
37 is a perspective view schematically showing an electrode assembly according to another embodiment.
38 is a cross-sectional view schematically showing the electrode stack of the electrode assembly shown in Fig.
Figures 39-42 are perspective views schematically illustrating an electrode assembly according to further embodiments.

Hereinafter, an electrode assembly and a secondary battery having the same will be described in detail with reference to the accompanying drawings. In the following drawings, like reference numerals refer to like elements, and the size of each element in the drawings may be exaggerated for clarity and convenience of explanation.

1 is a perspective view schematically showing the configuration of an electrode assembly 100 according to an embodiment. 1, the electrode assembly 100 according to the present embodiment includes a rectangular electrode jelly roll 10 and first and second electrode tabs 21 and 22 extended from the electrode jelly roll 10, And the like. At least one end of the first electrode tab 21 and the second electrode tab 22 may be bent in the opposite direction from the pulling direction so as to face the outer surface of the electrode jellyroll 10. Although the first electrode tab 21 and the second electrode tab 22 are illustrated as being opposed to the outer surface of the electrode jellyroll 10 in FIG. 1 as an example, Only the electrode tabs 21 and 22 of the electrode jelly roll 10 may be opposed to the outer surface of the electrode jelly roll 10.

The electrode jelly roll 10 is formed by winding a first electrode plate, a second electrode plate, and a separator interposed between the first and second electrode plates together, and then pressing the separator, as shown in FIG. 1, It may be flat and square. Before the electrode jelly roll 10 is pressed, the electrode jelly roll 10 wrapped with the tape 15 or the like may be closed to prevent the electrode jelly roll 10 from being unwound. The outer surface of this electrode jellyroll 10 may include an upper surface 10a and a lower surface 10e parallel to the winding axis. The electrode jelly roll 10 also has two mutually opposing sides 10d and 10f perpendicular to the winding axis and two curved surfaces 10b and 10c between the upper surface 10a and the lower surface 10e . The upper surface 10a and the lower surface 10e are formed as flat surfaces and the gap between the upper surface 10a and the lower surface 10e can be constant.

The first electrode tab 21 is electrically connected to the first electrode plate 22 and the second electrode tab 22 is electrically connected to the second electrode plate. 1, the first and second electrode tabs 21 and 22 are arranged on both sides 10d and 10f of the electrode jelly roll 10 in the winding axis direction of the electrode jelly roll 10, respectively Can be withdrawn. The first electrode tab 21 is pulled out from the first side face 10d perpendicular to the winding axis so that the end thereof is opposed to the upper surface 10a of the electrode jellyroll 10 by about 180 degrees Direction). The second electrode tab 22 may also be bent at about 180 degrees such that the end of the second electrode tab 22 that is drawn out from the second side face 10f perpendicular to the winding axis faces the upper surface 10a of the electrode jellyroll 10.

Here, the minimum radius of curvature at the bent portions of the first electrode tab 21 and the second electrode tab 22 may be in a range of about 0.006 mm to 5 mm. When the minimum radius of curvature is smaller than the minimum radius of curvature, the risk of breakage of the electrode tabs 21 and 22 increases. If the minimum radius of curvature is larger than the minimum radius of curvature, the electrode tabs 21 and 22 protrude in the direction of the side surfaces 10d and 10f, The energy density can be lowered. The end portions of the electrode tabs 21 and 22 may be in close contact with the upper surface 10a of the electrode jelly roll 10, but may be slightly spaced apart. Considering that the energy density of the battery may be lower if the distance between the end portions of the electrode tabs 21 and 22 and the upper surface 10a is excessively large, The distance between the surfaces 10a may be within 1 mm.

FIGS. 2 and 3 schematically show the configuration of the electrode plates 11 and 12 and the electrode tabs 21 and 22 used in the electrode jelly roll 10 of FIG. Referring first to FIG. 2, the first electrode plate 11 may be, for example, a positive electrode plate. In this case, the first electrode plate 11 may include an electrode current collector 11a serving as a substrate elongated in one direction and a cathode active material 11b applied thereon. The positive electrode active material 11b may further be mixed with a conductive material and a binder. The first electrode tab 21 can be fixed to a part of the electrode collector 11a to which the cathode active material 11b is not applied (i.e., the anode uncoated portion). For example, the first electrode tab 21 may be welded or soldered to the electrode current collector 11a.

3, the second electrode plate 12 may be, for example, a negative electrode plate. In this case, the second electrode plate 12 may include an electrode current collector 12a and a negative electrode active material 12b applied thereon. The negative electrode active material 12b may further be mixed with a binder and a conductive material. The second electrode tab 22 can be fixed to a part of the electrode current collector 12a to which the negative electrode active material 12b is not applied (i.e., the negative electrode uncoated portion). For example, the second electrode tab 22 may be welded or soldered to the electrode current collector 12a.

The electrode jelly roll 10 has a separating film (not shown) interposed between the first and second electrode plates 11 and 12 shown in Figs. 2 and 3, and the first and second electrode tabs 21, 22 may be wound up from the fixed portion. Then, a part of the first and second electrode tabs 21 and 22 is buried in the electrode jelly roll 10, and the remaining part is exposed to the outside of the electrode jelly roll 10. After the electrode jelly roll 10 is pressed and flattened to have a square shape as described above, the exposed portion of the first electrode tab 21 or the second electrode tab 22 is bent to form the electrode jelly roll 10, I.e., the upper surface 10a or the lower surface 10e.

According to this embodiment, by limiting the protrusion of the first and second electrode tabs 21 and 22 in the lateral direction of the electrode assembly 100, the shape of the secondary battery including the electrode assembly 100 can be freely Can be configured. Therefore, the electronic equipment employing the secondary battery according to the disclosed embodiment can have a more free shape. In particular, a secondary battery having a shape suitable for a portable electronic device requiring a morphological diversity can be constructed, and the energy density of the secondary battery can be further improved.

1, the first and second electrode tabs 21 and 22 are drawn out from both sides 10d and 10f of the electrode jelly roll 10 in a direction completely parallel to the winding axis of the electrode jelly roll 10 However, the present invention is not limited thereto. At least one of the first and second electrode tabs 21 and 22 may be drawn in an inclined direction with respect to the winding axis of the electrode jelly roll 10, if necessary. If the drawing direction of the first and second electrode tabs 21 and 22 drawn out from both sides 10d and 10f of the electrode jelly roll 10 includes the component in the winding axis direction, 21, 22 can be drawn at any angle.

FIGS. 4 to 17 and FIGS. 21 to 25 are perspective views schematically showing the configuration of an electrode assembly according to various modified embodiments.

4, both the first electrode tab 21 and the second electrode tab 22 are not opposed to the outer surface of the electrode jellyroll 10, as shown in FIG. 4, Likewise, only one of the electrode tabs 21 may be opposed to the outer surface of the electrode jelly roll 10.

1, the first electrode tab 21 and the second electrode tab 22 are drawn out from two opposite side surfaces 10d and 10f, respectively. However, as shown in FIG. 5, The one electrode tab 21 and the second electrode tab 22 may be drawn out from the same one side surface 10d. Here, the lengths of the first electrode tab 21 and the second electrode tab 22 on the outer surface of the electrode jelly roll 10 may be the same, but they may be different as shown in FIG.

1, both the first electrode tab 21 and the second electrode tab 22 are bent so as to face the upper surface 10a of the electrode jelly roll 10, but the present invention is not limited thereto. 7, the first electrode tab 21 is bent so as to face the upper surface 10a and the second electrode tab 22 is bent to face the lower surface 10e of the electrode jellyroll 10, As shown in Fig.

In the case where the first electrode tab 21 and the second electrode tab 22 are respectively drawn out from two opposite sides 10d and 10f of the electrode jelly roll 10, The electrode tabs 21 and the second electrode tabs 22 may be arranged to be offset from each other. That is, the line extending the first electrode tab 21 in the winding axis direction and the line extending in the winding axis direction of the second electrode tab 22 may not coincide with each other. However, as shown in FIG. 8, the first electrode tab 21 and the second electrode tab 22 may be arranged to face each other. That is, the line extending in the winding axis direction of the first electrode tab 21 and the line extending in the winding axis direction of the second electrode tab 22 can coincide with each other. In this case, the position of the portion where the first electrode plate 11 and the first electrode tab 21 are connected and the position of the portion where the second electrode plate 12 and the second electrode tab 22 are connected to each other, May be different from each other in the height direction of the base 10. 9, when viewed in a direction perpendicular to the upper surface 10a of the electrode jelly roll 10, the first electrode tab 21 embedded in the electrode jelly roll 10 and the first electrode tab 21 embedded in the electrode jelly roll 10, The portions of the two electrode tabs 22 may overlap each other.

10, when the first electrode tab 21 and the second electrode tab 22 are drawn out from the same side surface 10d, the first electrode tab 11 and the first electrode tab 22 21 and the position of the portion where the second electrode plate 12 and the second electrode tab 22 are connected may be different from each other in the height direction of the electrode jelly roll 10. That is, the height of the electrode jelly roll 10 from which the first electrode tab 21 is drawn may be different from the height of the electrode jelly roll 10 from which the second electrode tab 22 is drawn.

Referring to FIG. 11, a plurality of first electrode tabs 21 and a plurality of second electrode tabs 22 may be disposed for one electrode jelly roll 10. 11 shows that three first electrode tabs 21 are drawn from the first side 10d of the electrode jellyroll 10 and three second electrode tabs 22 are drawn from the second side of the electrode jellyroll 10 10f. ≪ / RTI > It is also shown that the three first electrode tabs 21 and the second electrode tabs 22 are arranged to face each other. However, as described above, a plurality of first and second electrode tabs 21 and 22 may be drawn from one side, or a plurality of first and second electrode tabs 21 and 22, respectively, 22 may be staggered from each other.

Although the end portions of the first and second electrode tabs 21 and 22 opposed to the outer surface of the electrode jelly roll 10 have been described as simple straight lines up to now, The ends of the electrode tabs 21 and 22 can be deformed.

For example, referring to FIG. 12, the ends of the first and second electrode tabs 21 and 22 may be bent once toward one curved surface 10c of the electrode jelly roll 10. That is, the end portions of the first and second electrode tabs 21 and 22 are divided into the first portions 23 and 26 extending in the winding axis direction and the first portions 23 and 26 extending in the direction perpendicular to the winding axis from the first portions 23 and 26 And a second portion 24, 27 extending therefrom. Here, the first portions 23, 26 may be disposed obliquely with respect to the winding axis, and the second portions 24, 27 may be arranged obliquely with respect to the direction perpendicular to the winding axis. The first portions 23 and 26 and the second portions 24 and 27 may both extend in a direction parallel to the outer surface of the electrode jelly roll 10, for example, the upper surface 10a. The second portions 24 and 27 may protrude beyond the electrode jelly roll 10 over the curved surface 10c of the electrode jellyroll 10 as shown in Fig.

13, the end portions of the first and second electrode tabs 21 and 22 are arranged in a direction perpendicular to the winding axis and perpendicular to the outer surface 10a of the electrode jellyroll 10, And a third portion 25, 28 extending from the portion 24, 27, respectively. For example, the third portions 25, 28 may be erected perpendicularly to the upper surface 10a.

Although the ends of the first and second electrode tabs 21 and 22 are shown as having the second portions 24 and 27 and the third portions 25 and 28 in Figures 12 and 13, Only one of the second electrode tabs 21 and 22 may have the second portion 24 or 27 or the third portion 25 or 28. [ 12 and 13, the second portions 24 and 27 are shown bent in the same direction, but they may be bent in opposite directions. For example, the second portion 24 of the first electrode tab 21 is bent toward the one curved surface 10c and the second portion 27 of the second electrode tab 22 is bent toward the opposite curved surface 10b It may be bent.

14, in the first and second electrode tabs 21 and 22, the portion embedded in the electrode jelly roll 10 and the portion facing the outer surface of the electrode jelly roll 10 are not overlapped with each other . For example, the first and second electrode tabs 21 and 22 may include first tab portions 21a and 22a embedded in the electrode jelly roll 10, opposite side surfaces 10d of the electrode jelly roll 10, Second tab portions 21b and 22b that are opposite to the electrode jelly roll 10 and third tab portions 21c and 22c that are opposite to the outer surface of the electrode jelly roll 10. [ The first tab portions 21a and 22a and the third tab portions 21c and 22c extend in the winding axis direction and the second tab portions 21b and 22b extend from the first tab portions 21a and 22a to the third tab portion 21c, 22c may extend in a direction perpendicular to the winding axis so that they do not overlap each other. By doing so, it is possible to prevent the thickness of the electrode assembly 100 from becoming excessively thick at the positions where the first and second electrode tabs 21 and 22 are disposed. 14 shows that the two second tab portions 21b and 22b are all facing the same side face 10d but the first electrode tab 21 is drawn out to the first side face 10d and the second electrode tab 21b 22 are drawn out to the second side face 10f, the two second tab portions 21b, 22b may face the opposite side faces 10d, 10f. The third tab portion 21c of the first electrode tab 21 is disposed on the upper surface 10a and the second tab portion 21c of the second electrode tab 21 is disposed on the upper surface 10a instead of all of the third tab portions 21c and 22c being disposed on the upper surface 10a. And the third tab portion 22c of the second electrode 22 may be disposed on the lower surface 10e.

Although the overall shape of the first and second electrode tabs 21 and 22 shown in Fig. 14 is not straight, the electrode tabs 21 and 22 having a straight shape can achieve the same effect as that shown in Fig. 14 . For example, as shown in Fig. 15, portions of the electrode tabs 21 and 22 having a straight shape facing the side surface 10d are successively folded by 90 degrees so that the first tab portions 21a and 22a, (21c, 22c) do not overlap with each other.

16, the first and second electrode tabs 21 and 22 further include fourth tab portions 21d and 22d extending from the third tab portions 21c and 22c in a direction perpendicular to the winding axis can do. The fourth tabs 21d and 22d may extend in a direction parallel to the outer surface of the electrode jelly roll 10, for example, the upper surface 10a. The fourth tab portions 21d and 22d may protrude from the electrode jelly roll 10 beyond the curved surface 10b of the electrode jelly roll 10. [

17 shows an example in which the first and second electrode tabs 21 and 22 are integrally formed with the electrode plates 11 and 12 used in the electrode jelly roll 10. 18 and 19 schematically show the configuration of the electrode plates 11 and 12 and the electrode tabs 21 and 22 used in the electrode jelly roll 10 of FIG.

Referring first to FIG. 18, the first electrode plate 11 may be, for example, a positive electrode plate. In this case, the first electrode plate 11 may include an electrode current collector 11a serving as a substrate elongated in one direction and a cathode active material 11b applied thereon. The positive electrode active material 11b may further be mixed with a conductive material and a binder. 18, the first electrode tab 21 may be a part of the first electrode current collector 11a protruding in a direction perpendicular to the longitudinal direction of the first electrode current collector 11a. The first electrode tab 21 may be formed by protruding from the end of the first electrode current collector 11a to which the cathode active material 11b is not applied (i.e., the anode uncoated portion). 19, the second electrode tab 22 may be a part of the second electrode current collector 12a protruding in a direction perpendicular to the longitudinal direction of the second electrode current collector 12a . The second electrode tab 22 may be formed by protruding from an end of the second electrode collector 12a to which the negative electrode active material 12b is not applied (i.e., the negative electrode non-coated portion).

20, a part of the anode uncoated portion of the first electrode current collector 11a is cut, and then the first electrode current collector 11a is cut off so as to protrude in a direction perpendicular to the longitudinal direction of the first electrode current collector 11a, It is also possible to form the first electrode tab 21 by bending a part of the non-coated portion. Although not shown, the second electrode tab 22 can be formed on the second electrode current collector 12a by the process shown in Fig. That is, a part of the cathode uncoated portion of the second electrode current collector 12a is cut, and a part of the incomplete cathode uncoated portion is bent so as to protrude in the direction perpendicular to the longitudinal direction of the second electrode current collector 12a, The tab 22 may be formed.

21, the electrode assembly according to the above-described embodiments includes a first lead 31 electrically connected to the first electrode tab 21, and a second lead 31 electrically connected to the second electrode tab 22 And a second conductive line 32 formed on the second conductive line. The first and second leads 31 and 32 may extend in a direction perpendicular to the winding axis, but are not limited thereto. In FIG. 21, the first and second conductive lines 31 and 32 are shown protruding from the right curved surface 10c, but they may protrude from the left curved surface 10b. In addition, although FIG. 21 shows the electrode assembly of the embodiment shown in FIG. 17, the conductors 31 and 32 may also be disposed in the electrode assembly according to other embodiments. These conductors 31 and 32 can be formed in a long, flat sheet-like shape. For example, the width of the conductors 31, 32 may be at least ten times the thickness, e.g., about 50 to 10,000 times. Such sheet-like conductors 31, 32 may be useful when flexibly connecting a plurality of electrode jelly rolls 10. In addition, the material of the conductors 31 and 32 may include at least one of aluminum, copper, stainless steel, and nickel, for example. In particular, aluminum, stainless steel or the like can be used as the material of the conductor 31 connected to the anode, and copper, stainless steel, nickel or the like can be used as the material of the conductor 32 connected to the cathode. The materials of the conductors 31 and 32 can be applied to the material of the electrode tabs 21 and 22. [

22, the electrode assembly according to the above-described embodiments may include lead tabs 41 and 42 instead of lead wires 31 and 32. [ That is, the electrode assembly may further include a first lead tab 41 electrically connected to the first electrode tab 21 and a second lead tab 42 electrically connected to the second electrode tab 22 have. For example, the first and second lead tabs 41, 42 may extend in a direction perpendicular to the winding axis, but are not limited thereto. The lead tabs 41 and 42 may serve to connect the electrodes of the secondary battery to the electrode tabs 21 and 22 of the electrode assembly when the secondary battery is formed by packing the electrode assembly with a casing such as a pouch. A thermoplastic material 43 such as polyproplene (PP) may be attached to the middle portion of the lead tabs 41, 42 to bond together with the casing to seal the electrode assembly. However, instead of using separate lead tabs 41 and 42, the first and second electrode tabs 21 and 22 may themselves serve as lead tabs. For example, a thermoplastic material 43 may be attached to the ends of the first and second electrode tabs 21 and 22 as a lead tab.

23, other electrode assemblies in the above-described embodiments may include both leads 31, 32 and lead tabs 41, 42. For example, the electrode assembly includes a first lead 31 electrically connected to the first electrode tab 21, a second lead 32 electrically connected to the second electrode tab 22, a first lead 31 A first lead tab 41 electrically connected to the first lead 32 and a second lead tab 42 electrically connected to the second lead 32. Here, the first and second lead wires 31 and 32 and the first and second lead tabs 41 and 42 may extend in a direction perpendicular to the winding axis, but the present invention is not limited thereto.

On the other hand, the electrode tabs 21 and 22 can be performed by using only the electrode plates 11 and 12 shown in FIGS. 2 and 3 without using the separate electrode tabs 21 and 22. 24, an electrode assembly according to an embodiment includes a first electrode plate 11, a second electrode plate 12, and a first electrode plate 11 and a second electrode plate 12 Shaped electrode jelly roll 10 formed by winding together a separation membrane 13 interposed between the electrode jelly roll 10 and the electrode jelly roll 10. Here, the end of the first electrode current collector 11a, which is not coated with the cathode active material 11b and exposed to the outside of the electrode jelly roll 10, may serve as the first electrode tab 21. [ Likewise, the end of the second electrode current collector 12a, which is not coated with the negative electrode active material 12b and exposed to the outside of the electrode jelly roll 10, may serve as the second electrode tab 22. [

24, the first electrode tab 21 is an exposed end of the electrode uncoated portion of the first electrode current collector 11a disposed so as to face the outer surface of the electrode jelly roll 10, The second electrode tab 22 is an exposed end of the electrode uncoated portion of the second electrode current collector 12a arranged to face the outer surface of the electrode jellyroll 10. The ends of the first electrode current collector 11a and the second electrode current collector 12a exposed to the outside of the electrode jelly roll 10 may be folded in a predetermined shape. 24, the end portions of the first electrode current collector 11a and the end portions of the second electrode current collector 12a are arranged in a direction 90 parallel to the winding axis of the electrode jellyroll 10, respectively, So that the first and second electrode tabs 21 and 22 can function as the first electrode tab 21 and the second electrode tab 22 which are drawn out in a direction parallel to the winding axis. 24, a part of the end portion of the first electrode current collector 11a folded in the direction parallel to the winding axis of the electrode jellyroll 10 and a part of the end portion of the second electrode current collector 12a And it is bent 180 degrees in the opposite direction from the drawing-out direction again.

Referring to FIG. 25, the outer surface of the rectangular electrode jelly roll 10 may be formed of the first electrode current collector 11a. 25 includes a first electrode plate 11, a second electrode plate 12 and a second electrode plate 12 interposed between the first electrode plate 11 and the second electrode plate 12, A first electrode tab 21 electrically connected to the first electrode plate 11 and disposed on an outer surface of the electrode jelly roll 10, and a second electrode tab 21 electrically connected to the first electrode plate 11, And a second electrode tab 22 electrically connected to the second electrode plate 12 and drawn in a direction parallel to the winding axis of the electrode jelly roll 10. The end of the electrode uncoated portion of the first electrode current collector 11a exposed to the outside of the electrode jelly roll 10 is surrounded by the outer surface of the electrode jellyroll 10 without the positive electrode active material 11b applied thereto . In this case, a part of the second electrode tab 22 is embedded in the electrode jelly roll 10 and is drawn out from the inside of the electrode jelly roll 10, while the first electrode tab 21 is exposed to the outside The first electrode current collector 11a may be formed on the end portion of the electrode uncoated portion. The first electrode tab 21 and the second electrode tab 22 may be drawn in a direction parallel to the winding axis of the electrode jelly roll 10, as shown in FIG. Although only the first electrode tab 21 is shown bent in the opposite direction from the pull-out direction in Fig. 25, the second electrode tab 22 can also be bent in the opposite direction from the pull-out direction.

26A and 26B are perspective views schematically showing an electrode assembly 120 according to another embodiment in which a plurality of electrode jelly rolls 10 are connected in parallel. 26A, the electrode assembly 120 includes a plurality of electrode jelly rolls 10 and a plurality of first and second electrode tabs 21 and 22 disposed on the plurality of electrode jelly rolls 10, respectively. . For example, the plurality of electrode jelly rolls 10 may be electrically connected in parallel via the leads 31 and 32. To this end, a single first lead 31 extending in a direction perpendicular to the winding axis is electrically connected to the plurality of first electrode tabs 21, and a single lead 31 extending in a direction perpendicular to the winding axis 2 lead 32 may be electrically connected to the plurality of second electrode tabs 22. The first lead tab 41 and the second lead tab 42 may be connected to the first lead 31 and the second lead 32, respectively.

The connection between the first and second electrode tabs 21 and 22 and the first and second leads 31 and 32 is such that the first and second electrode tabs 21 and 22 Before bending over the outer surface of the electrode jelly roll 10. For example, after connecting the first and second leads 31 and 32 to the first and second electrode tabs 21 and 22 drawn in the winding axis direction from the electrode jelly roll 10, The first and second electrode tabs 21 and 22 may be bent naturally by attaching the second wires 31 and 32 to the outer surface of the electrode jelly roll 10.

In addition, the plurality of electrode jelly rolls 10 may be electrically connected in series through the plurality of leads 31 and 32. Referring to FIG. 27, the electrode assembly 130 may include a plurality of electrode jelly rolls 10 electrically connected in series. A plurality of electrode jelly rolls 10 may include a plurality of first and second electrode tabs 21 and 22 and a plurality of electrode jelly rolls 10, The electrode tabs 21 and 22 can be connected to each other. For example, one first lead 31 may electrically connect two first electrode tabs 21 between adjacent two electrode jelly rolls 10. The second conductive line 32 may electrically connect the two second electrode tabs 22 between the adjacent two electrode jelly rolls 10 in a manner staggered with the first conductive line 31.

According to the embodiments shown in FIGS. 26A and 27, since the reliability of the electrical connection between the plurality of electrode jelly rolls 10 is high, it is possible to realize a flexible battery having high reliability and durability. The flexible battery thus constructed can be bendable and have a high energy density. In addition, since the electrical connection process between the plurality of electrode jelly rolls 10 is simple, the production process of the large-capacity battery can be simplified and the manufacturing cost can be reduced.

Further, the electrode assemblies shown in Fig. 21 may be stacked to overlap each other. 28, the electrode assembly 140 includes a plurality of electrode jelly rolls 10 stacked, a plurality of first and second electrode tabs 21 (not shown) disposed respectively in the plurality of electrode jelly rolls 10, And a plurality of first and second leads 31 and 32 electrically connected to the first and second electrode tabs 21 and 22, respectively.

26A shows a case in which the first and second electrode tabs 21 and 22 are drawn out to the opposite side surfaces 10d and 10f of the electrode jelly roll 10, respectively. However, it is also possible to connect a plurality of electrode jelly rolls 10 even when the first and second electrode tabs 21, 22 are drawn out to the same side 10d of the electrode jellyroll 10. 29, the electrode assembly 150 includes a plurality of electrode jelly rolls 10, a plurality of first and second electrode tabs 21 and 22 having different lengths, and a plurality of first electrode tabs 22, And an insulating film 16 formed to cover a part of the insulating films 21. For example, the second electrode tab 22 may be formed longer than the first electrode tab 21. The insulating film 16 may cover the remainder of the second electrode tabs 22 except for the end portions thereof. The first electrode tabs 21 are disposed on the insulating film 16. Thereafter, the first conductor 31 may be disposed on the first electrode tabs 21 and the insulating film 16, and the second conductor 32 may be disposed on the end of the second electrode tabs 22 . The first lead 31 may be connected to the first electrode tabs 21 and the second lead 32 may be connected to the second electrode tabs 22 without shorting the positive electrode and the negative electrode.

30, the electrode assembly 16 includes a plurality of electrode jelly rolls 10, a plurality of first electrode tabs 21 extended to the same side 10d of the electrode jelly roll 10 and having different lengths, A second electrode tab 22 and a first electrode 31 connected to the first electrode tabs 21 and a second electrode 32 connected to the second electrode tabs 22, And a plurality of insulating films 16 disposed between the tabs 22 and the first conductive lines 31, respectively. 30, the first conductive line 31 and the second conductive line 32 may be disposed above the plurality of electrode jelly rolls 10, as shown in FIG. The second electrode tab 22 having a long length is connected to the second lead 32 through the first lead 31 and the first electrode tab 21 having a short length is connected to the first lead 31 Can be connected. At this time, an insulating film 16 may be disposed between the second electrode tab 22 and the first conductive line 31 to prevent an electrical short between the second electrode tab 22 and the first conductive line 31 have. In addition, the length of the first conductor 31 may be shorter than the length of the second conductor 32. 30, since the first conductor contacts only the first electrode tab 21 and does not overlap with the second electrode tab 22 on the electrode jelly roll 10 arranged on the leftmost side, The electrode jelly roll 10 does not need the folded film 16. 30 shows that the second conductor 32 is disposed below the second electrode tab 22 but the second electrode tab 22 is disposed first and the second conductor 32 is later disposed And the second lead 32 may be disposed above the second electrode tab 22. Also, it is possible that the first electrode tabs 21 are disposed below the first conductive line 31.

31 includes a plurality of electrode jelly rolls 10, a plurality of first electrode tabs 21 and second electrode tabs 22 and a plurality of first electrode tabs 21, (Not shown). In this embodiment, the insulating film 16 may be formed to cover a plurality of first electrode tabs 21 and a whole of the first lead wire 31 connected to the plurality of first electrode tabs 21. A plurality of second electrode tabs 22 and a second lead 32 connected to the plurality of second electrode tabs 22 may be disposed on the insulating film 16. In this case, the lengths of the first electrode tab 21 and the second electrode tab 22 may be the same or different. The width of the first conductor 31 and the second conductor 32 may be substantially the same as the width of the electrode jelly roll 10. The width of the insulating film 16 may be slightly larger than the width of the first conductor 31 and the second conductor 32.

32 is a perspective view schematically showing an electrode assembly 180 according to another embodiment having a curved electrode jelly roll 10 '. 32, the electrode jelly roll 10 'includes an upper surface 10a and a lower surface 10e parallel to the winding axis, two mutually opposing sides 10d and 10f perpendicular to the winding axis, And may include two curved surfaces 10b and 10c between the upper surface 10a and the lower surface 10e. And, the distance between the upper surface 10a and the lower surface 10e is approximately constant, and the upper surface 10a and the lower surface 10e can be curved. 32, the axis that curves the upper surface 10a and the lower surface 10e may be parallel to the winding axis of the electrode jelly roll 10 '. Therefore, the stress at the portion where the electrode tabs 21 and 22 and the electrode plates 11 and 12 are connected is limited. The electrode jelly roll 10 'is formed by winding a first electrode plate, a second electrode plate, a separator interposed between the first and second electrode plates together, then pressing the electrode with a curved mechanism to form a curved shape Respectively.

33 is a perspective view schematically showing an electrode assembly 190 according to an embodiment in which a plurality of curved electrode jelly rolls 10 'shown in FIG. 32 are connected in parallel. Although only the curved electrode jelly roll 10 'is shown in Fig. 33, the flat electrode jelly roll 10 and the curved electrode jelly roll 10' may be mixed and connected as required. With the electrode assembly 190 shown in FIG. 33, it is possible to realize a battery having a complex curved surface, and such a battery can be used as a power source for a wearable device. For example, it is possible to form a battery having a curved shape that can bend and can be worn on the wrist.

Up to now, the configurations of the electrode assemblies 100, 110, 120, 130, 140, 150, 160, 170, 180 according to various examples have been described. The disclosed electrode assemblies 100, 110, 120, 130, 140, 150, 160, 170 and 180 may be used in conjunction with a mobile device such as a mobile phone, smartphone, tablet computer, notebook computer, (Such as a flexible smart phone, a non-breaking smart phone, a flexible tablet computer, an electronic book terminal, a wearable device, etc.), or a battery-related system It can be usefully applied to an automobile battery or a power storage device which needs to utilize space efficiently. Hereinafter, an actual implementation of the electrode assembly 100, 110, 120, 130, 140, 150, 160, 170, 180 based on the above description will be briefly described.

(Example 1)

LiCoO ₂ as a cathode active material, polyvinylidene fluoride (PVDF) as a binder, and carbon as a conductive material were mixed in this order at a weight ratio of 92: 4: 4, respectively, and dispersed in N-methyl- To prepare a cathode active material layer composition. The cathode active material layer composition was coated on both sides of an aluminum foil having a thickness of 13.5 占 퐉, dried and rolled to prepare a positive electrode.

(SBR) as a first binder, and carboxymethyl cellulose (CMC) as a second binder were mixed in a weight ratio of 98: 1: 1, respectively, and dispersed in water to prepare a negative electrode To prepare an active material layer composition. The anode active material layer composition was coated on both sides of a copper foil having a thickness of 8 탆 and dried and rolled to prepare a negative electrode.

The electrode jelly roll 10 was fabricated between the anode and the cathode fabricated as described above with a polyethylene separator interposed therebetween. The metal foil current collector of the positive electrode and the negative electrode and the electrode tab were welded at the central portion of the electrode jelly roll 10 at the beginning of winding thereof so as to be arranged in parallel to the winding axis direction. After the electrode jelly roll 10 was wound, And the outermost end of the roll 10 was fixed. Then, the electrode tabs of the positive electrode and the negative electrode protruding from the side opposite to each other were respectively bent 180 degrees and brought into close contact with the outer surface. Further, the electrode tabs of the positive electrode and the negative electrode were further folded so that the ends of the electrode tabs protruded toward the curved surface. Here, the electrode assembly was manufactured such that the longest length between the curved portions of the electrode jelly roll 10 was about 40 mm, and the length between both opposite side surfaces was about 20 mm.

On the other hand, an electrolyte was prepared by dissolving LiPF ₆ in a concentration of 1.3 M in a mixed solution of ethylene carbonate (EC) and diethyl carbonate (DEC) in a mixing ratio of 3: 7. The above-described electrode assembly was surrounded by a pouch (D-EL35H of DNP Company, hereinafter the same pouch was used in all Examples and Comparative Examples), filled with the above electrolyte, and then vacuum-sealed to produce a laminate battery . When measured outside the tabs protruding from the outside, the length of the finished battery was 49.5 mm, the width was 24.0 mm, the maximum thickness was 2.78 mm, the measured discharge energy was about 822 mWh, and the energy density was about 249 Wh / l (based on a rectangular parallelepiped).

(Example 2)

The battery of Example 1 was bent so as to have a curved shape with an inner curvature radius of 50 mm. The measured discharge energy was about 835 mWh.

(Comparative Example 1)

A negative electrode and a positive electrode were prepared in the same manner as in Example 1. An electrode jelly roll was fabricated with a polyethylene separator interposed between the anode and the cathode. The metal foil current collector of the positive electrode and the negative electrode and the electrode tab were welded and arranged in parallel with the winding axis direction at the center of the electrode jelly roll as the start of the winding of the electrode jelly roll. After winding the electrode jelly roll, . The electrode assembly was completed with the electrode tab extended to the side of the electrode jelly roll. The longest length between the curved portions of both sides of the electrode jelly roll was about 40 mm, and the length between the two opposing side portions was about 20 mm.

The electrode assembly as described above was enclosed in a pouch, filled with the same electrolyte as used in Example 1, and vacuum sealed to produce a laminated battery. The measured length of the finished battery was 44.5 mm, the width was 30.0 mm, and the maximum thickness was 2.76 mm, except for the tabs protruding outside. The measured discharge energy was about 833 mWh, and the energy density was about 226 Wh / l (based on a rectangular parallelepiped).

(Comparative Example 2)

The battery of Comparative Example 1 was bent so as to have a curved shape with an inner curvature radius of 50 mm. At this time, the measured discharge energy was about 823 mWh.

As described above, in the case of Example 1, the energy density was improved as compared with Comparative Example 1 by changing the connecting direction of the electrode tabs and the conductors with respect to the shape of the electrode jelly roll. In the case of a curved battery as in the second embodiment, a useful cell shape can be obtained due to the lead tab drawing direction. Although the direct energy density is not compared with that of Comparative Example 2 because the shape of Embodiment 2 is not a rectangular parallelepiped, it can be judged that the energy density is improved in that the cells of Example 1 and Comparative Example 1 are curved. Particularly, considering the drawing direction of the battery lead tab, the difference in usability of the space utilized in the electronic device by the battery is more significant.

(Example 3)

A positive electrode and a negative electrode were prepared in the same manner as in Example 1. An electrode jelly roll was fabricated with a polyethylene separator interposed between the anode and the cathode. The metal foil current collector of the positive electrode and the negative electrode and the electrode tab were welded and arranged in parallel with the winding axis direction at the center of the electrode jelly roll as the start of the winding of the electrode jelly roll. After winding the electrode jelly roll, . The positive electrode tab (aluminum of 3 mm width) and the negative electrode tab (nickel of 3 mm width) were drawn to the opposite sides of the electrode jelly roll. The width of the positive electrode plate was 19 mm, the width of the negative electrode plate was 21 mm, the width of the separating membrane was 23 mm, and the length of the electrode jellyroll after completion (that is, the distance between two opposed sides of both electrodes) was 23 mm, Was 8 mm, and the thickness (i.e., between the top surface and the bottom surface) was 3.7 mm.

A total of three electrode jelly rolls as described above were fabricated to produce a laminate battery having the structure shown in FIG. That is, three electrode jelly rolls were arranged in a row so that the shortest distance between the curved portions of the adjacent electrode jelly rolls was 2.5 mm, and two copper foils having a width of 10 mm and a thickness of 15 탆 were laid as conductive wires of the negative electrode, And two aluminum foils having a width of 10 mm and a thickness of 15 占 퐉 were stacked and welded to three positive electrode tabs, respectively, as lead wires of the positive electrode. The tabs were folded about 180 degrees around the sides of the electrode jelly rolls so that the leads were disposed adjacent to the outer surface of each electrode jelly roll. And the positive electrode lead tab 41 and the negative electrode lead tab 42 were welded again to the ends of the positive electrode and the negative electrode lead, respectively, thereby completing an electrode assembly in which three electrode jelly rolls were connected in parallel.

The electrode assembly was surrounded by two upper and lower pouch films, filled with the electrolyte of Example 1, and then vacuum-sealed to produce a laminate battery. The width of the sealing part was about 5 mm. The length of the finished battery (the direction in which the electrode jelly rolls were arranged) was 43 mm, the width (the winding axis direction of the electrode jellyroll) was 33 mm, and the thickness was 4.2 mm. At this time, the measured discharge energy was about 1022 mWh and the energy density was about 171 Wh / l.

(Comparative Example 3)

An electrode jelly roll was prepared in the same manner as in Example 3, and a positive electrode tab (aluminum having a width of 3 mm) and a negative electrode tab (nickel having a width of 3 mm) were drawn out to the opposite sides of the electrode jelly roll. Three electrode jelly rolls were made in total and three electrode jelly rolls were arranged in a line so that the shortest interval between the curved portions of adjacent electrode jelly rolls was 2.5 mm. Unlike the third embodiment, however, three electrode jelly rolls are not connected in parallel and all the electrode tabs 21 and 22 are drawn out to the outside of the pouch 50 without breaking them, as shown in Fig. 35 .

The electrode jelly rolls were surrounded by two upper and lower pouch films, filled with the electrolyte of Example 1, and vacuum sealed to produce a laminate battery. The width of the sealing part was about 5 mm. The three positive electrode tabs 21 drawn out to the outside were welded and connected by a wire having an outer diameter of about 1 mm. The three negative electrode tabs 22 drawn out to the outside were connected by soldering to a wire having an outer diameter of about 1 mm. The length of the completed battery (arrangement direction of the electrode jelly roll) including the connection portion of the pouch 50 to the outside of the package was 42 mm, the width was 42 mm, and the thickness was 4.0 mm . At this time, the measured discharge energy was about 1007 mWh and the energy density was about 146 Wh / l.

(Comparative Example 4)

An electrode jelly roll was prepared in the same manner as in Example 3, and a positive electrode tab (aluminum having a width of 3 mm) and a negative electrode tab (nickel having a width of 3 mm) were drawn out to the opposite sides of the electrode jelly roll. Three electrode jelly rolls were made in total and three electrode jelly rolls were arranged in a line so that the shortest interval between the curved portions of adjacent electrode jelly rolls was 2.5 mm. However, unlike in Example 3, three electrode jelly rolls were connected in parallel by welding the lead tabs 41 and 42 with electrode taps having polarities as shown in Fig. 36 without breaking the electrode tabs.

The thus prepared electrode assembly was surrounded by two upper and lower pouch films, filled with the electrolyte of Example 1, and vacuum-sealed to produce a laminate battery. The width of the sealing part was about 5 mm. The length of the completed battery (arrangement direction of the electrode jelly roll) was 42 mm, the width (winding axis direction of the electrode jellyroll) was 42 mm, the thickness was 4.0 mm. At this time, the measured discharge energy was about 1014 mWh and the energy density was about 144 Wh / l.

(Example 4)

A positive electrode and a negative electrode were prepared in the same manner as in Example 1. An electrode jelly roll was fabricated with a polyethylene separator interposed between the anode and the cathode. The metal foil current collector of the positive electrode and the negative electrode and the electrode tab were welded and arranged in parallel with the winding axis direction at the center of the electrode jelly roll as the start of the winding of the electrode jelly roll. After winding the electrode jelly roll, . The positive electrode tab (aluminum of 3 mm width) and the negative electrode tab (nickel of 3 mm width) were drawn to the opposite sides of the electrode jelly roll. The width of the positive electrode plate was 19 mm, the width of the negative electrode plate was 21 mm, the width of the separating membrane was 23 mm, and the length of the electrode jellyroll after completion (that is, the distance between two opposed sides of both electrodes) was 23 mm, Was 8 mm, and the thickness (i.e., between the top surface and the bottom surface) was 3.3 mm.

A total of three electrode jelly rolls as described above were fabricated to produce a laminate battery having the structure shown in FIG. That is, three electrode jelly rolls were arranged in a row so that the shortest distance between the curved portions of the adjacent electrode jelly rolls was 2.5 mm, and two copper foils having a width of 10 mm and a thickness of 15 탆 were laid as conductive wires of the negative electrode, And two aluminum foils having a width of 10 mm and a thickness of 15 占 퐉 were stacked and welded to three positive electrode tabs, respectively, as lead wires of the positive electrode. The tabs were folded about 180 degrees around the sides of the electrode jelly rolls so that the leads were disposed adjacent to the outer surface of each electrode jelly roll. And the positive electrode lead tab 41 and the negative electrode lead tab 42 were welded again to the ends of the positive electrode and the negative electrode lead, respectively, thereby completing an electrode assembly in which three electrode jelly rolls were connected in parallel.

The electrode assembly was surrounded by two upper and lower pouch films, filled with the electrolyte of Example 1, and then vacuum-sealed to produce a laminate battery. The width of the sealing part was about 5 mm. The length of the completed battery (arrangement direction of the electrode jelly rolls) was 43 mm, the width (winding axis direction of the electrode jelly roll) was 33 mm, the thickness was 3.8 mm. At this time, the discharge energy measured at the flat state of the cell was 915 mWh, and the discharge energy measured at the curved radius of 10 mm was 922 mWh. The discharge energy was 920 mWh after 1000 cycles of bending with a radius of curvature of 10 mm.

In the above embodiments, the discharge capacity was measured with a TOYO SYSTEM TOSCAT-3000 system. Charging and discharging were carried out at 25 ° C, and the cut-off voltage was 3.0 to 4.35 V. Example 1, Example 2, Comparative Example 1 and Comparative Example 2 were subjected to initial charging and discharging at 24.4 mA, and discharge energy was measured at 121.8 mA. In Example 3, Comparative Example 3, and Comparative Example 4, initial charging and discharging were performed at 30.7 mA, and discharge energy was measured at 153.3 mA. In Example 4, initial charging and discharging were performed at 25.0 mA, and discharge was performed at a current of 125.0 mA to measure discharge energy.

Although the winding type electrode assembly including the jar roll has been described so far, the above-described configuration can be applied to the stacked electrode assembly including the electrode assembly. For example, FIG. 37 is a perspective view schematically showing an electrode assembly 200 according to another embodiment. Referring to FIG. 37, the electrode assembly 70 may include first and second electrode tabs 61 and 62 extended from the electrode stack 70. Here, at least one end of the first electrode tab 61 and the second electrode tab 62 may be bent in the opposite direction from the pull-out direction so as to face the outer surface of the electrode stack body 70. 37 illustrate that both the first electrode tab 61 and the second electrode tab 62 are opposed to the outer surface of the electrode stack 70, May be opposed to the outer surface of the electrode stack body 70.

38 is a cross-sectional view schematically showing the electrode laminate 70 of the electrode assembly 200 shown in Fig. 38, the electrode stack 70 includes a plurality of first electrode plates 72, 73, a plurality of second electrode plates 75, 76, a plurality of first electrode plates 72, 73, And a plurality of insulating separators 74 interposed between the plurality of second electrode plates 75 and 76, respectively. The first electrode plates 72 and 73 and the second electrode plates 75 and 76 are positioned such that the separation membrane 74 is positioned between the first electrode plates 72 and 73 and the second electrode plates 75 and 76, The electrode stack body 70 can be formed by stacking a plurality of separation membranes 74 and a plurality of second electrode plates 75 and 76. In FIG. 38, the first electrode plates 72 and 73 are positioned at the bottom and top of the electrode stack 70, but the invention is not limited thereto. Each of the first electrode plates 72 and 73, the second electrode plates 75 and 76, and the separation membrane 74 may be in the form of a flat plate, but are not limited thereto. For example, it is also possible to make the electrode laminate 70 and then bend it. It is also possible that the electrode stack 70 includes only one first electrode plate 72, 73, separation membrane 74 and second electrode plate 75, 76. At least one of the first electrode plates 72 and 73, the second electrode plates 75 and 76 and the separator 74 may form the electrode stack 70 in a folding manner. For example, the separator 74 may be stacked in a folded manner to form a single serpentine separation membrane 74 between the first and second electrode plates 72 and 73 and the plurality of second electrode plates 75 and 76, So that the electrode stack body 70 can be formed.

Each of the first electrode plates 72 and 73 of the electrode stack body 70 has a first electrode collector 72 and a first active material layer 73 applied to the first electrode collector 72 . Similarly, each of the second electrode plates 75 and 76 may include a second electrode current collector 75 and a second active material layer 76 applied to the second electrode current collector 75. For example, the first electrode plates 72 and 73 may be a positive electrode plate, and the first active material layer 73 may be formed by mixing a positive electrode active material, a conductive material, and a binder. The second electrode plates 75 and 76 may be a negative electrode plate, and the second active material layer 76 may be formed by mixing a negative electrode active material, a conductive material, and a binder. 38, the electrode laminate 70 is shown to include a plurality of separated first electrode current collectors 72 and a plurality of separated second electrode current collectors 75. However, The current collector 72 and the second electrode current collector 75 may be provided only.

Referring again to FIG. 37, the outer surface of this electrode stack 70 may include an upper surface 70a and a lower surface 70e that are perpendicular to the stacking direction of the electrode stack 70 and opposed to each other. The electrode stacked body 70 has a first side face 70d and a second side face 70f parallel to the stacking direction of the electrode stacked body 70 and parallel to the stacking direction of the electrode stacked body 70 And a front surface 70b and a back surface 70c facing each other. The upper surface 70a and the lower surface 70e may be formed as a smooth surface and the gap between the upper surface 70a and the lower surface 70e may be constant. For example, the upper surface 70a and the lower surface 70e may be formed of any one of the first electrode current collector 72 and the second electrode current collector 75. The first electrode plates 72 and 73, the separation membrane 74 and the second electrode plates 75 and 76 are formed on the first side surface 70d and the second side surface 70f and the front surface 70b and the back surface 70c. May be partially exposed. Thus, the first side 70d and the second side 70f, and the front 70b and the back 70c are not one surface that is connected smoothly, but the first electrode plate 72, 73, separator 74, And the edges of the second electrode plates 75 and 76 are connected to each other.

The first electrode tabs 61 may be electrically connected to the first electrode plates 72 and 73 and the second electrode tabs 62 may be electrically connected to the second electrode plates 75 and 76. The first electrode tab 61 may be drawn out from the first side surface 70d of the electrode stack 70 in a direction perpendicular to the first side surface 70d. The first electrode tab 61 can be bent at about 180 degrees (that is, in the opposite direction to the drawing direction) so that its end portion faces the upper surface 70a of the electrode stack body 70. Further, the second electrode tab 62 can be drawn out from the second side surface 70f of the electrode stack body 70 in a direction perpendicular to the second side surface 70f. The second electrode tab 62 may then be bent about 180 degrees such that its end is opposite the top surface 70a of the electrode stack 70. [ 37 that the first electrode tab 61 and the second electrode tab 62 are drawn out from the first side surface 70d and the second side surface 70f opposite to each other, 61 and the second electrode tab 62 may both be pulled out from the first side face 70d or both may be pulled out from the second side face 70f.

Here, the ends of the first and second electrode tabs 61 and 62 may be completely in contact with the upper surface 70a of the electrode stack 70, but may be spaced apart at a slight interval. Considering that the energy density of the battery may be lowered when the distance between the end of the first and second electrode tabs 61 and 62 and the upper surface 70a is excessively large, the first and second electrode tabs 71 , 72 and the upper surface 70a may be, for example, within 1 mm. The ends of the first and second electrode tabs 61 and 62 may be formed on the upper surface 70a of the electrode stack 70 so as to prevent electrical shorting when the upper surface 70a of the electrode stack 70 is contacted. An insulating film 65 may be disposed on the insulating film 70a.

37, when the electrode laminate 70 has a plurality of first electrode plates 72 and 73 and a plurality of second electrode plates 75 and 76, The plurality of first electrode tabs 61 may be drawn out from the first side surface 70d of the first electrode tab 70 and the plurality of second electrode tabs 62 may be drawn out of the second side surface 70f. The plurality of first electrode tabs 61 may be joined together and bent together on the upper surface 70a of the electrode stack body 70. [ Likewise, a plurality of second electrode tabs 62 may also be joined together and bent together over the top surface 70a of the electrode stack 70. The plurality of first electrode tabs 61 are electrically connected to the plurality of first electrode plates 72 and 73 and the plurality of second electrode tabs 62 are electrically connected to the plurality of second electrode plates 75 and 76 Respectively. For example, the plurality of first electrode tabs 61 may be respectively connected to the electrode uncoated portions of the first electrode current collectors 72, or may be connected to the electrode uncoated portions of the plurality of first electrode current collectors 72 Or may be an integral extension. The plurality of second electrode tabs 62 may be respectively connected to the electrode uncoated portions of the plurality of second electrode current collectors 25 or may be integrally formed from the electrode uncoated portions of the plurality of second electrode current collectors 25 It may be extended.

37, the electrode assembly 200 shown in FIG. 37 includes a first lead 31 electrically connected to the first electrode tab 61, and a second lead 31 electrically connected to the second electrode tab 22, And a second conductive line 32 formed on the second conductive line. The first conductive line 31 and the second conductive line 32 may extend in a direction perpendicular to the drawing direction of the first electrode tab 61 and the second electrode tab 22 as shown in FIG. Although the first and second leads 31 and 32 are shown protruding from the back surface 70c of the electrode assembly 200 in FIG. 39, they may protrude from the front surface 70b. The first and second leads 31 and 32 may be formed in a long, flat sheet-like shape. For example, the widths of the first and second conductors 31 and 32 may be at least ten times the thickness, for example, about 50 to 10,000 times. These sheet-like first and second leads 31 and 32 may be useful when flexibly connecting a plurality of electrode stacks 70. Although the first and second leads 31 and 32 are shown below the first and second electrode tabs 61 and 62 in FIG. 39, the first and second electrode tabs 61 and 62, 62, respectively.

40 is a perspective view schematically showing an electrode assembly 210 according to another embodiment in which a plurality of electrode stacks 70 are connected in parallel. 40, the electrode assembly 210 includes a plurality of electrode stacks 70 and a plurality of first and second electrode tabs 61 and 62, respectively, disposed on the plurality of electrode stacks 70 . The plurality of electrode stacks 70 can be electrically connected in parallel through the first and second leads 31 and 32. [ To this end, a first conductive line 31 extending in a direction perpendicular to the drawing direction of the first electrode tab 61 is electrically connected to the plurality of first electrode tabs 21, One second conductive line 32 extending in a direction perpendicular to the drawing direction of the second electrode tabs 62 may be electrically connected to the plurality of second electrode tabs 22. Although not shown in FIG. 40, the first and second lead tabs 41 and 42 shown in FIG. 23 may be connected to the first and second leads 31 and 32, respectively. The use of the electrode assembly 210 shown in FIG. 40 makes it possible to realize a flexible battery having high reliability and durability, and the energy density of the flexible battery can be increased.

41 is a perspective view schematically showing an electrode assembly 220 according to yet another embodiment. In the embodiment shown in FIG. 41, the first electrode tab 61 and the second electrode tab 62 may each include two portions. For example, the first electrode tab 61 may include a plurality of first portions 61a that are drawn out to the first side surface 70d of the electrode stack body 70 and bonded to each other, And a second portion 61b bent at about 90 degrees to face the first side surface 70a and the first side surface 70d at the same time. The first portion 61a and the second portion 61b of the first electrode tab 61 may be joined to each other on the first side surface 70d of the electrode stack body 70. [ For example, the first portion 61a may be formed by protruding electrode fingers of a plurality of the first electrode current collectors 72 to the first side face 70d of the electrode stack 70. [ The first portion 61a may be bent about 180 degrees to enclose two opposing outer surfaces of the second portion 61b and the second portion 61b may be bent such that the first portion 61a is bent about 180 degrees And can be fitted into the formed groove.

Likewise, the second electrode tab 62 includes a plurality of first portions 62a drawn out to the second side surface 70f of the electrode stack body 70 and bonded to each other, and an upper surface 70a of the electrode stack body 70 And a second portion 62b that is bent at about 90 degrees to face the second side surface 70f at the same time. The first portion 62a and the second portion 62b of the second electrode tab 62 may be joined to each other on the second side surface 70f of the electrode stack body 70. [ For example, the first portion 62a of the second electrode tab 62 protrudes from the second side surface 70f of the electrode stack 70 to the electrode unions of the plurality of second electrode collectors 75 May be formed. The first portion 62a of the second electrode tab 62 may be bent about 180 degrees so as to surround the opposite two surfaces of the end region of the second portion 62b, The second portion 62b can be fitted in the groove formed by bending the first portion 62a by about 180 degrees.

41, the electrode assembly 220 shown in FIG. 41 also includes a first lead 31 electrically connected to the first electrode tab 61, and a second lead 31 electrically connected to the second electrode tab 22 electrically. And may further include a second lead wire 32 connected thereto. For example, the first conductor 31 may be bonded to the second portion 61b of the first electrode tab 61 on the upper surface 70a of the electrode stack 70, May be bonded to the second portion 62b of the second electrode tab 62 on the upper surface 70a of the electrode stack 70. [ Further, by using the first conductor 31 and the second conductor 32, the plurality of electrode stacks 70 shown in Fig. 41 can be connected in parallel, as in the embodiment shown in Fig.

Up to now, to facilitate understanding of the present invention, an exemplary embodiment of a wound electrode assembly and a secondary battery having the same is described and shown in the accompanying drawings. It should be understood, however, that such embodiments are merely illustrative of the present invention and not limiting thereof. And it is to be understood that the invention is not limited to the details shown and described. Since various other modifications may occur to those of ordinary skill in the art.

10, 10 '..... electrode jelly roll 11, 12 ..... electrode plate
13 ..... membrane 16 ..... insulating film
21, 22, 61, 62 ..... electrode tabs 31, 32 ..... wires
41, 42 ..... lead tab 43 ..... thermoplastic material
50 ..... Pouch 70 ..... Electrode laminate
100, 110, 120, 130, 140, 150, 160, 170, 180,
200, 210, 220 ..... electrode assembly

Claims (39)

A first electrode plate, a second electrode plate, and a separator interposed between the first electrode plate and the second electrode plate are wound together to form an outer surface parallel to the winding axis and two mutually opposed An angular electrode jellyroll having a side surface;
A first electrode tab electrically connected to the first electrode plate and extending in a winding axis direction of the electrode jelly roll; And
And a second electrode tab electrically connected to the second electrode plate and extending in a winding axis direction of the electrode jelly roll,
Wherein at least one of the first electrode tab and the second electrode tab is bent in an opposite direction from the pulling direction and disposed to face the outer surface of the electrode jellyroll. The method according to claim 1,
Wherein the first electrode plate includes a first electrode current collector and a first active material coated on the first electrode current collector, the second electrode plate includes a second electrode current collector and a second electrode current collector coated on the second electrode current collector, 2 active material,
The first electrode tab is fixed to the electrode uncoated portion of the first electrode current collector to which the first active material is not applied and the second electrode tab is fixed to the electrode uncoated portion of the second electrode current collector to which the second active material is not applied, Wherein the electrode assembly is fixed to the base. The method according to claim 1,
Wherein the first electrode plate includes a first electrode current collector and a first active material coated on the first electrode current collector, the second electrode plate includes a second electrode current collector and a second electrode current collector coated on the second electrode current collector, 2 active material,
Wherein the first electrode tab is a portion of the electrode uncoated portion of the first electrode current collector protruding in a direction perpendicular to the longitudinal direction of the first electrode current collector, Wherein the electrode assembly is part of an electrode non-conductive portion of the second electrode current collector protruding in a direction perpendicular to the longitudinal direction. The method according to claim 1,
Wherein the first electrode tab and the second electrode tab each serve as a lead tab. The method according to claim 1,
Wherein an outer surface parallel to the winding axis of the electrode jelly roll includes a flat upper surface and a lower surface opposite to each other and wherein the electrode jellyroll further comprises two curved surfaces between the upper surface and the lower surface. 6. The method of claim 5,
Wherein the first electrode tab and the second electrode tab are drawn from the same one side. 6. The method of claim 5,
Wherein the first electrode tab and the second electrode tab are drawn from two opposite sides, respectively. 8. The method of claim 7,
Wherein a line extending in the winding axis direction of the first electrode tab and a line extending in the winding axis direction of the second electrode tab correspond to each other. 8. The method of claim 7,
Wherein a line extending in the winding axis direction of the first electrode tab and a line extending in the winding axis direction of the second electrode tab do not coincide with each other. 6. The method of claim 5,
Wherein a position of a portion where the first electrode plate and the first electrode tab are connected and a position of a portion where the second electrode plate and the second electrode tab are connected are different from each other in the height direction of the electrode jelly roll. 6. The method of claim 5,
Wherein the first electrode tab is bent to face the upper surface and the second electrode tab is bent to face the lower surface. 6. The method of claim 5,
Wherein at least one of the first electrode tab and the second electrode tab includes a first tab portion embedded in the electrode jellyroll roll, a second tab portion opposed to one of the side surfaces, and a third tab portion opposed to the upper surface or the lower surface, Wherein the first tab portion and the third tab portion extend in the direction of the winding axis and the second tab portion extends in a direction perpendicular to the winding axis so that the first tab portion and the third tab portion do not overlap each other, Assembly. 13. The method of claim 12,
At least one of the first electrode tab and the second electrode tab further includes a fourth tab portion extending from the third tab portion in a direction perpendicular to the winding axis. The method according to claim 1,
Wherein the first electrode plate includes a first electrode current collector and a first active material coated on the first electrode current collector, the second electrode plate includes a second electrode current collector and a second electrode current collector coated on the second electrode current collector 2 active material,
The end of the electrode non-coated portion of the first electrode current collector exposed to the outside of the electrode jellyroll forms the first electrode tab without the first active material applied thereto, and the second active material is not coated, And an end of the electrode non-coated portion of the second electrode collector exposed to the outside of the electrode jelly roll forms the second electrode tab. 15. The method of claim 14,
At least one of an end portion of the electrode non-coated portion of the first electrode current collector exposed to the outside of the electrode jelly roll and an end portion of the electrode non-coated portion of the second electrode current collector exposed to the outside of the electrode jellyroll roll, To be pulled out. 16. The method of claim 15,
Wherein a part of the end of the first electrode current collector or the electrode non-coin part of the second electrode current collector folded to be pulled out in the winding axis direction is bent in the opposite direction from the drawing direction. The method according to claim 1,
Wherein the first electrode plate includes a first electrode current collector and a first active material coated on the first electrode current collector, the second electrode plate includes a second electrode current collector and a second electrode current collector coated on the second electrode current collector 2 active material,
And an end of the electrode non-coated portion of the first electrode current collector to which the first active material is not applied forms the outer surface of the electrode jellyroll. 18. The method of claim 17,
Wherein a portion of the second electrode tab is embedded in the electrode jelly roll and is drawn out from the inside of the electrode jelly roll, and the first electrode tab is formed on an end portion of the electrode non-coated portion of the first electrode current collector exposed to the outside Wherein the electrode assembly is disposed within the housing. The method according to claim 1,
Wherein a plurality of first electrode tabs and a plurality of second electrode tabs are disposed for one electrode jellyroll. The method according to claim 1,
Wherein at least one of the first electrode tab and the second electrode tab opposite the outer surface of the electrode jelly roll has a first portion parallel to the winding axis and a first portion parallel to the winding axis and parallel to the outer surface of the electrode jelly roll And a second portion extending from the first portion in one direction. 21. The method of claim 20,
Wherein at least one of the first electrode tab and the second electrode tab opposing the outer surface of the electrode jellyroll roll extends from the second portion in a direction perpendicular to the winding axis and perpendicular to the outer surface of the electrode jellyroll And a third portion of the second electrode. The method according to claim 1,
Wherein the lengths of the first and second electrode tabs are different. The method according to claim 1,
A first lead electrically connected to the first electrode tab, and a second lead electrically connected to the second electrode tab. 24. The method of claim 23,
A first lead tab electrically connected to the first lead, and a second lead tab electrically connected to the second lead. 24. The method of claim 23,
Wherein the first and second leads are formed in a sheet shape, and the widths of the first and second leads are 10 times to 10000 times the thickness. 24. The method of claim 23,
Wherein the first and second leads comprise at least one of aluminum, copper, stainless steel, and nickel. The method according to claim 1,
A first lead tab electrically connected to the first electrode tab, and a second lead tab electrically connected to the second electrode tab. The method according to claim 1,
A plurality of electrode jelly rolls and a plurality of first and second electrode tabs respectively disposed in the plurality of electrode jelly rolls, wherein the plurality of electrode jelly rolls are electrically connected in series. The method according to claim 1,
Wherein the electrode jelly roll further comprises two curved surfaces between the upper surface and the lower surface, wherein the upper surface and the lower surface are opposite to each other, Wherein the gap between the lower surfaces is constant and the upper surface and the lower surface are curved. The method according to claim 1,
Wherein an interval between at least one of the first electrode tab and the second electrode tab disposed opposite the outer surface of the electrode jelly roll and an outer surface of the electrode jelly roll is within 1 mm. The method according to claim 1,
Wherein the minimum radius of curvature in the bent portion of at least one of the first electrode tab and the second electrode tab disposed opposite the outer surface of the electrode jelly roll is in the range of 0.006 to 5 mm. A first electrode plate, a second electrode plate, and a separator are stacked so that a separation membrane is positioned between the first electrode plate and the second electrode plate, and the outer surface perpendicular to the stacking direction and the second electrode plate parallel to the stacking direction, An electrode stacked body having side surfaces;
A first electrode tab electrically connected to the first electrode plate and extended to one of two sides of the electrode stack body; And
And a second electrode tab electrically connected to the second electrode plate and extending to one of two sides of the electrode stack body,
Wherein at least one of the first electrode tab and the second electrode tab is bent in an opposite direction from the drawing direction and is arranged to face an outer surface of the electrode stack. 33. The method of claim 32,
A first conductor electrically connected to the first electrode tab and opposed to an outer surface of the electrode stack, and a second conductor electrically connected to the second electrode tab and opposed to an outer surface of the electrode stack, ≪ / RTI > 33. The method of claim 32,
The electrode assembly includes a plurality of first electrode plates and a plurality of second electrode plates, and a plurality of first electrode tabs electrically connected to the plurality of first electrode plates are bonded to each other, And a plurality of second electrode taps electrically connected to the plurality of second electrode plates are bonded to each other to be bent together with the outer surface of the electrode stack. 33. The method of claim 32,
Wherein the first electrode tab has a first portion drawn out to one side of the electrode stack and a second portion bent at an angle of about 90 degrees so as to face the outer surface of the electrode stacked body at the same time Wherein a first portion and a second portion of the first electrode tab are bonded to each other at any one side of the electrode stack. 36. The method of claim 35,
Wherein the first portion of the first electrode tab is bent about 180 degrees so as to surround the opposite two surfaces of the end region of the second portion. 36. An electrode assembly, comprising: an electrode assembly according to any one of claims 1 to 36;
A casing covering the electrode assembly; And
And an electrolyte contained in the outer casing together with the electrode assembly. 39. The method of claim 37,
At least a part of the first lead tab or the second lead tab connected to at least part of the first electrode tab or the second electrode tab of the electrode assembly or to the first electrode tab or the second electrode tab protrudes out of the casing The secondary battery. An electronic device comprising the secondary battery according to claim 38.

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