KR20170025772A - Electrode Assembly Comprising Separator Having Folded Edge - Google Patents

Abstract

The present invention relates to an electrode assembly, comprising: a positive electrode of which a positive electrode active material is applied on a current collector; a negative electrode of which a negative electrode active material is applied on a current collector; and a separator interposed between the positive electrode and the negative electrode, wherein the separator has the length extended in the outer direction beyond the outer peripheries of the positive electrode and the negative electrode corresponding to the outer peripheries. In the extended outer peripheries of the separator, at least one outer periphery is bent at least once in the inner direction.

Description

(Electrode Assembly Comprising Separator Having Folded Edge)

The present invention relates to an electrode assembly including a separator having an outer periphery bent.

In recent years, the demand for environmentally friendly alternative energy sources has become an indispensable factor for the future, as the increase in the price of energy sources due to depletion of fossil fuels and the interest in environmental pollution are amplified. Various researches on power generation technologies such as nuclear power, solar power, wind power, and tidal power have been continuing, and electric power storage devices for more efficient use of such generated energy have also been attracting much attention.

Particularly, as technology development and demand for mobile devices are increasing, the demand for batteries as energy sources is rapidly increasing, and accordingly, a lot of researches on batteries that can meet various demands have been conducted.

Typically, in terms of the shape of a battery, there is a high demand for a prismatic secondary battery and a pouch-type secondary battery which can be applied to products such as mobile phones with a small thickness, and has advantages such as high energy density, discharge voltage, There is a high demand for lithium secondary batteries such as lithium ion batteries and lithium ion polymer batteries.

Also, the secondary battery is classified according to the structure of the electrode assembly having the positive electrode, the negative electrode, and the separator interposed between the positive electrode and the negative electrode. Typically, the long battery- A stacked (stacked) electrode assembly in which a plurality of positive electrodes and negative electrodes cut in a predetermined size unit are sequentially stacked with a separator interposed therebetween, the jelly-roll type (wound type) electrode assembly having a structure in which a separator is interposed; In recent years, in order to solve the problems of the jelly-roll type electrode assembly and the stack type electrode assembly, an electrode assembly having an advanced structure, which is a combination of the jelly-roll type and the stack type, A stack / folding type electrode having a structure in which unit cells stacked with a separator interposed between an anode and a cathode are sequentially wound while being placed on a separation film Developed body lip.

FIG. 1 is a schematic view schematically showing an end structure of a conventional electrode assembly.

Referring to FIG. 1, an electrode assembly 100 includes an anode 110, a cathode 120, and a separator 130 interposed between the anode 110 and the cathode 120.

The separator 130 has a length in which the outer periphery 131 extends outward beyond the outer peripheries 111 and 121 of the anode 110 and the cathode 120.

In general, the separator 130 of the electrode assembly 100 uses an insulating thin film having high ion permeability and mechanical strength. For example, an olefin polymer such as polypropylene, which is chemically resistant and hydrophobic; A sheet or nonwoven fabric made of glass fiber, polyethylene or the like is used.

Accordingly, when the temperature of the electrode assembly 100 itself rises abnormally due to the operation of the secondary battery at a high temperature or the continuous charging / discharging, the separation membrane 130 may be shrunk by heat, The anode 110 and the cathode 120 are directly brought into contact with each other 140. This increases the risk of internal short-circuiting of the secondary battery and the generation of a toxic substance, thereby deteriorating the safety of the secondary battery.

Therefore, there is a high need for a technique capable of fundamentally solving such problems.

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

The inventors of the present application have conducted intensive studies and various experiments and have found that at least one outer periphery of the separating membrane constituting the electrode assembly is bent at least once in the inner direction The outer periphery of the bent separator has a thicker thickness than other portions of the separator interposed between the positive and negative electrodes so that the outer periphery of the separator is separated from the space between the positive and negative electrodes It is possible to prevent the risk of an internal short circuit or fire that may be caused by direct contact between the anode and the cathode and to improve the safety of the electrode assembly, And has reached the completion of the invention.

According to an aspect of the present invention, there is provided an electrode assembly comprising:

A positive electrode on which a positive electrode active material is applied on a current collector;

A negative electrode to which a negative electrode active material is applied on a current collector; And

A separator interposed between the anode and the cathode;

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The separator has a length which extends in the outer direction beyond the outer peripheries of the anode and the cathode corresponding to the outer peripheries,

Among the extended outer peripheries of the separator, at least one outer peripheries may be bent at least one time in the inner direction.

Therefore, the outer periphery of the bent separator has a thicker thickness than other portions of the separator interposed between the positive electrode and the negative electrode, so that the outer periphery of the separator is separated from the space between the anode and the cathode So that the risk of an internal short circuit or fire which may be caused by direct contact between the anode and the cathode can be prevented and the safety of the electrode assembly can be improved.

In one specific example, the positive electrode and the negative electrode have the same shape in a plan view, and the negative electrode may be a structure having a relatively larger size than the positive electrode.

Generally, a lithium secondary battery has a structure in which a non-aqueous electrolyte containing a lithium salt is impregnated in an electrode assembly in which a porous polymer film is interposed between a positive electrode and a negative electrode coated with a coating layer on a current collector. The anode coating layer is mainly composed of a lithium cobalt oxide, a lithium manganese oxide, a lithium nickel oxide, a lithium composite oxide and the like, and the cathode coating layer is mainly composed of a carbon-based material.

However, in the lithium secondary battery using the carbon-based material as the negative electrode coating layer, irreversible capacity is generated from a part of the lithium ions inserted into the layered structure of the carbon-based material at the time of the initial charge / discharge, resulting in a decrease in the discharge capacity. Also, the carbon material has a low oxidation / reduction potential of about 0.1 V relative to the potential of Li / Li +, which causes decomposition of the nonaqueous electrolyte on the surface of the negative electrode. The carbon material reacts with lithium to form a passivating layer or a solid electrolyte interface (SEI film) is formed. These SEI membranes have different thicknesses and states at the interface depending on the electrolyte system used, which affects the charging and discharging characteristics. Moreover, in a secondary battery such as a power tool, which is used in a field where high output characteristics are required, even with such a thin SEI film, the resistance can be increased to become a rate determining step (RDS). Further, since the lithium compound is generated on the surface of the negative electrode, the reversible capacity of lithium gradually decreases with repetition of charging and discharging, resulting in a decrease in discharge capacity and a cycle deterioration.

Therefore, since the anode and the cathode have the same shape in plan view, the electrode assembly according to the present invention maximizes an area where the anode and the cathode face each other with the separator interposed therebetween, thereby maximizing the electrical performance, It is possible to eliminate or minimize the problem of the decrease of the discharge capacity and the occurrence of the SEI film due to the relatively large size of the anode.

The separation membrane may have the same shape as the anode and the cathode in plan view.

As described above, the positive electrode and the negative electrode have the same shape in a planar manner. Accordingly, the separator also has the same shape in plan view as the positive electrode and the negative electrode, thereby completely separating the positive electrode and the negative electrode, It is possible to prevent direct contact.

However, the shape of the separator is not limited thereto, and the outer peripheries extend in the outer direction relative to the outer peripheries of the anodes and the cathodes so as to completely separate the anodes and the cathodes from each other between the anodes and the cathodes, It is of course possible to have a shape which is different from the anode and the cathode in plan view if the structure is such that at least one outer periphery can be bent at least once in the inner direction.

However, since the separation membrane has the same shape in plan view as the anode and the cathode, the use of unnecessary separation membrane can be minimized, thereby minimizing the cost of manufacturing the electrode assembly.

Among the extended outer peripheries of the separator, the extended length of the outer perimeter excluding the outer peripheries bent in the inward direction is preferably 1% to 30% of the width or length of the anodes and cathodes corresponding to the extending direction . ≪ / RTI >

If the extension length of the outer periphery of the outer periphery of the separator except for the outer periphery bent in the inner direction is too small beyond the above range, even if the remaining outer periphery of the separation membrane is finely shrunk, In contrast, if the electrode assembly is excessively large beyond the above range, the overall size of the electrode assembly including the separation membrane becomes excessively large or unnecessary portions of the separation membrane occur, There is a problem in that it increases.

In one specific example, among the extended outer peripheries of the separator, the extension length of the outer peripheries that are bent in the inner direction may be a size of 200% to 800% of the extension length of the outer perimeter.

In this case, among the extended outer peripheries of the separator, the extension length after the outer peripheries bent in the inner direction are bent may have the same structure as the extension length of the outer peripheries.

As described above, the outer periphery of the separator that is bent in the inward direction may be a structure that is bent at least once.

Therefore, the outer periphery of the separating film which is bent in the inward direction is maintained to extend in the outward direction beyond the outer peripheries of the corresponding anode and cathode, and the extended length of the outer perimeter after being bent in the inward direction, The same size as that of the conventional electrode assembly can be maintained, while contraction of the separator due to heat can be more easily prevented.

If the extension length of the outer periphery which is bent in the inner direction among the extended outer periphery of the separation membrane is less than 200% of the extension length of the remaining outer periphery, the length of the outer periphery bent in the inner direction When the extension length of the outer periphery bent in the inner direction exceeds 800% with respect to the extension length of the outer periphery of the remaining portion, The thickness of the outer periphery of the bent separator becomes too thick to cause interference with the separator located at a different site, thereby lowering the structural stability of the electrode assembly, such as lowering the adhesion of the anode and the cathode to the separator. .

In addition, among the extended outer peripheries of the separator, the thickness of the outer peripheries bent in the inward direction may be 20% to 100% of the thickness of the adjacent anodes or cathodes.

If the thickness of the outer periphery bent in the inward direction after bending is less than 20% of the thickness of the adjacent anode or cathode, the thickness after the bending may be too thin to achieve a desired effect, When the thickness of the adjacent anode or cathode exceeds 100%, the structural stability of the electrode assembly may be reduced, for example, the adhesion between the anode and the cathode to the separator may be reduced as described above.

On the other hand, among the extended outer peripheries of the separator, the outer peripheries bent in the inner direction may be thermally fused after being bent.

More specifically, when the extended outer peripheries of the separation membrane are bent in the inner direction, due to the physical characteristics of the separation membrane, they return to their original state, or when they are contracted by the heat of the separation membrane, The outer periphery that is bent in the inward direction among the extended outer peripheries of the separation membrane is thermally fused after being bent so as to stably maintain the bent state, The direct contact between the anode and the cathode due to the heat shrinkage of the anode can be prevented.

At this time, the thermal fusion may be performed at a temperature ranging from 40 degrees Celsius to 150 degrees Celsius.

If the thermal fusion is performed in a temperature range of less than 40 degrees Celsius, the thermal fusing temperature may be too low to achieve the desired effect of thermal fusion, The extended outer periphery of the separator may be rather contracted, damaged or deformed by the thermal fusion.

In one specific example, among the extended outer peripheries of the separator, the outer peripheries bent in the inner direction are at least two or more, and the extensions of the outer peripheries bent in the inner direction may be the same or different.

More specifically, the conventional electrode assembly includes at least two or more outer peripheries. Accordingly, the electrode assembly according to the present invention is also characterized in that, among the extended outer peripheries of the separator, By containing at least two of them, contraction of the separator due to heat can be effectively prevented.

In this case, the extension lengths of the outer peripheries bent in the inward direction may be the same or different from each other. More specifically, the electrode assembly may have various shapes such as a circular shape, a triangle shape, And the length of each outer periphery may vary, so that the outer periphery having a relatively higher probability of shrinkage due to heat may have a longer extension length.

In addition, the anode, the cathode, and the separator may have a rectangular shape in a plan view, and only the outer peripheries having a relatively short length may be bent inward in the extended outer periphery of the separator.

Generally, when the anode, the cathode, and the separator are formed in a rectangular shape in a plane, the extended outer peripheries of the separator have a first outer periphery and a third outer periphery having a relatively short length, and a relatively long length The second outer periphery and the fourth outer periphery.

In this case, the distance between the first outer circumference and the third outer circumference is longer than the length between the second outer circumference and the fourth outer circumference, so that contraction occurs at the same ratio between the outer circumference and the outer circumference The contraction length due to heat generated between the first outer circumference and the third outer circumference can be relatively larger between the second outer circumference and the fourth outer circumference.

Therefore, when the anode, the cathode, and the separator are formed in a rectangular shape in a plane, only the outer peripheries of both sides having at least a relatively short length among the extended outer peripheries of the separator, By bending, separation membrane shrinkage can be minimized.

Here, in order to maximize the effect of the present invention, it is needless to say that the extended outer peripheries of the separator may be all bent inward, regardless of their length.

According to another aspect of the present invention, there is provided a battery cell including the electrode assembly, wherein the electrode assembly includes electrode terminals extending in one side or opposite sides of the electrode assembly, It may be a structure in which the assemblies are wound in a long sheet-like separation film and embedded in the battery case together with the electrolytic solution.

In this case, the separation film may have a structure in which the outer periphery of the separation film at the portion where the electrode terminals are exposed and / or the portion opposite thereto extends relatively to the outer periphery of the anode and the cathode.

More specifically, the separation film may be wrapped around the side surface of the electrode assembly so that the electrode terminals of the electrode assembly are exposed to the outside and interposed between the electrode assemblies.

Accordingly, when the separation film is shrunk by heat, shrinkage may occur at a portion where the electrode terminals of the electrode assembly are exposed and / or at a portion opposed to the electrode terminal. To prevent the problem, And the outer periphery of the separating film at the opposite side and / or the opposite side of the separating film may extend relative to the outer periphery of the anode and the cathode.

At this time, the separation film may have a structure in which a portion where the electrode terminals are exposed and / or an extended outer periphery of the portion facing the electrode terminal is bent at least once in the inward direction.

In other words, since the separation film is interposed between the outermost positive electrode and the negative electrode of the electrode assemblies adjacent to each other like the separation membrane interposed between the positive electrode and the negative electrode of the electrode assembly, the separation film may also suffer from heat shrinkage Wherein at least a portion of the electrode assembly is exposed and the outer periphery of the portion where the electrode terminals are exposed and / or the outer periphery thereof is bent at least once in the inward direction, It is possible to prevent the phenomenon that the cathode contacts directly.

Also, as with the separator interposed between the positive electrode and the negative electrode of the electrode assembly, the thickness of the elongated outer periphery of the separator film is 20% to 100% of the thickness of the positive electrode or negative electrode of the electrode assembly adjacent thereto Size.

If the thickness of the bent outer periphery is less than 20% of the thickness of the positive electrode or the negative electrode of the adjacent electrode assembly, the thickness of the outer periphery of the bent electrode may be excessively thin, If the thickness of the positive electrode or the negative electrode of the adjacent electrode assembly is more than 100%, the adhesion between the positive electrode and the negative electrode of the electrode assembly facing the separation film may be deteriorated.

In addition, the bent outer circumference of the separation film may be thermally fused, so that the bending elongated outer circumference returns to its original state due to the physical properties of the separation film And it is possible to effectively prevent the direct contact between the positive electrode and the negative electrode of the adjacent electrode assemblies by heat shrinkage of the separation film by stably maintaining the bent state around the outer periphery.

According to another aspect of the present invention, there is provided a method of manufacturing the battery cell,

a) fabricating at least two electrode assemblies whose outer periphery is relatively extended relative to the outer periphery of the anode and cathode;

b) bending the outer periphery of the electrode terminals extended portion and / or the outer periphery thereof facing the outer periphery of the separator of the electrode assemblies in the inward direction and thermally fusing the electrode terminals;

c) arranging the electrode assemblies on an elongate sheet-shaped separation film so that the electrode terminals of the electrode assemblies are aligned in the same direction or opposite to each other;

b) bending and fusing the outer periphery of the separating film, the outer periphery of a portion corresponding to the electrode terminals of the electrode assemblies and / or a portion facing the electrode terminals;

e) winding the electrode assemblies by a separation film;

f) sealing the electrode assemblies wound with the separation film in a battery case together with an electrolytic solution;

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That is, among the outer peripheries of the separating film constituting the battery cell, the portions corresponding to the electrode terminals of the electrode assemblies and / or the outer peripheries of the portions facing the electrode terminals may be formed by winding the electrode assemblies Bending and heat-sealing are performed.

The present invention also provides a device including a battery pack including the battery cell and a sac battery pack as a power source, wherein the device is used for a mobile phone, a tablet computer, a notebook computer, a power tool, a wearable electronic device, An electric vehicle, a plug-in hybrid electric vehicle, and a power storage device.

Since the battery pack and the device are well known in the art, a detailed description thereof will be omitted herein.

As described above, the electrode assembly according to the present invention is configured such that at least one outer periphery of at least one outer periphery of the separation membrane constituting the electrode assembly is bent at least once in the inward direction, The periphery of the separator is thicker than other portions of the separator interposed between the anode and the cathode so that the outer periphery of the separator is physically prevented from contracting to a space between the anode and the cathode by heat or heat at a high temperature. Accordingly, there is an effect that the risk of an internal short circuit or fire which may be caused by direct contact between the anode and the cathode is prevented, and the safety of the electrode assembly is improved.

1 is a schematic view schematically showing an end structure of a conventional electrode assembly;
2 is a schematic view schematically showing the structure of an electrode assembly according to one embodiment of the present invention;
3 is a schematic view illustrating a pre-winding structure of an electrode assembly assembly constituting a battery cell according to another embodiment of the present invention;
4 is a vertical cross-sectional view schematically illustrating an outer peripheral structure of the electrode assembly assembly of FIG.

Hereinafter, the present invention will be described in detail with reference to the drawings according to the embodiments of the present invention, but the scope of the present invention is not limited thereto.

FIG. 2 is a schematic view schematically showing the structure of an electrode assembly according to an embodiment of the present invention.

2, the electrode assembly 200 includes an anode 210, a cathode 220, and a separator 230 interposed between the anode 210 and the cathode 220.

The anode 210, the cathode 220 and the separator 230 have a rectangular shape in a plan view and the cathode 220 has a relatively large size as compared with the anode 210.

The anode 210 and the cathode 220 each include a cathode terminal 215 and a cathode terminal 225 formed in the same outer peripheral direction.

The separator 230 has a larger size than the anode 210 and the cathode 220 so that the outer peripheries 231, 232, 233 and 234 of the separator 230 are connected to the corresponding anode 210, And the outer periphery of the cathode 220.

Outer periphery 231 232 232 233 234 of the separator 230 has a second outer periphery 232 adjacent to the first outer periphery 231 in the direction in which the positive electrode terminal 215 and the negative electrode terminal 225 protrude The extension length 231a of the first outer periphery 231 is equal to the extension length 231a of the second outer periphery 231 with respect to the outer periphery of the anode 210, Is 200% of the extension length 232a, 234a of the outer periphery 232 and the fourth outer periphery 234.

The extension length 233a of the third outer periphery 233 opposed to the first outer periphery 231 is larger than the extension length 233a of the second outer periphery 232 and the fourth outer periphery 234 Of the extension lengths 232a and 234a of the protrusions 232a and 234a.

According to the above structure, the first outer periphery 231 and the third outer periphery 233 of the separation membrane 230 are bent once and twice inwardly, respectively, and the first outer periphery 231 and the second outer periphery 231, The extension lengths 231b and 233b of the outer periphery 233 are the same as the extension length 232a and 234a of the second outer periphery 232 and the fourth outer periphery 234, respectively.

Here, the first outer periphery 231 is bent at a smaller number of times than the third outer periphery 233 facing the first outer periphery 233 so as to avoid interference with the positive electrode terminal 215 at the time of bending.

The first outer periphery 231 and the third outer periphery 233 are thermally welded while bent inward so that the separation membrane 230 excluding the first outer periphery 231 and the third outer periphery 233, 231c and 233c, respectively, as compared with the remaining portions of the first and second shielding plates 231a and 231b.

Here, the first outer periphery 231 and the third outer periphery 233 have a thickness 231c and 233c which are thinner than the anode 210 in the inwardly bent state, Interference can be avoided.

Therefore, when the separator 230 contracts due to high temperature or heat, the first outer periphery 231 and the third outer periphery 233 can be physically prevented from shrinking due to the relatively thick thickness.

FIG. 3 is a schematic view schematically showing a pre-winding structure of an electrode assembly assembly constituting a battery cell according to another embodiment of the present invention.

Referring to FIG. 3, electrode assemblies 301, 302, and 303 having the same structure as the electrode assembly 200 of FIG. 2 are alternately arranged on a long sheet-like separation film 340.

Each of the electrode assemblies 301, 302 and 303 includes a positive electrode terminal 315 and a negative electrode terminal 325 which are formed in the same one direction and the positive electrode terminal 315 and the negative electrode terminal 325 Are all exposed in the same direction.

The separation film 340 is formed such that the extended outer periphery 341 of the portion where the positive electrode terminal 315 and the negative electrode terminal 325 are exposed and the extended outer periphery 342 of the portion opposite thereto extend inward once and twice Folding bends 351 and 352 are formed.

The separation film 340 is formed on the outer periphery 341 of the portion where the positive electrode terminal 315 and the negative electrode terminal 325 of the electrode assemblies 301, 302 and 303 are exposed, The electrode assemblies 301, 302 and 303 are sequentially wound 353 from the first electrode assembly 301 to the second electrode assembly 302 after the electrode assemblies 342 are bent 351 and 352.

According to this structure, a separation film 340 is interposed between each adjacent electrode assembly 301, 302, 303.

4 is a vertical cross-sectional view partially illustrating the structure of the electrode assembly assembly of FIG.

Referring to FIG. 4, a separation film 340 is interposed between the electrode assemblies 303, 305, 307, and 309.

Each of the electrode assemblies 303, 305, 307 and 309 has an extended outer periphery 331 at a portion where the positive electrode terminal 315 and the negative electrode terminal 325 are formed, The outer periphery 332 is bent inward.

The separation film 340 positioned between the electrode assemblies 303, 305, 307 and 309 is also exposed to the positive electrode terminal 315 and the negative electrode terminal 325 of the electrode assemblies 303, 305, 307 and 309 The extended outer periphery 341 of the separation film 340 and the outer periphery 342 opposite thereto are inwardly bent and have a relatively thick thickness 341c and 342c as compared with other portions of the separation film 340. [

Therefore, when the separation film 340 interposed between the separator 330 of the electrode assemblies 303, 305, 307, 309 and the electrode assemblies 303, 305, 307, 309 is shrunk by high temperature or heat, It is possible to prevent the occurrence of internal short circuit or fire due to direct contact between the anode 310 and the cathode 320. [

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

Claims (20)

A positive electrode on which a positive electrode active material is applied on a current collector;
A negative electrode to which a negative electrode active material is applied on a current collector; And
A separator interposed between the anode and the cathode;
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The separator has a length which extends in the outer direction beyond the outer peripheries of the anode and the cathode corresponding to the outer peripheries,
Wherein at least one outer periphery of the extended outer periphery of the separation membrane is bent at least once in an inner direction. The electrode assembly according to claim 1, wherein the positive electrode and the negative electrode have the same shape in a plan view, and the negative electrode has a relatively larger size than the positive electrode. The electrode assembly according to claim 1, wherein the separator has the same shape as the anode and the cathode in plan view. [3] The method of claim 1, wherein, among the extended outer peripheries of the separator, the extension length of the outer perimeter excluding the outer peripheries bent in the inward direction is in the range of 1% to 1% of the width or length of the anode and the cathode, 30%. ≪ / RTI > 2. The electrode assembly according to claim 1, wherein an extension length of the outer periphery which is bent in the inward direction among the extended outer peripheries of the separator is 200 to 800% . [6] The electrode assembly of claim 5, wherein an extension length of the outer periphery of the separator after the inner periphery is bent is equal to an extension length of the outer periphery of the separator. [3] The method of claim 1, wherein the thickness of the outer periphery of the separator after folded inward in the outward direction is 20% to 100% of the thickness of the adjacent anode or cathode. Electrode assembly. 2. The electrode assembly of claim 1, wherein outermost peripheries of the separator that are bent inward are thermally fused after being bent. 9. The electrode assembly of claim 8, wherein the thermal fusion is performed at a temperature ranging from about 40 degrees Celsius to about 150 degrees Celsius. [2] The apparatus of claim 1, wherein the outermost peripheries of the separator that are bent inward are at least two or more, and the extensions of the peripheries that are bent in the inward direction are the same or different from each other. Assembly. 2. The separator according to claim 1, wherein the anode, the cathode, and the separator are formed in a rectangular shape in a planar shape, and only the outer peripheries of both sides having a relatively short length are bent inward in the extended outer periphery of the separator . A battery cell comprising the electrode assembly according to claim 1,
Wherein the electrode assembly includes at least one electrode terminal extending in one side or opposite sides of the electrode assembly and at least two electrode assemblies are wound by a long sheet- And the battery cell is embedded in the battery case. 13. The battery cell according to claim 12, wherein the separating film has a portion where the electrode terminals are exposed and / or an outer periphery of the separating film facing the electrode film extends relatively to the outer periphery of the positive electrode and the negative electrode. 14. The battery cell according to claim 13, wherein the separation film is bent at least once in an inward direction at a portion where the electrode terminals are exposed and / or an extended outer periphery of a portion opposed thereto. 15. The battery cell according to claim 14, wherein a thickness of the bent outer peripheral portion of the separator film is 20% to 100% of the thickness of the anode or the cathode of the electrode assembly adjacent thereto. 15. The battery cell according to claim 14, wherein the bent outer periphery of the separation film is thermally fused. A method of manufacturing a battery cell according to claim 12,
a) fabricating at least two electrode assemblies whose outer periphery is relatively extended relative to the outer periphery of the anode and cathode;
b) bending the outer periphery of the electrode terminals extended portion and / or the outer periphery thereof facing the outer periphery of the separator of the electrode assemblies in the inward direction and thermally fusing the electrode terminals;
c) arranging the electrode assemblies on an elongate sheet-shaped separation film so that the electrode terminals of the electrode assemblies are aligned in the same direction or opposite to each other;
b) bending and fusing the outer periphery of the separating film, the outer periphery of a portion corresponding to the electrode terminals of the electrode assemblies and / or a portion facing the electrode terminals;
e) winding the electrode assemblies by a separation film;
f) sealing the electrode assemblies wound with the separation film in a battery case together with an electrolytic solution;
And forming a battery cell. A battery pack comprising a battery cell according to claim 12. A device comprising the battery pack according to claim 18 as a power source. 20. The device of claim 19, wherein the device is selected from the group consisting of a cell phone, a tablet computer, a notebook computer, a power tool, a wearable electronic device, an electric vehicle, a hybrid electric vehicle, a plug- . ≪ / RTI >

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