KR101735157B1 - Electrode assembly and secondary battery with the same - Google Patents

Abstract

The present invention relates to an electrode assembly, a method of manufacturing the same, and a secondary battery including the same, wherein an insulation layer is formed on a positive electrode tab, which can prevent an internal short circuit between the positive electrode and the negative electrode. Accordingly, the electrode assembly can suppress the physical short circuit between the positive electrode and the negative electrode due to the deformation of the electrode assembly or the shrinkage of the separator in a high-temperature atmosphere. Thus, the safety and reliability of the secondary battery including the electrode assembly can be greatly improved have.

Description

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

The present invention relates to an electrode assembly, a method of manufacturing the same, and a secondary battery including the same, wherein an insulation layer is formed on a positive electrode tab, which can prevent an internal short circuit between the positive electrode and the negative electrode.

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

Typically, in view of the shape of the battery, there is a demand for a prismatic battery and a pouch type battery which can be applied to products such as cellular phones with a thin thickness, and a lithium cobalt polymer battery having excellent energy density, discharge voltage, Demand for secondary batteries is high.

Also, the secondary battery is classified according to the structure of the electrode assembly having the positive electrode / separator / negative electrode structure. Typically, the positive electrode / separator / negative electrode structure has a structure in which a long-sheet type positive electrode and negative electrode are wound in a jelly- A stacked (laminated) electrode assembly in which a plurality of positive electrodes and negative electrodes cut in units of a predetermined size are sequentially stacked with a separator interposed therebetween, a stacked (stacked) electrode assembly in which a predetermined unit of positive and negative electrodes are stacked A stack / folding type electrode assembly having a structure in which a bi-cell or a full-cell stacked in a state is wound.

Recently, a pouch type secondary battery having a structure in which a stack type or stack / folding type electrode assembly is embedded in a pouch-shaped battery case of an aluminum laminate sheet due to low manufacturing cost, small weight, easy shape deformation, And the usage is also increasing.

FIG. 1 schematically shows a general structure of a typical pouch-type secondary battery.

1, the pouch type secondary battery 10 includes an electrode assembly 30, electrode taps 40 and 50 extending from a current collector of the electrode assembly 30, and electrode taps 40 and 50, And a battery case 20 for accommodating the electrode leads 60 and 70 and the electrode assembly 30 welded to each other.

The electrode assembly 30 is a power generation element in which an anode and a cathode are sequentially stacked with a separation membrane interposed therebetween. The electrode assembly 30 has a stacked or stacked / folded structure. The electrode tabs 40 and 50 extend from the respective electrode plates of the electrode assembly 30 and the electrode leads 60 and 70 include a plurality of electrode tabs 40 and 50 extending from each electrode plate, Respectively, and are exposed to the outside of the battery case 20. An insulating film 80 is attached to a portion of the upper and lower surfaces of the electrode leads 60 and 70 so as to increase the degree of sealing with the battery case 20 and at the same time to ensure an electrically insulated state.

The battery case 20 is generally made of an aluminum laminate sheet and provides a space for accommodating the electrode assembly 30, and has a pouch shape as a whole.

Meanwhile, one of the main tasks of the secondary battery including the pouch type secondary battery is to improve safety. The main cause of battery safety related accidents is due to abnormal temperature conditions due to a short circuit between the anode and the cathode. That is, under normal circumstances, the electrode assembly maintains electrical insulation between the anode and the cathode. However, when the battery is overcharged or overdischarged, or dendritic growth of the electrode material or internal short circuit is caused by foreign matter In case of abnormal abuse such as raising, penetration of a sharp object such as a nail or a screw into the battery, or excessive stress applied to the battery due to external force, the existing separator only shows a limit.

In general, a microporous membrane made of a polyolefin resin is mainly used as the separation membrane, but its heat-resistant temperature is about 120 to 160 占 폚, which is insufficient in heat resistance. Therefore, if an internal short circuit occurs, there is a problem that the short-circuit reaction heat shrinks the short-circuit due to shrinkage of the separator, resulting in a thermal runaway state in which larger and more reaction heat is generated.

Fig. 2 schematically shows a problem of the electrode assembly.

Referring to FIG. 2, the electrode assembly 30 includes a cathode on which a cathode active material is coated on a cathode current collector, and a cathode on which an anode active material is coated on a cathode current collector. In order to prevent physical short- And a structure in which a separator is inserted. In this case, in order to lower the risk of physical short-circuiting between the positive electrode and the negative electrode of the electrode assembly, the negative electrode is largely made larger than the positive electrode. However, the negative electrode active material and the positive electrode collector react with each other, There is a problem that the physical short circuit becomes larger.

Thus, various methods have been explored to reduce the possibility of cell deformation, external impact, or physical shorting of the anode and cathode.

For example, in order to prevent the electrode tab from coming into contact with the upper end of the electrode assembly due to the movement of the electrode assembly in the state where the battery is completed, There is a method of attaching. As such insulating tape, a polyimide film is usually used, and it is generally recommended to wind the insulating tape to a length extending slightly from the top of the collector to the bottom. Further, in order to prevent loosening, it is usually wound about 2 to 3 times.

However, such winding work of the insulating tape is very troublesome, and such an area may cause an increase in the thickness of the electrode assembly when the insulating tape is wound up to a length extending slightly downward from the top of the current collector. Further, there is a problem that the electrode tab can be easily released when bent.

KR 2012-0124613 A

The present invention has been made in order to solve the problems of the prior art as described above, and an object of the present invention is to provide a positive electrode and a negative electrode, Assembly.

Another object of the present invention is to provide a method of manufacturing the electrode assembly.

Still another object of the present invention is to provide a secondary battery including the above electrode assembly.

According to an aspect of the present invention, there is provided a positive electrode comprising a positive electrode coated with a positive electrode active material on a positive electrode collector, a negative electrode coated with a negative electrode active material on the negative electrode collector, and a separator interposed between the positive electrode and the negative electrode, Wherein the insulating layer is formed between the cathode current collector and the separator and is formed to be less than the end portion position line of the separator led out in the protruding direction of the anode tab, And is spaced apart from an end of a region where the cathode active material is applied.

The present invention also provides a method of manufacturing a battery, comprising: applying a thermosetting resin on a positive electrode tab; And thermally curing the thermosetting resin applied region by applying heat to the insulating layer to form an insulating layer.

The present invention also provides a method of manufacturing a light emitting device, comprising: applying a photocurable resin on a positive electrode tab; And irradiating light to the photocurable resin application site to form an insulating layer by photocuring.

Further, the present invention provides a secondary battery including the electrode assembly.

The electrode assembly according to the present invention can suppress physical deformation of the anode assembly and cathode due to deformation of the electrode assembly or shrinkage of the separator in a high temperature atmosphere by including the insulation layer on the anode tab.

Therefore, the safety and reliability of the secondary battery including the electrode assembly can be greatly improved.

Therefore, the secondary battery including the electrode assembly and the electrode assembly can be easily applied to the battery industry, particularly, the secondary battery industry.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments of the invention and, together with the description of the invention, It should not be construed as limited.
1 schematically shows a structure of a conventional pouch type secondary battery.
2 schematically shows a structure of a conventional electrode assembly.
3 is a cross-sectional view of a structure in which a positive electrode and a negative electrode included in a conventional electrode assembly and a separation membrane interposed between the positive electrode and the negative electrode are sequentially stacked.
FIG. 8 is a cross-sectional view of an electrode assembly having a structure in which a positive electrode and a negative electrode, which are spaced apart from a positive electrode active material application region and formed with an insulating layer, and a separator interposed between the positive and negative electrodes are sequentially stacked on a positive electrode tab according to an embodiment of the present invention Sectional area.
FIG. 9 is a cross-sectional view of a positive electrode and a negative electrode separated from a positive electrode active material coating area on a positive electrode tab according to an embodiment of the present invention in which an insulating layer is formed up to an end position line of the negative electrode active material application area, and a separator interposed between the positive and negative electrodes, Sectional area of an electrode assembly having a structure in which the electrode assembly is stacked.
10 is a cross-sectional view of a positive electrode tab according to an embodiment of the present invention, showing a positive electrode and a negative electrode which are spaced apart from the positive electrode active material application region and have a thickness smaller than the thickness of the positive electrode active material application region, Sectional area of an electrode assembly having a stacked structure.
FIG. 11 is a cross-sectional view illustrating a positive electrode and a negative electrode, which are spaced apart from the positive electrode active material coating area on the positive electrode tab and thinner than the coating area of the positive active material according to an embodiment of the present invention, Sectional area of an electrode assembly having a structure in which a separator interposed between an anode and a cathode is sequentially laminated.
12 schematically shows a structure of a secondary battery including an electrode assembly according to an embodiment of the present invention.

Hereinafter, preferred embodiments of an electrode assembly, a method of manufacturing the same, and a secondary battery including the same according to the present invention will be described with reference to the accompanying drawings. In this process, the thicknesses of the lines and the sizes of the components shown in the drawings may be exaggerated for clarity and convenience of explanation. In addition, the terms described below are defined in consideration of the functions of the present invention, which may vary depending on the intention or custom of the user, the operator. Therefore, definitions of these terms should be made based on the contents throughout this specification.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. The use of the terms "comprises" or "having" in this application is intended to specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof in which one or more other features or numbers , Steps, operations, components, parts, or combinations thereof, as a matter of principle.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be interpreted in an ideal or overly formal sense unless expressly defined herein Do not.

The present invention provides an electrode assembly in which an insulating layer is formed on a positive electrode tab to prevent a short circuit between the positive electrode and the negative electrode.

The electrode assembly according to an embodiment of the present invention includes a positive electrode coated with a positive electrode active material on a positive electrode collector, a negative electrode coated with a negative electrode active material on the negative electrode collector, and a separator interposed between the positive electrode and the negative electrode, The positive electrode has an insulating layer formed on the positive electrode tab protruding from the positive electrode collector and the insulating layer is disposed between the positive electrode collector and the separating film and is located below the end portion position line of the separator led out in the positive electrode tab projecting direction And is formed to be spaced apart from an end of a region to which the cathode active material is applied.

Hereinafter, a general electrode assembly will be described with reference to FIG.

3, the electrode assembly 30 includes an anode 120, a cathode 140, and a separator 130 interposed between the anode 120 and the cathode 140, The anode 120 includes a cathode current collector 121 and a cathode active material 122 coated on the cathode current collector 121. The cathode 14 includes an anode current collector 141, And an anode active material 142 applied on the anode active material 142. The cathode 140 is formed to have a somewhat larger size than the anode 120 in order to suppress a physical short circuit between the anode 120 and the cathode 140. Accordingly, A portion T ₁ where the regions coated with the negative electrode active material 142 are not overlapped with each other results in a problem that an internal short circuit is increased when a problem such as shrinkage of the separator occurs in a high temperature atmosphere.

Therefore, in order to solve the above problems, the electrode assembly of the present invention is characterized in that it comprises a positive electrode coated with a positive electrode active material on a positive electrode current collector, a negative electrode coated with a negative electrode active material on the negative electrode collector and a separator interposed between the positive electrode and the negative electrode And a positive electrode having a positive electrode tab protruded from the positive electrode collector and an insulating layer formed between the positive electrode collector and the separator.

The positive electrode tab may be a non-coated portion to which the positive electrode active material is not applied, and the size of the negative electrode may be larger than the size of the positive electrode. That is, the length of the cathode may be longer than the length of the anode.

The electrode assembly according to another embodiment of the present invention may be formed such that an insulating layer is spaced apart from an end of a region to which the cathode active material 122 is applied.
The insulating layer 150 is disposed between the positive electrode collector 121 and the separator 130 and may be formed on the positive electrode tab so as to partially overlap the region where the negative electrode active material 142 is applied. have.
Specifically, a general electrode assembly has a structure in which a negative electrode has a structure larger than that of a positive electrode, and a region where the positive electrode active material is applied and a region where the negative electrode active material is applied are not overlapped with each other and a short circuit occurs between the positive electrode and the negative electrode . Therefore, the electrode assembly 30 according to the present invention includes a portion T ₁ where the region where the cathode active material 122 is applied and the region where the anode active material 142 is not overlapped to improve the above problem And an insulating layer 150 may be formed on the positive electrode tab to partially overlap the region where the negative electrode active material 142 is applied.
The insulating layer 150 may be formed to have an exposed portion T _{3 at one} end of the positive electrode tab and may be formed to be less than the end portion position line Lp ₁ of the separator protruding in the positive electrode tab projecting direction May be preferably formed. That is, the positive electrode tab may have a portion (T ₃ ) in which one end of the positive electrode tab is not provided with an insulating layer, and the insulating layer may have a length less than a position line Lp ₁ of the end of the separator protruding in the positive electrode tab projecting direction As shown in FIG. At this time, it is preferable that the separation membrane protrudes longer than the positive electrode tab in the positive electrode tab projecting direction.
The insulating layer 150 according to the present invention is intended to prevent an internal short circuit between the anode 120 and the cathode 140, particularly to prevent an increase in short circuit due to contraction of the separator 130, When the electrode 150 is formed excessively beyond the position line Lp _{1 at the} end of the separation membrane, it may act as a resistance and degrade the performance of the battery.
The length T ₂ of the insulating layer 150 can be appropriately adjusted in accordance with the purpose of the present invention within a range not exceeding the position line Lp _{1 at the} end of the separation membrane as described above, May be 1% to 50% of the total length (T ₄ ) of the positive electrode tab in the protruding direction. The total length T ₄ of the positive electrode tab is equal to the sum of the length T ₂ of the insulating layer and the length of the exposed portion T ₃ . It is preferable that the thickness D ₁ of the insulating layer is 5% to 100% of the thickness D ₃ of the cathode active material 122 applied perpendicularly to the direction in which the positive electrode tab protrudes. At this time, the total length (T ₄ ) of the positive electrode tab is not particularly limited and can be adjusted according to the desired positive electrode. The thickness (D ₃ ) of the region coated with the positive electrode active material 122 is not particularly limited, To 200 [mu] m.

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Hereinafter, the electrode assembly of the present invention will be described in more detail with reference to FIGS. 8 to 11. FIG. 8 to 11 illustrate an electrode assembly according to another embodiment of the present invention. The electrode assembly of FIGS. 8 to 11 may have a slightly different structure depending on the length and thickness of the insulating layer.

8 to 11, an electrode assembly 30 according to another embodiment of the present invention includes an anode 120, a cathode 140, and a separator 130 interposed between the anode 120 and the cathode 140. [ (130), and the anode (120) comprises a cathode current collector (121); A cathode active material 122 applied on the cathode current collector 121; And a positive electrode tab protruding from the positive electrode collector 121, and the negative electrode 140 includes a negative electrode collector 141; A negative electrode active material 142 coated on the negative electrode current collector 141; And a negative electrode tab protruding from the negative electrode collector 141. Here, the positive electrode tab and the negative electrode tab may each be a non-coated portion in which the positive electrode active material and the negative electrode active material are not coated, and the size of the negative electrode 140 may be larger than the size of the positive electrode 120.

The positive electrode 120 according to the present invention is characterized in that an insulating layer 150 is formed on a positive electrode tab protruding from the positive electrode collector 121. The insulating layer 150 is formed on the positive electrode active material 122, Is spaced apart from the end of the applied area.

The insulating layer 150 is disposed between the positive electrode current collector 121 and the separator 130 and includes a portion T ₁ where the region to which the positive electrode active material 122 is applied and the region where the negative electrode active material 142 is not overlapped And an insulating layer 150 is formed on the positive electrode tab to partially overlap the region to which the negative active material 142 is applied.

When the insulating layer 150 is formed to be spaced from the end of the region to which the cathode active material 122 is applied and the insulating layer 150 is formed apart from the end of the region to which the cathode active material 122 is applied A material forming the insulating layer 150 may be transferred to the cathode active material 122 to prevent side reactions acting as a resistor. At this time, it is preferable that the spacing has a spacing distance Ts of 1% to 50% of the total length between the end position line Lp ₂ of the area coated with the negative electrode active material and the end of the area coated with the positive electrode active material 122 Lt; / RTI >

The insulating layer 150 may be formed to have an exposed portion T _{3 at one} end of the positive electrode tab and may be formed to be less than the end portion position line Lp ₁ of the separator protruding in the positive electrode tab projecting direction May be preferably formed.

The length (T ₂₎ may be from 1% to 50% of the length (T ₄₎ of the positive electrode tab to the protruding direction of the positive electrode tab, and the thickness (D ₁₎ of the insulating layer of the insulating layer 150 is the The cathode active material 122 in the direction perpendicular to the direction of protrusion of the positive electrode tab may be 5% to 100% of the applied area thickness D ₃ . At this time, the total length (T ₄ ) of the positive electrode tab is not particularly limited and can be adjusted according to the desired positive electrode. The thickness (D ₃ ) of the region coated with the positive electrode active material 122 is not particularly limited, To 200 [mu] m.

Specifically, the insulating thickness of the layer 150 as shown in FIG. 8 (D ₁₎ is the length of the positive electrode active material 122, an insulating layer equal to the area applied with a thickness (D ₃₎ 150 (T ₂₎ is May be 1% to 50% of the total length (T ₄ ) of the positive electrode tab within a range not passing through the end position line Lp ₁ of the separator as described above, and the insulating layer 150 The thickness D _{1 of the} insulating layer 150 is equal to the thickness D ₃ of the region to which the cathode active material 122 is applied and the length T ₂ of the insulating layer 150 is the length Lp ₂ , that is, a portion T ₁ where the region where the cathode active material 122 is applied and the region where the anode active material 142 is coated do not overlap. The length T ₂ of the insulation layer 150 includes a separation distance Ts and the length T ₂ of the insulation layer 150 may be increased or decreased according to the separation distance Ts. have.

10 and 11, the length (T ₂ ) of the insulating layer 150 is set to be equal to or smaller than the total length (T ₄ ) of the positive electrode tab within a range not exceeding the end position line Lp ₁ of the separator. And the thickness T of the insulating layer 150 may be the same as the thickness T _{1 of} the insulating layer 150 or the portion T ₁ where the region where the cathode active material 122 is applied and the region where the anode active material 142 is coated do not overlap. D ₁ may be 5% to 100% of the region thickness D _{3 to} which the cathode active material 122 is applied. The thickness D ₃ of the region where the cathode active material 122 is applied is the sum of the thickness D ₁ of the insulating layer 150 and the uncoated portion D ₂ where the insulating layer 150 is not formed, The length T ₂ of the insulating layer 150 includes a separation distance Ts and the length T ₂ of the insulation layer 150 may be increased or decreased according to the separation distance Ts.

On the other hand, the insulating layer according to the present invention is characterized by including a thermosetting resin or a photocurable resin.

The thermosetting resin may be one or more selected from the group consisting of a melamine resin, a phenol resin, a urea resin, an epoxy resin, and a polyurethane. The photocurable resin may include a photopolymerizable compound and a photoinitiator.

Specifically, the photopolymerizable compound may be a polyfunctional (meth) acrylate compound, preferably a bifunctional (meth) acrylate compound or a trifunctional (meth) acrylate compound.

Examples of the bifunctional (meth) acrylate compound include, but are not limited to, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (Meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butylene glycol di (Meth) acrylate, 1,6-hexanediol di (meth) acrylate, glycerin di (meth) acrylate, pentaerythritol di (meth) acrylate, ethylene glycol diglycidyl ether di Ethylene glycol diglycidyl ether di (meth) acrylate, hydroxypivalic acid-modified neopentyl glycol di (meth) acrylate, isocyanuric acid ethylene oxide (Meth) acryloyloxyethyl acid phosphate diester, bis (hydroxy) tricyclo [5.2.1.02,6] decane di (meth) acrylate, bis Bis (hydroxymethyl) tricyclo [5.2.1.02,6] decane di (meth) acrylate, bis (hydroxymethyl) tricyclo [5.2.1.02,6] decane acrylate methacrylate, Bis (hydroxy) pentacyclo [6.5.1.13,6.02,7.09,13] pentadecane di (meth) acrylate, bis (hydroxy) Acrylate methacrylate, bis (hydroxymethyl) pentacyclo [6.5.1.13,6.02,7.09,13] pentadecane di (meth) acrylate, cyclo [6.5.1.13,6.02,7.09,13] Bis (hydroxyethyl) pentacyclo [6.5.1.13,6.02,7.09,13] pentadecane acrylate methacrylate, 2,2-bis [4- (β- (meth) acryloyloxyethoxy) Sycelle Bis ((meth) acryloyloxyethyl) cyclohexane, 1,4-bis ((meth) acryloyloxymethyl) cyclohexane, (Meth) acryloyloxyethyl) cyclohexane, phthalic acid diglycidyl ester di (meth) acrylate, ethylene oxide modified bisphenol A (2,2'- (Meth) acrylate and dipentaerythritol hexa (meth) acrylate and dipentaerythritol hexa (meth) acrylate and dipentaerythritol hexa (meth) acrylate.

The trifunctional (meth) acrylate compound is not particularly limited, and examples thereof include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) Tri (meth) acryloyloxyethoxytrimethylol propane, glycerin polyglycidyl ether poly (meth) acrylate, isocyanuric acid ethylene oxide (meth) acrylate, (Meth) acrylate, ethylene oxide-modified dipentaerythritol penta (meth) acrylate, ethylene oxide-modified dipentaerythritol hexa (meth) acrylate, ethylene oxide-modified dipentaerythritol tri (meth) Pentaerythritol tetra (meth) acrylate, 1,3,5-tris (( (Meth) acryloyloxymethyl) cyclohexane and 1,3,5-tris ((meth) acryloyloxyethyloxymethyl) cyclohexane.

The photoinitiator is not particularly limited, and examples thereof include benzophenone, benzoin methyl ether, benzoin propyl ether, diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2,6-dimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and the like.

The electrode assembly according to the present invention is not particularly limited, but may be stacked or stacked / folded.

The electrode assembly according to the present invention includes an insulating layer formed on a positive electrode tab, thereby preventing an internal short circuit between the positive electrode and the negative electrode due to shrinkage of the separator in a high temperature atmosphere. Therefore, battery safety of the secondary battery including the electrode assembly can be improved.

The present invention also provides a method of manufacturing the electrode assembly.

The method of manufacturing the electrode assembly according to an embodiment of the present invention may be manufactured through a somewhat different method depending on the material forming the insulating layer. Specifically, when the material forming the insulating layer is the thermosetting resin, A method of manufacturing an electrode assembly includes: applying a thermosetting resin on a positive electrode tab; And forming an insulation layer by applying heat to the thermosetting resin application site to thermally cure the insulation layer. When the material forming the insulation layer is the photo-curable resin, Applying a photocurable resin on the tab; And irradiating light to the photocurable resin application site to form an insulating layer by photocuring.

The application is not particularly limited, but spraying may be preferred.

Specifically, the electrode assembly may be manufactured by a conventional method known in the art, except for forming the insulating layer. For example, the anode, the separator, and the cathode having the insulating layer formed thereon may be sequentially May be laminated.

The positive electrode having the insulating layer may be manufactured through a somewhat different step depending on the material forming the insulating layer as described above. The positive electrode active material is coated on the upper surface of the positive electrode collector and dried to form the positive electrode coated with the positive electrode active material A current collector may be manufactured by applying a thermosetting resin on one side of a positive electrode tab which is an uncoated region where a positive electrode active material is not applied and thermally curing by applying heat or by curing a photocurable resin by applying light and irradiating light . The above-mentioned thermosetting resin and photo-curable resin are as mentioned above.

The cathode current collector generally has a thickness of 3 탆 to 500 탆, and is not particularly limited as long as it has high conductivity without causing chemical changes in the battery. Examples of the anode current collector include stainless steel, aluminum, nickel , Titanium, sintered carbon, or a surface treated with carbon, nickel, titanium or silver on the surface of aluminum or stainless steel can be used. The cathode current collector may have various shapes such as a film, a sheet, a foil, a net, a porous body, a foam, a nonwoven fabric, or the like, by forming minute irregularities on the surface thereof to increase the adhesive force of the cathode active material.

The cathode active material may further include a binder, a conductive agent, and an additive such as a filler and a dispersing agent. The cathode active material may be a layered compound such as lithium cobalt oxide (LiCoO ₂ ) or lithium nickel oxide (LiNiO ₂ ), or a compound substituted with one or more transition metals; Lithium manganese oxide (LiMnO ₂ ); Lithium copper oxide (Li ₂ CuO ₂ ); Vanadium oxide; Nickel-situ type lithium nickel oxide; A lithium manganese composite oxide, a disulfide compound, or a composite oxide formed by combination thereof, but the present invention is not limited thereto.

The binder is a component that assists in bonding of the positive electrode active material and the conductive agent and bonding to the positive electrode collector, and includes, for example, polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose, starch, hydroxypropylcellulose, Polyethylene, fluorine rubber, and the like.

The conductive agent is not particularly limited as long as it has electrical conductivity without causing a chemical change in the battery, and examples thereof include graphite such as natural graphite and artificial graphite; Carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, and lamp black; Conductive fibers such as carbon fibers and metal fibers, and the like.

The filler is a component for suppressing the expansion of the anode. The filler is not particularly limited as long as it can be used or not, as long as it is a fibrous material without causing any chemical change in the battery. Examples thereof include olefin polymers such as polyethylene polypropylene; Glass fiber, carbon fiber, or the like.

The dispersing agent (dispersion liquid) is not particularly limited, but may be, for example, isopropyl alcohol, N-methylpyrrolidone (NMP), acetone and the like.

The cathode active material may be coated by a conventional method known in the art and may be uniformly dispersed using a doctor blade, die casting, comma coating, coating, screen printing, and the like.

The drying is not particularly limited, but may be carried out within one day in a vacuum oven at 50 ° C to 200 ° C.

The negative electrode is not particularly limited, but may be prepared by applying a negative electrode active material to an upper surface of the negative electrode collector and drying the negative electrode active material. The negative electrode active material may further include a binder, a conductive material, and an additive such as a filler and a dispersant .

The negative electrode current collector may be the same as or included in the positive electrode current collector.

The anode active material is not particularly limited and a carbonaceous material, lithium metal, silicon, or tin, which is commonly known in the art and capable of intercalating and deintercalating lithium ions, may be used. Preferably, carbon materials can be used, and carbon materials such as low-crystallinity carbon and high-crystallinity carbon can be used. Examples of low crystalline carbon include soft carbon and hard carbon. Examples of highly crystalline carbon include natural graphite, kish graphite, pyrolytic carbon, High temperature calcined carbon such as mesophase pitch based carbon fiber, meso-carbon microbeads, mesophase pitches and petroleum or coal tar pitch derived cokes.

Additives such as binders, conductive materials and fillers and dispersants used for the negative electrode may be the same as those used for the above-mentioned positive electrode manufacturing.

The separator may be an insulating thin film having high ion permeability and mechanical strength, and may have a pore diameter of 0.01 to 10 m and a thickness of 5 to 300 m. As such a separation membrane, a porous polymer film such as a porous polymer film made of a polyolefin-based polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer and an ethylene / methacrylate copolymer may be used alone Or they can be laminated, or a nonwoven fabric made of a conventional porous nonwoven fabric such as a glass fiber having a high melting point, polyethylene terephthalate fiber or the like can be used, but the present invention is not limited thereto.

In addition, the present invention provides a secondary battery including the electrode assembly.

By including the electrode assembly according to the present invention, internal shorting of the positive electrode and the negative electrode can be prevented, and battery safety can be excellent.

Hereinafter, the secondary battery according to an embodiment of the present invention will be described with reference to FIG.

12, a secondary battery 100 according to an embodiment of the present invention includes an electrode assembly 30, a positive electrode tab extending from the positive electrode collector of the electrode assembly 30, A lead 60, a negative electrode lead 70 welded to a negative electrode tab extending from the negative electrode collector, and a battery case 20 accommodating the electrode assembly 30. The positive electrode lead 40 and the negative electrode lead 50 are exposed to the outside of the battery case 20 when the electrode assembly 30 is impregnated with the ion containing electrolyte solution .

In addition, the electrode assembly 30 has a structure in which an anode and a cathode are sequentially stacked with a separator interposed therebetween. An insulating layer 150 is disposed between the upper surface of the anode tab and the separator, An insulating film 80 for increasing the degree of sealing with the battery case 20 and securing an electrically insulated state may be attached to the upper and lower surfaces of the cathode lead 60 and the cathode lead 70. The battery case 20 is generally made of an aluminum laminate sheet and provides a space for accommodating the electrode assembly 30. [

The secondary battery according to the present invention is not particularly limited, but may be a pouch type battery.

On the other hand, the electrolyte may include an organic solvent and a lithium salt commonly used in an electrolyte, and is not particularly limited.

With the lithium salt of the anion is ^{F -, Cl -, I -} , NO 3 -, N (CN) 2 -, BF 4 -, ClO 4 -, PF 6 -, (CF 3) 2 PF 4 -, (CF 3 ^{_{) 3 PF 3 -, (CF}} 3) 4 PF 2 -, (CF 3) 5 PF -, (CF 3) 6 P -, CF 3 SO 3 -, CF 3 CF 2 SO 3 -, (CF 3 SO 2 _{^{) 2 N -, (FSO 2}} ) 2 N -, CF 3 CF 2 (CF 3) 2 CO -, (CF 3 SO 2) 2 CH -, (SF 5) 3 C -, (CF 3 SO 2) 3 _{^{C -, CF 3 (CF 2}} ) 7 SO 3 -, CF 3 CO 2 -, CH 3 CO 2 -, SCN - , and _{(CF 3 CF 2 SO 2)} 2 N - be at least one selected from the group consisting of have.

Examples of the organic solvent include propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, dipropyl carbonate, dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, vinylene carbonate , Sulfolane, gamma-butyrolactone, propylene sulfite, and tetrahydrofuran.

In particular, ethylene carbonate and propylene carbonate, which are cyclic carbonates in the carbonate-based organic solvent, are highly-viscous organic solvents having a high dielectric constant and can dissociate the lithium salt in the electrolyte well. Therefore, such cyclic carbonate dimethyl carbonate and diethyl carbonate And low-dielectric-constant linear carbonates, which have a low viscosity and a low dielectric constant, are mixed in an appropriate ratio, an electrolytic solution having a high electric conductivity can be prepared, and thus the electrolyte can be used more preferably.

The electrolyte may further contain at least one selected from the group consisting of pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, glyme, hexylphosphoric triamide, nitrobenzene and the like to improve charge / discharge characteristics, flame- It is possible to additionally include an organic solvent such as an organic amine or a derivative thereof, a sulfur, a quinone imine dyestuff, an N-substituted oxazolidinone, an N, N-substituted imidazolidine, an ethylene glycol dialkyl ether, an ammonium salt, pyrrole, 2-methoxyethanol, have. In some cases, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride may be further added to impart nonflammability. In order to improve the high-temperature storage property, a carbon dioxide gas may be further added. FEC (fluoro-ethylene carbonate ), PRS (propene sultone), FPC (fluoro-prpylene carbonate), and the like.

The lithium secondary battery according to the present invention can be used not only in a battery cell used as a power source of a small device but also as a unit cell in a middle- or large-sized battery module including a plurality of battery cells. Preferable examples of the above medium and large-sized devices include, but are not limited to, electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric power storage systems, and the like.

0: secondary battery 20: battery case
30: electrode assembly 40: positive electrode tab
50: negative electrode tab 60: positive electrode lead
70: negative electrode lead 80: insulating film
120: positive electrode 121: positive electrode collector
122: cathode active material 130: separator
140: cathode 141: cathode collector
142: cathode material 150: insulating layer
T ₁ : a portion where the area coated with the positive electrode active material and the negative electrode active material do not overlap
T ₂ : length (width) of the insulating layer T ₃ : exposed portion at one end of the positive electrode tab
T ₄ : Total length of positive electrode tab Ts: Distance
D ₁ : thickness of insulating layer
D ₂ : an uncoated portion in which an insulating layer is not formed
D ₃ : Thickness of the region to which the cathode active material is applied
Lp ₁ : End position of membrane
Lp ₂ : End position line of the area coated with the negative electrode active material

Claims (23)

A negative electrode coated with a negative electrode active material on a positive electrode collector, a negative electrode coated with a negative electrode active material on a negative electrode collector, and a separator interposed between the positive electrode and the negative electrode,
Wherein the positive electrode has an insulating layer formed on the positive electrode tab projected from the positive electrode collector,
Wherein the insulating layer is disposed between the cathode current collector and the separator and is formed to be less than a positional line of the end portion of the separator led in the protruding direction of the cathode tab and is spaced apart from the end of the region to which the cathode active material is applied .
The method according to claim 1,
Wherein the positive electrode tab is an uncoated portion to which the positive electrode active material is not applied.
The method according to claim 1,
Wherein the insulating layer is formed on the positive electrode tab so that the negative electrode partially overlaps with a region to which the negative electrode active material is applied.
delete The method according to claim 1,
The spacing is located between the end position line of the area coated with the negative electrode active material from the end of the area coated with the positive electrode active material,
And a distance of 1% to 50% of the total length between the electrodes.
The method according to claim 1,
Wherein the length of the insulating layer is 1% to 50% of the total length of the positive electrode tab in the protruding direction of the positive electrode tab.
The method according to claim 1,
Wherein the thickness of the insulating layer is 5% to 100% of the thickness of the region where the cathode active material is applied in the direction perpendicular to the direction of protrusion of the positive electrode tab.
The method according to claim 1,
Wherein the insulating layer is formed to have an exposed portion at one end of the positive electrode tab.
delete The method according to claim 1,
Wherein the insulating layer comprises a thermosetting resin or a photocurable resin.
The method of claim 10,
Wherein the thermosetting resin is at least one selected from the group consisting of a melamine resin, a phenol resin, a urea resin, an epoxy resin, and a polyurethane.
The method of claim 10,
Wherein the photocurable resin comprises a photopolymerizable compound and a photoinitiator.
The method of claim 12,
Wherein the photopolymerizable compound is a polyfunctional (meth) acrylate compound.
The method of claim 12,
Wherein the photopolymerizable compound is a bifunctional (meth) acrylate compound or a trifunctional (meth) acrylate compound.
15. The method of claim 14,
The bifunctional (meth) acrylate-based compound may be at least one compound selected from the group consisting of ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (Meth) acrylate, neopentyl glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, dipropylene glycol di (Meth) acrylate, glycerin di (meth) acrylate, pentaerythritol di (meth) acrylate, ethylene glycol diglycidyl ether di (meth) acrylate, diethylene glycol diglycidyl ether Di (meth) acrylate, hydroxypivalic acid-modified neopentyl glycol di (meth) acrylate, isocyanuric acid ethylene oxide-modified di (meth) Bis (hydroxy) tricyclo [5.2.1.02,6] decane di (meth) acrylate, bis (hydroxy) tricyclo [5.2.1.02,6] decane Acrylate methacrylate, bis (hydroxymethyl) tricyclo [5.2.1.02,6] decane di (meth) acrylate, bis (hydroxymethyl) tricyclo [5.2.1.02,6] decane acrylate (Hydroxy) pentacyclo [6.5.1.13,6.02,7.09,13] pentadecane di (meth) acrylate, bis (hydroxy) pentacyclo [6.5.1.13,6.02,7.09,13] (Hydroxymethyl) pentacyclo [6.5.1.13,6.02,7.09,13] pentadecane di (meth) acrylate, bis (hydroxymethyl) pentacyclo [6.5.1.13 , 6.02,7.09,13] pentadecane acrylate methacrylate, 2,2-bis [4- (β- (meth) acryloyloxyethoxycyclopentyl] propane, 1,3-bis Meth) acrylate ((Meth) acryloyloxymethyl) cyclohexane, 1,4-bis ((meth) acryloyloxyethyl) cyclohexane, 1,4-bis (Meth) acryloyloxyethyl) cyclohexane, phthalic acid diglycidyl ester di (meth) acrylate, ethylene oxide modified bisphenol A (2,2'-diphenylpropane) type di (meth) acrylate and propylene oxide modified And bisphenol A (2,2'-diphenylpropane) type di (meth) acrylate.
15. The method of claim 14,
The trifunctional (meth) acrylate compound may be at least one selected from the group consisting of trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) Tri (meth) acryloyloxyethoxy trimethylol propane, glycerin polyglycidyl ether poly (meth) acrylate, isocyanuric acid ethylene oxide modified tri (meth) acrylate, ethylene (Meth) acrylate, ethylene oxide-modified dipentaerythritol hexa (meth) acrylate, ethylene oxide modified dipentaerythritol tri (meth) acrylate, ethylene oxide modified pentaerythritol tetra (meth) 1,3,5-tris ((meth) acryloyloxymethyl) cyclohexane and 1,3, And at least one selected from the group consisting of 5-tris ((meth) acryloyloxyethyloxymethyl) cyclohexane.
The method of claim 12,
The photoinitiator is selected from the group consisting of benzophenone, benzoin methyl ether, benzoin propyl ether, diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2,6-dimethylbenzoyldiphenylphosphine oxide, 2,4,6- Benzoyldiphenylphosphine oxide, and combinations thereof.
The method according to claim 1,
Wherein the electrode assembly is of the stacked or stacked / folded type.
Applying a thermosetting resin on the positive electrode tab; And
And forming an insulating layer by applying heat to the thermosetting resin application site to thermally cure the thermosetting resin.
Applying a photocurable resin on the positive electrode tab; And
And irradiating light to the photocurable resin application site to form an insulating layer by photocuring.
The method according to claim 19 or 20,
Wherein the application is a spray application.
A secondary battery comprising the electrode assembly according to claim 1.
23. The method of claim 22,
Wherein the secondary battery is a pouch type battery.

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