KR20170082239A - Battery Cell Having Extended Electrode Lead - Google Patents

Abstract

The present invention relates to an electrode assembly having a separator structure interposed between an anode, a cathode, and an anode and a cathode; Electrode tabs protruding from both ends of the electrode assembly to the anode and the cathode; Electrode leads coupled to the electrode tabs for electrical connection and having a length or area expanded in at least one direction of a first lateral direction and a second lateral direction of the electrode assembly; And a battery case having a housing part in which the electrode assembly is housed.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a battery cell having an extended electrode lead,

The present invention relates to a battery cell including an extended electrode lead.

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

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

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

The lithium secondary battery may be classified into a cylindrical battery cell, a prismatic battery cell, and a pouch-shaped battery cell depending on its shape. Among them, a pouch-type battery cell which can be stacked with a high degree of integration, has a high energy density per unit weight, and is inexpensive and easy to deform is attracting much attention.

FIG. 1 schematically shows a typical structure of a typical secondary battery including a stacked electrode assembly, and FIG. 2 schematically shows a structure in which the secondary battery of FIG. 1 is broken by an external impact.

1, the secondary battery 10 includes an electrode assembly 30 including a positive electrode, a negative electrode, and a separator disposed therebetween in a pouch-shaped battery case 20, The tabs 31 and 32 are welded to the two electrode leads 40 and 41 and sealed (sealed) so as to be exposed to the outside of the battery case 20.

The battery case 20 is made of a soft packaging material such as an aluminum laminate sheet and includes a case body 21 including a concave shaped storage portion 23 on which the electrode assembly 30 can be seated, And a lid 22 to which one side is connected.

The electrode assembly 30 used in the secondary battery 10 may have a jelly-roll structure or a stack / folding structure other than the stacked structure as shown in FIG. In the stacked electrode assembly 30, a plurality of positive electrode tabs 31 and a plurality of negative electrode tabs 32 are welded to the electrode leads 40 and 41, respectively.

In such a pouch type secondary battery, charging and discharging are repeated at the time of use, heat is concentrated in the electrode leads according to the current flow, and the battery case portion which is in contact with the electrode leads due to overheating melts down and the sealing portion of the battery case may be damaged, The electrolyte inside the case may be exposed to the outside and the safety of the battery may be deteriorated.

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.

An object of the present invention is to provide a battery cell capable of preventing damage to a battery case which may occur due to overheating of an electrode lead and dispersing heat concentrated in an electrode lead in a charging and discharging process of the battery cell, will be.

According to an aspect of the present invention, there is provided a battery cell comprising:

An electrode assembly having a separator structure sandwiched between an anode, a cathode, and an anode and a cathode;

Electrode tabs protruding from both ends of the electrode assembly to the anode and the cathode;

Electrode leads coupled to the electrode tabs for electrical connection and having a length or area expanded in at least one direction of a first lateral direction and a second lateral direction of the electrode assembly; And

A battery case having a housing portion in which the electrode assembly is housed;

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Therefore, in the battery cell according to the present invention, the electrode leads are branched in at least one of the first side direction and the second side direction of the electrode assembly so that the length or area is extended, The battery case can be prevented from being damaged due to overheating of the electrode lead, and safety can be ensured.

The first side direction may be a direction toward a first side which is one surface of a relatively large area among the surfaces adjacent to the surface on which the electrode tabs are formed and the second side direction may be a direction toward the first side surface To the second side located opposite to the first side.

The electrode assembly may have a folding structure, a stacking structure, or a stacking / folding structure, or a lamination / stacking structure.

The electrode structures of the folding type, the stacking type, the stacking / folding type, and the lamination / stacking type will be described in detail as follows.

First, a unit cell of a folding structure can be produced by coating a mixture containing an electrode active material on each metal current collector, placing the separator sheet between a cathode and an anode in the form of a sheet dried and pressed, and winding .

The unit cells of the stacked structure are formed by coating each electrode collector with an electrode mixture, drying and pressing the separator, and separating the positive and negative plates with a predetermined size corresponding to the positive and negative plates, And then laminating them.

The unit cell of the stack / folding type structure includes two or more unit cells in which the anode and the cathode face each other and in which two or more electrode plates are stacked, and the unit cells are wound with at least one separating film in a non- Or by bending the separation film to a size of the unit cell and interposing it between the unit cells.

In some cases, the positive electrode and the negative electrode face each other, and one or more single electrode plates may be further included between any unit cells and / or an outer surface of the outermost unicell.

The unit cell may be an S-type unit cell in which the outermost electrode plates on both sides have the same electrode, and a D-type unit cell in which the outermost electrode plates on opposite sides have opposite electrodes.

The S type unit cell may be an SA type unit cell in which the outermost electrode plates on both sides are the anode, and an SA type unit cell in which the outermost electrode plates on both sides are the cathodes.

The unit cells of the lamination / stacked structure are obtained by coating each metal current collector with an electrode mixture, drying, pressing and cutting to a predetermined size, sequentially forming a negative electrode from the bottom, a separator, And a separator is laminated thereon.

The battery case may include a pouch-shaped case having a laminate structure including a metal layer and a resin layer.

As a specific example of the battery case, the battery case is made of a laminate sheet including a resin outer layer of excellent durability, a metal layer of barrier property, and a heat-fusible resin sealant layer, and the resin sealant layers are heat- .

Since the resin outer layer must have excellent resistance from the external environment, it is necessary to have a tensile strength and weather resistance higher than a predetermined level. In this respect, polyethylene terephthalate (PET) and stretched nylon film can be preferably used as the polymer resin of the outer resin layer.

The barrier metal layer may preferably be made of aluminum so as to exhibit a function of improving the strength of the battery case, in addition to a function of preventing foreign matter such as gas or moisture from leaking or leaking.

The resin sealant layer may preferably be a polyolefin resin having low heat absorbability (thermal adhesiveness), low hygroscopicity to suppress penetration of an electrolyte solution, and not being swollen or eroded by an electrolytic solution, Preferably, lead-free polypropylene (CPP) can be used.

In one specific embodiment of the electrode lead,

A tab joint coupled to the electrode tabs;

A tab member having a tab portion that is bent in a first side direction of the electrode assembly protruding in a first direction from a portion corresponding to an end portion of the electrode tab in the tab joint portion and has a length or an area expanded on a first side surface of the electrode assembly; One lead extension portion; And

Wherein the electrode assembly is bent in a second side direction of the electrode assembly protruding from a portion where the electrode tab is in contact with the electrode tab in a second direction opposite to the first direction in the tab engagement portion, A second lead extending portion having a structure in which the first lead extending portion is formed;

As shown in FIG.

The first direction may be a direction perpendicular to a direction in which the electrode tabs protrude, and the second direction may be a direction perpendicular to a direction in which the electrode tabs protrude and a direction opposite to the first direction .

In one embodiment of the present invention, the electrode leads may comprise a first electrode lead and a second electrode lead. Specifically, the first electrode lead may be a positive electrode lead, and the second electrode lead may be a negative electrode lead. Conversely, the first electrode lead may be a negative electrode lead, and the second electrode lead may be a positive electrode lead.

In one specific embodiment, the first lead extension portion and the second lead extension portion of the first electrode lead may have a structure that faces the first side and the second side of the electrode assembly, respectively, The first lead extension portion and the second lead extension portion of the lead may be configured to face the outer surfaces of the first lead extension portion and the second lead extension portion of the first electrode lead, respectively.

That is, the first lead extension portion and the second lead extension portion of the first electrode lead are located on the outer surfaces of the first side surface and the second side surface of the electrode assembly with reference to the electrode assembly, The first lead extension portion and the second lead extension portion may be located on the outer surfaces of the first lead extension portion and the second lead extension portion of the first electrode lead.

An insulating material is applied between the lead extensions of the first electrode lead and the lead extensions of the second electrode lead so as to prevent a short circuit from occurring due to contact between the first electrode lead and the second electrode lead Or an insulating member may be interposed therebetween.

In one embodiment of the present invention, the lead extensions of the first electrode lead may extend to one side of the first side and the second side of the electrode assembly, and the lead extensions of the second electrode lead may be extended And may extend to the other end of the first side and the second side. The length or the area of the electrode leads may be adjusted to be enlarged according to the amount of heat generated in the charging and discharging process of the battery cell.

In one embodiment of the present invention, the tab joint portion and the lead extensions are formed to have the same thickness.

In another embodiment of the present invention, the tab-engaging portion and the lead extensions may be formed to have different thicknesses.

Specifically, the thickness of each of the lead extensions may be 50% to 90% of the thickness of the tab joint. When the thickness of the lead extending portion is less than 50% of the thickness of the tab connecting portion, heat concentrated on the electrode lead may not be sufficiently dispersed. If the thickness of the lead extending portion exceeds 90% The thickness of the battery cell may be increased to decrease the capacity of the battery cell. Thus, the thickness of each of the lead extensions may preferably be in the range of 10 micrometers to 900 micrometers.

In an embodiment of the present invention, the electrode leads may have a porous structure in order to effectively dissipate heat generated during the charging and discharging process of the battery cells. Specifically, the porous structure may include the electrode leads, And the first and second side surfaces of the electrode assembly may be formed on the first lead extension portion and the second lead extension portion facing each other.

In one embodiment of the present invention, a gas adsorbing material may be coated on the inner surface of the pores of the electrode lead so as to remove gas generated during charging and discharging of the battery cell.

Specifically, the gas adsorbing material may be BaTiO ₃ , PB (Mg ₃ Nb _2/3 ) O ₃ -PbTiO ₃ (PMN-PT), hafnia (HfO ₂ ) SrTiO ₃ , SnO ₂ , CeO ₂ , MgO, , ZnO, ZrO ₂ , Y ₂ O ₃ , Al ₂ O ₃ , TiO _2, sodium hydroxide (NaOH), calcium hydroxide (Ca (OH) ₂ ) and potassium hydroxide .

The battery cell may be a lithium secondary battery, specifically, a lithium ion battery or a lithium ion polymer battery.

Generally, a lithium secondary battery is composed of a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte containing a lithium salt.

The positive electrode is prepared, for example, by coating a mixture of a positive electrode active material, a conductive material and a binder on a positive electrode current collector, and then drying the mixture. Optionally, a filler may be further added to the mixture.

The cathode active material may be a layered compound such as lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), or a compound substituted with one or more transition metals; The formula Li _{1 + x} Mn _{2 - x} O ₄ (Where x is 0 to 0.33), lithium manganese oxides such as LiMnO ₃ , LiMn ₂ O ₃ and LiMnO ₂ ; Lithium copper oxide (Li ₂ CuO ₂ ); Vanadium oxides such as LiV ₃ O ₈ , LiFe ₃ O ₄ , V ₂ O ₅ and Cu ₂ V ₂ O ₇ ; A Ni-site type lithium nickel oxide expressed by the formula LiNi _1-x M _x O ₂ (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga and x = 0.01 to 0.3); Formula _{LiMn 2-x M x O 2} ( where, M = Co, Ni, Fe , Cr, and Zn, or Ta, x = 0.01 ~ 0.1 Im) or Li ₂ Mn ₃ MO ₈ (where, M = Fe, Co, Ni, Cu, or Zn); LiMn ₂ O _{4 in} which a part of Li in the formula is substituted with an alkaline earth metal ion; Disulfide compounds; Fe ₂ (MoO ₄ ) ₃ , and the like. However, the present invention is not limited to these.

The conductive material is usually added in an amount of 1 to 30% by weight based on the total weight of the mixture including the cathode active material. Such a conductive material is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, for example, graphite such as natural graphite or artificial graphite; Carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and summer black; Conductive fibers such as carbon fiber and metal fiber; Metal powders such as carbon fluoride, aluminum, and nickel powder; Conductive whiskey such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used.

The binder is a component which assists in bonding of the active material and the conductive material and bonding to the current collector, and is usually added in an amount of 1 to 30% by weight based on the total weight of the mixture containing the cathode active material. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene , Polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butylene rubber, fluorine rubber, various copolymers and the like.

The filler is optionally used as a component for suppressing the expansion of the anode, and is not particularly limited as long as it is a fibrous material without causing a chemical change in the battery. Examples of the filler include olefin polymers such as polyethylene and polypropylene; Fibrous materials such as glass fibers and carbon fibers are used.

The negative electrode is manufactured by applying and drying a negative electrode active material on a negative electrode collector, and if necessary, the above-described components may be selectively included.

Examples of the negative electrode active material include carbon such as non-graphitized carbon and graphite carbon; _{Li x Fe 2 O 3 (0≤x≤1} ), Li x WO 2 (0≤x≤1), Sn x Me 1-x Me 'y O z (Me: Mn, Fe, Pb, Ge; Me' : Metal complex oxides such as Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, Halogen, 0 < x &lt; Lithium metal; Lithium alloy; Silicon-based alloys; Tin alloy; _{SnO, SnO 2, PbO, PbO} 2, Pb 2 O 3, Pb 3 O 4, Sb 2 O 3, Sb 2 O 4, Sb 2 O 5, GeO, GeO 2, Bi 2 O 3, Bi 2 O 4, and Bi ₂ O ₅ ; Conductive polymers such as polyacetylene; Li-Co-Ni-based materials and the like can be used.

The separation membrane is interposed between the anode and the cathode, and an insulating thin film having high ion permeability and mechanical strength is used. The pore diameter of the separator is generally 0.01 to 10 mu m and the thickness is generally 5 to 300 mu m. Such separation membranes include, for example, olefinic polymers such as polypropylene, which are chemically resistant and hydrophobic; A sheet or nonwoven fabric made of glass fiber, polyethylene or the like is used. When a solid electrolyte such as a polymer is used as an electrolyte, the solid electrolyte may also serve as a separation membrane.

The non-aqueous electrolyte solution containing a lithium salt is composed of a polar organic electrolyte and a lithium salt. As the electrolytic solution, a non-aqueous liquid electrolytic solution, an organic solid electrolyte, an inorganic solid electrolyte and the like are used.

Examples of the nonaqueous liquid electrolytic solution include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma -Butyrolactone, 1,2-dimethoxyethane, tetrahydroxyfuran, 2-methyltetrahydrofuran, dimethylsulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane , Acetonitrile, nitromethane, methyl formate, methyl acetate, triester phosphate, trimethoxymethane, dioxolane derivatives, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate Nonionic organic solvents such as tetrahydrofuran derivatives, ethers, methyl pyrophosphate, ethyl propionate and the like can be used.

Examples of the organic solid electrolyte include a polymer electrolyte such as a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, an agitation lysine, a polyester sulfide, a polyvinyl alcohol, a polyvinylidene fluoride, Polymers containing ionic dissociation groups, and the like can be used.

Examples of the inorganic solid electrolyte include Li ₃ N, LiI, Li ₅ NI ₂ , Li ₃ N-LiI-LiOH, LiSiO ₄ , LiSiO ₄ -LiI-LiOH, Li ₂ SiS ₃ , Li ₄ SiO ₄ , Nitrides, halides and sulfates of Li such as Li ₄ SiO ₄ -LiI-LiOH and Li ₃ PO ₄ -Li ₂ S-SiS ₂ can be used.

The lithium salt is a material that is readily soluble in the non-aqueous electrolyte, for example, LiCl, LiBr, LiI, LiClO 4, LiBF 4, LiB 10 Cl 10, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF _{6, LiSbF 6, LiAlCl 4,} CH 3 SO 3 Li, CF 3 SO 3 Li, (CF 3 SO 2) 2 NLi, chloroborane lithium, lower aliphatic carboxylic acid lithium, lithium tetraphenyl borate and imide have.

For the purpose of improving the charge-discharge characteristics and the flame retardancy, the non-aqueous liquid electrolyte may contain, for example, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, glyme, N, N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxyethanol, aluminum trichloride, etc. are added It is possible. In some cases, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride may be further added to impart nonflammability, or a carbon dioxide gas may be further added to improve high-temperature storage characteristics.

The present invention also provides a battery pack including at least one battery cell.

The present invention also provides a device including the battery pack as a power source.

The device may be selected from a cell phone, a wearable electronic device, a portable computer, a smart pad, a netbook, a LEV (Light Electronic Vehicle), an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, and a power storage device.

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

As described above, in the battery cell according to the present invention, the separation inducing portion capable of separating and separating the electrode breaks from each other is formed in the housing portion of the battery case, so that even if the electrode assembly is broken due to external impact or vibration , It is possible to prevent short-circuiting between broken electrode breaks, thereby suppressing ignition and explosion of the battery, and securing structural safety.

1 is an exploded view of a conventional lithium secondary battery;
2 is a side view of a battery cell according to one embodiment of the present invention;
3 is a top view of the electrode lead of Fig. 2;

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

2 is a schematic side view of a battery cell according to an embodiment of the present invention.

2 and 3, the battery cell 100 includes an electrode assembly 110 having a separator structure sandwiched between an anode, a cathode, and an anode and a cathode, and an anode assembly 110 protruding from both ends of the electrode assembly 110 to an anode and a cathode The electrode leads 120 and 130 are electrically connected to the electrode tabs 111 and 112 and the battery case 110 in which the electrode assembly 110 is housed, (Not shown).

The electrode leads 120 and 130 are composed of a positive electrode lead 120 and a negative electrode lead 130.

The cathode lead 120 is formed in a structure having a length and an area expanded by being divided into an upper surface which is the first side of the electrode assembly 110 and a lower side which is the second side. 110 and the second side in the width direction, and the length and the area are expanded.

The positive electrode lead 120 is composed of a tab joint portion 121, a first lead extension portion 122 and a second lead extension portion 123 coupled to the positive electrode tabs 111.

The first lead extension portion 122 of the positive electrode lead 120 is bent in the direction of the top surface of the rear electrode assembly 110 protruding upward in the vertical direction from the portion corresponding to the end portion of the positive electrode tab 111 in the tab engagement portion 121 And extends in length and area from the upper surface of the electrode assembly 110 to the right end of the electrode assembly 110.

The second lead extension portion 123 of the positive electrode lead 120 protrudes downward in the vertical direction from the portion where the positive electrode tab 111 is in contact with the tab engagement portion 121 and is bent in the lower direction of the electrode assembly 110 And the length and area of the electrode assembly 110 are extended from the lower surface of the electrode assembly 110 to the right end of the electrode assembly 110.

The negative electrode lead 130 includes a tab joint portion 131 coupled to the negative electrode tabs 112, a first lead extension portion 132, and a second lead extension portion 133.

The first lead extension 132 of the negative electrode lead 130 extends in the direction of the top surface of the rear electrode assembly 110 protruding upward in the vertical direction from a portion corresponding to the end of the negative electrode tab 112 in the tab engagement portion 131 And extends in length and area from the upper surface of the electrode assembly 110 to the left end of the electrode assembly 110.

The second lead extension portion 133 of the negative electrode lead 130 protrudes downward in the vertical direction from the portion where the negative electrode tab 111 is in contact with the tab engagement portion 131 and is bent in the lower direction of the electrode assembly 110 And the length and area of the electrode assembly 110 are extended from the lower surface of the electrode assembly 110 to the left end of the electrode assembly 110.

The first lead extension part 122 and the second lead extension part 123 of the positive electrode lead 120 are positioned facing the upper and lower surfaces of the electrode assembly 110 respectively and the first lead extension part 122 and the second lead extension part 123 of the positive electrode lead 120, The first lead extension 132 and the second lead extension 133 are located on the outer surfaces of the first lead extension 122 and the second lead extension 123 of the cathode lead 120, respectively.

Between the lead extensions 122 and 123 of the positive electrode lead 120 and the lead extensions 132 and 133 of the negative electrode lead 130 so as to prevent a short circuit between the positive electrode lead 120 and the negative electrode lead 130, An insulating member 140 is interposed.

The thickness T2 of the lead extensions 122 and 123 of the positive electrode lead 120 is 50% of the thickness T1 of the tab joint 121. The negative electrode lead 130 has the same thickness structure as the positive electrode lead 120.

The electrode leads 120 and 130 are made of a porous structure and are formed on the inner surfaces of the pores of the electrode leads 120 and 130 so as to remove gas generated during charging and discharging of the battery cell 100, The material is coated.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.

Claims (19)

An electrode assembly having a separator structure sandwiched between an anode, a cathode, and an anode and a cathode;
Electrode tabs protruding from both ends of the electrode assembly to the anode and the cathode;
Electrode leads connected to the electrode tabs for electrical connection and branched in at least one of a first side direction and a second side direction of the electrode assembly to have a length or an area expanded; And
A battery case having a housing portion in which the electrode assembly is housed;
The battery cell comprising: The battery cell according to claim 1, wherein the electrode assembly is a folding structure, a stacking structure, a stacking / folding structure, or a lamination / stacking structure. The battery cell according to claim 1, wherein the battery case comprises a laminate sheet including a resin outer layer, a barrier metal layer, and a heat-meltable resin sealant layer. The electrode assembly according to claim 1,
A tab joint coupled to the electrode tabs;
A tab member having a tab portion that is bent in a first side direction of the electrode assembly protruding in a first direction from a portion corresponding to an end portion of the electrode tab in the tab joint portion and has a length or an area expanded on a first side surface of the electrode assembly; One lead extension portion; And
Wherein the tab assembly is bent in a second side direction of the electrode assembly protruding from a portion where the electrode tab is in contact with the tab connection portion in a second direction opposite to the first direction, A second lead extending portion having a structure in which the first lead extending portion is formed;
The battery cell comprising: The battery cell according to claim 4, wherein the electrode leads comprise a first electrode lead and a second electrode lead. [6] The apparatus of claim 5, wherein the first lead extension portion and the second lead extension portion of the first electrode lead face each of the first side face and the second side face of the electrode assembly, Wherein the first lead extension portion and the second lead extension portion are formed to face the outer surfaces of the first lead extension portion and the second lead extension portion of the first electrode lead, respectively. The battery cell according to claim 6, wherein an insulating material is applied or an insulating member is interposed between the lead extensions of the first electrode lead and the lead extensions of the second electrode lead. 6. The electrode assembly of claim 5, wherein the lead extensions of the first electrode lead extend to one side of the first side and the second side of the electrode assembly, And extending to the other end of the two side surfaces of the battery cell. The battery cell according to claim 4, wherein the tab connecting portion and the lead extending portions are formed to have the same thickness. The battery cell according to claim 4, wherein the tab-engaging portion and the lead extensions are formed to have different thicknesses. 11. The battery cell according to claim 10, wherein the thickness of each of the lead extensions is 50% to 90% of the thickness of the tab joint. 11. The battery cell of claim 10, wherein the thickness of each of the lead extensions is 10 micrometers to 900 micrometers. The battery cell according to claim 1, wherein the electrode lead has a porous structure. 14. The battery cell according to claim 13, wherein a gas adsorbing material is coated on the inner surface of the pores of the electrode lead. 15. The method of claim 14, wherein the gas adsorbing material is selected from the group consisting of BaTiO ₃ , PB (Mg ₃ Nb _2/3 ) O ₃ -PbTiO ₃ (PMN-PT), hafnia (HfO ₂ ) SrTiO ₃ , SnO ₂ , CeO ₂ , MgO, one member selected from the group consisting of _{NiO, CaO, ZnO, ZrO 2} , Y 2 O 3, Al 2 O 3, TiO 2, sodium hydroxide (NaOH), calcium hydroxide (Ca (OH) ₂₎ and potassium hydroxide (KOH) Or more. The battery cell according to claim 1, wherein the battery cell is a lithium secondary battery. A battery pack comprising at least one battery cell according to claim 1. A device as claimed in claim 17 comprising a battery pack as a power source. 19. The device of claim 18, wherein the device is selected from a cell phone, a wearable electronic device, a portable computer, a smart pad, a netbook, a LEV (Light Electronic Vehicle), an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, Lt; / RTI &gt;

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