KR20180085144A - Battery Cell Comprising Branched Electrode Tabs - Google Patents

Abstract

The present invention relates to a battery cell having a structure in which an electrode assembly in which a plurality of electrode plates and separation films are alternately stacked is embedded in a battery case together with an electrolyte. Each of the electrode plates comprises: an electrode body in which an electrode assembly including an electrode active material is applied to one surface or both surfaces of a current collector; and an electrode tab extended outward from the electrode body while the electrode assembly is not coated, and electrically connecting the electrode plates and an external terminal. The electrode tab has a branched structure which is divided into two or more branches in a protruding direction from the electrode body. According to the present invention, electrode tabs of a plurality of electrode plates are connected to an electrode lead by a tap-lead coupling unit.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a battery cell comprising branched electrode tabs,

The present invention relates to a battery cell comprising branched electrode taps.

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 and miniaturization are strongly demanded.

The lithium secondary battery can 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.

The electrode assembly having the structure in which the electrode tabs are coupled to the electrode leads is typically a stacked or stacked / folded electrode assembly in which a plurality of positive electrodes and negative electrodes are stacked with a separator interposed therebetween. In the stack / folding type electrode assembly, a plurality of electrode taps (positive tab or negative tab) are bonded to one electrode lead (positive lead or negative lead) by ultrasonic welding.

In recent years, a pouch-shaped battery cell having a structure in which an electrode assembly is embedded in a pouch-shaped battery case of an aluminum laminate sheet has been attracting much attention due to low manufacturing cost, low weight, easy shape deformation, .

As described above, the pouch-shaped battery cell has a structure in which the electrode assembly is attached to the pouch-shaped case of the laminate sheet, and the electrode leads connected to the electrode tabs of the electrode assembly have opposite ends to the connection portion with the electrode tabs End portion of the electrode lead is thermally fused together with the battery case in a state of being exposed to the outside of the battery case, and the end of the electrode lead exposed to the outside forms an electrode terminal.

In the secondary battery having such a structure, a plurality of electrode tabs are coupled to the electrode leads, and the widths of the electrode tabs are made to be approximately the same as the widths of the electrode leads and bonded by a method such as fusion.

1 schematically shows a perspective view of an electrode assembly and a battery case of a general pouch-shaped battery cell.

1, the electrode assembly 10 includes a laminate portion 11, an electrode tab 12, an electrode lead 16, and a lead tape 14. The battery case 20 includes an electrode assembly 12, An outer covering layer 22 of the laminate sheet, an inner sealant layer 23, and a cover portion 24, as shown in Fig.

Specifically, the electrode assembly 10 includes a plate-like laminate portion 11 in which two or more structures in which a separator is interposed between the positive electrode and the negative electrode are repeatedly laminated, and an electrode The tabs 12 protrude from the relatively narrow surface of the electrode assembly 10.

Each of the electrode tabs 12 is electrically connected to the electrode lead 16 and the electrode lead 16 is connected to the battery case 20 And a lead tape 14 for improving the sealing property is attached.

The battery case 20 is a pouch-type case made of a laminate sheet. A cover layer 22 made of a weather-resistant polymer is formed on the outside of the laminate sheet, and a sealant layer 23 made of a heat- 22 and the inner sealant layer 23, a barrier layer containing aluminum or an aluminum alloy is formed.

An electrode assembly accommodating portion 21 is formed in the battery case 20 so as to accommodate the electrode assembly 10 and the electrolytic solution together and the electrode assembly 10 and the electrolyte solution are accommodated in the cover portion 24 When the electrode assembly accommodating portion 21 is covered and then the inner sealant layer 23 is thermally fused and sealed, one independent battery cell can be manufactured.

On the other hand, the secondary battery as described above may require a large output momentarily depending on the use environment of the device. The larger the area of the electrode tab is, the more the loss due to the resistance is reduced and the battery can be used stably. .

However, as the area of the electrode tab increases, there arises a problem that the electrode tab is damaged such as folding or tearing of the electrode tab, for example, when passing through continuous rollers or winding the electrode plate during the manufacturing process. This is because the folding or tearing of the electrode tab is continuously diffused and propagated due to the large area of the electrode tab.

In order to prevent the above problems, the prior art (KR2016-0092748) attempted to solve the problem by forming round portions on both sides of the electrode tab. However, when the area of the electrode tab exceeds the predetermined area, There was a limit to the occurrence of damage.

Therefore, even if the area of the electrode tab is increased, the tension acting on the surface of the electrode tab is reduced to prevent the occurrence of damage such as folding and tearing, and even if damage occurs at a part of the electrode tab, There is a high need for a technique capable of using the battery stably by reducing the amount of the battery.

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 research and various experiments and, as will be described later, by using an electrode tab having a branched structure, it is possible to prevent folding or tearing of the electrode tab, which may occur due to a large area And the present invention has been accomplished.

Accordingly, a battery cell according to the present invention is a battery cell having a structure in which an electrode assembly in which a plurality of electrode plates and separators are alternately stacked is embedded in a battery case together with an electrolyte solution,

Wherein the electrode plate comprises: an electrode body having an electrode mixture containing an electrode active material coated on one surface or both surfaces of the current collector; And

An electrode tab extending outward from the electrode body in a state where the electrode mixture is not applied, and electrically connecting the electrode plate and the external terminal;

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The electrode tabs may have a branch structure divided into two or more numbers in a protruding direction from the electrode body, and the electrode tabs of the plurality of electrode plates may be connected to the electrode leads by the tab-lid coupling portion.

The prior art attempts to use an electrode tab having a large area in order to minimize the loss of current due to the resistance. However, the electrode tab tends to be easily folded or torn during the manufacturing process, Which causes a short circuit with the external terminal, and acts as a risk factor for safety such as explosion and ignition.

Furthermore, since the tensile force acting on the surface of the electrode tab is proportional to the size of the area, not only the possibility of occurrence of folding or tearing increases as the area of the electrode tab increases, but also the spreading and propagation degree of damage, Which is greater than that of the small electrode tab.

On the other hand, since the electrode tab according to the present invention has a structure in which a certain portion is divided into a branched structure, it is possible to prevent damage of the electrode tab, such as folding or tearing of the electrode tab, which may occur due to the electrode tab having a large area.

Specifically, by dispersing and reducing the tension acting on the surface of the electrode tab through the branch structure, the possibility that the electrode tab is folded or torn is significantly reduced, and the damage generated at some position diffuses , It can block the propagation.

Further, even if some of the electrode tabs and the electrode leads are short-circuited due to folding or tearing in some of the electrode tabs, the other electrode tabs and the electrode leads are still connected to each other, so that the secondary battery can be stably and continuously used.

The electrode plate is collectively referred to as a positive electrode and a negative electrode. The positive electrode may be manufactured by, for example, applying a positive electrode mixture mixed with a positive electrode active material, a conductive material and a binder to a positive electrode collector, A filler may be further added.

The cathode current collector generally has a thickness of 3 to 300 탆 and is not particularly limited as long as it has high conductivity without causing chemical changes in the battery. Examples of the cathode current collector include stainless steel, aluminum, nickel, titanium , And a surface treated with carbon, nickel, titanium or silver on the surface of aluminum or stainless steel can be used. Specifically, aluminum can be used. The current collector may have fine irregularities on the surface thereof to increase the adhesive force of the cathode active material, and various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a nonwoven fabric are possible.

The cathode active material may be, for example, 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 oxides such as Li _{1 + x} Mn _{2 -x} O ₄ (where x is 0 to 0.33), LiMnO ₃ , LiMn ₂ O ₃ , LiMnO ₂ and the like; Lithium copper oxide (Li ₂ CuO ₂ ); Vanadium oxides such as LiV ₃ O ₈ , LiV 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 positive electrode material mixture containing the positive electrode 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-butadiene 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.

On the other hand, the negative electrode may be manufactured by applying a negative electrode mixture containing a negative electrode active material, a conductive material, and a binder to a negative electrode collector, and a filler or the like may further be optionally included.

The negative electrode current collector is not particularly limited as long as it has electrical conductivity without causing a chemical change in the battery. For example, the negative electrode current collector may be formed on the surface of copper, stainless steel, aluminum, nickel, titanium, sintered carbon, Carbon, nickel, titanium, silver or the like, an aluminum-cadmium alloy, or the like can be used. In addition, like the positive electrode collector, fine unevenness can be formed on the surface to enhance the bonding force of the negative electrode active material, and it can be used in various forms such as films, sheets, foils, nets, porous bodies, foams and nonwoven fabrics.

In the present invention, the thickness of the anode current collector may be the same within the range of 3 to 300 탆, but they may have different values depending on the case.

The negative electrode active material may include, for example, carbon such as non-graphitized carbon or 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 membrane is generally 0.01 to 10 micrometers, and the thickness is generally 5 to 30 micrometers. 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 electrolyte solution may be a non-aqueous electrolyte containing a lithium salt, and the non-aqueous electrolyte containing a lithium salt is composed of a non-aqueous electrolyte and a lithium salt. Non-aqueous organic solvents, organic solid electrolytes, inorganic solid electrolytes, The present invention is not limited thereto.

Examples of the non-aqueous organic solvent 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 derivatives, Tetrahydrofuran derivatives, ether, 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 A polymer containing an acid dissociation group and the like may 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 substance that is soluble in the nonaqueous electrolyte and includes, 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 ₂ ) ₂ NLi, chloroborane lithium, lower aliphatic carboxylate lithium, lithium tetraphenylborate, and imide.

The nonaqueous electrolyte may contain, for the purpose of improving charge / discharge characteristics, flame retardancy, etc., for example, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, glyme, N, N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxyethanol, aluminum trichloride and the like may be added have. In some cases, halogen-containing solvents such as carbon tetrachloride and ethylene trifluoride may be further added to impart nonflammability. In order to improve the high-temperature storage characteristics, carbon dioxide gas may be further added. FEC (Fluoro-Ethylene Carbonate, PRS (Propene sultone), and the like.

In one specific _{example, LiPF 6, LiClO 4, LiBF} 4, LiN (SO 2 CF 3) 2 , such as a lithium salt, a highly dielectric solvent of DEC, DMC or EMC Fig solvent cyclic carbonate and a low viscosity of the EC or PC of And then adding it to a mixed solvent of linear carbonate to prepare a lithium salt-containing nonaqueous electrolyte.

In one specific example, the electrode taps according to the present invention are composed of positive electrode tabs and negative electrode tabs, and the protruding directions of the positive electrode tabs and the negative electrode tabs may be the same or different from each other.

As described above, since the battery cell according to the present invention maintains a generally similar structure to that of the conventional electrode tab, it is advantageous to manufacture a battery cell in which damage to the electrode tab is prevented without changing the existing manufacturing equipment have.

In one specific example, the electrode assembly may be of a stacked structure or a stacked / folded structure.

The battery cell according to the present invention can effectively prevent the damage of the electrode tab, which may occur in the case of the electrode assemblies in which the electrode tabs of the same polarity are combined with the respective electrode leads, by employing the branched electrode tabs do.

However, since the jelly-roll type electrode assembly has a structure in which one electrode tab and the electrode lead are coupled to each other, the overall structure of the electrode plate, the electrode tab, the electrode lead, and the electrode terminal is different from that of the electrode assembly, There may be a limit to applying the structure according to the present invention.

The battery cell according to the present invention may be a plate-shaped battery cell using a battery case of a laminate sheet including a resin layer and a metal layer in one specific example.

The laminate sheet may be an aluminum laminate sheet. Specifically, a resin outer layer having excellent durability is added to one surface (outer surface) of the metal barrier layer, and a thermally fusible resin sealant layer is provided on the other surface Structure.

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

The metal barrier layer may include aluminum or aluminum alloy 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.

As the polymer resin of the resin sealant layer, a polyolefin resin having a low heat absorbing property (heat adhesion property) and low hygroscopicity in order to suppress penetration of an electrolyte solution and not being swollen or eroded by an electrolytic solution is preferably used And more particularly, lead-free polypropylene (CPP) may be used.

In general, a polyolefin resin such as polypropylene has a low adhesive force with a metal. Therefore, as a method for improving the adhesion with the metal barrier layer, more specifically, an adhesive layer is additionally provided between the metal layer and the resin sealant layer, And blocking characteristics can be improved. Examples of the material of the adhesive layer include a urethane-based material, an acryl-based material, a composition containing a thermoplastic elastomer, and the like, but are not limited thereto.

The split length of the branched electrode tab may be 20% to 100%, preferably 40% to 100%, based on the length of the electrode tab in one specific example.

If the division length is less than 20%, the tension of the electrode tab can not be reduced and it is not possible to prevent folding or tearing. On the contrary, when the division length exceeds 80% The capacity of the battery can be reduced, which is undesirable.

Therefore, it is preferable that the division length of the electrode tab is 40% to 80% in order to prevent folding or tearing of the electrode tab and ensure safety and capacity of the battery.

The division width of the branched electrode tab may be, in one specific example, between 0% and 50% of the width of the electrode tab.

If the dividing width is larger than 50% of the electrode tab, folding or tearing of the electrode tab can not be effectively prevented, and the capacity of the battery can be reduced due to the occurrence of unnecessary space.

In a more specific example, the dividing width of the branched electrode tab may be between 5% and 33%, based on the width of the electrode tab.

The thickness of the electrode tab may, in one specific example, be between 5 μm and 50 μm.

If the thickness of the electrode tab is less than 5 占 퐉, tearing of the electrode tab tends to occur. On the contrary, if the thickness of the electrode tab is more than 50 占 퐉, the capacity of the battery is undesirably decreased.

The structure of the divisional surface of the branched electrode tab is not particularly limited, but may be a linear structure or may be divided into a structure in which at least a part of the divisional surface is curved.

The electrode tab is generally rectangular in shape. However, in order to prevent the electrode tab from folding or tearing and to provide the electrode tab with excellent bonding with the electrode lead, the electrode tab has a linear structure And / or a folded surface of the electrode tab can be formed with a curved structure that can effectively prevent folding, damage, and the like.

In one specific example, the branched electrode tab is divided into two to form a first tab portion and a second tab portion, and mutually facing sides of the first tab portion and the second tab portion may be in contact with each other.

The number of the electrode tabs to be branched according to the present invention is not particularly limited. In one specific example, the electrode tabs may be divided into two to form a branched structure. In this case, the mutually facing sides of the branched first tab portion and the second tab portion The first tab portion and the second tab portion may be in contact with each other so as not to damage the electrode tab during the manufacturing process and to prevent the first tab portion and the second tab portion from being deformed when an external force or the like acts in a direction perpendicular to the outward extension direction of the electrode tab, They may be in contact with each other so as to disperse them to prevent tearing.

The branched electrode tabs, in one specific example, may have their end portions welded to the electrode leads.

In this case, the electrode tabs of the same polarity are each a cluster, and the divided end portions of the respective electrode tabs are electrically connected to the electrode leads by a conventional welding method such as resistance welding, laser welding, arc welding, And the electrode lead may be provided with a lead tape for improving the sealing property with the battery case.

The present invention also provides a method of manufacturing such an electrode tab.

The electrode tab according to the present invention can be formed by cutting a non-coated portion where the electrode mixture is not applied to the current collector by laser processing.

In some cases, the division of the electrode tab may be formed together with or after the formation of the electrode tab, and in one specific example, the division of the electrode tab may be accomplished by laser processing or die / punching .

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

The device may be selected from a cellular phone, a smart pad, a notebook computer, a power tool, an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a power storage device, A detailed description thereof will be omitted in this specification.

As described above, in the battery cell according to the present invention, even if the size of the electrode tab is increased by using the branched electrode tab, the tensile force acting on the surface of the electrode tab is reduced so that damage such as folding or tearing .

Furthermore, even if a portion of the electrode tab is damaged, it is prevented that the electrode tab is diffused and propagated, thereby preventing a complete short circuit with the electrode lead.

In addition, even if some electrode tabs and electrode leads are short-circuited due to damage or tear on some of the electrode tabs, the other electrode tabs and the electrode leads are still connected to each other, so that the secondary batteries can be continuously used.

1 is a perspective view schematically showing an electrode assembly and a battery case of a general pouch-shaped battery cell.
2 is a partially enlarged view of Fig.
FIG. 3 is a vertical cross-sectional view schematically showing a location where electrode taps and electrode leads of the electrode assembly of FIG. 1 are located.
Fig. 4 is a photograph showing a roll used when moving the position of the battery in a continuous production structure during a battery manufacturing process. Fig.
FIG. 5 is a schematic view showing that the electrode tab according to an embodiment of the present invention is branched into two electrodes. FIG.
FIG. 6 is a schematic view showing that the electrode tab according to another embodiment of the present invention is branched into two. FIG.
FIG. 7 is a schematic view showing that the electrode tab according to an embodiment of the present invention is branched into three. FIG.
FIG. 8 is a schematic view showing that the first tab portion and the second tab portion of the electrode tab are in contact with each other according to an embodiment of the present invention.
FIG. 9 is a schematic view showing a structure in which the entire parting plane of the electrode tab according to an embodiment of the present invention is a curved line. FIG.
FIG. 10 is a schematic view showing a structure in which all of the divisional surfaces of the electrode tab according to another embodiment of the present invention are curved. FIG.
11 is a schematic view showing a structure in which a part of a divided surface of an electrode tab according to another embodiment of the present invention is a curved line.

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.

FIG. 2 is a partial enlarged view of FIG. 1, and FIG. 3 is a vertical cross-sectional view schematically showing a location where electrode taps and electrode leads of the electrode assembly 1 are located. There is shown a photograph showing a roll used when moving the position of the battery in a production structure.

2 to 4, a battery cell according to the present invention includes a battery case 20 having an electrode assembly 10 and an electrolyte tab (not shown) The electrode tab 12 has a branched structure divided from the electrode body in the protruding direction and is electrically connected to the electrode lead 16 by the tab-lead coupling portion 19.

Specifically, the electrode assembly 10 includes a laminated portion 11, electrode tabs 12, a positive electrode lead 16, and a tab-and-lead fitting portion 19 in which a separator 18 is interposed between an anode and a cathode The electrode tabs 12 are connected to the electrode plates 12 and protrude from the electrode plates 12 and the electrode tabs 12 are connected to the positive electrode lead 16 through the tab-

Each of the electrode tabs 12 is electrically connected to the electrode lead 16 and the electrode lead 16 is connected to the battery case 20 And a lead tape 14 for improving the sealing property is attached.

On the other hand, the separation membrane 18 has a relatively larger size than the electrode plates and is partly protruded from the lamination portion 11. [

As shown in Fig. 4, the battery cell according to the present invention has an effect of preventing damage such as folding and tearing of the electrode tab 12 in the winding process and the like during the manufacturing process by using the branched electrode tab 12 .

FIG. 5 is a schematic view illustrating an electrode tab according to an embodiment of the present invention, which is branched into two electrodes. FIG. 6 illustrates an electrode tab according to another embodiment of the present invention, Structure shown in Fig.

5 and 6, the electrode tab 12 according to the present invention, in one specific example, extends outward from the non-coated portion 26 of the electrode body to which the electrode mixture is not applied, And the electrode tab 12 is connected to the electrode lead 16 by the tab-and-lid coupling portion 19. The split length of the branched electrode tabs 12 may be equal to the length of the electrode tabs 12 as shown in Figure 5 or may be less than the length of the electrode tabs 12 as shown in Figure 6 .

FIG. 7 is a schematic view showing that the electrode tab according to an embodiment of the present invention is branched into three.

The number of division of the electrode tab 12 according to the present invention is not particularly limited, and if the electrode tab can be prevented from being damaged such as folding or tearing, as shown in FIG. 7, It is possible.

FIG. 8 is a schematic view showing that the first tab portion and the second tab portion of the electrode tab are in contact with each other according to an embodiment of the present invention.

8, the electrode tab 12 is formed in a structure in which the first tab portion 12a and the second tab portion 12b of the electrode tab 12 are in contact with each other, thereby preventing the electrode tab 12 from being damaged, Even if an external force is applied, it is dispersed, thereby reducing the occurrence of folding and the like.

9 to 11 are schematic views showing a structure in which the structure of the divisional surface of the electrode tab according to the present invention is a straight line or all or at least a part thereof is a curved line.

9 to 11, the structure of the divisional surface of the electrode tab 12 is a structure that can prevent damage to the electrode tab 12 when passing through a continuous roller or winding an electrode plate But is not particularly limited and may be a structure in which the divisional surface is a straight line or a structure in which all or at least a part of the divisional surface is a curved line.

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 (16)

A battery cell having a structure in which an electrode assembly in which a plurality of electrode plates and separators are alternately stacked is built in a battery case together with an electrolyte,
Wherein the electrode plate comprises: an electrode body having an electrode mixture containing an electrode active material coated on one surface or both surfaces of the current collector; And
An electrode tab extending outward from the electrode body in a state where the electrode mixture is not applied, and electrically connecting the electrode plate and the external terminal;
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Wherein the electrode tabs have a branched structure divided into two or more numbers in a protruding direction from the electrode body and the electrode tabs of the plurality of electrode plates are connected to the electrode leads by the tab- . The battery cell according to claim 1, wherein the electrode tabs are composed of positive electrode tabs and negative electrode tabs, and the protruding directions of the positive electrode tabs and the negative electrode tabs are the same or different from each other. The battery cell according to claim 1, wherein the electrode assembly has a stacked structure or a stacked / folded structure. The battery cell according to claim 1, wherein the battery cell is a plate-shaped battery cell using a battery case of a laminate sheet including a resin layer and a metal layer. The battery cell according to claim 1, wherein the divided length of the branched electrode tab is 40% to 100% of the length of the electrode tab. The battery cell according to claim 1, wherein the width of the branched electrode tab is 0% to 50% of the width of the electrode tab. The battery cell according to claim 1, wherein the branched electrode tabs are divided into a straight line structure. The battery cell according to claim 1, wherein the branched electrode tabs are divided into a structure in which at least a part of the divided surfaces is curved. The battery module according to claim 1, wherein the branched electrode tab is divided into two to form a first tab portion and a second tab portion, and mutually facing sides of the first tab portion and the second tab portion are in contact with each other, . The battery cell of claim 1, wherein the branched electrode tabs are divided into end portions welded to an electrode lead. The method according to claim 1,
Wherein the electrode tab is formed by cutting a non-coated portion of the current collector to which an electrode mixture is not applied by laser processing;
Wherein the division of the electrode tabs is formed together with or after the formation of the electrode tabs. The battery cell according to claim 1, wherein the division of the electrode tabs is achieved by laser processing or die / punch processing. The battery cell according to claim 1, wherein the thickness of the electrode tab is 5 占 퐉 to 50 占 퐉. A battery pack comprising a battery cell according to any one of claims 1 to 13. A device comprising a battery pack according to claim 14. 16. The device of claim 15, wherein the device is a mobile phone, a smart pad, a notebook computer, a power tool, an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a power storage device.

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