KR102052920B1 - Battery Cell Having Folded Portion for Sealing - Google Patents

Abstract

The present invention is an electrode assembly of a separator structure between the positive electrode, the negative electrode and the positive electrode and the negative electrode; A first battery case in which a housing part in which the electrode assembly is built is formed; And a second battery case mounted on the first battery case to surround the accommodating part, wherein an outer circumference of the first battery case is formed at a portion where the first battery case and the second battery case are in contact with each other. Forming a sealing folding portion in the form of surrounding the outer peripheral end of the sealing battery provides a battery cell, characterized in that the first battery case and the second battery case is coupled to each other by welding.

Description

Battery cell having a folding part for sealing {Battery Cell Having Folded Portion for Sealing}

The present invention relates to a battery cell including a sealing folding part.

Secondary batteries are widely used as a power source for mobile devices such as mobile phones, laptops and camcorders. In particular, the use of lithium secondary batteries is rapidly increasing due to the advantages of high operating voltage and high energy density per unit weight.

The lithium secondary battery may be classified into a lithium ion battery, a lithium ion polymer battery, a lithium polymer battery, and the like according to the composition of the electrode and the electrolyte, and among them, the amount of leakage of the electrolyte is less likely, and the amount of the lithium ion polymer battery that is easy to manufacture is used. This is increasing.

A lithium ion polymer battery (LiPB) is a structure in which an electrolyte solution is impregnated into an electrode assembly in which electrodes (anode and cathode) and a separator are heat-sealed. Thus, lithium ion polymer batteries are often referred to as pouch cells.

1 schematically illustrates a general structure of a typical pouch type battery including a stacked electrode assembly, and FIG. 2 schematically illustrates a bottom view of the pouch type battery of FIG. 1.

Referring to FIG. 1, the battery cell 10 includes an electrode assembly 30 formed of a positive electrode, a negative electrode, and a separator disposed therebetween inside a pouch-type battery case 20, and a positive electrode and a negative electrode thereof. The tabs 31 and 32 are welded to the two electrode leads 40 and 41, respectively, and are sealed (sealed) 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 main body 21 and a main body 21 including a recess 23 having a concave shape in which the electrode assembly 30 can be seated. One side is made of a cover 22 is connected.

The electrode assembly 30 used in the battery cell 10 may have a jelly roll structure or a stack / folding structure in addition to the stacked structure as shown in FIG. 1. 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.

Referring to FIG. 2 together with FIG. 1, the battery cell 10 presses and heats both sides and the top side of the battery case 20 by pressing to seal the electrode assembly completely from the outside. In order to seal both sides of the battery case 20 by the press, the sealing portions 24 are formed at both sides of the housing 23. In the conventional general structure, the sealing portion 24 is formed with a width W1 having a size of 5 to 7 mm.

As such, the process of sealing the battery case by pressurizing and heating by a press has to additionally form a sealing part separately from forming an accommodating part for embedding the electrode assembly in the battery case, thereby increasing the amount of the base material into the battery case. there is a problem.

In addition, since the laminate sheet, which is the base material of the battery case, is made of a soft packaging material, a part of the sealing part may be broken or perforated during the pressing and heating process by the press, and thus may not be completely sealed. As a result, a problem may occur in which the electrolyte inside the battery cell is leaked, which causes an increase in manufacturing failure rate.

Therefore, there is a need for a battery cell that can solve the above problems.

The present invention aims to solve the problems of the prior art as described above and the technical problems that have been requested from the past.

An object of the present invention is to minimize the consumption of the base material generated in the process of sealing the battery case of the battery cell manufacturing process to reduce the manufacturing cost, battery cells that can ensure the safety by reducing the sealing failure rate of the battery case To provide.

Battery cell according to the present invention for achieving this object,

An electrode assembly having a positive electrode, a negative electrode, and a separator structure interposed between the positive electrode and the negative electrode;

A first battery case in which a housing part in which the electrode assembly is built is formed; And

A second battery case mounted on the first battery case to surround the accommodating part;

Including,

At a portion where the first battery case and the second battery case are in contact with each other, an outer circumferential portion of the first battery case forms a sealing folding portion so as to surround an outer circumferential end of the second battery case, and the first folding case has a first folding case. The battery case and the second battery case may be of a structure that is coupled to each other by welding.

Therefore, in the battery cell according to the present invention, the outer peripheral portion of the first battery case forms a sealing folding portion in a form surrounding the outer peripheral end of the second battery case, the conventional sealing process is a battery for heating and pressurizing with a press Unlike having to form a wide sealing portion in the case, since the sealing folding portion of a compact structure is formed, it is possible to minimize the consumption of the base material generated in the process of sealing the battery case to reduce the manufacturing cost.

In addition, by welding the sealing folding portion formed by the winding structure to combine the first battery case and the second battery case, the sealing failure rate of the battery case can be lowered to prevent leakage of the electrolyte solution, thereby ensuring the safety of the battery cell have.

The electrode assembly is a battery cell, characterized in that the folding structure, or a stacked structure, or a stack / folding type structure, or a lamination / stack type structure.

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

The folding, stacking, stack / folding, and lamination / stack type electrode structures will now be described in detail.

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

The unit cell of the stack-type structure is a separator obtained by coating an electrode mixture on each metal current collector, drying and pressing them, and then cutting a predetermined size corresponding to the positive and negative plates between the positive and negative plates cut to a predetermined size. It can manufacture by laminating | stacking after interposing.

The unit cell of the stack / foldable structure has a structure in which an anode and a cathode face each other, and includes two or more unit cells in which two or more pole plates are stacked, and the unit cells are wound with one or more separation films in a non-overlapping form. Alternatively, the separation film may be manufactured to be interposed between the unit cells by bending the separation film to the size of the unit cell.

In some cases, the anode and the cathode face each other, and one or more single electrode plates may be further included between arbitrary unit cells and / or on the outer surface of the outermost uncell.

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

The S-type unit cell may be an SC-type unit cell in which both outermost pole plates are positive electrodes, and an SA-type unit cell in which both outermost pole plates are negative electrodes.

The unit cell of the lamination / stack type structure is coated with the electrode mixture on each metal current collector, dried, pressed and cut into a predetermined size, and then sequentially from the bottom to the cathode, the separator on the cathode, and the anode, and It can be prepared by laminating a separator on top.

In one embodiment of the present invention, the first battery case and the second battery case may be made of different materials.

For example, the first battery case may be made of a metal material.

Specifically, the first battery case may be made of a metal plate, it may be made of a structure in which the accommodating portion is indented corresponding to the shape of the electrode assembly.

The first battery case may be made of aluminum or an aluminum alloy, but is not limited thereto as long as the housing portion may be easily formed and the desired rigidity may be ensured.

The first battery case may be coated with an electrically insulating material on an inner surface of the first battery case so as to be electrically insulated from the electrode assembly included in the housing.

Specifically, the electrically insulating material may be a polyolefin resin, but is not limited thereto as long as the coating on the inner surface of the battery case is easy and the electrical insulation between the battery case and the electrode assembly can be secured.

Unlike the first battery case made of a metal material, the second battery case may be made of a laminate sheet including a resin outer layer, a barrier metal layer, and a heat-melt resin sealant layer.

Since the resin outer layer should have excellent resistance from the external environment, it is necessary to have a predetermined tensile strength and weather resistance. In such aspect, polyethylene terephthalate (PET) and a stretched nylon film may be preferably used as the polymer resin of the outer resin layer.

The barrier metal layer is preferably aluminum may be used to exhibit a function of improving the strength of the battery case in addition to the function of preventing the inflow or leakage of foreign substances such as gas, moisture.

The resin sealant layer has a heat sealability (heat adhesiveness), a low hygroscopicity to suppress the penetration of the electrolyte solution, a polyolefin resin that is not expanded or eroded by the electrolyte solution may be preferably used. Preferably unstretched polypropylene (CPP) can be used.

The second battery case may have a flat sheet-like sheet structure, and an outer circumferential surface of the second battery case may have a shape corresponding to the planar shape of the first battery case. The planar area of the second battery case may have a size of 95 to 100% based on the planar area of the first battery case.

In one embodiment of the present invention, in the sealing folding portion, the outer peripheral portion of the first battery case and the outer peripheral end of the second battery case may be integrally coupled by laser welding.

In one embodiment, the laser welding may be performed on the upper surface of the battery cell by a laser welder. That is, since the welding is performed on the upper surface of the battery cell, the welding portion may be formed on the upper surface of the sealing folding part along the outer peripheral portions of the first battery case and the second battery case.

In another embodiment, the laser welding may be welded from the side of the battery cell by a laser welder. That is, laser welding may be performed from a side surface of which the cross section is exposed on the vertical surface of the sealing folding part. In the case of such a laser process, the welding part may be formed only inside the sealing folding part.

Specifically, the outer circumferential portion of the first battery case positioned outside the sealing foldable portion is first melted by the heat of the laser, and then the outer circumferential end of the second battery case positioned inside the sealing foldable portion is fused. The outer circumferential portion of the first battery case and the outer circumferential end of the second battery case may be integrally coupled.

When the second battery case is made of a laminate sheet including a resin outer layer, a barrier metal layer, and a heat-melt resin sealant layer, the resin outer layer and the resin sealant layer are melted by heat, and the barrier metal layer is the first battery. The first battery case and the second battery case may be combined by laser welding in contact with the case.

The electrode terminal of the electrode assembly may protrude from one side or different sides of the first battery case and the second battery case. That is, when the battery cell is formed in a quadrangular shape on the plane to form four sides, the electrode terminal is the first side, second side, third side or fourth side of the first battery case and the second battery case It may be formed to protrude from.

In addition, the positive electrode terminal of the electrode terminal may be formed to protrude on one side, the negative terminal may be formed on one side adjacent to the one side or one side opposite to the one side.

One side or different sides protruding from the electrode terminals of the first battery case and the second battery case may be heated and pressed by a press to be bonded and sealed.

Protruding sides of the electrode terminals of the first battery case and the second battery case may be limited in performing laser welding on the formation portions of the electrode terminals. Therefore, only the side where the electrode terminals of the first battery case and the second battery case protrude, can be heated and pressed by a press to bond and seal the site.

In the sealing folding part, the outer circumference of the first battery case may be bent to be in contact with the outer surface of the second battery case, which is an opposite surface of the housing part. That is, the sealing folding part may have a structure located on an upper surface of the second battery case.

In one embodiment of the present invention, it may be made of a size of 1% to 5% of the width of the second battery case of the width of the sealing folding portion. When the width of the sealing folding portion is less than 1% of the width of the second battery case, the sealing folding portion may be formed small, which may cause difficulty in laser welding. On the other hand, when the width of the sealing folding portion is made larger than 5% of the width of the second battery case, the size of the sealing folding portion is unnecessarily increased to limit the configuration of the battery cell of a compact structure This can be.

Specifically, the width of the sealing folding portion may be made of a size of 1 mm to 2 mm, thereby minimizing the base material consumed in the sealing process of the battery case compared to the conventional battery cells, and compact The battery cell of a structure can be comprised.

In one embodiment of the present invention, the sealing folding portion may be made of a rectangular or square shape on the vertical cross section, but may also be of a circular or elliptical or polygonal shape.

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

In general, a lithium secondary battery is composed of a positive electrode, a negative electrode, a separator, and a lithium salt-containing nonaqueous electrolyte.

The positive electrode is prepared by, for example, applying a mixture of a positive electrode active material, a conductive material, and a binder to a positive electrode current collector, followed by drying, and optionally, a filler is further added to the mixture.

The positive electrode 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; 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 , LiFe ₃ O ₄ , V ₂ O ₅ , Cu ₂ V ₂ O ₇ and the like; Ni-site type lithium nickel oxide represented by the formula LiNi _1-x M _x O ₂ , wherein 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 (wherein M = Co, Ni, Fe, Cr, Zn or Ta and x = 0.01 to 0.1) or Li ₂ Mn ₃ MO ₈ (wherein M = Fe, Co, Lithium manganese composite oxide represented by Ni, Cu or Zn); LiMn ₂ O _{4 in} which a part of Li in the formula is substituted with alkaline earth metal ions; Disulfide compounds; Fe ₂ (MoO ₄ ) ₃ and the like, but are not limited to these.

The conductive material is typically added in an amount of 1 to 30 wt% based on the total weight of the mixture including the positive electrode active material. Such a conductive material is not particularly limited as long as it has conductivity without causing chemical change in the battery, and examples thereof include graphite such as natural graphite and artificial graphite; Carbon blacks such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, and summer black; Conductive fibers such as carbon fibers and metal fibers; Metal powders such as carbon fluoride powder, aluminum powder and nickel powder; Conductive whiskeys 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 that assists the bonding of the active material and the conductive material to the current collector, and is generally added in an amount of 1 to 30 wt% based on the total weight of the mixture including the positive electrode active material. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, 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 inhibiting expansion of the positive electrode, and is not particularly limited as long as it is a fibrous material without causing chemical change in the battery. Examples of the filler include olefinic polymers such as polyethylene and polypropylene; Fibrous materials, such as glass fiber and carbon fiber, are used.

The negative electrode is manufactured by coating and drying a negative electrode active material on a negative electrode current collector, and optionally, the components as described above may optionally be further included.

As said negative electrode active material, For example, carbon, such as hardly graphitized carbon and graphite type 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 ≦ 1; 1 ≦ y ≦ 3; 1 ≦ z ≦ 8); Lithium metal; Lithium alloys; Silicon-based alloys; Tin-based alloys; 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 metal oxides such as Bi ₂ O ₅ ; Conductive polymers such as polyacetylene; Li-Co-Ni-based materials and the like can be used.

The separator 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 from 0.01 to 10 ㎛ ㎛, thickness is generally 5 ~ 300 ㎛. As such a separator, for example, olefin polymers such as chemical resistance and hydrophobic polypropylene; Sheets or non-woven fabrics made of glass fibers or polyethylene are used. When a solid electrolyte such as a polymer is used as the electrolyte, the solid electrolyte may also serve as a separator.

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

As said non-aqueous liquid electrolyte solution, N-methyl- 2-pyrrolidinone, a propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma, for example Butyl lactone, 1,2-dimethoxy ethane, tetrahydroxy franc, 2-methyl tetrahydrofuran, dimethyl sulfoxide, 1,3-dioxorone, formamide, dimethylformamide, dioxolon , Acetonitrile, nitromethane, methyl formate, methyl acetate, phosphate triester, trimethoxy methane, dioxorone derivatives, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbo Aprotic organic solvents such as nate derivatives, tetrahydrofuran derivatives, ethers, methyl pyroionate and ethyl propionate can be used.

Examples of the organic solid electrolyte include polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide derivatives, phosphate ester polymers, polyedgetion lysine, polyester sulfides, polyvinyl alcohols, polyvinylidene fluorides, Polymers containing ionic dissociating 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, sulfates, and the like of Li, such as Li ₄ SiO ₄ —LiI-LiOH, Li ₃ PO ₄ —Li ₂ S-SiS ₂ , and the like, may be used.

The lithium salt is a good material to dissolve 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.

In addition, for the purpose of improving charge / discharge characteristics, flame retardancy, etc., the non-aqueous electrolyte solution includes, for example, pyridine, triethyl phosphite, triethanolamine, cyclic ether, ethylene diamine, n-glyme, hexaphosphate triamide, and the like. Nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N, N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrroles, 2-methoxy ethanol, aluminum trichloride, etc. It may be. In some cases, in order to impart nonflammability, halogen-containing solvents such as carbon tetrachloride and ethylene trifluoride may be further included, and carbon dioxide gas may be further included to improve high temperature storage characteristics.

The present invention also provides a battery pack including two or more of the battery cells.

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

The device may be selected from mobile phones, wearable electronics, portable computers, smart pads, netbooks, light electronic vehicles (LEVs), electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, and power storage devices.

Since the structure of these devices and their fabrication methods are known in the art, detailed description thereof is omitted herein.

As described above, in the battery cell according to the present invention, since the outer circumferential portion of the first battery case forms the sealing folding portion in the form of surrounding the outer circumferential end of the second battery case, the conventional sealing process is heated by a press and Unlike the need to form a wide sealing portion in the battery case in order to pressurized, since the sealing folding portion of a compact structure is formed, it is possible to minimize the consumption of the base material generated in the process of sealing the battery case to reduce the manufacturing cost.

In addition, by welding the sealing folding portion formed by the winding structure to combine the first battery case and the second battery case, the sealing failure rate of the battery case can be lowered to prevent leakage of the electrolyte solution, thereby ensuring the safety of the battery cell have.

1 is an exploded view of a conventional pouch type battery;
2 is a bottom view of the pouch-type battery of 1;
3 is a vertical cross-sectional view of a battery cell according to one embodiment of the present invention;
FIG. 4 is an enlarged view of a state before (a) and after (b) welding of the 'A' portion of FIG. 3; FIG.
5 is a bottom view of the battery cell of FIG. 3;
6 is a vertical cross-sectional view of a battery cell according to another embodiment of the present invention.

Hereinafter, although described with reference to the drawings according to an embodiment of the present invention, this is for easier understanding of the present invention, the scope of the present invention is not limited thereto.

3 is a vertical cross-sectional view of a battery cell according to an embodiment of the present invention is schematically shown, Figure 4 is an enlargement of the state before welding (a) and after welding (b) of the 'A' site of FIG. Figure is schematically shown, and Figure 5 is a bottom view of the battery cell of Figure 3 schematically.

3 to 5, the battery cell 100 includes a first battery case 110, a second battery case 120, and an electrode assembly 130.

The first battery case 110 is formed of an aluminum-based metal plate, and has a structure in which the accommodating part 111 is indented corresponding to the shape of the electrode assembly 110. The inner surface of the first battery case 110 is coated with a polyolefin resin, which is an electrically insulating material, for electrical insulation with the electrode assembly 130.

The electrode assembly 130 has a positive electrode, a negative electrode, and a separator structure interposed between the positive electrode and the negative electrode, and is embedded in the accommodating part 111 formed in the first battery case 110.

The second battery case 120 is mounted on the upper part of the first battery case 110 to surround the accommodating part 111 in a state in which the electrode assembly 130 is embedded in the first battery case 110.

The second battery case 120 is composed of a laminate sheet including a resin outer layer 121, a barrier metal layer 122, and a heat-melt resin sealant layer 123, and has a planar sheet structure in plan view. . The planar shape of the second battery case 120 has a rectangular shape corresponding to the planar shape of the first battery case 110.

In the sealing folding part 140, the outer circumferential portion of the first battery case 110 and the outer circumferential end of the second battery case 120 are integrally coupled by laser welding.

The sealing folding part 140 is formed in a form in which the outer circumferential portion of the first battery case 110 surrounds the outer circumferential end of the second battery case 120 in a state before welding (a).

The sealing foldable part 140 is first melted by the heat of the laser, and the outer circumference of the first battery case 110 positioned outside the sealing foldable part 140 is first melted, and then the second battery located inside the sealing foldable part. The resin outer layer 121 and the resin sealant layer 123 of the case 120 are melted and moved to the inside of the sealing folding part 140, and the outer circumference of the melted first battery case 110 is the second battery case ( It is integrally coupled with the metal layer 122 of 120. Through the welding process as described above, the sealing folding part 140 is made of the same structure as the state after the welding (b).

The electrode terminals 131 of the electrode assembly 130 protrude from upper sides of the first battery case 110 and the second battery case 120.

The side where the electrode terminals of the first battery case and the second battery case protrude may be limited in performing laser welding on the electrode terminal forming portion, so that the electrode terminals of the first battery case and the second battery case protrude. Only the side which is set is heated and pressed by a press, and it adheres and seals.

The width W2 of the sealing folding part 140 has a size of 1 mm, which is 1% of the width W3 of the second battery case 120. Accordingly, the base material consumed in the sealing process of the battery case can be minimized as compared with the conventional general battery cell, it is possible to configure a battery cell of a compact structure.

The sealing folding part 140 has a rectangular shape on a vertical cross section.

6 is a vertical cross-sectional view of a battery cell according to another embodiment of the present invention.

Referring to FIG. 6, the outer circumferential portion of the first battery case 210 in the sealing folding portion 240 is bent to contact the upper and outer surfaces of the second battery case 220, which is an opposite surface of the accommodating portion 211. Accordingly, the sealing folding part 240 has a structure located on the upper surface of the second battery case 220.

Except for the structure in which the sealing folding part 240 is disposed on the upper surface of the second battery case 220, the remaining structure is the same as the embodiment described with reference to FIGS. 3 to 5, and thus description thereof will be omitted.

Although described with reference to the drawings according to an embodiment of the present invention, those of ordinary skill in the art will be able to perform various applications and modifications within the scope of the present invention based on the above contents.

Claims (20)

An electrode assembly having a positive electrode, a negative electrode, and a separator structure interposed between the positive electrode and the negative electrode;
A first battery case having an inner surface formed of a metal plate coated with an electrically insulating material, and having a structure in which an accommodating part in which the electrode assembly is built is indented corresponding to the shape of the electrode assembly; And
And a second battery case comprising a planar plate-shaped laminate sheet including a resin outer layer, a barrier metal layer, and a heat-melt resin sealant layer mounted on the first battery case to surround the accommodating part.
At a portion where the first battery case and the second battery case are in contact with each other, an outer circumferential portion of the first battery case forms a sealing folding portion so as to surround an outer circumferential end of the second battery case, and the first folding case has a first folding case. The outer circumferential ends of the battery case and the second battery case are coupled to each other by laser welding, wherein the sealing folding part has a width of 1 mm to 2 mm. The battery cell of claim 1, wherein the electrode assembly has a folding structure, a stacking structure, a stacking / folding structure, or a lamination / stacking structure. delete delete The battery cell of claim 1, wherein the first battery case is made of aluminum or an aluminum alloy. delete The battery cell according to claim 1, wherein the electrically insulating material is a polyolefin resin. delete delete delete The battery cell of claim 1, wherein the electrode terminals of the electrode assembly protrude from one side or different sides of the first battery case and the second battery case. The battery cell according to claim 11, wherein one side or different sides of the electrode terminals protruding from the first battery case and the second battery case are heated and pressed by a press to be bonded and sealed. . The battery cell according to claim 1, wherein in the sealing folding portion, an outer circumference of the first battery case is bent to contact an outer surface of the second battery case, which is an opposite surface of the housing portion. delete delete The battery cell according to claim 1, wherein the sealing folding part has a rectangular or square shape on a vertical cross section. The battery cell of claim 1, wherein the battery cell is a lithium secondary battery. A battery pack comprising two or more battery cells according to claim 1. A device comprising the battery pack according to claim 18 as a power source. 20. The device of claim 19, wherein the device is selected from mobile phones, wearable electronics, portable computers, smart pads, netbooks, light electronic vehicles (LEVs), electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, and power storage devices. Device characterized in that the.

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