KR20160074209A - Can Type Curved Battery and Method for Manufacturing the Same - Google Patents

Abstract

The present invention relates to a secondary battery in which an electrode assembly including an anode, a cathode, and a separation film is included in a square-shape can while being immersed in an electrolyte and a manufacturing method thereof. The electrode assembly includes one or more curved surface portions on the laminated surface of the anode, cathode, and separation film. The square-shape can includes: a first can body which has a curved shape corresponding to one surface including the curved surface portion and has a structure surrounding one surface including the curved surface portion of the electrode assembly and part of an adjacent lateral surface; a second can body which has a structure surrounding the other surface including the curved surface portion of the electrode assembly and part of an adjacent lateral surface; and a top cap which is combined with the first can body and the second can body and includes a cap terminal.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a curved secondary battery,

The present invention relates to a prismatic curved secondary battery and a method of manufacturing the same, and more particularly, to a prismatic secondary battery having a structure in which an electrode assembly having a curved surface portion is embedded in a square can in a state impregnated with an electrolyte, .

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

In addition, in such a secondary battery, since electronic devices are becoming smaller and thinner depending on the taste of the consumer, the shape of the battery is also required to be reduced in size and thickness to minimize unnecessary space waste. Therefore, it is necessary to realize various shapes of the battery according to the shape of the device and efficiently utilize the inner space of the device.

In particular, in recent years, since the design of the device itself is a very important factor in the selection of the product of the consumer, various designs are being designed by avoiding the planar design considering the productivity and the like. For example, a device such as a mobile phone, a notebook, or the like can be designed with a predetermined curved surface for an ergonomic design.

As described above, many designs having a curved surface formed on the outer surface have been developed and put into practical use. However, since most of the commercialized batteries are flat, unnecessary space is wasted and it is difficult to stably install the battery There is a problem that the battery may be damaged due to external impact.

Therefore, when a curved surface is formed at a position where a battery is to be mounted in a device in which a curved surface is formed, a battery having a curved portion and being bent so that the device can be stably mounted on such a device is being developed.

FIG. 1 shows a schematic view of an electrode assembly having a curved surface portion curved along an imaginary line segment X'-X "as an example. 1 shows a structure in which one positive electrode plate 11, one separator plate 12 and one negative electrode plate 13 are stacked for convenience of explanation. However, the electrode assembly 10 includes a plurality of positive plates, Separators, and a plurality of negative plates.

Such a bent electrode assembly is built in a pouch-type secondary battery, which is embedded in a pouch case which is generally excellent in flexibility because of its curved shape.

However, in the case of the pouch-type secondary battery which can be easily changed, wrinkles are generated on the pouch case according to the curved surface formation, thereby causing insulation breakdown or leakage of electrolyte due to exposure of the metal layer, There is a problem in that the active materials repeatedly expand and contract during the charging or discharging process of the secondary battery due to the pressure or the electrode assembly can not maintain the bending state.

Accordingly, there is a great need for a secondary battery capable of solving the problems of the pouch type secondary battery and supporting the electrode assembly to maintain the bending state.

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 to solve the problems of the pouch case and to maintain the bending state of the electrode assembly regardless of the period of use when the electrode assembly including the curved surface portion is embedded in the square can And the present invention has been accomplished.

Therefore, in the secondary battery according to the present invention,

A secondary battery in which an electrode assembly including an anode, a cathode, and a separator is embedded in a square can with the electrolyte solution impregnated,

The electrode assembly includes at least one curved surface portion in the lamination plane of the anode, the cathode, and the separator,

In the square can,

A first can body having a curved shape corresponding to one surface including the curved surface portion of the electrode assembly and having a surface including a curved surface portion of the electrode assembly and a portion surrounding a side surface adjacent to the curved surface portion;

A second can body having a curved surface shape corresponding to the other surface facing the one surface and including a curved surface portion of the electrode assembly and surrounding the other surface including the curved surface portion of the electrode assembly and a part of the side surface adjacent thereto; And

A top cap coupled to the first can body and the second can body, the cap including a cap terminal;

And a control unit.

Here, the square can is made of a metal material.

In general, an electrode assembly including a curved surface portion is not flat and is not embedded in a rectangular or cylindrical can made of a metal material and hardly deformable, and it is also difficult to form a metal material into a can having a curved surface, It has to be embedded in a relatively flexible pouch case.

However, when the curved secondary battery is constructed by inserting the electrode assembly into the pouch case, wrinkles and cracks are generated on the pouch, thereby causing insulation breakdown or electrolyte leakage due to exposure of the metal layer in the pouch In addition, there is a problem that the active materials repeatedly expand and contract during external charging or discharging of the secondary battery, but are deformed together without supporting the curvature radial deformation of the electrode assembly.

Accordingly, the inventors of the present application have conducted intensive research and developed a method of embedding an electrode assembly including a curved surface portion into a rectangular can made of metal. The rectangular prismatic secondary battery thus manufactured has a rectangular can The electrode assembly is supported by the pouch case. Therefore, it is confirmed that the above-described problem that occurs when using the conventional pouch case can be fundamentally solved.

Therefore, the electrode assembly according to the present invention is not limited to the degree of warping, but may have a smaller radius of curvature R than an electrode assembly embedded in a pouch case that easily returns to a flat state without being supported in a bent state.

Specifically, the curvature radius R of the curved surface portion may be 500 mm or less, more specifically, 20 mm to 300 mm.

However, if the radius of curvature is too small, stress may be concentrated on the central portion of the secondary battery, resulting in deformation such as distortion. On the contrary, if the radius of curvature If it is too large, it is not preferable to control the radius of curvature.

On the other hand, the electrode assembly may include at least one non-curved surface portion, and the non-curved portion may be present on the side of the electrode assembly that is not parallel to the lamination surface or the lamination surface, May be present on the side of the electrode assembly which is not parallel to the laminate surface. At this time, the side surface means a surface perpendicular to the laminated surface.

In the non-curved surface, the positive electrode terminal and the negative electrode terminal extending from the positive electrode and the negative electrode of the electrode assembly may be positioned. When the electrode assembly includes two non-curved portions, the positive electrode terminal and the negative electrode terminal are all formed on one non- A positive electrode terminal may be located on one non-curved surface, and a negative electrode terminal may be formed on the other non-curved surface. Here, any one of the positive electrode terminal and the negative electrode terminal may be connected to a cap terminal formed on the top cap.

The type of the electrode assembly having the curved surface portion according to the present invention is not particularly limited and includes stacked electrode assemblies having a structure in which sheet-type anodes and cathodes are stacked with a separator interposed therebetween, stacked positive electrodes and negative electrodes A jelly-roll type electrode assembly having a structure in which a separator is interposed, a bi-cell or full cell in which a positive electrode and a negative electrode are laminated with a separator interposed therebetween, Stacked / stacked type electrode assembly, or stacked / folded type electrode assembly having a structure in which the bi-cells or pull cells are stacked with a separator interposed therebetween. In particular, / Stacked electrode assembly, and more particularly a stacked / folded electrode assembly.

Specifically, the stack / folding type electrode assembly is structured such that the bi-cell and / or pull-cell is wound by a separation film so as to face the opposite polarity after winding, and the bi- For example, an A-type bi-cell having a structure in which an anode is located at both ends of a unit cell, such as a positive electrode-separator-negative electrode-separator-positive electrode, and a negative electrode- separator- And a C-type bi-cell having a structure in which the cathode is located at both ends of the unit cell as shown in Fig. When the electrode assembly is formed using only the bi-cells, the A-type bi-cell and the C-type bi-cell may be included. The pull cells have a stacked structure in which different kinds of electrodes are located on both sides of the cell, and examples thereof include a cell made of a cathode-separator-cathode or a cell made of a cathode-separator-cathode-separator-anode.

Details of other stack / folding type electrode assemblies are disclosed in Korean Patent Application Laid-Open Nos. 2001-0082058, 2001-0082059 and 2001-0082060, the contents of which are incorporated herein by reference .

In the case of manufacturing the secondary battery according to the present invention by using the stack / folding type electrode assembly as described above, problems that may occur when the jelly-roll type electrode assembly is used, for example, It is possible to solve the problem that the active material layer is entirely coated so that disconnection occurs as the active material layer is separated from both ends where the active material layer is bent.

On the other hand, as described above, in the conventional manufacturing method, the prismatic can is hardly deformable, and it is almost impossible or impossible to embed it in the curved secondary battery.

SUMMARY OF THE INVENTION Accordingly, the present invention provides a method of manufacturing a secondary battery, which solves the above problems and easily incorporates an electrode assembly including a curved portion into a square can.

In one example, the method for manufacturing the secondary battery includes:

(i) fabricating an electrode assembly including an anode, a cathode, and a separator, and forming at least one curved portion on a lamination surface of the electrode assembly;

(ii) attaching a top cap to an upper portion of the electrode assembly having the curved portion;

(iii) fabricating a first can main body and a second can main body in which a housing portion is formed to have a curved shape corresponding to a curved portion of the electrode assembly;

(iv) attaching the first can main body and the second can main body such that the electrode assembly having the top cap is embedded in the first can main body and the second can main body; And

(v) welding and sealing the first can main body and the second can main body, the first can main body and the top cap, and the second can main body and the top cap to each other;

. ≪ / RTI >

In this case, the process of attaching the top cap and the assembling process of the main body may be changed in order. In another example, the method of manufacturing the secondary battery includes:

(i) fabricating an electrode assembly including an anode, a cathode, and a separator, and forming at least one curved portion on a lamination surface of the electrode assembly;

(ii) fabricating a first can body and a second can body in which a housing portion is formed to have a curved shape corresponding to a curved portion of the electrode assembly;

(iii) attaching the first can main body and the second can main body such that the electrode assembly is contained in the first can main body and the second main can main body, except for the upper part of the electrode assembly;

(iv) attaching a top cap to an upper portion of the electrode assembly; And

(v) welding and sealing the first can main body and the second can main body, the first can main body and the top cap, and the second can main body and the top cap to each other;

. ≪ / RTI >

In one specific example, the curved surface portion of the electrode assembly may be formed by a curved jig. Specifically, the curved jig includes a lower jig in the form of a receiving portion having a predetermined curvature radius and a corresponding upper jig, The electrode assembly may be inserted into the lower jig and then pressed by the upper jig to form a curved portion in the electrode assembly.

Meanwhile, the first can body and the second can body having a curved shape corresponding to the curved portion of the electrode assembly can be easily manufactured using a mold having a curved shape.

The first can main body and the second can main body are made of separate members and are then attached so as to surround the outside of the electrode assembly having the curved surface portion and welded together with the top cap as described above, The method of welding one can body and the second can body, the first can main body and the top cap, and the second can main body and the top cap are not limited, but may be made by laser.

The method of manufacturing the secondary battery may further include, in any subsequent method,

(vi) injecting the electrolyte through the electrolyte injection port of the top cap into the can containing the electrode assembly.

Needless to say, the manufacturing method of the secondary battery according to the present invention is not limited to the above-described manufacturing method, but may be a manufacturing method in which two or more members are welded. For example, The cap assembly includes a main body, a top cap corresponding to an upper portion of the can main body, and a cap portion including the side cap portion and the side portion corresponding to one side of the can main body. A manufacturing method can also be used.

Meanwhile, the positive electrode constituting the electrode assembly is prepared by applying a mixture of a positive electrode active material, a conductive material and a binder on a positive electrode collector, followed by drying and pressing, and if necessary, a filler may be further added to the mixture.

The cathode current collector generally has a thickness of 3 to 500 mu m. Such a positive electrode current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery. Examples of the positive electrode current collector include stainless steel, aluminum, nickel, titanium, sintered carbon, aluminum or stainless steel A surface treated with carbon, nickel, titanium, silver or the like may 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 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 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); A lithium manganese composite oxide having a spinel structure represented by LiNi _x Mn _2-x O ₄ ; 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 prepared by coating, drying and pressing the negative electrode active material on the negative electrode current collector, and may optionally further include a conductive material, a binder, a filler, and the like as described above.

The negative electrode current collector is generally made to have a thickness of 3 to 500 mu m. Such an anode current collector is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, and examples of the anode current collector include copper, stainless steel, aluminum, nickel, titanium, sintered carbon, a surface of copper or stainless steel A surface treated with 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.

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 < 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. A separation film used when the electrode assembly is a stack / folding type electrode assembly also corresponds to the description of the separation membrane.

Meanwhile, the secondary battery according to the present invention may be a lithium secondary battery, and the electrolyte injected through the electrolyte injection port of the top cap may be a non-aqueous electrolyte containing a lithium salt.

The nonaqueous electrolytic solution containing a lithium salt is composed of a nonaqueous electrolyte and a lithium salt. Nonaqueous organic solvents, organic solid electrolytes, inorganic solid electrolytes, and the like are used as the nonaqueous electrolytic solution, but 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 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, A polymer containing an ionic 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 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 2) 2 NLi, chloroborane lithium, lower aliphatic carboxylic acid lithium, lithium tetraphenyl borate and imide.

For the purpose of improving the charge / discharge characteristics and the flame retardancy, the electrolytic solution is preferably mixed with an organic solvent such as pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, glyme, Benzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N, N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrrole, 2-methoxyethanol, . 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 To a mixed solvent of linear carbonate to prepare a nonaqueous electrolyte solution containing a lithium salt.

The present invention also provides a battery module including at least two secondary batteries, a battery pack including the battery module, and a device including the battery pack.

Specific examples of the device include mobile electronic devices such as mobile phones, portable computers, smart phones, tablet PCs, smart pads, and netbooks; A power tool powered by an electric motor; LEV (Light Electronic Vehicle); An electric vehicle including an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and the like; An electric motorcycle including an electric bike (E-bike) and an electric scooter (E-scooter); An electric golf cart; Power storage; , But are not limited thereto.

The structure of the battery module and the battery pack, the method of manufacturing the same, the structure of the device, and the manufacturing method thereof are well known in the art, so a detailed description thereof will be omitted herein.

As described above, the secondary battery according to the present invention has a structure in which the electrode assembly including the curved surface portion is embedded in the square can, so that wrinkles and cracks on the pouch case, which may occur when the electrode assembly is embedded in the pouch case, Therefore, it is possible to solve the problem that the curvature radius of the curved portion is deformed without maintaining the bending state according to the use period.

1 is a schematic view of a bent-shaped electrode assembly;
2 to 5 are schematic views of a method of manufacturing a secondary battery according to an embodiment of the present invention.

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

2 to 5, for convenience of understanding, a method of manufacturing a secondary battery according to an embodiment of the present invention is schematically shown.

Figs. 2 to 5 show, as an example, a method of manufacturing the secondary battery according to the present invention in order.

Referring to FIG. 2, a process (a) of forming at least one curved surface portion 130 on a laminated surface of an electrode assembly 100 including an anode, a cathode, and a separator is illustrated.

Specifically, the electrode assembly 100 is a stack / folding type electrode assembly having, on its upper portion, positive electrode taps 111 and negative electrode tabs 121 extending from the positive electrode and the negative electrode of the electrode assembly 100, The positive electrode terminal 110 and the negative electrode terminal 120 which are made of the positive electrode lead 112 and the negative electrode lead 122 are formed.

The process of forming the curved surface portion 130 having a predetermined radius of curvature in the electrode assembly 100 is performed by the carving jig 200. Specifically, the carving jig 200 includes a lower jig 220 having a predetermined curvature radius and a corresponding upper jig 210. When the electrode assembly 100 is inserted into the lower jig 220, And the upper jig 210 is pressed to form the curved surface portion 130 in the electrode assembly 100.

3, a curved portion 130 is formed on the electrode assembly 100, and a top cap 300 (see FIG. 3) is formed on the electrode assembly 100 having the cathode terminal 110 and the cathode terminal 120 formed thereon. (B) is shown.

Specifically, the top cap 300 includes a cap terminal 301 electrically connected to the cathode terminal 120 of the electrode assembly 100, and a cap terminal 301 electrically connected to the electrolyte inlet 302, respectively.

The top cap 300 is attached to the upper portion of the electrode assembly 100 and the method of attachment is not limited to that described above. The cap terminal 301 of the top cap 300 and the cathode terminal 120 of the electrode assembly 100, And welding to be electrically connected to the positive electrode terminal 110 and the top cap 130 itself. At this time, the negative electrode terminal 120 is insulated from the top cap 300 by the insulating member 303.

4, a can main body 400 including a first can main body 410 and a second can main body 420 as a member for housing the electrode assembly 100 with the top cap 300 attached thereto, And a step (c) of attaching them.

Specifically, the first can main body 410 and the second can main body 420 are respectively manufactured to include the receiving portions 411 and 421 having curved shapes corresponding to the curved portions 130 of the electrode assembly 100 .

The first can main body 410 and the second can main body 420 thus manufactured are arranged in the first can main body 410 and the second main can body 420 in both directions of the laminate surface of the electrode assembly 100 411, and 421. The electrode assemblies 100,

In this case, the attachment method is not limited, but an insulating adhesive may be used. Although not shown, the first can body 410 and the second can body 420 may be provided with one or more And one or more fastening grooves may be formed to be coupled to the fastening holes.

5, when the attachment of the first can main body 410 and the second can main body 420 is completed as described above, the first can main body 410, the second can main body 420, A step (d) of welding the main body 410 and the top cap 300, and the second can body 420 and the top cap 300 along the contact surfaces to seal them is performed.

Referring to Fig. 5, as an example, the welding with laser 500 (shown in red) is shown.

Finally, although not shown separately, a process of injecting an electrolyte through the electrolyte injection port 302 of the top cap 300 is performed on the can containing the electrode assembly.

When the electrolyte injection is completed in this way, the electrode assembly has a curved surface shape corresponding to one surface including the curved surface portion of the electrode assembly (not shown), and has a first surface including the curved surface portion of the electrode assembly, A can body 410 having a curved surface shape corresponding to the other surface facing the one surface and including a curved surface portion of the electrode assembly and having a surface including a curved surface portion of the electrode assembly and a portion of a side surface adjacent to the curved surface portion, And a top cap 300 coupled to the first can main body and the second can main body and including a cap terminal, the secondary battery having a structure in which the electrode assembly is embedded in the electrolyte solution, 600) is completed.

Meanwhile, although not shown in the drawing, the order (b) of attaching the top cap 300 and the step (c) of attaching the can body 400 may be reversed.

As described above with reference to the drawings, the electrode assembly including the curved surface portion can be easily embedded in the square can, and the secondary battery 600 manufactured in this manner can be mounted on the pouch case It is possible to improve the safety of the battery by solving the occurrence of wrinkles and cracks and to solve the problem that the curvature radius of the curved portion is deformed without maintaining the bending state according to the use period because the electrode assembly is supported by the square can .

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

Claims (20)

A secondary battery in which an electrode assembly including an anode, a cathode, and a separator is embedded in a square can with the electrolyte solution impregnated,
The electrode assembly includes at least one curved surface portion in the lamination plane of the anode, the cathode, and the separator,
In the square can,
A first can body having a curved shape corresponding to one surface including the curved surface portion of the electrode assembly and having a surface including a curved surface portion of the electrode assembly and a portion surrounding a side surface adjacent to the curved surface portion;
A second can body having a curved surface shape corresponding to the other surface facing the one surface and including a curved surface portion of the electrode assembly and surrounding the other surface including the curved surface portion of the electrode assembly and a part of the side surface adjacent thereto; And
A top cap coupled to the first can body and the second can body, the cap including a cap terminal;
And a secondary battery. The secondary battery according to claim 1, wherein the square can is made of a metal material. The secondary battery according to claim 1, wherein the radius of curvature (R) of the curved portion is 500 mm or less. The secondary battery according to claim 3, wherein the radius of curvature (R) of the curved portion is 20 mm to 300 mm. The secondary battery of claim 1, wherein the electrode assembly includes at least one non-curved surface portion. The secondary battery according to claim 1, wherein the side surface of the electrode assembly, which is not parallel to the lamination surface, comprises at least one non-curved portion. The secondary battery according to claim 5, wherein a cathode terminal and an anode terminal extending from the anode and the cathode of the electrode assembly are located on the non-curved surface portion. The secondary battery according to claim 7, wherein one of the positive electrode terminal and the negative electrode terminal is connected to a cap terminal formed on the top cap. The method according to claim 1, wherein the electrode assembly comprises a stacked electrode assembly having a structure in which sheet-like anodes and cathodes are stacked with a separator interposed therebetween, a structure in which a long-sheet anode and a cathode are wound with a separator interposed therebetween A stack / folding type electrode assembly having a jelly-roll type electrode assembly, a bi-cell or a full cell stacked with a separator interposed therebetween in a predetermined unit, Wherein the bi-cell or the full cell is laminated in a state in which a separator is interposed therebetween. The secondary battery according to claim 1, wherein the secondary battery is a lithium secondary battery. A method of manufacturing a secondary battery according to claim 1,
(i) fabricating an electrode assembly including an anode, a cathode, and a separator, and forming at least one curved portion on a lamination surface of the electrode assembly;
(ii) attaching a top cap to an upper portion of the electrode assembly having the curved portion;
(iii) fabricating a first can main body and a second can main body in which a housing portion is formed to have a curved shape corresponding to a curved portion of the electrode assembly;
(iv) attaching the first can main body and the second can main body such that the electrode assembly having the top cap is embedded in the first can main body and the second can main body; And
(v) welding and sealing the first can main body and the second can main body, the first can main body and the top cap, and the second can main body and the top cap to each other;
Wherein the first electrode and the second electrode are electrically connected to each other. A method of manufacturing a secondary battery according to claim 1,
(i) fabricating an electrode assembly including an anode, a cathode, and a separator, and forming at least one curved portion on a lamination surface of the electrode assembly;
(ii) fabricating a first can body and a second can body in which a housing portion is formed to have a curved shape corresponding to a curved portion of the electrode assembly;
(iii) attaching the first can main body and the second can main body such that the electrode assembly is contained in the first can main body and the second main can main body, except for the upper part of the electrode assembly;
(iv) attaching a top cap to an upper portion of the electrode assembly; And
(v) welding and sealing the first can main body and the second can main body, the first can main body and the top cap, and the second can main body and the top cap to each other;
Wherein the first electrode and the second electrode are electrically connected to each other. 13. The method of manufacturing a secondary battery according to claim 11 or 12, wherein the curved portion of the electrode assembly is formed by a curved jig. [14] The apparatus of claim 11 or 12, wherein the first can body and the second can body each include at least one fastener and at least one fastening groove coupled to the fastener, Gt; The method for manufacturing a secondary battery according to claim 11 or 12, wherein the welding is performed by a laser. The secondary battery according to claim 11 or 12, further comprising: (vi) injecting an electrolyte through the electrolyte injection port of the top cap into the can containing the electrode assembly. ≪ / RTI > A battery module comprising at least two secondary batteries according to claim 1. A battery pack comprising the battery module according to claim 17. A device according to claim 18, comprising the battery pack as a power source. 20. The method of claim 19, wherein the device is selected from the group consisting of a mobile phone, a portable computer, a smart phone, a tablet PC, a smart pad, a netbook, a LEV (Light Electronic Vehicle), an electric vehicle, a hybrid electric vehicle, ≪ / RTI > device.

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