KR101807271B1 - Pouch-Typed Battery Cell Comprising a Thin Plate and Method for Preparing the Same - Google Patents

Abstract

The present invention is characterized in that an electrode assembly having a separator interposed between an anode and a cathode is embedded in a pouch-shaped case in a state of being impregnated with an electrolyte; The pouch-type case includes a receiving portion for mounting the electrode assembly, and the outer surface of the case is formed of a metal layer; And a sealing portion formed by welding between the metal layers of the pouch-shaped case is disposed on the outer circumferential surface of the housing portion, characterized in that the battery has a high energy to volume ratio and the mechanical strength of the outer member is improved .

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a pouch-type battery cell including a thin plate and a method of manufacturing the same.

The present invention relates to a battery cell, and more particularly, to a battery cell in which an outer surface of a pouch-shaped case is formed of a metal layer and metal layers of the pouch-shaped cases are welded to each other by welding.

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.

Generally, a lithium secondary battery is formed by stacking or winding up an electrode assembly composed of an anode, a cathode, and a separator interposed between the anode and the cathode, and inserting the electrolyte into a battery case of a metal can or a laminate sheet, .

Recently, due to the high capacity of the battery, much attention has been paid to the large-sized case and the processing of a thin material. Accordingly, a structure in which a stacked or stacked / folded electrode assembly is embedded in a pouch-shaped battery case of an aluminum laminate sheet The pouch-shaped battery cell of the present invention has been gradually increased in usage due to low manufacturing cost, small weight, and easy shape deformation.

FIG. 1 schematically shows an exploded perspective view of a conventional pouch-type battery cell which includes a stacked electrode assembly.

1, the pouch-shaped battery cell 10 includes an electrode assembly 30 housed inside a pouch-shaped battery case body 20, and the electrode taps 31 and 32 thereof are electrically connected to two electrode leads 30, And are sealed to be exposed to the outside of the battery case body 20 by being welded to the battery case body 40 and 41, respectively.

1 illustrates a pouch type battery cell using the stacked electrode assembly 30, it is needless to say that the same method can also be used when a wound or jelly-roll type electrode assembly is used.

The pouch type case 20 includes a case body 21 including a concave shaped storage portion 23 on which the electrode assembly 30 can be placed and a cover 22 having one side connected to the case body 21, Lt; / RTI >

The pouch-shaped case 20 is made of a laminated sheet including an outer coating layer 20b, a thin metal layer 20a and a resin layer 20c. The pouch-shaped case 20 is a soft packaging material and is susceptible to external impact such as a needle- There is a danger of causing ignition or explosion by the power source, and safety may be a problem.

In addition, in order to seal the battery case, the resin layer 20c is thermally fused to form a closed structure, which requires a large-area sealing portion 24 for this purpose. In order to form the sealing portion 24, the pouch type case 20 includes a predetermined folded portion. As the size of the cell increases, the area of the sealing portion 25, which is unnecessary for the battery characteristic, The energy efficiency of the bar and the cell is lower than that of the cell.

Therefore, there is a high need for a technique for securing safety by increasing the mechanical strength of the pouch-type battery case and reducing unnecessary space to achieve energy efficiency.

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.

Specifically, an object of the present invention is to provide a battery cell including a metal layer which can be welded to a pouch-shaped battery case, and which has improved mechanical strength.

Another object of the present invention is to provide a method of manufacturing a battery cell in which the outer surface of the pouch-shaped case is formed of a metal layer, and the sealing portion is formed by welding the metal layers of the pouch-shaped case to each other to minimize the area of the sealing portion.

According to an aspect of the present invention, there is provided a battery cell comprising: an electrode assembly having a separator interposed between an anode and a cathode;

The pouch-type case includes a receiving portion for mounting the electrode assembly, and the outer surface of the case is formed of a metal layer;

And a sealing portion formed by welding between the metal layers of the pouch-shaped case is positioned on the outer peripheral surface of the storage portion.

That is, the battery cell according to the present invention includes the metal layer that can be welded to the outer surface of the pouch-shaped battery cell, thereby improving the mechanical strength and forming the sealing portion by welding between the metal layers. , A battery cell having improved stability and energy efficiency.

Generally, an electrode assembly included in a battery cell has a structure in which an anode, a cathode, and a separator interposed between an anode and a cathode are stacked, and can be divided into a jelly-roll type, a stack type, and a stack / have.

The jelly-roll type (wound type) electrode assembly is a structure in which a long sheet type anode and negative electrodes are wound with a separator interposed therebetween. A stacked (laminate) electrode assembly includes a plurality of positive electrodes and negative electrodes And a structure in which layers are sequentially stacked with a separator interposed therebetween. In recent years, electrode assemblies having a progressive structure of the jelly-roll type and the stack type have been proposed, in which unit cells stacked in a state in which a predetermined unit of positive and negative electrodes are stacked with a separator interposed therebetween are sequentially A stacked / folded electrode assembly having a wound structure has been developed, making it possible to manufacture a high capacity, low cost battery cell.

In one specific example, the electrode assembly may comprise one of the following structures:

(i) a jelly-roll structure in which a positive electrode sheet and a negative electrode sheet are wound with a separator interposed therebetween;

(ii) a laminated structure in which two or more positive electrode plates and two or more negative electrode plates are stacked with a separator interposed therebetween; And

(iii) a stack / folding structure in which at least two positive electrode plates and at least one negative electrode plate are laminated and joined together with a separator interposed therebetween, the two or more unit cells being wound by a separator film.

As described above, the pouch-shaped battery cell according to the present invention can be applied to an electrode assembly having various structures.

The pouch-shaped battery cell according to the present invention includes a metal layer weldable to the pouch-shaped case, sealing (sealing) the metal layers formed in the case by mutual welding, securing the durability of the case and improving safety .

Specifically, the metal layer is in the form of a thin plate and may have a thickness ranging from 0.01 mm to 1.5 mm, and more specifically, a range from 0.02 mm to 1.0 mm.

A sheet is generally a steel sheet of 3 mm or less in thickness, which is hot rolled or cold rolled, and is also referred to as a thin steel sheet. The metal layer of a typical pouch-shaped case is in the form of a thin film rather than a sheet, and is not weldable. Further, the metal layer in the form of a thin plate is liable to be damaged by a sharp member from the outside, and safety may be a problem. Accordingly, the pouch-type case according to the present invention has the advantage of a pouch-shaped case that includes a thin metal layer having a predetermined thickness, improves safety, enables welding, and is flexible in shape and easy to manufacture .

If the thickness of the metal layer exceeds 1.5 mm, it is difficult to secure the flexibility of the pouch-shaped case, and it is not preferable because the ease of manufacture, which is the strength of the pouch-shaped case, can not be ensured and the thickness of the metal layer is less than 0.01 mm , Welding can not be performed, and it is difficult to achieve the desired mechanical strength, which is not preferable.

Meanwhile, the pouch-type case may be made of aluminum, copper, iron, an alloy thereof, or the like, provided that the pouch-shaped case is made of a metal layer whose outer surface is weldable and can form a sealing portion through welding. The pouch-type case may be composed of a single metal layer or may include a polymer resin layer on one side. The polymer resin layer may be formed in the form of a coating layer by spraying, dipping or the like, or may be formed in a laminate structure using dry lamination or extrusion lamination.

In one specific example, when a layer other than the metal layer is included as described above, one or more resin layers may be added to the inner surface of the metal layer in the pouch-shaped case.

Specifically, the resin layer can reinforce the durability, moisture resistance and other mechanical strength of the case, and can be added in consideration of cost and manufacturing method. In addition, the resin layer may be a polymer resin having heat-sealability (thermal adhesiveness), low hygroscopicity to an electrolyte to suppress the penetration of an electrolyte, and not being swollen or eroded by an electrolytic solution. And a new polypropylene film (CPP).

It is preferable that such a resin layer is added to a portion corresponding to the inner surface of the pouch-shaped case in the metal layer so as not to interfere with the welding for forming the sealing portion of the metal layer.

The resin layer added to the inner surface of the metal layer as described above not only improves the durability of the pouch-shaped case but also makes the sealing of the sealed portion more robust, thereby further improving the safety. Specifically, in the sealing portion of the pouch-shaped case, the resin layer can be mutually fused by the heat transferred during the welding of the metal layer.

That is, the pouch-shaped case of the battery cell according to the present invention is formed by welding the metal layers formed on the outer surface to each other to form a sealing portion, and by mutually fusion bonding the resin layers added to the inner surface of the metal layer by the heat during welding, As a result of the sealing, the sealing property can be further enhanced.

The thickness of the resin layer may be 5 mu m to 100 mu m, and more specifically 10 mu m to 50 mu m. If the thickness of the resin layer is too thin, it is difficult to expect the effect of blocking the material, moisture resistance, sealing property, and the like. On the contrary, if it is too thick, the workability is deteriorated and the thickness of the sheet is increased.

The shape of the pouch-type case includes, but is not limited to, an upper case formed with an upper accommodating portion corresponding to an upper shape of the electrode assembly and a lower case formed with a lower accommodating portion corresponding to the lower shape of the electrode assembly The outer circumferential metal layer of the upper case and the outer circumferential metal layer of the lower case may be welded to each other to form a sealing portion;

A case in which a housing portion corresponding to the shape of the electrode assembly is formed and a cover which extends in a bent state from one end of the case and encloses the housing portion, and the outer circumferential metal layer of the case and the outer circumferential metal layer of the cover are welded to each other A sealing portion may be formed.

Therefore, the battery cell according to the present invention is not limited to the size and outer shape of the electrode assembly, and can be manufactured in the most appropriate form including the pouch case of various shapes, taking into consideration the use and cost.

When the pouch-type case is composed of the upper case formed with the upper storage portion and the lower case formed with the lower storage portion, the sealing portion is formed at the central portion with respect to the height of the pouch-shaped case, And the cover is extended from the cover in a bent state to enclose the housing portion, the sealing portion is formed at the upper corner portion with reference to the height of the pouch-shaped case.

The upper case and the lower case, or the case and the cover may be connected to each other or may be separated from each other, but they are preferably connected to each other in order to simplify the process and reduce the area of the sealing portion.

The welding for forming the sealing portion is not particularly limited and may be arc welding, gas welding, friction welding, thermite welding, laser welding or the like, but in detail, it is possible to use a laser capable of precise welding, Welding is preferable.

In one specific example, an electrically insulating resin may be further applied to the outer surface of the sealing portion so as to enhance the sealing property of the pouch-shaped case.

Therefore, in the battery cell according to the present invention, the sealing portion can be formed at various positions according to the shape of the pouch-shaped case, and the electric insulating resin is applied to the outer surface of the sealing portion formed by welding and a part of heat fusion, As compared with the sealing portion formed only through the through-hole.

That is, in the conventional pouch-type case, the sealing portion is formed only by heat fusion. In order to ensure the sealing property, the sealing portion is formed on the pouch-type case including the predetermined bending portion. On the other hand, the battery cell according to the present invention may not include the bending portion in the pouch-type case except for the electrode terminal portion.

Thus, the efficiency of sealing is high, manufacturing cost and time are saved, and unnecessary parts for sealing are reduced, so that the energy efficiency is equal to that of the same volume.

As described above, the battery cell according to the present invention does not include the bending portion in the pouch-type case, and the shape of the battery cell may have a cylindrical shape, a prismatic shape, or other polyhedron shape, You can have an appearance. Therefore, it is possible to efficiently stack a plurality of battery cells through regular arrangement.

The present invention also provides a method of manufacturing the battery cell.

The method of manufacturing a battery cell includes:

(i) preparing an electrode assembly;

(ii) preparing a battery case having a housing portion having a shape corresponding to the electrode assembly, the battery case including a metal layer on an outer surface thereof;

(iii) after the electrode assembly is mounted on the receiving part, welding the metal layers to each other except one side of the outer circumferential surface of the receiving part; And

(iv) injecting an electrolyte through the remaining portion not welded, welding and sealing the same;

. ≪ / RTI >

On the other hand, in the above manufacturing process, after the step (iv), an electric insulating resin is added to the outer surface of the sealing portion formed by welding and the peripheral portion thereof so as to improve the sealing property and protect the battery cell from external impact May further include a process.

Further, in the method of manufacturing the battery cell,

(i) preparing an electrode assembly;

(ii) preparing a battery case having a housing portion having a shape corresponding to the electrode assembly, the battery case including a metal layer on an outer surface thereof;

(iii) mounting the electrode assembly on the receiving part and injecting an electrolyte; And

(iv) welding and sealing the metal layers on the outer circumferential surface of the accommodating portion;

. ≪ / RTI >

That is, the electrolyte injection process may be performed before the sealing process through mutual welding of the metal layers, may be performed in the middle process of sealing, or may be performed after the sealing process.

Meanwhile, in the manufacturing process, the process of adding the electrically insulating resin to the outer surface of the sealing portion formed by welding and the peripheral portion thereof after the step (iv) so as to enhance the sealing property and protect the battery cell from external impact May be further included.

The battery cell has a structure in which an electrode assembly is housed in a storage portion of a pouch-shaped battery case. That is, a housing portion for mounting the electrode assembly is formed on a sheet including a metal layer on its outer surface, and an outer peripheral surface of a sheet or cover on which the upper housing portion is formed is welded with the electrode assembly mounted on the housing portion Lt; / RTI >

In the step (i) of preparing the electrode assembly, the electrode assembly includes a cathode, a cathode, and a separator.

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

The cathode active material may be a layered compound such as lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), or a compound substituted with one or more transition metals; 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); 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 wt% to 30 wt% 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 that 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 wt% based on the total weight of the mixture containing the cathode active material. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene , Polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butylene rubber, fluorine rubber, various copolymers and the like.

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

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

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

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

The step (ii) is a process of preparing a battery case with a sheet material including a metal layer having a predetermined thickness so as to be weldable, and comprises a lower case including an upper case and an upper case including the upper case of the electrode assembly A case including an entire receiving portion of the electrode assembly, and a cover surrounding the entire receiving portion. In addition, the upper and lower cases, the case and the cover may use separate sheets separated from each other, or one sheet to which one side of the upper and lower sheets is connected.

The battery case may be formed by partially compressing a sheet having a metal layer of a predetermined thickness formed on its outer surface by a drawing process using a die and a punch so that a housing portion having a shape corresponding to the electrode assembly can be formed.

Specifically, a step of preparing a forming mold in which the shape corresponding to the storage portion is stamped is prepared; Disposing a sheet having a metal layer of a predetermined thickness formed on an upper surface of the molding die; And pressing the sheet on which the metal layer with the predetermined thickness is formed by a molding jig to manufacture a sheet on which the housing section is formed.

The above process (iii, iv) is a step of mounting each of the electrode assembly in the receiving units, and injecting and sealing the electrolyte solution, the electrolyte solution is prepared by inserting a non-aqueous electrolyte solution containing a lithium salt such as LiPF _6. Therefore, the electrolyte solution is composed of a polar organic electrolyte and a lithium salt. As the electrolyte solution, a non-aqueous liquid electrolyte, an organic solid electrolyte, and an inorganic solid electrolyte are used.

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

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

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

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

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

As described above, the process of injecting the electrolyte may be performed during the sealing process or may be performed before the sealing process.

When the electrolyte solution is injected before the sealing process, the metal layers may be welded to each other along the outer peripheral surface of the storage portion after the electrolyte is injected. In the case of injecting the electrolyte solution during the sealing process, After the metal layers are welded to each other, an electrolyte is injected, and the non-welded portion is secondarily welded and sealed.

Since the method of injecting the electrolyte before the sealing process does not require the secondary welding, there is a merit that the process is simple. In the method of injecting the electrolyte during the sealing process, the electrolyte solution may leak, Which is advantageous for the degassing process.

On the other hand, in the case where the polymer resin layer is formed on the inner surface of the sheet in the above sealing process, the polymer resin layer is thermally fused by the heat used for welding, so that the sealing property can be more firmly maintained.

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

Typical examples of the device include, but are not limited to, a mobile phone, a notebook, a tablet PC, a wearable electronic device, an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle or a power storage system.

Since the structure of the device and the method of manufacturing the device are well known in the art, a detailed description thereof will be omitted herein.

INDUSTRIAL APPLICABILITY As described above, the battery cell according to the present invention includes a pouch-type case having an outer surface formed of a metal layer and capable of forming a sealing portion by welding between metal layers, thereby reducing an unnecessary sealing portion, It is possible to improve the safety and the energy efficiency by improving the mechanical strength.

1 is an exploded perspective view schematically showing the structure of a conventional typical pouch-shaped battery cell including a stacked electrode assembly;
2 is an exploded perspective view schematically illustrating a battery cell including a stacked electrode assembly according to an embodiment of the present invention;
3 is an exploded perspective view schematically showing a battery cell including a stacked electrode assembly according to yet another embodiment of the present invention;
FIG. 4A is a perspective view schematically showing the battery cell shown in FIG. 2; FIG.
FIG. 4B is a perspective view schematically showing the battery cell shown in FIG. 3; FIG.
5 is an exploded perspective view schematically showing a battery cell including a stack / folding type electrode assembly according to yet another embodiment of the present invention;
FIG. 6A is a perspective view schematically showing the battery cell shown in FIG. 5; FIG. And
FIG. 6B is a perspective view schematically showing a battery cell including the stack / folding type electrode assembly and another embodiment of the battery cell shown in FIG. 5; FIG.

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

2 is a schematic exploded perspective view of a battery cell including a stacked electrode assembly according to an embodiment of the present invention.

Referring to FIG. 2, the battery cell 100 has a structure in which the electrode assembly 300 is embedded in the pouch-type case 200. The pouch-type case 200 is composed of a cover 220 integrally connected to the case body 210. The case body 210 is formed with a receiving portion 230 for accommodating the electrode assembly.

The electrode assembly 300 includes a stacked electrode assembly 310 having electrode tabs 310 and 320 extended therefrom and the electrode tabs 310 and 320 are welded to the two electrode leads 400 and 410, An insulating tape is attached.

The battery cell 100 has the electrode assembly 300 attached to the housing part 230 so that the electrode leads 400 and 410 are exposed to the outside of the pouch case 200 and the cover 220 and the case body 210 To weld the outer circumferential surface of the sealing part 240 to form a sealing part 240.

Specifically, the pouch-type case 200 is formed of a laminate sheet including a metal layer 200A and a resin layer 200C having a predetermined thickness on the outer surface. The metal layer 200A having a predetermined thickness can be welded in the form of a thin plate having a thickness ranging from 0.01 mm to 1.5 mm. Therefore, the sealing portion 240 is formed by welding the metal layer included in the cover 220 and the metal layer included in the main body 210 to each other.

At this time, all or a part of the resin layer 200C is mutually fused by the heat conducted at the time of mutual welding of the metal layer 200A, and the sealing portion 240 includes a sealing structure by welding, a sealing structure by heat sealing .

Comparing the conventional pouch-type battery cell 10 shown in Fig. 1 with the battery cell 100 shown in Fig. 2, the battery case body 20 constituting the battery cell 10 shown in Fig. (Shaded portion) for forming the battery cell 100, but the pouch-shaped case 200 constituting the battery cell 100 of FIG. 2 does not include the bent portion. Therefore, the sealing portion 24 shown in Fig. 1 occupies a considerably large area as compared with the sealing portion 240 shown in Fig. 2, which is unnecessary for charging and discharging the battery, .

The metal layer 200A included in the pouch-shaped case 200 of FIG. 2 is a thin metal layer, which is thicker than the thin metal layer 20a included in the battery case body 20 of FIG. 1, Outer needle member, and other external impacts, and can be welded to each other, thereby forming a double seal structure together with heat fusion.

3 is a schematic exploded perspective view of a battery cell including a stacked electrode assembly according to still another embodiment of the present invention. Fig. 4A is a perspective view schematically showing the battery cell shown in Fig. 2, and Fig. 4B is a perspective view schematically showing the battery cell shown in Fig.

Referring to FIG. 3, the battery cell 101 has a structure in which a stacked electrode assembly 301 is embedded in a pouch-shaped case 201. The pouch type case 201 includes an upper case 221 having an upper accommodating portion corresponding to the upper shape of the electrode assembly 301 and a lower case 211 having a lower accommodating portion corresponding to the lower shape of the electrode assembly ).

In other words, unlike the battery cell 100 of FIG. 2, the battery cell 101 of FIG. 3 includes an upper case formed with an upper housing part instead of a cover of the pouch-type housing, As shown in FIG.

4A and 4B, the battery cell 100 shown in FIG. 4A includes a cover and a case body, and the electrode lead 400 and 410 are exposed. 240 are formed on the upper corner of the pouch-shaped case.

4B, the pouch-type case is formed of an upper case and a lower case, so that the sealing portion 241 is formed at the central portion of the side surface of the pouch-type case in a state in which the electrode leads are exposed .

On the other hand, all of the battery cells 100 and 101 form the sealing portions 240 and 241 by welding the metal layer formed on the outer surface, and do not include the bent portions for securing the sealing property. Therefore, the battery cells 100 and 101 have a roughly hexahedral structure.

5 is an exploded perspective view illustrating a battery cell including a stack / folding type electrode assembly, according to another embodiment of the present invention. FIG. 6A is a perspective view schematically showing the battery cell shown in FIG. 5, and FIG. 6B is a schematic perspective view showing another perspective view of the battery cell including the stack / folding type electrode assembly. That is, the battery cell according to the present invention is not limited to the structure of the electrode assembly, and an electrode assembly suited to the characteristics of each device can be used.

Referring to FIG. 5, the battery cell 103 has a structure in which the electrode assembly 303 is housed inside the pouch case 203. The pouch-type case 203 includes an upper case 223 having an upper accommodating portion corresponding to the upper shape of the stack / folding type electrode assembly 303 and a lower accommodating portion corresponding to the lower shape of the electrode assembly And a lower case 213.

The electrode assembly 303 is a stack / folding type electrode assembly in which electrode tabs extending from the electrode assembly are welded to the two electrode leads 403 and 413, respectively, to attach an insulating tape.

The battery cell 103 shown in FIG. 5 has a structure in which the electrode leads 403 and 413 are exposed to the outside of the pouch type case 203, similarly to the battery cells shown in FIG. 2 or 3 303 are attached to the lower storage portion 233 and welded to the outer circumferential surfaces of the upper case 223 and the lower case 213. At this time, it is needless to say that the resin layers included in the pouch-shaped case 203 are fused to each other to form a double sealing structure.

Referring to FIG. 6A together with FIG. 5, a sealing portion of the battery cell 103 is formed at a central portion of a side surface of the pouch-shaped case with the electrode leads 410 and 413 exposed to the outside.

In contrast, the battery cell 102 shown in FIG. 6B has a pouch-shaped case formed of a cover and a case body, and the sealing portion is formed on the upper corner of the pouch-shaped case with the electrode leads exposed.

The battery cells 103 and 102 shown in Figs. 6A and 6B are different from the battery cells 100 and 101 shown in Figs. 4A and 4B including the stacked electrode assembly, A folding type electrode assembly, and a shape of a rectangular parallelepiped corresponding to the shape.

That is, the battery cell according to the present invention provides a pouch-shaped battery cell including a metal layer having a predetermined thickness formed on an outer surface thereof, which is easy to manufacture and has improved mechanical strength. In addition, a metal layer of a predetermined thickness is welded to form a sealing portion, which can form a double-sealing structure and does not include a bent portion for securing the sealing property. The battery cell has a substantially hexahedral structure, It is easy to stack a plurality of battery cells without loss of the battery, and even when a battery of a high capacity and a high energy is manufactured, a more compact structure can be secured.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (19)

An electrode assembly having a structure in which a separator is interposed between an anode and a cathode is embedded in a pouch-shaped case in a state of being impregnated with an electrolyte;
Wherein the pouch-shaped case includes a housing portion in which a layer-shaped material for mounting the electrode assembly is integrally formed, and the outer surface is formed of a metal layer;
Wherein a sealing portion formed by welding between outer metal layers of the pouch-shaped case is positioned on the outer circumferential surface of the storage portion in a state in which there is no separate folded sealing portion for welding or welding. The battery cell according to claim 1, wherein the electrode assembly comprises one of the following structures:
(i) a jelly-roll structure in which a positive electrode sheet and a negative electrode sheet are wound with a separator interposed therebetween;
(ii) a laminated structure in which two or more positive electrode plates and two or more negative electrode plates are stacked with a separator interposed therebetween; And
(iii) a stack / folding structure in which at least two positive electrode plates and at least one negative electrode plate are laminated and joined together with a separator interposed therebetween, the two or more unit cells being wound by a separator film. The battery cell according to claim 1, wherein the metal layer is in the form of a thin plate and has a thickness ranging from 0.01 mm to less than 1 mm. The battery cell according to claim 3, wherein the thickness ranges from 0.02 mm to 0.5 mm. The battery cell according to claim 1, wherein at least one resin layer is provided on the inner surface of the metal layer in the pouch-shaped case. The battery cell according to claim 5, wherein in the sealing portion of the pouch-type case, the resin layer is mutually fused by the heat transferred when the metal layer is welded. The pouch case according to claim 1, wherein the pouch-type case includes an upper case formed with an upper housing part corresponding to an upper shape of the electrode assembly, and a lower case formed with a lower housing part corresponding to a lower shape of the electrode assembly ,
Wherein the outer circumferential metal layer of the upper case and the outer circumferential metal layer of the lower case are welded to each other to form a sealing portion. The electronic apparatus according to claim 1, wherein the pouch-type case includes a case having a housing portion corresponding to the shape of the electrode assembly, and a cover extending from one end of the case in a bent state to cover the housing portion,
Wherein the outer peripheral metal layer of the case and the outer peripheral metal layer of the cover are welded to each other to form a sealing portion. The battery cell according to claim 1, wherein the welding is laser or ultrasonic welding. The battery cell according to claim 1, wherein an electrically insulating resin is additionally applied to an outer surface of the sealing portion. The battery cell according to claim 1, wherein the battery cell has no bent portion in the pouch-shaped case except for the electrode terminal portion. The battery cell according to claim 1, wherein the battery cell has a hexahedral shape. 13. A method for manufacturing a battery cell according to any one of claims 1 to 12,
(i) preparing an electrode assembly;
(ii) preparing a battery case having a housing portion having a shape corresponding to the electrode assembly and including a metal layer on an outer surface thereof;
(iii) after the electrode assembly is mounted on the receiving part, welding the metal layers to each other except one surface of the outer circumferential surface of the receiving part; And
(iv) injecting an electrolyte through the remaining portion not welded, welding and sealing the same;
≪ / RTI > The manufacturing method according to claim 13, further comprising the step of adding an electrically insulating resin to an outer surface of the sealing portion formed by welding and a peripheral portion thereof after the step (iv). 13. A method for manufacturing a battery cell according to any one of claims 1 to 12,
(i) preparing an electrode assembly;
(ii) preparing a battery case having a housing portion having a shape corresponding to the electrode assembly and including a metal layer on an outer surface thereof;
(iii) mounting the electrode assembly to the receiving part and injecting an electrolyte; And
(iv) welding and sealing the metal layers on the outer circumferential surface of the accommodating portion;
≪ / RTI > The manufacturing method according to claim 15, further comprising a step of adding an electrically insulating resin to the outer surface of the sealing portion formed by welding and the peripheral portion thereof after the step (iv). A battery pack comprising a battery cell according to any one of claims 1 to 12. A device according to claim 17, comprising a battery pack as a power source. 19. The device of claim 18, wherein the device is selected from a cell phone, a notebook, a tablet PC, a wearable electronic device, an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle or a system for power storage.

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