KR20140031581A - Battery case of excellent productivity and secondary battery comprising the same - Google Patents

Abstract

The present invention relates to a battery case of excellent productivity and a secondary battery comprising the same. More particularly, the present invention relates to a battery case of a laminate sheet structure where a receiving part corresponding to the shape of en electrode assembly is formed. The battery case includes an inner polymer layer touching the receiving part, a barrier layer preventing the movement of material, and an outer coating layer of a polymer film. At least one flow path where a fluid moves along the surface is formed on the surface of the inner polymer touching the receiving part.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a battery case having excellent manufacturing processability and a secondary battery including the battery case.

The present invention relates to a battery case having excellent manufacturing processability and a secondary battery including the battery case. More particularly, the present invention relates to a battery case having a laminated sheet structure in which a housing portion corresponding to the shape of an electrode assembly is formed, A barrier layer for blocking the movement of the substance, and an outer coating layer of the polymer film, wherein at least one flow path for moving the fluid along the surface is formed on the surface of the inner polymer in contact with the receiving portion And a secondary battery including the battery case.

As technology development and demand for mobile devices are increasing, the demand for batteries as energy sources is rapidly increasing, and accordingly, a lot of researches on batteries capable of meeting various demands have been conducted.

Typically, 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 thin thickness in terms of the shape of the battery. In view of the material, it has advantages such as high energy density, discharge voltage, There is a high demand for a lithium secondary battery such as a lithium ion battery and a lithium ion polymer battery. Particularly, there is a high interest in a pouch type battery which is easily deformed in shape, low in manufacturing cost, and small in weight.

In general, a pouch-type secondary battery includes a pouch-shaped battery case, an electrode assembly including an anode, a cathode, and a separator disposed between the anode and the cathode, and electrically connected to the anode and cathode tabs protruding from the electrode assembly. Are sealed so that the two electrode leads are exposed from one side of the battery case to the outside.

More specifically, FIG. 1 schematically shows a general structure of a typical conventional pouch-type secondary battery as an exploded perspective view.

1, the pouch type secondary battery 10 includes an electrode assembly 30, electrode tabs 32 and 34 extending from the electrode assembly 30, electrodes 34 and 36 welded to the electrode tabs 32 and 34, And a battery case 20 for accommodating the leads 40 and 41 and the electrode assembly 30.

The electrode assembly 30 is a power generation element in which an anode and a cathode are sequentially stacked with a separator interposed therebetween, and is formed of a folding type, a stack type, or a stack / folding type structure. The electrode tabs 32 and 34 extend from the respective electrode plates of the electrode assembly 30 and the electrode leads 40 and 41 are connected to a plurality of electrode tabs 32 and 34 extending from each electrode plate, Respectively, and a part of the battery case 20 is exposed to the outside. An insulating film 50 is attached to portions of the upper and lower surfaces of the electrode leads 40 and 41 in order to increase the degree of sealing with the battery case 20 and at the same time to ensure an electrically insulated state. The battery case 20 is made of an aluminum laminate sheet, provides a space for accommodating the electrode assembly 30, and has a pouch shape as a whole.

Most of the secondary batteries including the pouch-type battery are activated during the manufacturing process of the battery cell by charging and discharging. In order to manufacture the final battery cell, the gas generated during the activation process must be removed. Degassing process.

However, in the conventional method of manufacturing the pouch-type battery as described above, since the removal efficiency of the excess electrolyte added to the gas and the electrode assembly during the activation process is poor and it takes a long time to remove, There is a problem that the thickness of the battery becomes uneven due to the gas and surplus electrolytic solution which are collected in the cell and can not escape, thereby increasing the defect rate.

Therefore, there is a high need for a technique capable of effectively removing gas and surplus electrolyte generated during initial charging in a short time.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-described problems of the prior art and the technical problems required from the past.

The inventors of the present application have conducted intensive research and various experiments and have found that in a battery case having a laminate sheet structure in which a housing portion corresponding to the shape of an electrode assembly is formed, a fluid flows along the surface of the internal polymer in contact with the housing portion It is possible to effectively remove the gas generated during the activation process of the battery and the excess electrolyte added to the electrode assembly. Thus, the present invention has been accomplished.

Accordingly, the battery case according to the present invention is a battery case having a laminate sheet structure in which a storage portion corresponding to the shape of the electrode assembly is formed, wherein the battery case has an inner polymer layer in contact with the storage portion, And an outer coating layer of a polymer film, and at least one flow path for moving the fluid along the surface is formed on the surface of the inner polymer in contact with the receiving portion.

In one specific example, the fluid may be a gas generated during the activation of the cell and / or an electrolyte added to the electrode assembly.

In the activation process during the manufacturing process of the battery, after the electrolyte injection process is completed, the pouch cover is covered and the edges are firstly sealed, and after an aging process for stabilizing the battery, the battery is overcharged, Means a process of pre-charging the battery at a charging depth of 10% or less to prevent the casing from being ruptured due to gas generated therein. Through this process, gas is generated inside the pouch case, and the generated gas is removed through the open or incised exhaust port or moved to one side so as not to deform the battery case.

The inventors of the present application recognized the above problems and conducted intensive research. As a result, the inventors of the present application have found that, in the conventional method, since the gas removal rate is not good and the gas removal takes a long time, It has been found that the gas generated during the activation process and the excess electrolyte added to the electrode assembly can be easily and quickly removed through the flow path when the flow path is formed on the surface of the polymer.

In addition, due to the higher removal rate, the unevenness of the thickness of the battery due to the gas is reduced, thereby improving the quality of the battery cell, reducing the manufacturing cost of the battery cell, and enhancing the stability of the battery by increasing the adhesion between the electrode assembly and the battery case. .

The thickness of the polymer layer of the present invention can be appropriately determined in consideration of the capacity of the battery case and the size of the electrode assembly. However, if the thickness is too small, the sealing performance of the electrolyte solution may deteriorate. Conversely, The manufacturing cost is increased and the capacity ratio of the battery is decreased, so that the capacity of the battery may be decreased.

In one specific example, the polymer layer may be adhered or heat-sealed using a non-reactive adhesive that does not affect the operation of the battery in a corresponding region between the battery case and the electrode assembly during assembly of the secondary battery As shown in Fig.

The non-reactive adhesive means an adhesive that does not cause side reactions with an electrolyte solution, an electrode active material, etc., and may be, for example, a silicone polymer adhesive or a carbon fiber optical polymer adhesive.

In one specific example, the polymer layer is made of a material having electrolyte resistance and absorbs external impact due to the characteristics of the material itself or the morphological characteristics of the sheet. For example, the polymer layer may be formed of a material selected from the group consisting of polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), polyimethyimethacrylate And a hydrophobic polymer, and more specifically, it may be made of a polypropylene (PP) polymer.

In one specific example, the width of the flow path may be between 1 [mu] m and 50 [mu] m. The larger the width of the flow path, the larger amount of gas can be moved in a short time. However, if the flow path width is larger than 50 탆, the support area of the polymer layer becomes too small to cause problems in the durability of the battery. Mu m or less, it may be difficult to achieve the desired gas and electrolytic solution removal rates of the present invention.

The depth of the flow path is not particularly limited within a range in which the barrier layer is not exposed, but may be 5 占 퐉 to 20 占 퐉 in detail. When the depth of the flow path is 20 mu m or more, the flow path is formed too close to the barrier layer, so that the possibility of the electrolyte contacting the barrier layer in the manufacturing process becomes large and the defect rate can be increased. On the contrary, It may be difficult to achieve the removal rate of the excess electrolytic solution.

In one specific example, the bottom surface of the flow path may have a " U " shape on a vertical cross section and may be " U " shaped to minimize residual gas or excess electrolyte on the bottom surface of the flow path .

The flow path is preferably formed in one direction of the battery case, which is the discharge direction of the gas.

In one specific example, the flow path may form a repetitive pattern of two or more flow paths, and the patterns may be uniformly formed over the entire surface.

Although the shape of the patterns is not particularly limited, it is preferable that the patterns are repeated at uniform intervals and uniformly sized to uniformly remove the generated gas and excessive electrolyte on the surface of the electrode assembly. For example, a pattern of a polygonal pattern such as a diamond pattern, a honeycomb pattern, and a lattice pattern is possible, and in detail, it may be a lattice pattern.

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

The outer coating layer is made of a material having a predetermined tensile strength and weatherability so as to have excellent resistance to the external environment. Specifically, a stretched nylon film, polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) can be used .

The housing part may be formed on one side of the battery case to a size corresponding to the electrode assembly, or may be formed on both sides of the battery case.

The present invention also provides a secondary battery in which an electrode assembly is embedded in the battery case.

The secondary battery may be, for example, a lithium secondary battery, and is not particularly limited. For example, the secondary battery may be a so-called lithium ion polymer battery in which a lithium electrolyte is impregnated into the electrode assembly in the form of a gel .

The electrode assembly may have a wrap-around structure in the form of a jelly-roll, a stacked structure, or a stack / folding structure. The stack / folding type electrode assembly is formed as a stacked unit cell, in which the bipolar cells having the same electrodes on both sides or the pull cells having the different electrodes on both sides are wound in a long separation film.

In one specific example, the lithium secondary battery comprises a positive electrode, a negative electrode, a separator, and a nonaqueous electrolyte containing a lithium salt, and an electrode assembly having a separator interposed between the positive electrode and the negative electrode is built in a battery case, And then the electrolyte solution is impregnated into the electrode assembly.

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 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 change in the battery, and may be formed of a material such as stainless steel, aluminum, nickel, titanium, sintered carbon, or a surface of aluminum or stainless steel Treated with carbon, nickel, titanium, silver or the like may be used. In addition, the positive electrode collector may have fine unevenness on the surface thereof to increase the adhesive force of the positive electrode 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); 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 20 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 which assists in bonding of the active material and the conductive material and bonding to the collector, and is usually added in an amount of 1 to 20% 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.

In addition, other components such as a viscosity adjusting agent, an adhesion promoter and the like may be further included as a selective or a combination of two or more.

The viscosity adjusting agent may be added up to 30% by weight based on the total weight of the electrode mixture, so as to control the viscosity of the electrode mixture so that the mixing process of the electrode mixture and the coating process on the collector may be easy. Examples of such viscosity modifiers include carboxymethylcellulose, polyvinylidene fluoride and the like, but are not limited thereto. In some cases, the above-described solvent may play a role as a viscosity adjusting agent.

The adhesion promoter may be added in an amount of 10% by weight or less based on the binder, for example, oxalic acid, adipic acid, Formic acid, acrylic acid derivatives, itaconic acid derivatives, and the like.

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

The negative electrode material may be, for example, carbon such as hardly 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 negative electrode 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 conductivity without causing chemical change in the battery, and may be formed of a material such as copper, stainless steel, aluminum, nickel, titanium, fired carbon, 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 separator is an insulating thin film interposed between the anode and the cathode and having high ion permeability and mechanical strength. The pore diameter of the separator is generally 0.01 to 10 mu m and the thickness is generally 5 to 300 mu m. As such a separation membrane, for example, a sheet or a nonwoven fabric made of an olefin-based polymer such as polypropylene which is chemically resistant and hydrophobic, glass fiber, polyethylene or the like is used.

In some cases, a gel polymer electrolyte may be coated on the separation membrane to increase the stability of the cell. Representative of such gel polymers are polyethylene oxide, polyvinylidene fluoride, polyacrylonitrile and the like. When a solid electrolyte such as a polymer is used as an electrolyte, the solid electrolyte may also serve as a separation membrane.

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

Examples of the nonaqueous electrolytic solution include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, But are not limited to, lactone, 1,2-dimethoxyethane, tetrahydroxyfuran, 2-methyltetrahydrofuran, dimethylsulfoxide, 1,3-dioxolane, formamide, dimethylformamide, Nitrile, nitromethane, methyl formate, methyl acetate, phosphoric acid triester, trimethoxymethane, dioxolane derivatives, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivatives , Tetrahydrofuran derivatives, ether, methyl pyrophosphate, ethyl propionate and the like can be used.

Examples of the organic solid electrolyte include a polymer electrolyte such as a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, an agitation lysine, a polyester sulfide, a polyvinyl alcohol, a polyvinylidene fluoride, 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 charge / discharge characteristics, flame retardancy, etc., non-aqueous electrolytes may be used in the form of, for example, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, glyme, N, N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxyethanol, aluminum trichloride and the like 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, in the battery case according to the present invention, at least one flow path for moving the fluid along the surface is formed on the surface of the internal polymer in contact with the accommodating portion corresponding to the shape of the electrode assembly, The gas inside the battery generated during the activation process and the excess electrolyte added to the electrode assembly can be easily and quickly removed, thereby effectively shortening the process time.

In addition, there is an effect that the thickness irregularity of the battery caused by the gas and the defective ratio of the battery due to the gas are reduced, and the adhesion between the electrode assembly and the battery case is increased, thereby improving the stability of the battery.

1 is an exploded perspective view of a general structure of a conventional pouch type secondary battery;
2 is an exploded perspective view of a secondary battery according to a first embodiment of the present invention;
3 is a schematic enlarged view of a portion of a polymer layer formed on an upper portion or a lower portion of a battery case;
Figure 4 is a cross-sectional view of line A-A 'in Figure 3;
5 is a cross-sectional view of a polymer layer according to another embodiment of the present invention;
FIG. 6 is a schematic diagram further enlarging a part of the polymer layer in FIG. 3; FIG.

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

FIG. 2 is a schematic exploded perspective view of the secondary battery 100 according to the first embodiment of the present invention. FIG. 3 shows the upper or lower case 122, FIG. 4 is a cross-sectional view taken along the line A-A 'in FIG. 3, and FIG. 6 is a cross-sectional view of a polymer formed to discharge a gas and an electrolytic solution And the polymer layer is further enlarged so as to clearly show the flow path of the layer.

Referring to these figures, the pouch type secondary battery 100 includes an electrode assembly 130, electrode leads 140 and 141 welded to the electrode tabs 131 and 132 extending from the electrode assembly 130, And a battery case 120 having a housing part for housing the battery 130. In addition, the battery case includes an inner polymer layer 160, a barrier layer 170, and an outer coating layer 180. The inner polymer layer 160 is in contact with the storage portion.

The electrode assembly 130 is a power generation element in which an anode and a cathode are sequentially stacked with a separator interposed therebetween, and is formed of a folding type, a stack type, or a stack / folding type structure. The electrode tabs 131 and 132 extend from the respective electrode plates of the electrode assembly 130 and the electrode leads 140 and 141 are formed by a plurality of electrode tabs 131 and 132 extending from the respective electrode plates, And the battery case 120 is partially exposed to the outside. An insulating film 190 is attached to a portion of the upper and lower surfaces of the electrode leads 140 and 141 in order to increase the degree of sealing with the battery case 120 and at the same time to ensure an electrically insulated state.

The battery case 120 includes an upper case 122 and a lower case 121. The lower case 121 is formed with a housing part for mounting the electrode assembly 130 therein and has a pouch shape as a whole . A polymer layer 161 is formed on the upper end of the inner surface of the storage portion of the upper case 122 and a polymer layer 160 is formed on the lower surface of the inner surface of the storage portion of the lower case 121.

The secondary battery 100 may be manufactured by mounting the electrode assembly 130 on the receiving portion of the lower case 121, covering the upper case 122 on the upper surface thereof, and then thermally fusing the outer circumference.

3 to 5, the battery case 120 includes a polymer layer 160 in which a flow path 150 is formed, a barrier layer 170 of a metal foil as an intermediate layer, and an outer coating layer 180 as a lower layer. Layer structure.

The thickness of the polymer layer 160 may be about 20 占 퐉, the thickness of the barrier layer 170 of the metal foil may be about 10 占 퐉, the thickness of the outer coating layer 180 may be about 12 占 퐉, and the polymer layer 160 may be non- the metal foil of the barrier layer 170 may be made of aluminum, and the outer coating layer 180 may be made of a nylon film.

In the polymer layer 160, a channel 150 is formed so as to have a lattice pattern. The size of the lattice W and the length H of the lattice may be about 1 mm, respectively.

4, the width w of the flow path 150 may be about 20 μm and the depth d may be about 10 μm, and the bottom surface of the flow path 150 may have a "C" shape on the vertical cross section .

4, the bottom surface of the flow path 250 is formed in a U-shape having a predetermined radius R, and this structure is advantageous in that a gas, which may remain on the bottom surface of the flow path 250, This is particularly preferable in minimizing the excess electrolytic solution. The size of the radius R is not particularly limited and may be, for example, 50 to 300% of the width of the flow path 250.

6, the gas generated in the activation step and the surplus electrolyte added to the electrode assembly 130 are removed through the discharge port, or alternatively, (150). ≪ / RTI >

Therefore, it is possible to quickly remove the gas and the surplus electrolytic solution, thereby reducing the thickness irregularity of the battery caused by the gas and the defective rate of the battery, thereby improving the stability of the battery by increasing the adhesion between the electrode assembly and the battery case.

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 (16)

A battery case having a laminated sheet structure in which a housing portion corresponding to a shape of an electrode assembly is formed,
Wherein the battery case includes an inner polymer layer in contact with the accommodating portion, a barrier layer blocking the movement of the material, and an outer coating layer of the polymer film,
The battery case, characterized in that the surface of the inner polymer in contact with the receiving portion is formed with one or more flow path for the fluid to move along the surface. The battery case according to claim 1, wherein the fluid is an electrolyte solution added to a gas and / or an electrode assembly generated during the activation of a battery. The battery case according to claim 1, wherein the width of the flow path is 1 占 퐉 to 50 占 퐉. The battery case according to claim 1, wherein the depth of the flow path is 5 占 퐉 to 20 占 퐉 within a range in which the barrier layer is not exposed. The battery case according to claim 1, wherein the bottom surface of the flow passage has a vertical U-shape or a U-shape or a U-shape. The battery case according to claim 1, wherein the flow path is formed by a repetitive pattern of two or more flow paths. The battery case according to claim 6, wherein the pattern is a lattice pattern. The battery case according to claim 1, wherein two or more flow paths are uniformly formed on the entire surface of the inner polymer layer. The battery case according to claim 1, wherein the inner polymer layer is adhered or adhered by heat fusion using a non-reactive adhesive which does not affect the operation of the battery. The battery case according to claim 9, wherein the non-reactive adhesive is a silicone polymer adhesive or a carbon fiber polymer adhesive. The method of claim 1, wherein the polymer layer comprises at least one selected from the group consisting of polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), polyethlyl methacrylate Wherein the battery case is made of at least one material selected from the group consisting of polyacrylonitrile (PAN), and the like. The battery case according to claim 11, wherein the polymer layer is formed of polypropylene (PP). 2. The method of claim 1, wherein the barrier layer comprises aluminum or an aluminum alloy, and the outer coating layer comprises at least one selected from the group consisting of nylon, polyethylene terephthalate (PET), and polyethylene naphthalate Battery case. The secondary battery, characterized in that the electrode assembly is built in the battery case according to any one of claims 1 to 13. 15. The secondary battery according to claim 14, wherein the electrode assembly comprises a wound-type structure, a stacked structure, or a stack / folding structure. 15. The secondary battery according to claim 14, wherein the battery is a lithium secondary battery.

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