KR20170045564A - Battery Cell Comprising Inner Surface Coated with Electrical Insulating Material - Google Patents

Abstract

The present invention provides a battery cell having an inner surface coated with an electrical insulating material. The battery cell comprises: an electrode assembly with a positive electrode, a negative electrode, and a separation film structure interposed between the positive electrode and the negative electrode; a first battery case having a receiving unit in which the electrode assembly is embedded formed therein; and a second battery case installed on the first battery case to cover the receiving unit. The first battery case is composed of a metal material.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a battery cell having an inner surface coated with an electrically insulating material,

The present invention relates to a battery cell in which an inner surface of a battery case is coated with an electrically insulating material.

In recent years, the demand for environmentally friendly alternative energy sources has become an indispensable factor for the future, as the increase in the price of energy sources due to depletion of fossil fuels and the interest in environmental pollution are amplified. Various researches on power generation technologies such as nuclear power, solar power, wind power, and tidal power have been continuing, and electric power storage devices for more efficient use of such generated energy have also been attracting much attention.

Particularly, 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 that can meet various demands have been conducted.

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

Also, the secondary battery is classified according to the structure of the electrode assembly having the positive electrode, the negative electrode, and the separator interposed between the positive electrode and the negative electrode. Typically, the long battery- A stacked (stacked) electrode assembly in which a plurality of positive electrodes and negative electrodes cut in a predetermined size unit are sequentially stacked with a separator interposed therebetween, the jelly-roll type (wound type) electrode assembly having a structure in which a separator is interposed; In recent years, in order to solve the problems of the jelly-roll type electrode assembly and the stack type electrode assembly, an electrode assembly having an advanced structure, which is a combination of the jelly-roll type and the stack type, A stack / folding type electrode having a structure in which unit cells stacked with a separator interposed between an anode and a cathode are sequentially wound while being placed on a separation film Developed body lip.

The secondary battery includes a cylindrical battery and a prismatic battery in which the electrode assembly is housed in a cylindrical or rectangular metal can according to the shape of the battery case, and a pouch type battery in which the electrode assembly is housed in a pouch-shaped case of an aluminum laminate sheet .

In particular, in recent years, a pouch-shaped battery having a structure in which a stacked or stacked / folded electrode assembly is embedded in a pouch-shaped battery case of an aluminum laminate sheet has attracted much attention due to low manufacturing cost, small weight, And its usage is gradually increasing.

1 is an exploded perspective view schematically showing a structure of a conventional pouch-shaped battery cell.

1, the pouch-shaped battery cell 100 includes an electrode assembly 130, electrode tabs 131 and 132 extending from the electrode assembly 130, electrodes (electrodes) 131 and 132 welded to the electrode tabs 131 and 132, Leads 140 and 141, and a battery case 120 that accommodates the electrode assembly 130. [

The electrode assembly 130 is a power generation element in which an anode and a cathode are sequentially stacked with a separation membrane interposed therebetween, and has a stacked or stacked / folded 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 they are partially exposed to the outside of the battery case 120. [0051] An insulating film 150 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 secure an electrically insulated state.

The battery case 120 includes a case body 122 including a concave shaped storage portion 123 on which the electrode assembly 130 can be placed and a lid 121 integrally connected to the body 122 And the electrode assembly 130 is housed in the housing part 123 and the side parts 124 and the upper part 125, which are the contact parts, are joined to each other to complete the battery. The battery case 120 is made of an aluminum laminate structure of a resin outer layer / barrier metal layer / heat-sealable resin sealant layer and has a lid 121 which contacts with each other, both side portions 124 of the main body 122, And the resin layers are fused to each other to form bonded sealing surplus portions. Both side portions 124 are in direct contact with the same resin layers of the upper and lower battery case 120, so that they can be uniformly sealed by melting. Since the electrode leads 140 and 141 protrude from the upper end portion 125 of the battery case 120 in consideration of the thickness of the electrode leads 140 and 141 and the material of the battery case 120, And the leads 140 and 141 are thermally fused with the insulating film 150 interposed therebetween.

Generally, the pouch-shaped battery cell having such a structure can be manufactured by a process of storing an electrode assembly and an electrolyte solution in a battery case, a sealing process of a battery case by heat fusion, an aging process by charging and discharging, And a degassing process for forming the film.

At this time, each of the above processes is performed in a state where the pouch-shaped battery cell is fixed to a jig or a tool by a predetermined vacuum suction. Due to the material characteristics of the battery case, the pouch- The outer shape of the battery case can be deformed at the vacuum-absorbed portion, uniform positioning is difficult in the process of repeatedly joining and separating the jigs and the tools in each process, and the defects due to the positioning deviation There is a problem that occurs.

In addition, since the battery case made of the aluminum laminate sheet has low rigidity, the pouch-shaped battery cell has a limitation in forming the housing portion in a shape and size corresponding to the external shape of the electrode assembly, .

Therefore, there is a high need for a technique capable of fundamentally solving such problems.

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

The inventors of the present application have conducted intensive research and various experiments and, as will be described later, the first battery case having the storage portion is formed of a metal material and the inner surface thereof is coated with an electrically insulating material, It is possible to uniformly position the jigs or tools between the manufacturing processes of the cells and to prevent external deformations due to vacuum adsorption so that the defective rate of products can be minimized and the overall structural stability of the battery cells can be improved, It has been found that the battery cell can be more safely protected from an external impact, insulation can be ensured, and the sealing force of the battery case by heat fusion can be improved, thereby completing the present invention.

According to an aspect of the present invention, there is provided a battery cell comprising:

An electrode assembly having a separator structure sandwiched between an anode, a cathode, and an anode and a cathode;

A first battery case having a housing portion in which the electrode assembly is housed; And

A second battery case mounted on the first battery case to enclose the storage unit;

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The first battery case may be made of a metal material and the inner surface of the first battery case may be coated with an electrically insulating material.

Therefore, it is possible to uniformly position the battery cell during the manufacturing process of the battery cell during jig or tool bonding, and to prevent the outer shape deformation by vacuum suction, thereby minimizing the defective rate of the product and improving the overall structural stability of the battery cell. It is possible to more safely protect the battery cell from external impacts, to secure the insulation property, and to improve the sealing force of the battery case by heat fusion.

In addition, the inner surface of the first case is coated with an electrically insulating material, thereby preventing direct contact between the first battery case made of a metal material and the electrode assembly, thereby securing electrical insulation.

In one specific example, the first battery case is made of a metal plate, and the housing part is recessed corresponding to the shape of the electrode assembly.

Therefore, compared with the conventional pouch-shaped battery case made of an aluminum laminate sheet, the first battery case may have little or no restriction on the size and shape of the storage portion, and by providing a higher strength, The stability can be improved.

At this time, the receiving portion of the first battery case is formed by processing a metal plate, and more specifically, it may be formed by a deep drawing method.

The deep drawing method is a typical molding method for making a hollow container from a flat plate without a joint, and refers to a molding method in which a material plate placed on a die surface is pressed by a punch and subjected to plastic working.

However, the method of forming the receiving portion is not limited to this. If the first battery case made of the metal plate is not damaged and the receiving portion can be formed in a desired size and shape, the method is largely limited It is not.

On the other hand, if the first battery case exhibits desired strength and structural stability and can easily form the shape and size of the accommodating portion, the material of the first battery case is not limited to a great extent, Or an aluminum alloy that can prevent water inflow of water.

The second battery case may be a sheet-like sheet structure.

That is, unlike the first battery case, the second battery case is a plate-like sheet structure that does not include a separate housing part and is mounted on the first battery case so as to surround the housing part of the first battery case, The risk of damage or deformation due to processing may be smaller than that of the battery case.

Accordingly, the second battery case may be a pouch-type case made of the same aluminum laminate sheet as the conventional one. More specifically, the second battery case may include a resin outer layer, a barrier metal layer, and a heat- And a laminate sheet including a resin sealant layer.

More specifically, the resin outer layer exhibits excellent tensile strength, weather resistance, and the like relative to the thickness so as to protect the battery from the outside, and more specifically, it can be made of ONy (stretched nylon film). The barrier metal layer prevents air, moisture and the like from flowing into the battery, and may be made of aluminum (Al). The heat-sealable resin sealant layer is thermally fused by applying heat and pressure in a state in which the electrode assembly is embedded, thereby providing a sealability. Specifically, the sealant layer may be made of a polyolefin resin such as polyethylene or polypropylene .

In addition, the second battery case may be a structure in which the outer periphery is heated and pressed by a press to be attached and sealed while facing the housing portion of the first battery case.

That is, the second battery case may have a structure in which the outer periphery thereof is thermally fused to be adhered and sealed to the first battery case.

At this time, the electrically insulating material coated on the inner surface of the first battery case may be the same as the material of the heat-fusible resin sealant layer of the second battery case. Specifically, the electrically insulating material may be a polyolefin resin have.

Therefore, since the same material is adhered to each other at the outer peripheral portions of the heat-meltable resin sealant layer of the first battery case and the second battery case by thermal fusion bonding, an improved sealing force can be provided.

The electrically insulating material may have a thickness of 10 micrometers to 100 micrometers.

If the coating thickness of the electrically insulating material is less than 10 micrometers, the coating thickness of the electrically insulating material may be too thin to exhibit desired insulation properties, or may be damaged by direct contact with the electrode assembly, Failure to do so may reduce electrical stability.

On the contrary, when the thickness of the coating of the electrically insulating material exceeds 100 micrometers, the thickness of the coating of the electrically insulating material becomes excessively thick compared to the thickness required for exhibiting the desired insulating property, The space for pouring may be reduced, which may result in lowering the capacity of the electrode assembly housed in the receiving portion.

In one specific example, the electrically insulating material may be coated on the entire inner surface including the receiving portion of the first battery case and the outer peripheral portion.

Therefore, the outer peripheral portion can be thermally fused with the heat-fusible inner sealant layer of the second battery case, and an improved sealing force can be exhibited.

In another specific example, the electrically insulating material may be coated only on the inner surface of the housing portion except the outer peripheral portion of the first battery case.

More specifically, the electrode assembly is mounted on the housing portion of the first battery case, so that the portion of the first battery case that needs to be insulated from the electrode assembly is only the inner surface of the housing portion, The battery case is coated only on the inner surface of the battery compartment excluding the outer peripheral portion of the battery case, thereby saving time and cost for coating the electrically insulating material.

In this case, the surface of the metal material coated with the electrically insulating material may be surface-treated to form irregularities at the outer peripheral portion of the first battery case.

More specifically, in the case where the electrically insulating material is coated only on the inner surface of the accommodating portion except the outer peripheral portion of the first battery case, the outer peripheral portion of the first battery case may be formed of a metal material, The surface of the outer peripheral portion of the first battery case is surface-treated so as to form irregularities, so that the bonding force between the different materials can be improved.

Also, when the electrically insulating material is coated on the entire inner surface of the first battery case including the receiving portion and the outer peripheral portion, the surface of the outer peripheral portion of the first battery case is surface- The sealing force of the first battery case and the second battery case can be improved.

In this case, the surface treatment is not limited to a great extent as long as it can form a concavo-convex pattern on the surface of the metal material at the outer peripheral portion of the first battery case. Specifically, the surface treatment is not limited to sandblasting or etching etching can be performed.

Here, the sandblast is a method for machining a surface of a metal material, in which fine sand is pressed and accelerated by pressurized air to remove contaminants on the surface, and fine irregularities can be formed.

The etching is a method of corroding the surface of a metal material with acidic or basic chemicals, and the surface can be polished to form irregularities having a desired shape and size more easily.

Meanwhile, despite the above structure, the second battery case is made of aluminum or an aluminum alloy so as to exhibit the same structural stability as the first battery case and to prevent the penetration of moisture, ensuring insulation for the electrode assembly The inner surface of the first battery case facing the first battery case may be coated with the same material as the electrically insulating material coated on the inner surface of the first battery case so as to improve adhesion and sealing force with the first battery case.

In other words, the second battery case may be made of the same material as the first battery case, not the aluminum laminate sheet.

In this case, the electrically insulating material may be coated on the entire inner surface of the second battery case, like the coating structure of the electrically insulating material of the first battery case, or may have a structure in which the first battery case Or the inner surface of the inner wall of the housing.

However, in this case, the outer peripheral portion of at least one of the first battery case and the second battery case must be coated with an electrically insulating material, so that the bonding and sealing effect by heat fusion can be exerted.

Also, in this case, the surface of the metal material coated with the electrically insulating material at the outer peripheral portion of the second battery case is also surface-treated so as to form irregularities in order to improve the bonding force and sealing force to the first battery case Lt; / RTI >

The structure of the electrode assembly is not particularly limited as long as the electrode assembly can exhibit a desired capacity and electrical characteristics in a state of being housed in the housing portion of the first battery case. Specifically, the structure is not limited to a folding structure, Type structure, a stack / folding structure, or a lamination / stacking structure.

In one specific example, the type of the battery cell is not particularly limited, but specific examples thereof include a lithium ion battery having advantages such as a high energy density, a discharge voltage, and an output stability, a lithium secondary battery such as a lithium ion polymer battery, Battery.

Generally, a lithium secondary battery is composed of a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte containing a lithium salt.

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 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 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 &lt; Lithium metal; Lithium alloy; Silicon-based alloys; Tin alloy; _{SnO, SnO 2, PbO, PbO} 2, Pb 2 O 3, Pb 3 O 4, Sb 2 O 3, Sb 2 O 4, Sb 2 O 5, GeO, GeO 2, Bi 2 O 3, Bi 2 O 4, and Bi ₂ O ₅ ; Conductive polymers such as polyacetylene; Li-Co-Ni-based materials and the like can be used.

The separation membrane and the separation film are 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 130 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.

Further, in one specific example, in order to improve the safety of the battery, the separation membrane and / or the separation film may be an organic / inorganic composite porous SRS (Safety-Reinforcing Separators) separation membrane.

The SRS separator is manufactured by using inorganic particles and a binder polymer on the polyolefin-based separator substrate as an active layer component. In addition to the pore structure contained in the separator substrate itself, the SRS separator is formed by interstitial volume between inorganic particles And has a uniform pore structure.

The use of such an organic / inorganic composite porous separator has the advantage of suppressing an increase in thickness of the cell due to swelling at the time of chemical conversion compared with the case of using a conventional separator, When a gelable polymer is used when liquid electrolyte is impregnated, it can also be used as an electrolyte.

In addition, the organic / inorganic composite porous separator can exhibit excellent adhesion characteristics by controlling the contents of the inorganic particles and the binder polymer in the separator, so that the cell assembly process can be easily performed.

The inorganic particles are not particularly limited as long as they are electrochemically stable. That is, the inorganic particles usable in the present invention are not particularly limited as long as the oxidation and / or reduction reaction does not occur in the operating voltage range of the applied battery (for example, 0 to 5 V based on Li / Li +). Particularly, when inorganic particles having an ion-transporting ability are used, the ion conductivity in the electrochemical device can be increased and the performance can be improved. Therefore, it is preferable that the ionic conductivity is as high as possible. In addition, when the inorganic particles have a high density, it is difficult to disperse the particles at the time of coating, and there is a problem of an increase in weight during the production of the battery. In the case of an inorganic substance having a high dielectric constant, dissociation of an electrolyte salt, for example, a lithium salt, in the liquid electrolyte also contributes to increase ionic conductivity of the electrolyte.

The nonaqueous electrolyte solution containing a lithium salt is composed of a polar organic electrolyte and a lithium salt. As the electrolytic solution, a non-aqueous liquid electrolytic solution, an organic solid electrolyte, an inorganic solid electrolyte and the like 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.

The present invention also provides a battery pack including the battery cell and a device including the battery pack as a power source, wherein the device is used for a mobile phone, a tablet computer, a notebook computer, a power tool, a wearable electronic device, , A hybrid electric vehicle, a plug-in hybrid electric vehicle, and a power storage device.

Such devices or devices are well known in the art, so a detailed description thereof will be omitted herein.

As described above, in the battery cell according to the present invention, the first battery case in which the storage portion is formed is formed of a metal material and the inner surface thereof is coated with an electrically insulating material, It is possible to minimize the defective rate of the product and improve the overall structural stability of the battery cell so that the battery cell can be prevented from being damaged due to external impact, It is possible to protect the battery case more securely, to secure the insulation property, and to improve the sealing force of the battery case by heat fusion.

1 is an exploded perspective view schematically showing a structure of a conventional pouch-shaped battery cell;
2 is a schematic view showing a structure of a battery case constituting a battery cell according to an embodiment of the present invention;
3 to 5 are schematic views schematically showing the structure of a battery case according to another 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 is a schematic view schematically showing the structure of a battery case according to an embodiment of the present invention.

Referring to FIG. 2, the battery case 200 includes a first battery case 210 and a second battery case 220.

The first battery case 210 is formed in a structure in which the battery compartment 213 in which the electrode assembly is embedded is embedded in the second battery case 220. The second battery case 220 surrounds the compartment 213 of the first battery case 210 Like structure that is mounted on the upper surface of the first battery case 210. [

The first battery case 210 is made of an aluminum plate 211.

Therefore, even if the first battery case 210 is fixed to the jig or the tool by vacuum during the manufacturing process of the battery cell, the outer shape of the first battery case 210 is not deformed, And in the course of repeating the separation, uniform positioning is possible, and the defects that can be caused by the positioning deviation can be minimized.

The first and second battery cases 210 and 220 are formed on the inner and outer peripheral portions 214 and 214 of the first battery case 210 in which the electrode assembly is housed.

Therefore, the electrode assembly mounted on the storage part 213 of the first battery case 210 is electrically insulated from the aluminum plate 211 constituting the first battery case 210, so that the safety can be improved.

The second battery case 220 is made of a laminate sheet including an outer resin layer 221, a metal layer 222 of a barrier property, and a heat-sealable resin sealant layer 223 from the outside.

The electrically insulating material 212 coated on the first battery case 210 is made of the same material as the heat-fusible resin sealant layer 223 of the second battery case 220.

Therefore, when the outer peripheral portions 214 and 224 of the first battery case 210 and the second battery case 220 are pressed by the press, the electric insulating material 212 of the first battery case 210, 2, the heat-fusible resin sealant layer 223 of the battery case 220 is melted and adhered and sealed with each other.

3 to 5 are schematic views schematically showing the structure of a battery case according to another embodiment of the present invention.

3, the battery case 300 includes a first battery case 310 in which a storage portion 313 is formed and a second battery case 310 in a form of wrapping the storage portion 313 of the first battery case 310, And a second battery case 320 mounted on the second battery case 320.

The first battery case 310 is coated with the electrically insulating material 312 only on the inner surface of the storage portion 313 except for the outer peripheral portion 314.

The unevenness 315 is formed on the outer peripheral portion of the first battery case 310. [

Therefore, when the outer peripheral portions 314 and 324 of the first battery case 310 and the second battery case 320 are pressed by the press, the heat-fusible resin sealant layer 323 of the second battery case 320 Is melted and adhered to a wider surface, a higher sealing force can be exerted.

The remaining structure except for the above structure is the same as that of the battery case 200 (FIG. 2) in FIG. 2, so a detailed description thereof will be omitted.

4, the battery case 400 includes a first battery case 410 in which a storage unit is formed, and a second battery 420, which is mounted on the upper surface of the first battery case 410 in such a manner as to surround the storage unit 413 of the first battery case 410. [ And a case 420.

The second battery case 420 is formed of an aluminum plate 421 and has an electrically insulating material 423 coated on the inner surface of the first battery case 410 facing the receiving portion 413.

Therefore, the second battery case 420 can exhibit a relatively high strength as compared with the structure made of a laminated sheet, and the structural stability of the battery cell can be improved.

The inner surface of the second battery case 420 is coated with an electrically insulating material 423 of the same material as the electrically insulating material 412 coated on the inner surface of the first battery case 410, The electrode assembly mounted on the housing part 413 of the case 410 and the aluminum plate 421 constituting the second battery case 420 are electrically insulated from each other to improve the safety and the first battery case 410 Of the first battery case 410 and the outer peripheral portions 414 and 424 of the second battery case 420 are pressed by the press, The insulating material 423 is melted and adhered and sealed with each other.

The remaining structure except for the second battery case 420 is the same as that of the battery case 200 (FIG. 2) in FIG. 2, so that detailed description thereof will be omitted.

5, the battery case 500 includes a first battery case 510 in which a storage unit is formed, and a second battery 500, which is mounted on the upper surface of the first battery case 510 in such a manner as to enclose the storage unit 513 of the first battery case 510. [ And a case 520.

The first battery case 510 has the same structure as the first battery case 210 of FIG. 2 (FIG. 2).

The second battery case 520 is made of an aluminum plate 521 and has an electrically insulating material 523 coated on the inner surface of the first battery case 510 facing the receiving portion 513. [

The electrically insulating material 523 coated on the inner surface of the second battery case 520 is inserted into the accommodating portion 513 of the first battery case 510 except the outer peripheral portion 524 of the second battery case 520 It is coated only on the corresponding part.

The outer peripheral portion 524 of the second battery case 520 has unevenness 525 formed thereon.

Therefore, when the first battery case 510 and the outer peripheral portions 514 and 524 of the second battery case 520 are pressed by the press, the overall strength of the battery case 500 is improved, The electrically insulating material 512 of the case 510 is melted and adhered to a wider surface at the outer peripheral portion 524 of the second battery case 520 so that a higher sealing force can be exerted.

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 (22)

An electrode assembly having a separator structure sandwiched between an anode, a cathode, and an anode and a cathode;
A first battery case having a housing portion in which the electrode assembly is housed; And
A second battery case mounted on the first battery case to enclose the storage unit;
Lt; / RTI &gt;
Wherein the first battery case is made of a metal material and the inner surface is coated with an electrically insulating material. The battery cell according to claim 1, wherein the first battery case comprises a metal plate, and the housing part is recessed corresponding to the shape of the electrode assembly. The battery cell according to claim 1, wherein the first battery case is made of aluminum or an aluminum alloy. The battery cell according to claim 1, wherein the second battery case is a sheet-like sheet structure. The battery cell according to claim 1, wherein the second battery case comprises a laminate sheet including a resin outer layer, a barrier metal layer, and a heat-meltable resin sealant layer. The battery case according to claim 1, wherein the second battery case is adhered and sealed by being pressurized and pressurized by a press while the outer circumferential surface of the second battery case faces the housing portion of the first battery case . The battery cell according to claim 6, wherein the electrically insulating material coated on the inner surface of the first battery case is the same as the material of the heat-fusible resin sealant layer of the second battery case. The battery cell according to claim 7, wherein the electrically insulating material is a polyolefin resin. The battery cell according to claim 1, wherein the electrically insulating material is coated to a thickness of 10 micrometers to 100 micrometers. The battery cell according to claim 1, wherein the electrically insulating material is coated on the entire inner surface of the first battery case including the receiving portion and the outer peripheral portion. The battery cell according to claim 1, wherein the electrically insulating material is coated only on the inner surface of the accommodating portion excluding the outer peripheral portion of the first battery case. The battery cell according to claim 10 or 11, wherein a surface of the metal material coated with the electrically insulating material is surface-treated so as to form irregularities at an outer peripheral portion of the first battery case. 13. The battery cell according to claim 12, wherein the surface treatment is performed by sand blasting or etching. The battery case according to claim 1, wherein the second battery case is made of aluminum or an aluminum alloy, and the inner surface of the second battery case is coated with the same material as the first insulating case coated on the inner surface of the first battery case . 15. The battery cell according to claim 14, wherein the electrically insulating material is coated on the entire inner surface of the second battery case. 15. The battery cell according to claim 14, wherein the electrically insulating material is coated only on the inner surface of the first battery case corresponding to the accommodating portion except the outer peripheral portion of the second battery case. 17. The battery cell according to claim 15 or 16, wherein a surface of the metal material coated with the electrically insulating material on the outer peripheral portion of the second battery case is surface-treated to form irregularities. The battery cell according to claim 1, wherein the electrode assembly comprises a folding structure, a stacking structure, a stacking / folding structure, or a lamination / stacking structure. The battery cell according to claim 1, wherein the battery cell is a lithium secondary battery. A battery pack comprising the battery cell according to claim 1. A device as claimed in claim 20 comprising a battery pack as a power source. 22. The device of claim 21, wherein the device is any one selected from the group consisting of a cell phone, a tablet computer, a notebook computer, a power tool, a wearable electronic device, an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, . &Lt; / RTI &gt;

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