KR101554141B1 - Plate-Typed Battery Cell - Google Patents

Abstract

The present invention relates to a plate-shaped battery cell, and more particularly, to a plate-shaped battery cell in which an electrode assembly having a separator interposed between an anode and a cathode is sealed inside a battery case together with an electrolytic solution, Shaped electrode terminal, and an opening for exposing the plate-shaped electrode terminal is formed on one side or both sides of the sheet-sealing portion. The sheet- And a battery cell.

Description

[0001] Plate-Typed Battery Cell [0002]

The present invention relates to a plate-shaped battery cell, and more particularly, to a plate-shaped battery cell in which an electrode assembly having a separator interposed between an anode and a cathode is sealed inside a battery case together with an electrolytic solution, Shaped electrode terminal, and an opening for exposing the plate-shaped electrode terminal is formed on one side or both sides of the sheet-sealing portion. The sheet- And a battery cell.

The secondary battery, which has recently been used in an increasing amount, has 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. , Lithium secondary batteries, lithium ion batteries, and the like, which have advantages such as high output stability and output stability.

Also, the secondary battery is classified according to how the electrode assembly having the anode / separator / cathode structure is formed. Typically, the long battery-shaped anodes and cathodes are jelly- A stacked (stacked) electrode assembly in which a plurality of positive electrodes and negative electrodes cut in units of a predetermined size are sequentially stacked with a separator interposed therebetween, a stacked (stacked) electrode assembly in which a predetermined unit of positive and negative electrodes are stacked, A stack / folding type electrode assembly in which a Bi-cell or a full cell stacked in a single state is wound up as a separation film can be given.

Recently, 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 is attracting much attention due to low manufacturing cost, small weight, Its usage is also gradually increasing.

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 taps 40 and 50 extending from the electrode assembly 30, electrodes 40 and 50 welded to the electrode taps 40 and 50, Leads 60 and 70, and a battery case 20 for accommodating 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 separation membrane interposed therebetween. The electrode assembly 30 has a stacked or stacked / folded structure. The electrode tabs 40 and 50 extend from each electrode plate 30 of the electrode assembly 30 and the electrode leads 60 and 70 are connected to a plurality of electrode tabs 40 and 50 extending from each electrode plate, Respectively, and a part of the battery case 20 is exposed to the outside. An insulating film 80 is attached to the upper and lower surfaces of the electrode leads 60 and 70 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. 1, a plurality of positive electrode tabs 40 and a plurality of negative electrode tabs 50 may be coupled to the electrode leads 60 and 70. In the stacked electrode assembly 30, The inner top is spaced from the electrode assembly 30.

FIG. 2 is a partially enlarged view of a top portion of a battery case in which positive tabs are connected in a densely packed state in a state where the rechargeable battery of FIG. 1 is assembled and connected to a positive lead. In FIG. 2, only the positive electrode lead portion is shown for the sake of convenience of explanation, and such positive electrode structure can be easily applied to the negative electrode structure.

2, a plurality of positive electrode tabs 40 protruding from a positive electrode current collector (not shown) of the electrode assembly are integrally joined by, for example, welding and connected to the positive electrode lead 60 The positive electrode lead 60 is thermally fused together with the insulating film 80 in the upper sealing portion 21 of the battery case 20 with the end portion 61 opposed to the positive electrode tabs 40 exposed have. The two insulating films 80 attached to the positive electrode lead 60 are overlapped on both sides of the positive electrode lead 60 so that the upper end portion 81 and the lower end portion 82 of the insulating film 80 are mutually coincident . Generally, the insulating film 80 is integrated with the battery case 20 at the upper sealing portion 21 when heat-sealed.

In the secondary battery having such a structure, the positive electrode lead 60 and the insulating film 80 protrude from the upper end portion of the upper sealing portion 21, thereby causing an unnecessary increase in dimension of the battery case 20. Due to the projecting portion B, it is necessary to bend the upper sealing portion 21 in order to reduce the overall length of the secondary battery 10.

Accordingly, there is a great need for a technique capable of solving these 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.

That is, an object of the present invention is to provide a sheet-like electrode terminal in which a sheet-like electrode terminal is positioned at a position where the sheet is sealed by adhesion or heat fusion, and an opening for exposing the plate-like electrode terminal is formed on one side or both sides of the sheet- And the electrode terminal protrudes beyond the battery case size, thereby causing an unnecessary increase in dimensions.

It is still another object of the present invention to provide a battery cell which can solve the problem that the unnecessary dimension of the battery cell is increased, simplify the manufacturing process of the battery pack, and maximize space utilization.

To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a battery cell in which an electrode assembly having a separator interposed between an anode and a cathode is sealed in a battery case together with an electrolyte,

The battery case is formed of a sheet-like member and forms a sheet-sealing portion by adhesion or heat fusion at a position where the plate-like electrode terminal is located,

And an opening for exposing the plate-like electrode terminal is formed on one side or both sides of the sheet sealing portion.

That is, in the present invention, a plate-shaped electrode terminal is positioned at a position where the sheet is sealed by adhesion or heat fusion, and openings for exposing the plate-shaped electrode terminals are formed on one side or both sides of the sheet sealing portion. Therefore, the electrode terminal of the electrode assembly is exposed on at least one side of the sheet-sealing portion so as to be electrically connectable to the outside, and the outermost end of the electrode terminal is formed to have a size corresponding to the outer circumferential surface of the sheet- It is possible to solve the problem that the insulating film protrudes beyond the battery case size, causing an unnecessary increase in dimensions.

The battery cell according to the present invention can be suitably applied to a pouch-type secondary battery in which an electrode assembly is embedded in a laminate sheet including a metal layer and a resin layer, and in one specific example, a pouch-shaped case of an aluminum laminate sheet .

2. Description of the Related Art Generally, a pouch-type secondary battery has a structure in which an electrode assembly is housed in a storage portion of a pouch-shaped battery case made of, for example, an aluminum laminate sheet. That is, the pouch type secondary battery includes a laminated sheet having a receiving portion for mounting the electrode assembly, a separate sheet separated from the sheet in a state where the electrode assembly is mounted on the receiving portion, or a sheet extending therefrom, And then sealing it.

Therefore, the laminate sheet may have a structure in which the electrode assembly receiving part is formed on one side or both sides of the upper and lower laminate sheets. That is, it is possible to use separate upper and lower laminate sheets separated from each other or to use one sheet to which one side of the upper and lower laminate sheets are connected. Such a pouch case forms a receiving portion by partially compressing a laminate sheet having a thickness of several tens to several hundreds of micrometers by a drawing process using a die and a punch.

In one specific example, the battery case is formed of one laminate sheet, the electrode assembly accommodating portion is formed on one side of the laminate sheet, the other side is bent to cover the electrode assembly accommodating portion, and then the contact portion of the laminate sheet is thermally fused ≪ / RTI >

In another specific example, the battery case is formed of a pair of laminate sheets, and the electrode assembly accommodating portion is formed on one side laminate sheet or both side laminate sheets. After covering the electrode assembly accommodating portion by abutting the laminate sheets, And the contact portion may be thermally fused.

The battery case according to the present invention is characterized in that a sheet-sealing portion is formed on the outer circumferential surface of the battery case so that the electrode assembly can be sealed in the state that the electrode assembly is mounted on the housing portion, And the outermost end of the electrode terminal has a size corresponding to the outer circumferential surface of the sheet sealing portion.

On the other hand, the opening is preferably 50 to 80% of the width of the sheet sealing portion. When the width of the opening is 50% or less of the width of the sheet sealing portion, the area of the electrode terminal exposed to the outside is reduced to make it difficult to electrically connect to the external circuit. The area of the sheet sealing portion around the electrode terminal exposed to the electrode terminal may be reduced and the sealing property of the battery case may be deteriorated.

In addition, the battery having the electrode assembly described above generally has an insulating film attached to a contact portion between the electrode lead and the battery case, and the insulating film of the present invention has a size corresponding to the opening formed in the battery case, Terminal and the battery case.

The electrode assembly is not particularly limited in its structure, and preferably includes a folding structure, a stacking structure, and a stacking / folding structure. In one specific example, the tabs extending from the electrode plates of the electrode assembly are coupled to one electrode lead, and the plate-shaped electrode terminals are formed by the electrode leads.

Details of the stacked / folded structure of the electrode assembly are disclosed in Korean Patent Application Laid-Open Nos. 2001-0082058, 2001-0082059 and 2001-0082060, the contents of which are incorporated herein by reference. As a reference.

The battery according to the present invention is preferably a lithium ion secondary battery in which a lithium-containing electrolyte is impregnated in an electrode assembly, a lithium secondary battery such as a so-called lithium ion polymer battery in which an electrode assembly is impregnated with a lithium- Can be applied.

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 50% 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 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 50 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 an anode active material on an anode current collector, and may further include the above-described components as needed.

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 non-aqueous 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, sulfates and the like 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 at least one battery cell.

The battery pack as described above may be used in a battery pack used as a small or power source of a device, and may be preferably used as a unit battery in a battery pack including a plurality of battery cells used as a power source of a medium and large-sized device.

In one specific example, the device may include, but is not limited to, a laptop, a cell phone, a PDP, a PMP, an MP3 player, a DSC (Digital Still Camera), a DVR, a smart phone, a GPS system, and a camcorder.

As described above, in the battery cell according to the present invention, the plate-shaped electrode terminal is positioned at the position where the sheet is sealed by the adhesive or heat fusion, and the opening for exposing the plate-shaped electrode terminal to one side or both sides of the sheet- The conventional electrode terminal protrudes beyond the battery case size to cause unnecessary increase in dimensions, thereby simplifying the manufacturing process of the battery pack and maximizing the space utilization of the battery.

1 is an exploded perspective view of a general structure of a conventional pouch type secondary battery;
FIG. 2 is a vertical cross-sectional view of a top portion of a battery case in which positive electrodes tabs are coupled in a densely packed state in a state where the secondary battery of FIG. 1 is assembled and connected to a positive electrode lead;
3 is a perspective view of a battery case of a battery cell according to an embodiment of the present invention;
4 is a perspective view of an electrode assembly inserted into a battery case of a battery cell according to an embodiment of the present invention;
5 is a schematic view of a battery cell according to one embodiment of the present invention;
6 is a schematic view of a battery cell according to another embodiment of the present invention;
7 is a perspective view of a battery case of a battery cell according to another embodiment of the present invention;
8 is a schematic view of a battery cell based on 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.

3 is a perspective view of a battery case of a battery cell according to an embodiment of the present invention.

3, the battery case 100 includes a housing sheet 191 on which an electrode assembly (not shown) can be mounted, and a cover sheet 192 integrally connected to the housing sheet 191, And the lid part sheet is bonded to the sealing part 120 of the battery case by heat sealing in a structure of wrapping the receiving part sheet 191. [

In the battery case 100, openings 111, 112, 113, and 114 for exposing the plate-shaped electrode terminals are formed at positions where the plate-shaped electrode terminals are located.

Specifically, the openings 111, 112, 113, and 114 are formed in a structure in which the sheet-sealing portion is cut in the direction of the receiving portion of the battery case, and the cover portion sheet 192 and the receiving portion sheet 191 have the same size And a position.

4 is a perspective view of an electrode assembly inserted into a battery case of a battery cell according to an embodiment of the present invention.

4, an electrode assembly having a separator 133 interposed between a positive electrode current collector 131 and a negative electrode current collector 132 on which electrode active materials are coated on both surfaces, The positive electrode tab 140 and the negative electrode tab 150 are protruded from the top of the electrode tab 160 and welded to the electrode leads 160 and 170 serving as the electrode leads.

Insulating films 181 and 182 are attached to the electrode terminals 160 and 170 at the contact portions of the battery case and the insulating films 181 and 182 are formed to have a size corresponding to the opening formed in the battery case . For this attachment, adhesive is coated on one or both sides of the film members facing each other. The adhesive may be composed of, for example, a composition to be bonded by an adhesive method, a heat fusion method, or the like, and it is needless to say that known adhesives can be used.

FIG. 5 is a schematic view of a battery cell according to an embodiment of the present invention, and FIG. 6 is a schematic view of a battery cell according to another embodiment of the present invention.

Referring first to FIG. 5, the battery cell 200 has a structure in which a positive electrode / separator / negative electrode assembly is built in a pouch-shaped case. The battery cell 200 has a structure in which the electrode terminals 260 and 270 are exposed through openings formed in the upper surface of the battery case sealing part 220 to be electrically connected to an external circuit. 6, the openings of the battery cell 300 may be formed on the top and bottom surfaces of the battery case sealing portion 320 to expose the electrode terminals 360 and 370, Respectively.

As described above, the battery cell according to the present invention can have various forms according to the modification of the battery case, in addition to the structure exemplified above.

FIG. 7 is a perspective view of a battery case of a battery cell according to another embodiment of the present invention, and FIG. 8 is a schematic view of a battery cell based on FIG.

Referring to these figures, the battery case 400 includes a housing sheet 491 on which an electrode assembly (not shown) can be mounted, a cover sheet 492 integrally connected to the housing sheet 491, And openings 411 and 412 for exposing the plate-shaped electrode terminals are formed on one side surface of the sealing portion 420 of the sheet 491 of the accommodating portion.

8, the electrode terminals 560 and 570 are exposed through the openings formed at one side of the sealing portion of the battery cell 500 in the direction of the receiving portion of the battery case, thereby being electrically connected to the outside Lt; / RTI >

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 (15)

A plate-shaped battery cell in which an electrode assembly having a separator interposed between an anode and a cathode is sealed inside a battery case together with an electrolyte,
The battery case is formed of a sheet-like member and forms a sheet-sealing portion by adhesion or heat fusion at a position where the plate-like electrode terminal is located,
Wherein an opening for exposing the plate-shaped electrode terminal is formed on one side or both sides of the sheet sealing portion,
The outermost end of the plate-like electrode terminal has a size coinciding with an outer circumferential surface of the sheet-
And an insulating film is attached to an interface between the plate-shaped electrode terminal and the battery case. The battery cell according to claim 1, wherein the battery case comprises a laminate sheet including a resin layer and a metal layer. The battery cell according to claim 2, wherein the laminate sheet is an aluminum laminate sheet. The battery case according to claim 2, wherein the battery case is formed of one laminate sheet, the electrode assembly housing part is formed on one side of the laminate sheet, the other side is folded to cover the electrode assembly housing part and then the contact part of the laminate sheet is thermally fused . The battery case according to claim 2, wherein the battery case is formed of a pair of laminate sheets, and the electrode assembly receiving part is formed on one side laminate sheet or both side laminate sheets, and after covering the electrode assembly receiving part by abutting the laminate sheets, And the contact portion is thermally fused. delete The battery cell according to claim 1, wherein the opening is formed in a structure in which a sheet-sealed portion is cut off. The battery cell according to claim 1, wherein the width of the opening is 50 to 80% of the width of the sheet seal. delete 2. The battery pack according to claim 1, wherein the battery case is composed of a compartment sheet on which the electrode assembly can be mounted and a cover sheet integrally connected to the compartment sheet, wherein the cover sheet and the compartment sheet have the same size And a depressed portion is formed in a position. The electrode assembly according to claim 1, wherein the electrode assembly has a stacked or stacked / folded structure, and the tabs extending from the electrode plates of the electrode assembly are coupled to one electrode lead, And the battery cell. The battery cell according to claim 1, wherein the electrode assembly has a folding structure, and a plate-shaped electrode terminal is formed by an electrode lead attached to an electrode plate of the electrode assembly. A battery pack comprising at least one battery cell according to any one of claims 1 to 5, 7, 8 and 10 to 12. A device according to claim 13, wherein the battery pack is used as a power source. 15. The device of claim 14, wherein the device is selected from the group consisting of a notebook, a mobile phone, a PDP, a PMP, an MP3 player, a DSC (Digital Still Camera), a DVR, a smart phone, a GPS system and a camcorder.

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