KR20170021000A - Electrode Assembly of Irregular Structure Comprising Unit Cells with Different Capacity and Size and Battery Cell Having the Same - Google Patents

Abstract

The present invention relates to an electrode assembly which is built in a battery case together with an electrolyte to constitute a battery cell. At least one of cell capacity and cell size has a wound structure with at least one separation film while the unit cells of different n (n>=2) respectively have a curved surface.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an atypical electrode assembly composed of unit cells having different capacities and sizes, and a battery cell including the same.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an atypical electrode assembly composed of unit cells having different capacities and sizes, and a battery cell including the same.

As information technology (IT) technology has developed remarkably, various portable information and communication devices have been spreading, and the 21st century has been developed into a "ubiquitous society" capable of providing high quality information services regardless of time and place.

As a development base for such a ubiquitous society, a lithium secondary battery occupies an important position. Specifically, rechargeable lithium rechargeable batteries are widely used as energy sources for wireless mobile devices or wearable electronic devices worn on the body, as well as for air pollution in existing gasoline vehicles and diesel vehicles using fossil fuels Such as an electric vehicle or a hybrid electric vehicle, which are proposed as a solution to solve the problem.

As described above, as the devices to which the lithium secondary battery is applied are diversified, the lithium secondary battery has been diversified so as to provide a suitable output and capacity for the applied device. In addition, miniaturization is strongly demanded.

The lithium secondary battery is manufactured in consideration of the size and shape of a device using the same as a power source. In recent years, there have been various products in which a lithium secondary battery is used. In order to be applicable to various devices having curved or curved surfaces, Apart from structure, it is manufactured with various designs of geometric structure.

In particular, a new type of secondary battery cell is required due to recent slim type, curved type, or trend change of various designs.

Since the battery cell is constructed to include the electrode assembly of the same size as the battery cell, it is necessary to reduce the capacity of the electrode assembly or to design the device in a larger size And, in some cases, multiple electrode assemblies should be combined to correspond to the desired shape of the device.

However, due to the complexity of the electrical connection in such a design change process, it is difficult to fabricate an electrode assembly satisfying desired conditions, for example, a cell capacity and an electrode capacity, and a battery cell including the electrode assembly.

Therefore, there is a high demand for an electrode assembly that can be applied to various device shapes, and can configure various cell capacities.

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.

More specifically, it is an object of the present invention to design a structure that can be mounted on shapes and spaces of various devices to maximize the utilization of the internal space of a device, and to provide a variety of external shapes The present invention also provides an electrode assembly and a battery cell including the electrode assembly.

To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, the present invention provides an electrode assembly comprising a battery case and an electrolyte solution, the electrode assembly comprising n electrolyte cells each having at least one of cell capacity and cell size, Wherein the unit cells are each a curved surface and are wound together with at least one separating film.

Therefore, the electrode assembly according to the present invention can be applied to a device having a curved surface structure in which not only a unit cell of a different cell capacity is formed of various energy densities but also a unit cell of different size is wound up. Since the battery cell can be manufactured as a battery cell having various capacities and sizes based on the specific structure as described above, utilization of space inside the device can be maximized.

In one specific example, the n unit cells are bi-cells having a structure in which an anode, a separator, a cathode, a separator and an anode, or a cathode, a separator, an anode, a separator, and a cathode are sequentially stacked,

At least one of the n unit cells may have a structure in which at least one cell size selected from a vertical width, a horizontal width, and a thickness is larger than a cell size of the remaining unit cells or smaller than a cell size of the remaining unit cells .

That is, the electrode assembly according to the present invention includes a plurality of unit cells of a bi-cell structure having a high energy density, and the size of the unit cells is different from that of the unit cell. Structure and other irregular structures.

Here, at least one of the n unit cells is different from the remaining unit cells in the content of the active material of the anode and the cathode,

The active material content may be determined by at least one size selected from the width, width and thickness of the anode or cathode included in the unit cells.

That is, the present invention can more finely design various performance such as the energy density and the output of the electrode assembly by setting the current collector thickness of the positive electrode and the negative electrode and the application amount of the active material to be different from each other in the bi- Accordingly, it is possible to provide an electrode assembly capable of manifesting a high energy density without any error in the overall performance.

In the present invention, the bi-cells may be composed of an electrode assembly having a curved surface arranged and wound in a specific structure, as will be described in detail below.

In one specific example, the electrode assembly may have a structure in which the electrode assembly is wound up from one end of the unit cells to the other end opposite to the first unit cell to the nth unit cell in a stacked state with respect to the ground.

Such a structure is advantageous in that, for example, as compared with a jelly-roll structure electrode assembly in which a positive electrode sheet and a negative electrode sheet are wound with a separator interposed therebetween, many unit cells of bi- Each cell has a relatively high capacity. In addition to having an electromotive force by itself, the cell has a different size and cell capacity, more specifically, a cell having a different application amount of the electrode active material, , It should be noted that the energy density can be designed more finely.

In the electrode assembly, separation films are interposed between adjacent unit cells, and another separation film may be added to the upper surface of the first unit cell and the upper surface of the nth unit cell with respect to the ground.

Wherein the unit cells have a structure in which the vertical width or the horizontal width is reduced from the first unit cell to the nth unit cell,

The adjacent unit cells are stacked in a state where at least one ends do not coincide with each other due to a difference in the vertical width or the horizontal width, and then the unit cells can be wound.

In some cases, both the vertical width and the horizontal width of the unit cells may be reduced from the first unit cell to the n-th unit cell, or may be different from the first unit cell to the n-th unit cell.

In addition, in order to further configure the shape of the electrode assembly, it is needless to say that at least one size selected from the vertical width and the horizontal width may be increased from the first unit cell to the n th unit cell .

When the unit cells having different sizes are stacked, the unmatched ends may form a step on a part of the outer surface of the electrode assembly in a state in which the unit cells are wound. Such a step may be a vertical width, The thickness of the unit cells may be adjusted to prevent a large variation in the cell capacity of the unit cells even if the unit cells have different vertical widths and horizontal widths.

In the above structure, the unit cells have a structure in which the electrode taps are led out in a direction perpendicular to the winding direction, and the electrode assembly is formed by stacking the electrode taps of the unit cells in a state where they are aligned on the same axis, ≪ / RTI >

That is, when the unit cells are stacked, the electrode tabs may be stacked so as to be positioned side by side, and the unit cells may be wound with the electrode tabs arranged in such a manner that they are coupled to each other.

Alternatively, the electrode tabs may be coupled to each other to form electrode terminals of the electrode assembly when the winding of the unit cells is completed.

In this case, the electrode tabs may be coupled in a state of being projected side by side from the upper surface or the lower surface of the wound electrode assembly to form an electrode terminal of the electrode assembly.

If the electrode tabs of the unit cells, that is, the positive electrode tab and the negative electrode tab protrude from opposite directions, the positive electrode tabs of each unit cell are coupled in a protruding state from the top surface of the wound electrode assembly, And the negative electrode tabs of each of the unit cells are coupled in a protruding state from the lower surface of the wound electrode assembly to form the negative electrode terminal of the electrode assembly.

The specific winding structure of such an electrode assembly may be a structure in which stacked unit cells are wound with a structure in which the winding radius R increases from the first unit cell to the nth unit cell.

Herein, the winding radius (R) means the distance between the winding axis and the winding end portion of each unit cell from the winding axis, so that the first unit cell can be wound most inward in the electrode assembly, The winding end portion of the first unit cell is in close contact with the nth unit cell, the winding end portion of the second unit cell is in close contact with the first unit cell, and the winding end portion of the second unit cell The step up to the n-th unit cell may be formed in the structure, and a step may be formed at the end of winding.

Meanwhile, in another specific example of the electrode assembly according to the present invention, the electrode assembly includes a first unit cell to an n-th unit cell in a state in which n unit cells are arranged in a lateral direction between a pair of separation films Wound structure.

Specifically, the electrode assembly may have a structure in which separating films are interposed between adjacent unit cells, unit cells are horizontally arranged in a state in which the side faces of adjacent unit cells are in close contact with each other with the separator interposed therebetween, And The winding structure is such that in a state in which the first unit cell is wound, starting from one end of the second unit cell adjacent to the side of the first unit cell that is the winding end portion of the first unit cell, And when the n is 3 or more, the second unit cell to the nth unit cell may be wound in the structure.

In such an electrode assembly, the thicknesses of the unit cells may be equal to each other, and the unit cells may have a different width, width, or width and width.

If the vertical widths are different, a step may be formed on an upper surface or a lower surface of the electrode assembly in a state where the unit cells are wound due to a difference in the vertical width of the unit cells.

The electrode tabs of the unit cells extend in a direction perpendicular to the winding direction and may be coupled to each other at the upper or lower end of the electrode assembly in a state where the unit cells are wound.

The present invention also provides a method of manufacturing the electrode assembly.

Specifically,

(a) stacking the unit cells together with the separation films so that the width of the vertical width or the horizontal width is reduced in the stacking direction on the first unit cell having the largest vertical width and / or the horizontal width;

(b) winding the stacked unit cells from one end to the other end and fixing the winding end portion so that the winding radius R increases from the first unit cell to the n-th unit cell; And

(c) connecting the electrode tabs of the unit cells to each other to form a positive electrode terminal and a negative electrode terminal of the electrode assembly;

And a control unit.

Alternatively,

(a) arranging unit cells horizontally between a pair of separation films so that n unit cells are laterally arranged with respect to the paper surface, and interposing a separation membrane between the side surfaces of adjacent unit cells;

(b) winding the first unit cell from the end of the first unit cell;

(c) winding the second unit cell on the first unit cell, starting from one end of the second unit cell adjacent to one side of the first unit cell, which is the winding end portion of the first unit cell;

(d) winding unit cells from the second unit cell to the n-th unit cell in the same manner as in the step (c), and fixing one end of the n-th unit cell as the winding end portion; And

(e) connecting the electrode tabs of the unit cells to each other to form a positive electrode terminal and a negative electrode terminal of the electrode assembly;

. ≪ / RTI >

The present invention also provides a battery cell in which an electrode assembly is embedded in a battery case together with an electrolyte solution.

The battery case may be a pouch type case made of a cylindrical metal can, or a laminate sheet, but is not limited thereto.

The battery cell of the present invention may be a lithium ion battery having a high energy density, a lithium polymer battery, or a lithium ion polymer battery cell, but is not limited thereto.

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 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 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 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.

The present invention also provides a device comprising the battery cell as a power source, wherein the device is used in a mobile phone, a portable computer, a smart phone, a tablet PC, a smart pad, a netbook, a LEV (Light Electronic Vehicle) A hybrid electric vehicle, a plug-in hybrid electric vehicle, and a power storage device.

The present invention also provides a battery pack including one or more battery cells and a device including the battery pack.

As described above, the electrode assembly according to the present invention is a combination of unit cells having different cell capacities and has various energy densities. In addition, unit cells having different sizes are wound to form a curved surface, And can be fabricated as a battery cell having various capacities and sizes based on the specific structure as described above, thereby maximizing utilization of space inside the device.

1 is a schematic view of unit cells constituting the electrode assembly of the present invention;
2 is an enlarged schematic view of a portion of FIG. 1;
3 to 5 are schematic diagrams of an electrode assembly according to one embodiment of the present invention;
6 and 7 are schematic views of an electrode assembly according to another embodiment of the present invention.
8 is a schematic view of an electrode assembly according to another embodiment of the present invention;
9 and 10 are schematic views of an electrode assembly according to another embodiment of the present invention.

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.

FIG. 1 is a schematic view of unit cells constituting an electrode assembly of the present invention, and FIG. 2 is a schematic diagram of an enlarged view of a portion of FIG.

Referring to these figures, the unit cell 1a has a structure in which a first anode 10a, a separation membrane 11a, a cathode 12, a separation membrane 11b, and a second anode 10b are sequentially stacked. A bi-cell having such a laminated structure will be described below as a C-bi-cell.

The unit cell 1b has a structure in which a first cathode 20a, a separation membrane 21a, an anode 22, a separation membrane 21b, and a second cathode 20b are sequentially stacked. A bi-cell having such a laminated structure will be described below as an A-type bi-cell.

In the C-type bi-cell, the first anode 10a has a structure in which the cathode active material 31 is coated on both surfaces of the cathode current collector 30. The negative electrode 12 has a structure in which the negative electrode active material 33 is coated on both surfaces of the negative electrode collector 32. And the positive electrode active material 25 is applied to both surfaces of the second positive electrode current collector 34.

The A-type bi-cell may also have the same structure as the C-type bi-cell except for the order of arrangement of the cathode and the anode.

In addition, the structure of the bi-cells is an exemplary structure, and the structure in which the electrode active material is applied only on one surface of the current collector is also included in the scope of the present invention.

At least one electrode selected from the first and second positive electrodes 10a and 10b and the negative electrode 12 has a thickness of the current collector 30, It may be thinner or thicker, and the application amounts of the active materials 31, 33, and 35 may also be different.

That is, the present invention is advantageous in that the capacity of the electrode assembly can be finely structured by varying the size design of the anode and the cathode in the bi-cell including three electrodes.

In this regard, Figs. 3 to 5 schematically show an electrode assembly according to one embodiment of the present invention.

3, the electrode assembly includes a first unit cell 110, a second unit cell 120, a third unit cell 130, and a plurality of separation films 102a, 102b, 102c, and 102d do.

The unit cells 110, 120 and 130 are stacked on the first unit cell 110 with the separation film 102b interposed therebetween and the second unit cell 120 is stacked on the first unit cell 110, The third unit cells 130 are stacked in a state in which the separation film 102c is interposed on the cell 120 and the lower surface of the first unit cell 110 and the upper surface of the third unit cell 130 Other separation films 102a and 102d are added, respectively.

The unit cells 110, 120 and 130 are connected to each other at one end of the electrode tabs 150. The unit tabs 110, 120 and 130 are connected to the unit cells 110, They are superimposed on the same axis in a laminated state.

The unit cells 110, 120, and 130 are stacked on the first unit cell 110 in such a manner that one ends of the unit cells 110, 120, and 130 are aligned with each other.

The vertical width W1 of the first unit cell 110 is greater than the vertical width W2 of the second unit cell 120 and the vertical width W2 of the second unit cell 120 is greater than the vertical width W2 of the third unit cell 120. [ The width W3 of the unit cell 110 is set to be larger than the vertical width W3 of the unit cell 130 so that the end portions of the unit cells 110,

The steps derived from the unmatched ends thus form the stepped portions 112 at the winding end portions of the unit cells 110, 120, and 130 after winding.

The thickness T3 of the third unit cell 130 is greater than the thickness T1 of the first unit cell 110. The thickness T3 of the second unit cell 120 is greater than the thickness T1 of the first unit cell 110, And the thickness T1 of the first unit cell 110 is the thinnest.

That is, the electrode assembly 100 of the present invention includes a plurality of unit cells 110, 120, and 130 that are bi-cells, and each of the unit cells 110, 120, and 130 includes an anode The active material content of the negative electrode and the negative electrode may be finely or substantially different from each other, and the structure is easily designed to satisfy various performance indices required for the device, for example, capacity, energy density, or output characteristics.

The electrode assembly 100 of the present invention has a laminated structure of the unit cells 110, 120 and 130 shown in FIGS. 3 and 4 and has a curved surface as shown in FIG. 5, ) Are formed on the substrate. Such a structure has an advantage of being easily applied to a device having a curved surface and a narrow and complicated space.

Here, in the electrode assembly 100 in which the winding is completed, the winding radius R, which is a distance between the winding axis and each winding end portion of each unit cell, increases from the first unit cell 110 to the third unit cell 130 The unit cells 110, 120, and 130 are wound.

That is, the winding radius R1 of the first unit cell 110 is smaller than the winding radius R2 of the second unit cell 120, and the winding radius R2 of the second unit cell 120 is smaller than the winding radius Is smaller than the winding radius (R3) of the electrode assembly (130), so that a step is formed outside the inside of the electrode assembly (100).

6 and 7 illustrate an electrode assembly 200 according to another embodiment of the present invention.

6, the electrode assembly 200 includes a first unit cell 210, a second unit cell 220, and a third unit cell 230. The first unit cell 210, the second unit cell 220, and the third unit cell 230 have widths W4, W5, And the electrode tabs of the unit cells 210, 220, and 230 are aligned on the same axis.

That is, due to the difference in the widths W4, W5 and W6 of the unit cells 210, 220 and 230, one ends of the unit cells 210, 220 and 230 are stacked in a state where they do not coincide with each other, The ends of the unit cells 210, 220 and 230 are wound on the upper surface of the electrode assembly 200 and the electrode tabs of the unit cells 210, 200 so as to form electrode terminals of the electrode assembly 200.

6 and 7, the widths of the first unit cell to the third unit cell are increased from the first unit cell 310 to the third unit cell 330, The step 340 may be formed such that a part of the upper end of the electrode assembly 300 is indented inside rather than the outer surface of the electrode assembly 300,

9 and 10 schematically show an electrode assembly according to another embodiment of the present invention.

Referring first to FIG. 8, the electrode assembly 400 includes three unit cells 410, 420, and 430 (410, 420, and 430) extending in the lateral direction between the pair of separation films 402a and 402b Respectively.

Here, the first unit cell 410 to the third unit cell 430 may include a plurality of adjacent unit cells 410, 420, and 430, The first anode 412 of the first unit cell 410 is in intimate contact with the first cathode 422 of the second unit cell 420 and the first anode 420 of the first unit cell 420 is in close contact with the side face, The cathode 416 of the first unit cell 410 is in intimate contact with the anode 426 of the second unit cell 420 and the second anode 414 of the first unit cell 410 is in contact with the second And is in close contact with the cathode 424.

The first negative electrode 422 of the second unit cell 420 is closely contacted with the first positive electrode 432 of the third unit cell 430 and the positive electrode of the second unit cell 420 And the second negative electrode 424 of the second unit cell 420 is in intimate contact with the second positive electrode 434 of the second unit cell 420. The second electrode 426 of the second unit cell 420 is in close contact with the negative electrode 436 of the third unit cell 430, do.

The vertical width W7 of the second unit cell 420 is greater than the vertical width of the remaining unit cells 410, 420, 430, Lt; / RTI &gt;

When the unit cells 410, 420, and 430 are horizontally aligned and then wound from one end to the other end, the electrode assembly 400 may have a cylindrical structure as shown in FIG.

Specifically, the electrode assembly 400 includes a first unit cell 410, a first unit cell 410, a first unit cell 410, a first unit cell 410, The second unit cell 420 is wound on the first unit cell 410 starting from one end of the cell 420 so that the second anode 414 of the first unit cell 410 is wound on the second unit cell 410, And is in close contact with the first cathode 422 of the unit cell 420.

In this state, starting from one end of the third unit cell 430 adjacent to the side of the second unit cell 420, which is the winding end portion of the second unit cell 420, The second negative electrode 424 of the second unit cell 420 is closely adhered to the first positive electrode 432 of the third unit cell 430. As a result,

As described above, the electrode assembly of the present invention is a combination of unit cells having different cell capacities and is configured to have various energy densities. In addition, the electrode assembly is applied to a device having a curved surface structure, Since it is possible to fabricate a battery cell having various capacities and sizes based on the specific structure as described above, utilization of space inside the device can be maximized.

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 (22)

An electrode assembly comprising a battery case and an electrolyte solution, the electrode assembly comprising n (n? 2) unit cells having at least one of a cell capacity and a cell size different from each other, wherein the electrode assembly has a winding structure. The method according to claim 1, wherein each of the n unit cells is a bi-cell having a structure in which an anode, a separator, a cathode, a separator and an anode, or a cathode, a separator, an anode,
At least one of the n unit cells has a size of at least one selected from the group consisting of a vertical width, a horizontal width, and a thickness, which is larger than the cell size of the remaining unit cells or smaller than the cell size of the remaining unit cells. Electrode assembly. 3. The method according to claim 2, wherein at least one of the n unit cells is different from the remaining unit cells in the content of the active material of the anode and the cathode,
Wherein the content of the active material is determined by at least one size selected from a width, a width, and a thickness of the anode or the cathode included in the unit cells. 3. The electrode assembly according to claim 2, wherein the electrode assembly is wound up from one end of the unit cells to the other end opposite to the first unit cell to the n-th unit cell, . The method according to claim 4, wherein the electrode assembly has separation films interposed between adjacent unit cells, and further separating films are provided on the lower surface of the first unit cell and the upper surface of the n th unit cell with respect to the ground surface The electrode assembly comprising: The apparatus of claim 4, wherein the unit cells have a structure in which a width or a width is reduced from a first unit cell to an nth unit cell,
Wherein at least one end portion of the adjacent unit cells is stacked in a state in which they do not coincide with each other due to a difference in the vertical width or the horizontal width of the adjacent unit cells. The method according to claim 6, wherein the unmatched end portion forms a step on a part of the outer surface of the electrode assembly in a state in which the unit cells are wound, and the step is derived from a difference in width, width or thickness of adjacent unit cells . [5] The unit cell of claim 4, wherein the unit cells have a structure in which the electrode taps are led out in a direction perpendicular to the winding direction, and the electrode assemblies are stacked in a state where the electrode tabs of the unit cells are aligned on the same axis And then wound up. The electrode assembly according to claim 8, wherein the electrode tabs are protruded from an upper surface or a lower surface of the electrode assembly to form electrode terminals of the electrode assembly. The electrode assembly according to claim 4, wherein the electrode assembly is a structure in which stacked unit cells are wound with a structure in which a winding radius (R) increases from a first unit cell to an nth unit cell. The electrode assembly according to claim 2, wherein the electrode assembly is a structure in which n unit cells are wound from a first unit cell to an nth unit cell in a state where the unit cells are arranged in a lateral direction between a pair of separation films. Assembly. 12. The method according to claim 11, wherein the electrode assembly has separator films interposed between adjacent unit cells, unit cells are horizontally arranged in a state in which the side surfaces of adjacent unit cells are in close contact with each other with the separator interposed therebetween, Wherein the electrode assembly has a structure. 13. The apparatus according to claim 12,
In a state in which the first unit cell is wound, the second unit cell is wound on the first unit cell starting from one end of the second unit cell adjacent to the side of the first unit cell that is the winding end portion of the first unit cell , And when the n is 3 or more, the structure is wound in the structure from the second unit cell to the n-th unit cell. 13. The electrode assembly of claim 12, wherein the unit cells have the same thickness and the unit cells have different widths or widths. 15. The electrode assembly according to claim 14, wherein the electrode assembly has a step formed on an upper surface or a lower surface of the electrode assembly in a state in which unit cells are wound due to a difference in the vertical width of the unit cells. 12. The electrode assembly of claim 11, wherein the electrode tabs of the unit cells extend in a direction perpendicular to the winding direction and are coupled to each other at an upper or lower end of the electrode assembly in a state where the unit cells are wound, Assembly. 17. A method of manufacturing an electrode assembly according to any one of claims 1 to 16,
(a) stacking the unit cells together with the separation films so that the width of the vertical width or the horizontal width is reduced in the stacking direction on the first unit cell having the largest vertical width and / or the horizontal width;
(b) winding the stacked unit cells from one end to the other end and fixing the winding end portion so that the winding radius R increases from the first unit cell to the n-th unit cell; And
(c) connecting the electrode tabs of the unit cells to each other to form a positive electrode terminal and a negative electrode terminal of the electrode assembly;
&Lt; / RTI &gt; 17. A method of manufacturing an electrode assembly according to any one of claims 1 to 16,
(a) arranging unit cells horizontally between a pair of separation films so that n unit cells are laterally arranged with respect to the paper surface, and interposing a separation membrane between the side surfaces of adjacent unit cells;
(b) winding the first unit cell from the end of the first unit cell;
(c) winding the second unit cell on the first unit cell, starting from one end of the second unit cell adjacent to one side of the first unit cell, which is the winding end portion of the first unit cell;
(d) winding unit cells from the second unit cell to the n-th unit cell in the same manner as in the step (c), and fixing one end of the n-th unit cell as the winding end portion; And
(e) connecting the electrode tabs of the unit cells to each other to form a positive electrode terminal and a negative electrode terminal of the electrode assembly;
&Lt; / RTI &gt; A battery cell in which the electrode assembly according to any one of claims 1 to 16 is embedded in a battery case together with an electrolyte solution. The battery cell according to claim 19, wherein the battery case is a pouch-shaped case made of a cylindrical metal can, or a laminate sheet. A battery pack comprising at least one battery cell according to claim 19. A device comprising a battery pack according to claim 21.

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