KR101684325B1 - - Hybrid Stack Folding Typed Electrode Assembly and Secondary Battery Comprising the Same - Google Patents

Abstract

[0001] The present invention relates to a hybrid stack-folding type electrode assembly and a secondary battery including the same. More particularly, the present invention relates to a stack-folding type electrode assembly having a structure in which unit cells including an anode, a cathode, Type unit cells and two or more second type unit cells, wherein the first type unit cell and the second type unit cell have different electrode array structures; Wherein one kind of unit cell selected from the first type unit cell and the second type unit cell includes a carbon-based material as a negative electrode active material, and the remaining type of unit cell includes a silicon-based oxide as a negative electrode active material To a stack-folding type electrode assembly.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a hybrid stack-folding type electrode assembly and a secondary battery including the hybrid stack-folding type electrode assembly.

The present invention relates to a hybrid stack-folding type electrode assembly and a secondary battery including the same.

As technology development and demand for mobile devices have increased, there has been a rapid increase in demand for secondary batteries as energy sources. Among such secondary batteries, lithium secondary batteries, which exhibit high energy density and operational potential, long cycle life, Batteries have been commercialized and widely used.

Particularly, in the case of a lithium secondary battery, the demand for an energy source is rapidly increasing due to an increase in technology development and demand for a mobile device. Recently, the use of a lithium secondary battery as a power source for an electric vehicle (EV) and a hybrid electric vehicle , And the area of use is also expanding for applications such as power assisted power supply through gridization.

A lithium secondary battery used as a power source of an electric vehicle (EV) or a hybrid electric vehicle (HEV) has a high energy density and a characteristic capable of exhibiting a large output in a short period of time, and also, under severe conditions, It is inevitably required to have safety and long-term life characteristics far superior to conventional small-sized lithium secondary batteries.

In addition, a lithium secondary battery used as a large-capacity power storage device must have a high energy density and efficiency and a long lifetime. In addition, when malfunction of the system due to high performance and large capacity is caused, Is a particularly important task.

In this regard, a negative electrode of a conventional lithium secondary battery is mainly composed of a carbonaceous material capable of intercalating and desorbing reversible lithium ions while maintaining structural and electrical properties as a negative electrode active material.

Specifically, the carbon-based material has a very low discharge potential of about -3 V with respect to the standard hydrogen electrode potential and exhibits a highly reversible charge / discharge behavior due to the uniaxial orientation of the graphite plate layer (graphene layer) And when the Li-ion is charged, the electrode potential can exhibit a potential similar to that of a pure lithium metal as 0V Li / Li ⁺ . Therefore, when forming the battery with the oxide-based anode, Energy can be obtained.

However, the negative electrode made of such a carbon-based material has a theoretical maximum capacity of 372 mAh / g, which makes it difficult to cope with a rapidly changing role as an energy source for a next-generation mobile device.

In order to solve the above-mentioned problems, recently, there has been proposed a method of manufacturing a semiconductor device by a Li alloy alloy reaction using silicon (Si), germanium (Ge), tin (Sn) There are many studies on anode materials.

In the case of silicon, which is one of these alloy cathode materials, the theoretical maximum capacity is about 3580 mAh / g, which is very large compared to graphite materials, and tin also has a very large capacity of 990 mAh / g.

However, in the case of such an alloy-based negative electrode material, since the lifetime characteristic is remarkably low due to a large volume change occurring during charging and discharging, it is possible to use it only for limited use because it has a great restriction on use.

Therefore, there is a high need for a secondary battery technology capable of solving the problems of the negative electrode active materials and increasing the energy density while improving safety with increasing capacity of the battery.

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, in a stack-folding type electrode assembly including two types of unit cells having different electrode array structures, It has been confirmed that a desired effect can be achieved when the negative electrode active material includes a carbon-based material and the remaining types of unit cells include a silicon-based oxide as a negative electrode active material, thereby completing the present invention.

Accordingly, the stack-folding type electrode assembly according to the present invention is a stack-folding type electrode assembly in which unit cells including an anode, a cathode, and a separator are wound by a separator film,

At least two first type unit cells and at least two second type unit cells, wherein the first type unit cells and the second type unit cells have different electrode array structures;

One kind of unit cell selected from the first type unit cell and the second type unit cell includes a carbon-based material as a negative electrode active material, and the remaining type unit cells include a silicon-based oxide as a negative electrode active material .

In one specific example, the first type unit cell and the second type unit cell may be a bi-cell having a structure in which electrodes of the same polarity are located at both ends of the unit cell. More specifically, The second type unit cell may be a bi-cell having a structure in which the negative electrode is located at both ends of the unit cell.

In one specific example, the first type unit cell includes a carbon-based material as an anode active material, the second type unit cell may include a silicon-based oxide as a negative electrode active material, and conversely, The first type unit cell may contain a silicon-based oxide as an anode active material, and the first type unit cell may include a silicon-based oxide as an active material.

In one specific example, the total number of the second-type unit cells having the structure in which the cathodes are located at both ends of the unit cell is equal to or greater than the total number of the first-type unit cells having the structure in which the anode is located at both ends of the unit cell, It can be more than that.

Meanwhile, in one specific example, the outermost electrode of the unit cell in the first type unit cell or the second type unit cell located at the outermost side of the stack-folding type electrode assembly may be coated with a single side, The outermost electrode coated with the cross-section may have no active material coated on the outwardly facing surface of the electrode on both sides.

In some cases, the stack-folding type electrode assembly may further include one or more third-type unit cells other than the first-type unit cells and the second-type unit cells, and in this case, the third- And a polarity electrode may be positioned at both ends of the unit cell.

The third-type unit cell may include a carbon-based material or a silicon-based oxide as an anode active material.

In one specific example, the anode may comprise a lithium cobalt-based oxide represented by the following formula (1), and more specifically, the lithium cobalt-based oxide may be LiCoO ₂ .

Li _x (Co _(1-a) M _a ) O _2-y A _y (1)

In this formula,

M is at least one element selected from the group consisting of Ca, Zr, Mo, Fe, Cr, Ti, Zn, V, Al and Mg; A is an element selected from the group consisting of F, S and N; X? 1.2, 0? A? 0.2, 0? Y?

In one specific example, the anode may comprise a lithium nickel-manganese-cobalt oxide represented by the following formula 2, and more specifically, the lithium nickel-manganese-cobalt oxide may include LiNi _1/3 Mn _1/3 Co _{1 / 3} O ₂ , LiNi _0.7 Mn _0.05 Co _0.25 O _2, and LiNi _0.8 Mn _0.1 Co _0.1 O ₂ .

Li _{1 + x '} Ni _{1- (a' + b + c)} Mn _{a '} Co _b M _c O _2-y A _y (2)

In this formula,

M is at least one element selected from the group consisting of Ca, Zr, Mo, Fe, Cr, Ti, Zn, V, Al and Mg; A is an element selected from the group consisting of F, S and N; 0? Y? 0.1, 0.05? A? 0.6, 0.1? B? 0.4, 0? C? 0.2, and a '+ b + c <1.

The present invention also provides a secondary battery including the stack-folding type electrode assembly, wherein the secondary battery is provided as a unit battery, and the battery pack includes the battery module.

The battery pack may be used as a power source for devices requiring high temperature stability, long cycle characteristics, and high rate characteristics. Examples of the battery pack include small devices such as a computer, a mobile phone, and a power tool, An electric vehicle including an electric vehicle (EV) powered by a motor, a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and the like; An electric motorcycle including an electric bike (E-bike) and an electric scooter (E-scooter); An electric golf cart; Power storage systems, and the like.

As described above, the stack-folding type electrode assembly according to the present invention includes two types of unit cells having different electrode arrangements, and one of the unit cells is a carbon-based material And the remaining types of unit cells include a silicon oxide as a negative electrode active material, thereby exhibiting high energy density and improving overall battery performance such as high capacity, high cycle stability, and excellent rate characteristics, There is an effect that can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a configuration of a first type unit cell of the present invention; FIG.
2 is a schematic view showing a configuration of a second type unit cell of the present invention;
3 is a schematic diagram of a manner of arranging unit cells on a separation film according to one embodiment of the present invention;
Fig. 4 is a schematic diagram of a stack-folding type electrode assembly in which the Fig. 3 is wound; Fig.
5 is a schematic view showing the shape of a first type unit cell including an anode on both surfaces of which an active material is not coated on the outwardly facing surface;
6 is a schematic diagram of a manner of arranging unit cells on a separation film according to another embodiment of the present invention;
Fig. 7 is a schematic diagram of a stack-folding type electrode assembly in a state in which Fig. 6 is wound;
Figs. 8 and 9 are schematic diagrams showing the shape of a third type unit cell of the present invention. Fig.

As described above, the stack-folding type electrode assembly according to the present invention is a stack-folding type electrode assembly in which unit cells including an anode, a cathode, and a separator are wound by a separation film,

At least two first type unit cells and at least two second type unit cells, wherein the first type unit cells and the second type unit cells have different electrode array structures;

One kind of unit cell selected from the first type unit cell and the second type unit cell includes a carbon-based material as a negative electrode active material, and the remaining type unit cells include a silicon-based oxide as a negative electrode active material .

Therefore, when two types of unit cells having different electrode arrangements are used in the stack-folding type electrode assembly as in the present invention, and the negative electrode active material contained in each unit cell is different, It is easy to set optimum conditions to suit the characteristics of the negative electrode mixture, and it is also possible to apply a silicon-based oxide having excellent characteristics in terms of capacity and a carbon-based material having excellent lifetime and storage characteristics of the secondary battery, It is possible to improve the overall battery performance such as high capacity, high cycle stability, and excellent rate characteristics while exhibiting the energy density, and at the same time, improve the safety of the battery.

The present invention will be described in more detail below.

In one specific example, the first type unit cell and the second type unit cell may be a bi-cell having a structure in which electrodes of the same polarity are located at both ends of the unit cell. Specifically, The second type unit cell may be a bi-cell having a structure in which the negative electrode is located at both ends of the unit cell.

In Figs. 1 and 2, the two kinds of bi-cell structures are illustrated by way of example. Referring to FIG. 1, a cell including a positive electrode-separator-negative electrode-separator-positive electrode is shown as a bi-cell having a structure in which the positive electrode is located at both ends of the unit cell. A cell made up of a cathode-separator-anode-separator-cathode is shown as a bi-cell having a structure located at the center of the cell.

The bi-cells are an example, and more bi-cells of a stack number are possible.

On the other hand, FIGS. 3 and 4 show a schematic view in which these two kinds of unit cells are arranged on a separation film, and an electrode assembly in a state in which the unit cells are wound. However, the arrangement method of FIG. 3 is only one example, and the positive electrode and the negative electrode may be alternately arranged in the wound electrode assembly, so the present invention is not limited thereto.

In this case, the first type unit cell may include a carbon-based material as a negative active material, the second type unit cell may include a silicon-based oxide as an anode active material, and the second type unit cell may include a carbon Based material, and the first type unit cell may contain a silicon-based oxide as an anode active material. More specifically, the carbon-based material may be graphite and the silicon-based oxide may be SiO.

Generally, in order to prevent the waste of the capacity of the battery, the amount of the negative electrode must be greater than the amount of the positive electrode. Therefore, as shown in FIG. 3, the total number of the second type unit cells having the structure in which the negative electrode is located at both ends of the unit cell Type unit cell having the structure in which the anode is located at both ends of the unit cell.

On the other hand, in one embodiment, the outermost electrode of the unit cell in the first type unit cell or the second type unit cell located at the outermost position of the stack-folding type electrode assembly according to the present invention can be cross-sectional coated, , The active material may not be coated on the outwardly facing surfaces of both surfaces of the electrode.

In the case where the active material is not coated on the outwardly facing surface as described above, the amount of heat generated when the active material is coated can be reduced and the safety of the battery can be further improved.

At this time, the unit cell located at the outermost position of the stack-folding type electrode assembly may be the first type unit cell or the second type unit cell, and is not limited to it, specifically, it may be the first type unit cell.

As an example in FIG. 5, there is shown a structure in which one of the positive electrodes forming the first type unit cell is coated with no active material on the outward facing surface.

6 and 7 show a schematic view in which the first type unit cell having the outermost electrode coated with a single piece is arranged on a separation film so as to be located at an outermost position of the electrode assembly, and an electrode assembly in a state in which the first type unit cell is wound have.

As shown in FIGS. 6 and 7, in order to position the unit cell coated with the end face at the outermost position of the electrode assembly, two unit cells located farthest from the starting point (rightmost) (See Fig. 6). When the separating film thus arranged is folded inwardly so as to enclose the unit cell from the starting point of winding, the electrode having no coating of the active material on the outwardly facing surface is wound around the electrode assembly (See Fig. 7).

6 is an example only. When the electrode assembly in which the positive electrode and the negative electrode are alternately arranged in the wound electrode assembly and the electrode on which the active material is not coated on the outwardly facing surface is located at the outermost position of the electrode assembly The present invention is not limited thereto.

In some cases, the stack-folding type electrode assembly may further include one or more third type unit cells in addition to the first type unit cells and the second type unit cells. In this case, May be a full cell having a structure in which electrodes of different polarities are located at both ends of the unit cell.

The pull cell may be a positive electrode-separator-negative electrode structure, a positive electrode-separator-negative electrode-separator-positive electrode-separator-negative electrode structure, or the like, as shown in FIGS. 8 and 9, Of course, a full cell is also possible.

The third type unit cell may contain a carbon-based material or a silicon-based oxide as the negative electrode active material, and may be selected in accordance with the characteristics of the battery having the emphasis.

The position of the third type unit cell is not limited and may be located between the first type unit cell and the second type unit cells and may be located at the outermost position of the electrode assembly.

Meanwhile, in one specific example, the anode included in the stack-folding type electrode assembly according to the present invention may include a lithium cobalt-based oxide represented by the following formula 1, and more specifically, the lithium cobalt-based oxide may be LiCoO ₂ Lt; / RTI &gt;

Li _x (Co _(1-a) M _a ) O _2-y A _y (1)

In this formula,

M is at least one element selected from the group consisting of Ca, Zr, Mo, Fe, Cr, Ti, Zn, V, Al,

A is an element selected from the group consisting of F, S and N,

0.8? X? 1.2, 0? A? 0.2, 0? Y?

The lithium cobalt oxide may be a monolithic structure. Accordingly, the inner porosity is hardly provided, and as the size of the particles increases, the stability of the crystal grains improves, and the manufacture of the battery including the same is facilitated, thereby improving the efficiency of the manufacturing process.

For example, the lithium cobalt-based oxide may be a potato shaped single particle, and its D50 may be 10 탆 or more, specifically 15 탆 or more.

In another specific example, the anode may include a lithium nickel-manganese-cobalt oxide represented by the following formula (2), and more specifically, the lithium nickel-manganese-cobalt oxide may include LiNi _1/3 Mn _1/3 Co _1/3 O ₂ , LiNi _0.7 Mn _0.05 Co _0.25 O _2, and LiNi _0.8 Mn _0.1 Co _0.1 O ₂ .

Li _{1 + x '} Ni _{1- (a' + b + c)} Mn _{a '} Co _b M _c O _2-y A _y (2)

In this formula,

M is at least one element selected from the group consisting of Ca, Zr, Mo, Fe, Cr, Ti, Zn, V, Al,

A is an element selected from the group consisting of F, S and N,

0? X? 0.2, 0? Y? 0.1, 0.05? A? 0.6, 0.1? B? 0.4, 0? C? 0.2, and a '+ b + c <

Specifically, the lithium nickel-manganese-cobalt oxide may have an agglomerated structure, that is, in the form of agglomerates of fine powders, and thus may have a structure having internal voids. This type of agglomerated particle structure is characterized in that it can maximize the surface area reacted with the electrolytic solution to exhibit a high rate characteristic and can expand the reversible capacity of the anode.

For example, the lithium nickel-manganese-cobalt oxide of the flocculated structure has fine particles of 1 탆 to 5 탆 coagulated with each other and has a D50 of 10 탆 or less, specifically 8 탆 or less, more specifically 4 To 7 [mu] m. More particularly, more than 90% can be constructed as agglomerates of fine particles having a size (D50) of 1 to 4 mu m.

When the content of lithium exceeds 1.2 mol, the safety may be lowered during a high voltage (4.35 V or more) cycle. When the content of lithium is less than 0.8 mol, the crystallinity is insufficient and the low rate characteristic And the reversible capacity can be reduced, which is not preferable.

As described above, in the stack-folding type electrode assembly in which the lithium cobalt oxide and the lithium nickel-manganese-cobalt oxide are applied to the respective unit cells according to the present invention, It is possible to manufacture a lithium secondary battery having a very high capacity density and a high capacity density.

The basic constitution of the unit cells according to the present invention, that is, an anode, a cathode and a separator will be described below.

The positive electrode is prepared by applying a mixture of the positive electrode active material, the conductive material and the binder selected for each unit cell on the positive electrode collector, followed by drying and pressing, and if necessary, a filler is further added to the mixture .

The cathode current collector generally has a thickness of 3 to 500 mu m. Such a positive electrode current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery. Examples of the positive electrode current collector include stainless steel, aluminum, nickel, titanium, sintered carbon, aluminum or stainless steel A surface treated with carbon, nickel, titanium, silver or the like may be used. The current collector may have fine irregularities on the surface thereof to increase the adhesive force of the cathode active material, and various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a nonwoven fabric are possible.

The 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.

On the other hand, the negative electrode is manufactured by applying, drying and pressing an anode active material on an anode current collector, and may optionally further include a conductive material, a binder, a filler, and the like as described above.

The negative electrode current collector is generally made to have a thickness of 3 to 500 mu m. Such an anode current collector is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, and examples of the anode current collector include copper, stainless steel, aluminum, nickel, titanium, sintered carbon, a surface of copper or stainless steel A surface treated with carbon, nickel, titanium, silver or the like, an aluminum-cadmium alloy, or the like can be used. In addition, like the positive electrode collector, fine unevenness can be formed on the surface to enhance the bonding force of the negative electrode active material, and it can be used in various forms such as films, sheets, foils, nets, porous bodies, foams and nonwoven fabrics.

The 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.

On the other hand, the separation film in which such unit cells are arranged and wound may or may not be the same material as the separation membrane.

The present invention also provides a secondary battery comprising the stack-folding type electrode assembly, wherein the secondary battery is formed by impregnating a stacked-folding type electrode assembly according to the present invention with a non-aqueous electrolyte containing a lithium salt .

The lithium salt-containing nonaqueous electrolyte is composed of a nonaqueous electrolyte and a lithium salt. Examples of the nonaqueous electrolyte include nonaqueous organic solvents, organic solid electrolytes, inorganic solid electrolytes, and the like.

Examples of the non-aqueous organic solvent 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 derivatives, Tetrahydrofuran derivatives, ether, methyl pyrophosphate, ethyl propionate and the like can be used.

Examples of the organic solid electrolyte include a polymer electrolyte such as a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, an agitation lysine, a polyester sulfide, a polyvinyl alcohol, a polyvinylidene fluoride, A polymer containing an ionic dissociation group and the like may 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 substance that is soluble in the nonaqueous electrolyte and includes, 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 ₂ ) ₂ NLi, chloroborane lithium, lower aliphatic carboxylate lithium, lithium tetraphenylborate, and imide.

The nonaqueous electrolyte may contain, for the purpose of improving charge / discharge characteristics, flame retardancy, etc., 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 may be added have. In some cases, halogen-containing solvents such as carbon tetrachloride and ethylene trifluoride may be further added to impart nonflammability. In order to improve the high-temperature storage characteristics, carbon dioxide gas may be further added. FEC (Fluoro-Ethylene Carbonate, PRS (Propene sultone), and the like.

In a preferred _{embodiment, LiPF 6, LiClO 4, LiBF} 4, LiN (SO 2 CF 3) 2 , such as a lithium salt, a highly dielectric solvent of DEC, DMC or EMC Fig solvent cyclic carbonate and a low viscosity of the EC or PC of And then adding it to a mixed solvent of linear carbonate to prepare a lithium salt-containing nonaqueous electrolyte.

The present invention also provides a battery module including the secondary battery as a unit cell, and a battery pack including the battery module.

The battery pack may be used as a power source for devices requiring high temperature stability, long cycle characteristics, and high rate characteristics. Examples of the battery pack include small devices such as a computer, a mobile phone, and a power tool, A power tool powered by the motor; An electric vehicle including an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and the like; An electric motorcycle including an electric bike (E-bike) and an electric scooter (E-scooter); An electric golf cart; Power storage systems, and the like, but are not limited thereto.

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)

A stack-folding type electrode assembly having a structure in which unit cells including an anode, a cathode, and a separator are wound by a separator film,
At least two first type unit cells and at least two second type unit cells, wherein the first type unit cells and the second type unit cells have different electrode array structures;
One kind of unit cell selected from among the first type unit cell and the second type unit cell includes a carbon-based material as a negative active material, and the other type unit cell contains SiO as a negative active material,
The outermost electrodes of the unit cells in the first type unit cell or the second type unit cell located at the outermost part of the stack-folding type electrode assembly are coated on one side,
The outermost electrode having the cross-section coated thereon is not coated with an active material on the outwardly facing surface of both sides of the electrode,
Further comprising at least one third type unit cell in addition to the first type unit cell and the second type unit cell,
The third type unit cell is a full cell having a structure in which electrodes of different polarities are located at both ends of the unit cell,
Wherein the third type unit cell comprises a carbon-based material or a silicon-based oxide as a negative electrode active material. The stack-folding type electrode assembly according to claim 1, wherein the first type unit cell and the second type unit cell are bi-cells having electrodes of the same polarity positioned at both ends of the unit cell. The method of claim 2, wherein the first type unit cell is a bi-cell in which an anode is located at both ends of the unit cell, and the second type unit cell is a bi-cell in which a negative electrode is located at both ends of the unit cell Wherein the stacked electrode assembly is a stacked-type electrode assembly. The stack-folding type electrode assembly according to claim 3, wherein the first type unit cell includes a carbon-based material as an anode active material, and the second type unit cell includes a silicon-based oxide as a negative electrode active material. The stack-folding type electrode assembly according to claim 3, wherein the second type unit cell comprises a carbonaceous material as a negative electrode active material, and the first type unit cell comprises a silicon oxide as a negative electrode active material. The stack-folding type electrode assembly according to claim 3, wherein the total number of the second type unit cells is equal to or greater than the total number of the first type unit cells. delete delete delete delete delete The stack-folding type electrode assembly according to claim 1, wherein the carbon-based material is graphite. delete The stack-folding type electrode assembly according to claim 1, wherein the anode comprises a lithium cobalt-based oxide represented by the following formula (1)
Li _x (Co _(1-a) M _a ) O _2-y A _y (1)
In this formula,
M is at least one element selected from the group consisting of Ca, Zr, Mo, Fe, Cr, Ti, Zn, V, Al,
A is an element selected from the group consisting of F, S and N,
0.8? X? 1.2, 0? A? 0.2, 0? Y? 15. The method of claim 14 wherein the lithium cobalt oxide has a stack, characterized in that LiCoO ₂ - folding type electrode assembly. The stack-folding type electrode assembly according to claim 1, wherein the anode comprises a lithium nickel-manganese-cobalt oxide represented by the following formula (2)
Li _{1 + x '} Ni _{1- (a' + b + c)} Mn _{a '} Co _b M _c O _2-y A _y (2)
In this formula,
M is at least one element selected from the group consisting of Ca, Zr, Mo, Fe, Cr, Ti, Zn, V, Al,
A is an element selected from the group consisting of F, S and N,
0? X? 0.2, 0? Y? 0.1, 0.05? A? 0.6, 0.1? B? 0.4, 0? C? 0.2, and a '+ b + c < 17. The method of claim 16, wherein the lithium nickel-manganese-cobalt oxide is selected from the group consisting of LiNi _1/3 Mn _1/3 Co _1/3 O ₂ , LiNi _0.7 Mn _0.05 Co _0.25 O _2, and LiNi _0.8 Mn _0.1 Co _0.1 O ₂ &Lt; / RTI &gt; is selected from the group consisting of: A secondary battery comprising a stack-folding type electrode assembly according to any one of claims 1 to 6, 12 and 14 to 17. The battery module according to claim 18, wherein the secondary battery comprises a unit cell. A battery pack comprising the battery module according to claim 19. A device comprising a battery pack according to claim 19. 22. The device of claim 21, wherein the device is a computer, a mobile phone, a power tool, an electric vehicle (EV), a hybrid electric vehicle, a plug- Lt; / RTI &gt; system.

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