KR102340100B1 - Electrode for secondary battery and secondary battery comprising the same - Google Patents

Abstract

The present invention relates to an electrode for a secondary battery and a secondary battery including the same, and more particularly, to an electrode for a secondary battery having a multilayer structure and a secondary battery including the same.
An electrode for a secondary battery according to an embodiment of the present invention includes a first current collector; a first electrode mixture layer positioned on the first current collector; a separation layer positioned on the first electrode mixture layer; a second current collector positioned on the separation layer; and a second electrode mixture layer positioned on the second current collector.

Description

Electrode for a secondary battery and a secondary battery comprising the same

The present invention relates to an electrode for a secondary battery and a secondary battery including the same, and more particularly, to an electrode for a secondary battery having a multilayer structure and a secondary battery including the same.

As technology development and demand for mobile devices increase, the demand for secondary batteries as an energy source is rapidly increasing. Among such secondary batteries, there is a high demand for lithium secondary batteries having high energy density, high discharge voltage, and output stability.

In particular, lithium secondary batteries used as power sources for electric vehicles (EVs) and hybrid electric vehicles (HEVs) require high energy density and characteristics capable of exhibiting large output in a short time.

In general, a lithium secondary battery is manufactured by using a material capable of intercalating and deintercalating lithium ions as a negative electrode and a positive electrode, charging an organic electrolyte or a polymer electrolyte between the positive electrode and the negative electrode, and lithium ions are inserted from the positive electrode and the negative electrode Electrical energy is generated by oxidation and reduction reactions during intercalation and deintercalation.

At this time, the negative electrode and the positive electrode include an electrode mixture layer formed on the current collector of each electrode, and for example, a slurry is prepared by mixing and stirring a binder and a solvent, a conductive material, and a dispersing agent, if necessary, in the electrode active material. After that, it is applied to a current collector made of a metal material, compressed and dried to manufacture an electrode.

Such a conventional conventional electrode is manufactured by coating the electrode slurry once on the current collector of each electrode. That is, a conventional electrode is manufactured through a heat treatment process after applying a slurry in which an electrode active material, a binder, and a conductive material are properly mixed on a positive electrode or a negative electrode current collector. That is, it has a structure in which an electrode mixture layer including a binder and a conductive material is formed on a positive electrode or negative electrode current collector.

In this structure, when the thickness of the electrode mixture layer is increased to increase the capacity of the battery, the transfer path of lithium ions is lengthened, so that insertion and desorption of lithium from the current collector into the active material far from the current collector occurs, and the electrons through the current collector movement is restricted. In addition, the binder included in the electrode mixture layer is relatively light, so it is not evenly dispersed in the electrode mixture layer, and a phenomenon occurs on the surface. This is because the thicker the electrode mixture layer, the more severe the separation. Due to the separation of the current collector and the active material according to the change in volume, the cycle characteristics of the battery and the lifespan are unavoidable.

In order to solve these problems, conventionally, techniques such as multi-layer coating of electrode mixture layers having various porosity, types of electrode active materials, etc. have been developed. However, this structure also has a limitation in the amount of loading, and it is not possible to obtain desired levels of electronic conductivity and ionic conductivity, and there is a problem in that the electrode strength is reduced due to an increase in the thickness of the electrode mixture layer.

Accordingly, in order to manufacture an electrode having an improved energy density by increasing loading, there is a high need for an electrode technology having a new structure capable of solving the above problems.

KR 10-2017-0039976 A

The present invention provides an electrode for a secondary battery that has improved energy density and can prevent concentration imbalance in the electrode, and a secondary battery including the same.

An electrode for a secondary battery according to an embodiment of the present invention includes a first current collector; a first electrode mixture layer positioned on the first current collector; a separation layer positioned on the first electrode mixture layer; a second current collector positioned on the separation layer; and a second electrode mixture layer positioned on the second current collector.

The second current collector may include a plurality of through holes.

The through hole may accommodate a portion of at least one of the separation layer and the second electrode mixture layer therein.

The second current collector may have a three-dimensional mesh structure.

The separation layer may be formed of a porous polymer.

The porous polymer material may include a copolymer (PVdF-HFP) of polyvinylidene fluoride (PVdF) and hexafluoropropylene (HFP).

The hexafluoropropylene (HFP) may be contained in an amount of 3 to 25% by weight based on the total weight of the copolymer (PVdF-HFP) of polyvinylidene fluoride (PVdF) and hexafluoropropylene (HFP).

The separation layer may have a thickness of 0.1 to 10㎛.

The first electrode mixture layer and the second electrode mixture layer may include an active material having the same polarity.

The first electrode mixture layer and the second electrode mixture layer may be formed of the same material.

The first electrode mixture layer and the second electrode mixture layer may have the same thickness.

a first lead electrically connected to the first current collector; and a second lead electrically connected to the second current collector.

The first lead and the second lead may be electrically separated to be individually connected to an external conductor.

In addition, a secondary battery according to an embodiment of the present invention is a secondary battery including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, wherein at least one of the positive electrode and the negative electrode includes the above-described at least one secondary battery electrode do.

The secondary battery may include a lithium secondary battery.

According to the electrode for a secondary battery according to an embodiment of the present invention and a secondary battery including the same, by stacking a plurality of electrode mixture layers to form an electrode for a secondary battery in a multi-layer structure, while having an improved energy density, resistance increase due to this can be prevented. can

In addition, it is possible to design the electrode mixture layer forming the multilayer structure to have the same density, so that lithium ion (Li ⁺ ) It is possible to accurately analyze the concentration distribution in the movement direction, that is, in the vertical direction, and from this, it is possible to predict the concentration imbalance in the electrode and use it in designing an electrode having a high energy density.

1 is a view showing a state of a general electrode for a secondary battery.
2 is a view showing a cross-section of an electrode for a secondary battery according to an embodiment of the present invention.
3 is a view showing the appearance of a first current collector and a second current collector according to an embodiment of the present invention.

The electrode for a secondary battery according to the present invention and a secondary battery including the same present technical features that can be used in electrode design by measuring the concentration imbalance in the electrode when manufacturing a high energy density battery.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, and only the embodiments of the present invention allow the disclosure of the present invention to be complete, and the scope of the invention to those of ordinary skill in the art It is provided to fully inform

When it is referred to throughout the specification that one component, such as a film, region, or substrate, is located "on" another component, the one component directly contacts "on" another component, or between them. It may be construed that there may be other components intervening in the .

Also, relative terms such as "upper" or "lower" may be used herein to describe the relative relationship of certain elements to other elements as shown in the drawings. It may be understood that relative terms are intended to include other orientations of the element in addition to the orientation depicted in the drawings. In the drawings, like numbers refer to like elements.

1 is a view showing a state of a general electrode for a secondary battery.

Referring to FIG. 1 , a typical secondary battery electrode is manufactured through a heat treatment process after applying a slurry in which an electrode active material, a binder, and a conductive material are properly mixed on a positive electrode or negative electrode current collector. That is, it has a structure in which the electrode mixture layer 2 including a binder and a conductive material is formed on the positive or negative electrode current collector 1 .

In this structure, when the thickness of the electrode mixture layer 2 is increased to increase the capacity of the battery, the transfer path of lithium ions is lengthened, so that the intercalation and desorption of lithium into the active material far from the current collector 1 ( deintercalation) occurs, and concentration imbalance is deepened along the transfer direction of lithium ions, resulting in a lithium-plating phenomenon in which lithium ions cannot be inserted into the electrode mixture layer 2 during charging and are precipitated. There was a problem being

In order to minimize the lithium-plating phenomenon and to realize an electrode having an improved energy density, it is necessary to prevent a concentration imbalance inside the electrode.

To this end, in the prior art, a technique such as multi-layer coating of an electrode mixture layer having various porosity, type of electrode active material, etc. has been developed. However, this structure also has a problem in that it is difficult to measure the concentration of only the electrode mixture layer, as well as a limit in the loading amount, resulting in additional concentration imbalance.

Accordingly, in order to manufacture an electrode with improved energy density by increasing loading, the necessity of predicting the concentration imbalance in the electrode as a means for solving the above problems is increasing.

2 is a view showing a cross-section of an electrode for a secondary battery according to an embodiment of the present invention, and FIG. 3 is a view showing a first current collector and a second current collector according to an embodiment of the present invention.

2 and 3 , an electrode for a secondary battery according to an embodiment of the present invention includes a first current collector 10; a first electrode mixture layer 20 positioned on the first current collector 10; a separation layer 30 positioned on the first electrode mixture layer; a second current collector 40 positioned on the separation layer 30; and a second electrode mixture layer 50 positioned on the second current collector 40 .

The first current collector 10 has a first electrode mixture layer 20 formed on one surface, so that electrons provided from an external conductive wire (not shown) are supplied to the first electrode mixture layer 20 , or a result of an electrode reaction is generated It plays a role in discharging the electrons to the external conductor.

The first current collector 10 is a metal having high conductivity, and is easily adhered to the first electrode mixture layer 20 , and any type of metal may be used as long as it does not cause a chemical change in the voltage range of the battery. For example, copper, gold, iron, stainless steel, aluminum, nickel, titanium, calcined carbon, or a surface treated with carbon, nickel, titanium or silver on the surface of aluminum or stainless steel may be used, but the present invention is limited thereto. doesn't happen In addition, the thickness of the first current collector 10 is not particularly limited, and, for example, a thickness of 3 μm to 500 μm may be used.

The first electrode mixture layer 20 is formed and positioned on the first current collector 10 . The first electrode mixture layer 20 is formed of an electrode active material and a binder, and may further include a conductive material if necessary. Here, the electrode active material may be a positive active material or a negative active material depending on the polarity of the electrode for a secondary battery.

Among the electrode active materials, as the positive electrode active material, an active material generally used for the positive electrode of a secondary battery may be used. For example, _a lithium transition metal composite oxide such as _{LiM x} O _y (M = Co, Ni, Mn, Co a Ni _b Mn _c ) (eg, lithium manganese composite oxide such as _{LiMn 2} O _{4 , LiNiO 2 ,} etc.) Lithium nickel oxide _{of lithium cobalt oxide, LiCoO 2,} etc. and manganese, nickel, and cobalt of these oxides partially substituted with other transition metals, or vanadium oxide containing lithium) or chalcogen compounds (e.g., manganese dioxide, titanium disulfide, molybdenum disulfide, etc.) may be used. Specifically, LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , Li(Ni _a Co _b Mn _c )O ₂ (0<a<1, 0<b<1, 0<c<1, a+b _{+ c = 1), LiNi 1} - Y Co Y O 2, LiCo 1 -Y O 2, LiCo 1-Y Mn Y O 2, LiNi 1 - Y Mn Y O 2 ( here, 0≤Y≤1), _{Li (Ni a Co b Mn c} ) O 4 (0 <a <2, 0 <b <2, 0 <c <2, a + b + c = 2), LiMn 2 - Z Ni Z O 4, LiMn 2 _{- Z} Co _Z O (here, 0<Z<2), LiCoPO ₄ , LiFePO ₄ or a mixture thereof, etc. may be used, but is not limited thereto.

In addition, as the negative electrode active material among the electrode active materials, an active material generally used for the negative electrode of a secondary battery may be used. For example, a lithium adsorption material such as lithium alloy, carbon, petroleum coke, activated carbon, graphite, or other carbons may be used, and the potential for lithium _{A metal oxide such as TiO 2} , SnO _{2 ,} or Li ₄ Ti ₅ O ₁₂ having a value of less than 2V may be used, but is not limited thereto.

With respect to the electrode active material, the binder may be appropriately used in an amount of 1 to 10% by weight, and the conductive material may be used in an amount of 1 to 30% by weight based on the total weight of the electrode active material. Examples of binders that can be used include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), polyvinyl acetate, polyethylene oxide, polypyrrolidone, polyvinyl alcohol, polyacrylnitrile, polyacrylic acid ( polyacrylic acid, PAA), carboxymethylcellulose (CMC), and an aqueous binder such as styrene-butadiene rubber (SBR).

As the conductive material, carbon black may be generally used. Products currently marketed as conductive agents include acetylene black series (such as Chevron Chemical Company or Gulf Oil Company products). There are Ketjen Black EC series (products from Armak Company), Vulcan XC-72 (products from Cabot Company, etc.) and Super P (products from MMM), and also carbon nano tube, carbon (nano) There are also linear conductive materials such as fibers.

The first electrode mixture layer 20 may be formed on the current collector 10 by a method generally used. For example, the electrode active material is prepared by mixing a binder and a solvent, optionally a conductive material, and a dispersing agent, followed by stirring to prepare a slurry, and then applying the electrode slurry to one surface of the current collector of the present invention, compressing it, and drying it. can The method for applying the electrode slurry to the current collector is not particularly limited, and for example, it can be applied by a doctor blade, dipping, brushing, etc., and the amount of application is not particularly limited, but the electrode active material layer formed after removing the solvent or dispersion medium It may be an amount such that the thickness of is usually 0.005 to 5 mm, specifically, 0.05 to 2 mm.

The method of removing the solvent or the dispersion medium is not particularly limited, but stress concentration occurs and cracks occur in the first electrode mixture layer 20 , or the first electrode mixture layer 20 does not peel from the current collector 10 . Within the speed range of the degree, a method of adjusting and removing the solvent or dispersion medium to volatilize as quickly as possible may be used. For example, it may be dried in a vacuum oven at 50 to 200 ℃ for 0.5 to 3 days.

The separation layer 30 is formed and positioned on the first electrode mixture layer 20 . The separation layer 30 may be formed on the entire surface of the first electrode mixture layer 20 , and between the first electrode mixture layer 20 and the second electrode mixture layer 30 , lithium ions (Li ⁺ ) However, electrons supplied to the first electrode mixture layer 20 move to the second current collector 30 and are blocked from being transferred to the second electrode mixture layer 40 .

To this end, the separation layer 30 may be formed of a porous polymer. As such a porous polymer material, for example, polyvinylidene fluoride (PVdF), polyvinyl acetate, polyvinyl alcohol, polyvinyl ether, polyethylene, polyethylene oxide, alkylated polyethylene oxide, polypropylene, polymethyl (meth) Acrylate, polyethyl (meth)acrylate, polytetrafluoroethylene (PTFE), polyvinyl chloride, polyacrylonitrile, polyvinylpyridine, polyvinylpyrrolidone, styrene-butadiene rubber, acrylonitrile-butadiene rubber , ethylene-propylene-diene monomer (EPDM) rubber, sulfonated EPDM rubber, styrene-butylene rubber, fluororubber, carboxymethylcellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, and at least one selected from the group consisting of mixtures thereof; Alternatively, an olefin-based polymer such as polyethylene or polypropylene, glass fiber, etc. may be used, but preferably a copolymer of polyvinylidene fluoride (PVdF) and hexafluoropropylene (PVdF-HFP) may be used.

That is, the separation layer 30 may be formed of a copolymer of polyvinylidene fluoride (PVdF) and hexafluoropropylene (PVdF-HFP), and hexafluoropropylene (HFP) is a copolymer (PVdF-HFP). When the content is less than 3% by weight based on the total weight, the ^{conductivity of lithium ions (Li +} ) is rapidly reduced, and when hexafluoropropylene (HFP) exceeds 25% by weight, interfacial stability and heat resistance are reduced, Hexafluoropropylene (HFP) may be contained in an amount of 3 to 25 wt% based on the total weight of the copolymer (PVdF-HFP).

The separation layer 30 may be formed by coating the above-described porous polymer material on the first electrode mixture layer 20 . The porous polymer material may be coated on the first electrode mixture layer 20 in a state of being dissolved by an organic solvent such as acetone, and the organic solvent may be removed after application to form the separation layer 30 . Here, the separation layer 30 may have a thickness of 0.1 to 10 μm. When the thickness of the separation layer 30 is less than 0.1 μm, the effect of blocking electrons supplied to the first electrode mixture layer 20 from being transferred to the second electrode mixture layer 40 is insignificant, and the separation layer 30 . ^{When the thickness of is more than 10㎛, it is difficult to pass lithium ions (Li +} ) between the first electrode mixture layer 20 and the second electrode mixture layer 30, the separation layer 30 is 0.1 to 10㎛ It is preferable to form to a thickness of

The second current collector 40 is located on the separation layer 30 , and supplies electrons provided from an external conductive wire to the second electrode mixture layer 50 formed on the second current collector 40 , or electrode reaction. It plays a role in discharging electrons generated as a result of

Here, the second current collector 40 may include a plurality of through holes 45 . That is, as shown in FIG. 3 , in the second current collector 40 , a plurality of through-holes 45 are formed to be uniformly or irregularly spaced apart from each other. A plurality of through-holes 45 to form a moving path of the lithium ions (Li ^+), the second current collector 40, the surface and cross plurality of through to move uniformly lithium ion (Li ⁺⁾ in the direction of The holes 45 may be formed to be spaced apart from each other at regular intervals.

As such, in order to form the through hole 45 in the second current collector 40 , various methods for forming the through hole 45 in the metal foil may be used. For example, the plurality of through holes 45 may be formed in the metal foil by press working, or the plurality of through holes 45 may be formed by applying and etching a photosensitive film or ink to the metal foil. In addition, the through-hole 45 may be formed together when the metal foil is manufactured. For example, in the case of a copper foil, the through-hole 45 may be formed through an electrochemical method.

Here, the plurality of through holes 45 accommodate a portion of at least one of the separation layer 30 and the second electrode mixture layer 50 therein. That is, the second current collector 40 is formed on the separation layer 30 , and is applied in the form of an electrode slurry on the second current collector 40 to form the second electrode mixture layer 50 as will be described later. The interior of the plurality of through-holes 45 is filled with a partial material of at least one of the separation layer 30 and the second electrode mixture layer 50 . As described above, the plurality of through holes 45 accommodate a portion of at least one of the separation layer 30 and the second electrode mixture layer 50 therein, so that the second electrode is stacked on the second current collector 40 . The mixture layer 50 can be firmly bonded to the second current collector 40 , and the second electrode mixture layer 50 is prevented from peeling off due to repetition of expansion and contraction according to repeated charging and discharging of the battery. can do.

In addition, in order to provide a movement path of lithium ions (Li ⁺ ), the second current collector 40 may have a three-dimensional mesh structure. As such, when the second current collector 40 has a three-dimensional mesh structure, the first electrode mixture layer 20 and the second electrode mixture layer ( 50), lithium ions (Li ⁺ ) can move between them.

The same content as that of the first current collector 10 may be applied to the second current collector 40 , except for the plurality of through-holes 45 that are formed therethrough. That is, the second current collector 40 is a metal with high conductivity, and is easily adhered to the second electrode mixture layer 50, and any type of metal can be used as long as it does not cause a chemical change in the voltage range of the battery. , in this case, copper, gold, iron, stainless steel, aluminum, nickel, titanium, calcined carbon, or the surface of aluminum or stainless steel surface-treated with carbon, nickel, titanium or silver, etc. can be used as described above. same. In addition, the thickness of the second current collector 40 is not particularly limited, and for example, a thickness of 3 μm to 500 μm may be used, which is the same as in the case of the first current collector 10 .

The second electrode mixture layer 50 is formed and positioned on the second current collector 40 . The second electrode mixture layer 50 is formed of an active material, that is, an electrode active material and a binder, and may further include a conductive material if necessary. Here, as the electrode active material, a positive active material or a negative active material may be used depending on the polarity of the electrode for a secondary battery, and the electrode active material, binder, and conductive material are the same as in the case of the first electrode mixture layer 20 described above, so overlapping A description will be omitted.

Here, the first electrode mixture layer 20 and the second electrode mixture layer 50 may include an active material having the same polarity. That is, when the first electrode mixture layer 20 includes a positive electrode active material, the second electrode mixture layer 50 may also include a positive electrode active material, and the first electrode mixture layer 20 includes a negative electrode active material. In this case, the second electrode mixture layer 50 may also include an anode active material. Also, the first electrode mixture layer 20 and the second electrode mixture layer 50 may be formed of the same material. That is, when the first electrode mixture layer 20 includes a negative active material made of carbon, the second electrode mixture layer 50 may also include an anode active material made of carbon, and the same binder and A conductive material may be used. In addition, the first electrode mixture layer 20 and the second electrode mixture layer 50 may have the same thickness. In this way, by forming the material or thickness of the first electrode mixture layer 20 and the second electrode mixture layer 50 to be the same, resistance and current distribution (current) according to the thickness of the material or electrode mixture layer constituting the electrode mixture layer distribution) can be checked. In addition, the first electrode mixture layer 20 and the second electrode mixture layer 50 are formed of the same material, and the first electrode mixture layer 20 and the second electrode mixture layer 50 are formed to have the same thickness. ^{When designing to have the same density, the movement direction of lithium ions (Li +} ), that is, the vertical direction, through the measurement of resistance and current distribution of each electrode mixture layer 20 and 50 during charging or discharging of the secondary battery It is possible to more accurately analyze the concentration distribution in

In the above, the state in which the electrode for a secondary battery is formed in the two-layer structure of the first electrode mixture layer 20 and the second electrode mixture layer 50 is illustrated and described as an example, but the electrode for a secondary battery according to an embodiment of the present invention It goes without saying that the silver electrode mixture layer may be formed by stacking three or more layers. In this case, a separation layer and ^{a current collector positioned on the separation layer to provide a movement path of lithium ions (Li +} ) are formed between each electrode mixture layer, and lithium ions (Li ⁺ ) pass between each electrode mixture layer However, it blocks electrons from moving and being transmitted.

Hereinafter, a structure in which an external conductive wire is connected to the electrode for a secondary battery according to an embodiment of the present invention will be described.

Referring to FIG. 3 , an electrode for a secondary battery according to an embodiment of the present invention includes a first lead 17 electrically connected to a first current collector 10 ; and a second lead 47 electrically connected to the second current collector 40 . Here, the first lead 17 is electrically connected to the external conductive wire, and serves to supply electrons provided from the external conductive wire to the first electrode mixture layer 20 or to discharge electrons generated as a result of the electrode reaction to the external conductive wire. and the second lead 47 is electrically connected to the external conductor to supply electrons provided from the external conductor to the second electrode mixture layer 50, or to discharge electrons generated as a result of the electrode reaction to the external conductor. plays a role The first lead 17 and the second lead 47 may be formed to extend from the first current collector 10 and the second current collector 40, respectively, and the first current collector 10 and the second current collector, respectively. It may be formed integrally with the whole 40 .

Here, the first lead 17 and the second lead 47 are electrically separated so as to be individually connected to the external conductor. That is, when the first lead 17 is electrically connected to the external conductive wire, the second lead 47 may or may not be electrically connected to the external conductive wire. Also, when the second lead 47 is electrically connected to the external conductive wire, the first lead 17 may or may not be electrically connected to the external conductive wire. Accordingly, electrons may be individually supplied to the first electrode mixture layer 20 and the second electrode mixture layer 50 , or electrons may be individually discharged.

For example, when an external conductive wire is connected to the first lead 17 and an external conductive wire is not connected to the second lead 47 , electrons are transferred to the first electrode mixture layer 20 through the first lead 17 . is supplied, and the electrons supplied to the first electrode mixture layer 20 are blocked from moving to the second electrode mixture layer 50 by the separation layer 30 . That is, the first electrode mixture layer 10 and the second electrode mixture layer 50 are electrically insulated by the ^{separation layer 30 , and only lithium ions (Li +} ) are separated from the separation layer 30 and the second current collector ( 40) will move through.

In addition, when both the first lead 17 and the second lead 47 are connected to an external conductive wire, electrons are supplied to the first electrode mixture layer 20 through the first lead 17, and the second lead ( 47), electrons are supplied to the second electrode mixture layer 50 . The electrons supplied to each electrode mixture layer are blocked from moving to the other electrode mixture layer, and ^{only lithium ions (Li +} ) move through the separation layer 30 and the second current collector 40 .

The electrode for a secondary battery according to an embodiment of the present invention described above may be used in any device that undergoes an electrochemical reaction. For example, it may be used in all kinds of secondary batteries, fuel cells, solar cells, capacitors, and the like, and among them, it may be particularly suitably used in secondary batteries. Here, the secondary battery may include a lithium secondary battery, and the lithium secondary battery includes a lithium ion secondary battery, a lithium polymer secondary battery, or a lithium ion polymer secondary battery.

Such a secondary battery includes a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, wherein at least one of the positive electrode and the negative electrode may be an electrode for a secondary battery according to the above-described embodiment of the present invention. In addition, the secondary battery may include an electrolyte, and the electrolyte may include a non-aqueous solvent and an electrolyte salt.

The non-aqueous solvent is not particularly limited as long as it is commonly used as a non-aqueous solvent for the non-aqueous electrolyte, and cyclic carbonates, linear carbonates, lactones, ethers, esters or ketones may be used.

Examples of the cyclic carbonate include ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BE), and the like, and examples of the linear carbonate include diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), ethylmethyl carbonate (EMC) and methylpropyl carbonate (MPC). Examples of the lactone include gamma butyrolactone (GBL), and examples of the ether include dibutyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane, and the like. There is this. In addition, examples of the ester include n-methyl acetate, n-ethyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, methyl pivalate, and the like, and the ketone is polymethyl There are vinyl ketones. These non-aqueous solvents can be used individually or in mixture of 2 or more types.

The electrolyte salt is not particularly limited as long as it is usually used as an electrolyte salt for a nonaqueous electrolyte. Examples of the electrolyte salt include a salt having a structure such as ^{A +} B ^{- , A +} includes an ion consisting of an alkali metal cation such as ^{Li +} , Na ⁺ , K ^{+ or a combination thereof, and B -} is PF ₆ ^- , BF ₄ ^- , Cl ^- , Br ^- , I ^- , ClO ₄ ^- , AsF ₆ ^- , CH ₃ CO ₂ ^- , CF ₃ SO ₃ ^- , N(CF ₃ SO ₂ ) ₂ ^- , C(CF ₂ SO ₂ ) ₂ ^It is a salt containing an ion consisting of an anion such as - or a combination thereof. As an example, a lithium salt may be used. These electrolyte salts can be used individually or in mixture of 2 or more types.

A secondary battery according to an embodiment of the present invention may include a separator. The usable separator is not particularly limited, but it is preferable to use a porous separator, and for example, a polypropylene-based, polyethylene-based or polyolefin-based porous separator may be used.

In addition, the secondary battery of the present invention is not limited in appearance, but may have a cylindrical shape using a can, a prismatic shape, a pouch type, or a coin shape.

As described above, according to the electrode for a secondary battery according to an embodiment of the present invention and a secondary battery including the same, by stacking a plurality of electrode mixture layers to form an electrode for a secondary battery in a multilayer structure, while having an improved energy density, resistance is increased due to this can prevent

In addition, it is possible to design the electrode mixture layer forming the multilayer structure to have the same density, so that lithium ion (Li ⁺ ) It is possible to accurately analyze the concentration distribution in the movement direction, that is, in the vertical direction, and from this, it is possible to predict the concentration imbalance in the electrode and use it in designing an electrode having a high energy density.

In the above, preferred embodiments of the present invention have been described and illustrated using specific terms, but such terms are only for clearly explaining the present invention, and the embodiments of the present invention and the described terms are the spirit of the following claims And it is obvious that various changes and changes can be made without departing from the scope. Such modified embodiments should not be individually understood from the spirit and scope of the present invention, but should be said to fall within the scope of the claims of the present invention.

10: first current collector 17: first lead
20: first electrode mixture layer 30: separation layer
40: second current collector 45: through hole
47: second lead 50: second electrode mixture layer

Claims (15)

a first current collector;
a first electrode mixture layer positioned on the first current collector;
a separation layer disposed on the first electrode mixture layer and formed of an electrically insulating polymer material having porosity;
a second current collector including a plurality of through holes and positioned on the separation layer; and
Including; a second electrode mixture layer positioned on the second current collector;
The first electrode mixture layer and the second electrode mixture layer include an active material having the same polarity among the positive electrode and the negative electrode,
The separation layer is an electrode for a secondary battery formed on the entire surface of the first electrode mixture layer to block the movement of electrons between the first electrode mixture layer and the second electrode mixture layer.
delete The method according to claim 1,
The through hole is an electrode for a secondary battery accommodating a portion of at least one of the separation layer and the second electrode mixture layer therein.
delete delete The method according to claim 1,
The electrically insulating polymer material is a secondary battery electrode comprising a copolymer (PVdF-HFP) of polyvinylidene fluoride (PVdF) and hexafluoropropylene (HFP).
7. The method of claim 6,
The hexafluoropropylene (HFP) is a secondary battery electrode containing 3 to 25% by weight based on the total weight of the copolymer (PVdF-HFP) of polyvinylidene fluoride (PVdF) and hexafluoropropylene (HFP) .
The method according to claim 1,
The separation layer is an electrode for a secondary battery having a thickness of 0.1 to 10㎛.
delete The method according to claim 1,
The electrode for a secondary battery in which the first electrode mixture layer and the second electrode mixture layer are formed of the same material.
The method according to claim 1,
The first electrode mixture layer and the second electrode mixture layer have the same thickness as an electrode for a secondary battery.
The method according to claim 1,
a first lead electrically connected to the first current collector; and
A secondary battery electrode further comprising a; a second lead electrically connected to the second current collector.
13. The method of claim 12,
The first lead and the second lead are electrically separated from each other so as to be individually connected to an external conductive wire.
A secondary battery comprising a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode,
At least one of the positive electrode and the negative electrode is a secondary battery comprising the secondary battery electrode of any one of claims 1, 3, 6 to 8, and 10 to 13.
15. The method of claim 14,
The secondary battery is a secondary battery including a lithium secondary battery.

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