KR20170138636A - Method for Electrode Assembly of Irregular Structure and Electrode Assembly Having Irregular Structure - Google Patents

Abstract

The present invention provides a manufacturing method capable of fundamentally eliminating the problem caused by foreign matter flowing into a separation membrane by cutting a plurality of separation membranes in a desired shape in a state in which the plurality of separation membranes are joined so as to minimize the generation of the foreign matter. The present invention also provides an electrode assembly having an irregular structure applicable to devices of various designs.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of manufacturing an electrode assembly having an irregular structure,

The present invention relates to a method of manufacturing an electrode assembly having an irregular structure and an irregular electrode assembly.

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

Lithium battery cells occupy an important position in the development base for such a ubiquitous society. Specifically, lithium battery cells that can be charged and discharged are widely used as energy sources for wireless mobile devices or wearable electronic devices to be worn on the body, as well as air pollution such as 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 battery cells are applied are diversified, the lithium battery cells are diversified so as to provide an appropriate output and capacity for the applied devices. In addition, miniaturization is strongly demanded.

The lithium battery cell is manufactured in consideration of the size and shape of a device using the same as a power source. In recent years, a variety of products using a lithium battery cell have been developed. In order to be applicable to various devices having curved or curved surfaces, It is manufactured from at least five polygonal or geometric irregular designs.

1 and 2 show an exemplary electrode assembly of an irregular structure.

1 and 2, the electrode assembly 10 has a structure in which an anode 2, a separator 3a, a cathode 6, a separator 3b, and an anode 4 are sequentially stacked, It has a hexagonal structure with six interior angles.

It has four internal angles in a plane, and it can be seen that the overall shape of the hexahedron is more complicated than that of the rectangular structure while having more cabinets in a plane, compared with the rectangular structure. It can be called irregular.

In the present invention, the electrode structure shown in FIG. 1 is defined as an electrode assembly having an irregular structure under this concept.

Referring back to FIGS. 1 and 2, each of the electrodes 2, 4, and 6 has a shape in which the bottom edge is oblique with respect to the direction guides (x, y) The separation membranes 3a and 3b are relatively large in size relative to the electrodes 2, 4 and 6 because of contact between the electrodes 2 and 4 and 6 and blocking of foreign matter.

In manufacturing such an electrode assembly, the separation membranes 3a and 3b are stacked together with the electrodes 2, 4 and 6 so as to correspond to the bottom edge shapes of the electrodes 2, 4 and 6, Cut along the imaginary cutting line C, the separation membrane fragments generated at this time may be introduced into the anode 2, 4 or the cathode 4 by static electricity, thereby deteriorating the quality of the electrode.

In order to solve this problem, it is necessary to visually check the foreign object and remove foreign matters from the separator through manpower. However, the structure of the electrode may be damaged in this process, which may deteriorate the quality of the electrode assembly.

Therefore, there is a high need for a method capable of more stably manufacturing an irregular electrode assembly and an electrode assembly applicable to a more various devices as an irregular structure.

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 provide a manufacturing method capable of fundamentally eliminating the problem caused by foreign matter flowing into a separation membrane by cutting the separation membrane into a desired shape in a state in which a plurality of separation membranes are bonded so as to minimize the generation of foreign matter.

It is yet another object of the present invention to provide an unshaped electrode assembly having a stable structure.

According to an aspect of the present invention,

CLAIMS What is claimed is: 1. A method of fabricating an electrode assembly of an irregular structure consisting of at least six outer peripheries,

(a) a first separator interposed between the first electrode and the second electrode, the first separator having a plane area of 110% to 150% relative to any one of the electrodes, and a second separator interposed between the first electrode and the second electrode, A process of laminating the separator and electrodes;

(b) a second separator interposed between the second electrode and the third electrode having a plane area of 110% to 150% with respect to any one of the electrodes, and a second separator interposed between the second electrode and the third electrode, And laminating the electrodes;

(c) the outer peripheral surfaces of the first and second separation membranes adjacent to the outer periphery protruding from the outer peripheries of the first and second separation membranes at an angle of 30 to 60 degrees with respect to the outer periphery of the adjacent electrodes, Lamination process;

(d) cutting the laminated outer circumferential surfaces so that the outer peripheries of 0 to 10 degrees with respect to the outer periphery of the electrode in the step (c) are formed in the first and second separation membranes .

That is, in the manufacturing method of the present invention, the first separation membrane and the second separation membrane are not cut, but are mutually laminated and fused, that is, the fiber structures of the separation membranes are cut in a cured state, The degree of occurrence of foreign matter can be remarkably reduced and the separation membrane in which the fiber structure is hardly cured can not be easily induced by static electricity so that even if a small amount of foreign matter is generated, the inevitable phenomenon that foreign matter is adsorbed on the electrode can be considerably mitigated.

Particularly, since static electricity is hardly involved in the electrode adsorption of the foreign object, foreign matter can be removed from the surface of the electrode by a simple method such as blowing air.

In one specific example, the first separator and the second separator in the process (a) to the process (c) have a rectangular planar shape, and the first separator and the second separator in the step (d) Lt; / RTI >

That is, in the present invention, the first separator and the second separator, which are initially rectangular, are cut into a shape substantially corresponding to the electrodes in the step (d) to be processed into an amorphous structure, It should be noted that the cutting process is easy and the manufacturing process is excellent while the occurrence of foreign matter is reduced, and the electrode assembly of good products can be manufactured.

The lamination defined in the present invention means a process in which heat is applied to the surfaces of the separator and the electrodes in the state of surface contact and the surfaces of the separator and the separator are in contact with each other to bond them to each other.

The separation membrane is composed of an insulating thin polymer membrane having high ion permeability and mechanical strength, and the pore diameter is generally 0.01 to 10 mu m and the thickness may be generally 5 to 300 mu m. When two or more separation membranes made of polymer are bonded by heat, the fiber structure of the polymer is solidified, so that the phenomenon of the separation of fine particles into pieces can be reduced.

Examples of the polymer constituting the separation membrane include olefin polymers such as polypropylene having chemical resistance and hydrophobicity; A sheet or nonwoven fabric made of glass fiber, polyethylene, or the like can be used.

In some cases, the separator may be formed of an oil / inorganic complex porous SRS (Safety-Reinforcing Separator) membrane.

Such an SRS film does not cause high-temperature heat shrinkage due to the heat resistance of the inorganic particles. Even if the electrode assembly penetrates through the needle-like conductor, the elongation of the safety separator can be maintained.

The SRS separation membrane may have a structure in which inorganic particles and a binder polymer are coated on the polyolefin-based membrane substrate.

The SRS separation membrane may have a uniform pore structure formed by the interstitial volume between the inorganic particles, which is the active layer component, together with the pore structure included in the separation membrane substrate itself, The impact can be considerably alleviated, the lithium ion can smoothly move through the pores, a large amount of electrolyte can be filled, and a high impregnation rate can be exhibited, so that the performance of the battery can be improved at the same time.

The separator substrate and the active layer exist as anchoring between the pores on the surface of the polyolefin-based separator substrate and the active layer, so that the separator substrate and the active layer can physically and firmly bond to each other. Considering the bonding force and the pore structure existing on the separation membrane, it can have a thickness ratio of 9: 1 to 1: 9, and more specifically, a thickness ratio of 5: 5.

In the SRS separator, one of the active layer components formed on the surface of the polyolefin-based separator substrate and / or the pores of the substrate is an inorganic particle conventionally used in the art.

The inorganic particles enable the formation of voids between the inorganic particles to form micropores and serve as a kind of spacer capable of maintaining the physical shape. In addition, since the inorganic particles generally have a property that their physical properties do not change even at a high temperature of 200 DEG C or more, the formed organic / inorganic composite porous film has excellent heat resistance.

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

For the reasons stated above, the inorganic particles may be at least one selected from the group consisting of (a) inorganic particles having piezoelectricity and (b) inorganic particles having lithium ion transferring ability.

The piezoelectricity inorganic particle means a non-conductive material at normal pressure or a material having electrical conductivity due to a change in internal structure when a certain pressure is applied, and exhibits a high permittivity with a dielectric constant of 100 or more, The charge is generated in the case of applying tensile or compressive force, so that one side is charged positively and the other side is negatively charged, thereby generating a potential difference between both sides.

When inorganic particles having the above-described characteristics are used as a porous active layer component, if an internal short-circuit of both electrodes occurs due to an external impact such as a needle-like conductor, the anode and the cathode are directly Not only does not contact but also the potential difference in the particle occurs due to the piezoelectricity of the inorganic particles. As a result, the electrons move between the two electrodes, that is, the minute current flows, so that the voltage of the cell is reduced and the safety is improved .

Examples of the inorganic particles having piezoelectricity include BaTiO ₃ , Pb (Zr, Ti) O ₃ (PZT), Pb _{1 -x} La _x Zr _{1 -y} Ti _y O ₃ (PLZT), PB (Mg ₃ Nb _2/3 ) O ₃ -PbTiO ₃ (PMN-PT) and hafnia (HfO ₂ ), but the present invention is not limited thereto.

The inorganic particles having the lithium ion transferring ability refer to inorganic particles that contain a lithium element but do not store lithium but have a function of transferring lithium ions. The inorganic particles having lithium ion transferring ability exist in the particle structure Since lithium ions can be transferred and transferred due to a kind of defect, the lithium ion conductivity in the battery can be improved and the battery performance can be improved.

Examples of the inorganic particles having lithium ion transferring ability include lithium phosphate (Li ₃ PO ₄ ), lithium titanium phosphate (Li _x Ti _y (PO ₄ ) ₃ , 0 <x <2, 0 <y < titanium phosphate _{(Li x Al y Ti z (} PO 4) 3, 0 <x <2, 0 <y <1, 0 <z <3), (LiAlTiP) x O y series glass (0 <x <4, 0 <y <13), lithium lanthanum titanate _{(Li x La y TiO 3,} 0 <x <2, 0 <y <3), lithium germanium Mani help thiophosphate _{(Li x Ge y P z S} w, 0 <x (Li _x N _y , 0 <x <4, 0 <y <2), SiS ₂ (Li _x Si (0 <y <1, 0 <z < _{y S z, 0 <x <} 3, 0 <y <2, 0 <z <4) based glass, and _{P 2 S 5 (Li x P} y S z, 0 <x <3, 0 <y <3, 0 < z < 7) series glass, but the present invention is not limited thereto.

The composition ratio of the inorganic particles and the binder polymer as the active layer component is not particularly limited, but can be adjusted within a range of 10:90 to 99: 1 wt.%, And is preferably in a range of 80:20 to 99: 1 wt. When the ratio is less than 10: 90% by weight, the content of the polymer is excessively increased, resulting in a decrease in the pore size and porosity due to the reduction of the void space formed between the inorganic particles, , The mechanical properties of the final organic / inorganic composite porous membrane may be deteriorated due to the weakening of the adhesion between the inorganic materials because the polymer content is too small.

The active layer of the organic / inorganic composite porous separator may further include other commonly known additives in addition to the inorganic particles and polymers described above.

In the organic / inorganic composite porous separator, a substrate coated with a mixture of inorganic particles and a binder polymer as the active layer constituent may be a polyolefin-based separator commonly used in the art. Examples of the polyolefin-based separation membrane component include high-density polyethylene, linear low-density polyethylene, low-density polyethylene, ultra-high molecular weight polyethylene, polypropylene or derivatives thereof.

In one specific example, the first electrode and the third electrode are an anode or a cathode, and the second electrode may have a polarity different from that of the first electrode and the third electrode.

Accordingly, the electrode assembly manufactured by the method of the present invention can be applied to an A-type bi-cell structure in which an anode, a separator, a cathode, and a separator anode are sequentially laminated, or a C- Structure.

The A-type bi-cell generally refers to a bi-cell in which the polarity of an electrode located in an intermediate layer is an anode, and the C-type bi-cell has a polarity of an electrode located at an intermediate layer, Bicell.

The manufacturing method according to the present invention may further include a process of manufacturing a modified bi-cell type electrode assembly that further includes a separation membrane as well as the A-type bi-cell and the C-type bi-cell.

Specifically, in the step (a) of the manufacturing method, a third separator is further laminated on a surface of the first electrode on which the first separator is laminated, and in the step (c) 1 separator and the second separator may be further laminated on the outer peripheral surfaces of the first separator and the second separator.

Through this process, the electrode assembly may have a structure in which a third separation membrane, a first electrode, a first separation membrane, a second electrode, a second separation membrane, and a third electrode are sequentially stacked.

Similarly, in the process (b) of the manufacturing method, the fourth electrode may be further laminated on the opposite surface of the surface on which the second electrode is laminated, and in the process (c) 1 separator and the second separator may be further laminated on the outer peripheral surfaces of the first separator and the second separator.

Through this process, the electrode assembly may have a structure in which the first electrode, the first separator, the second electrode, the second separator, the third electrode, and the fourth separator are sequentially stacked.

In some cases, both the third and fourth separation membranes may be laminated to the first and third electrodes, respectively. In this state, the outer surfaces of the first and second separation membranes may be further laminated.

The third and fourth separators are disposed on the outermost electrode. When the third separator or the fourth separator located at the outermost portion of the electrode assembly passes through the needle-like conductor, The electrodes of mutually opposite polarities can be prevented from being directly energized through the needle-shaped conductors.

The present invention also provides an electrode assembly of an irregular structure applicable to various designs of devices.

Specifically, the electrode assembly is a structure in which n (n &gt; = 3) irregular electrodes composed of at least six outer peripheries in a plane are stacked with n, n-1, or n + 1 separators Each of the separation membranes having an area of 110% to 150% of a plane area of the electrodes so as to protrude outward beyond the outer peripheries of the adjacent electrodes;

The outer peripheral surfaces of the separators adjacent to the outer periphery protruding from the outer peripheries of the respective separators at an angle of 30 to 60 degrees with respect to the outer perimeter of the adjacent electrodes are bonded to each other at an angle of 0 deg. And the outer periphery of the junction of the structure cut to be 10 degrees.

That is, the electrode assembly according to the present invention has six or more polygonal deformations in a planar shape, and can be applied to a device such as a polygonal or geometric structure deviating from a general rectangular design, and further, a circular or curved surface.

In addition, the separation membranes are cut so as to correspond to the shapes of the irregular electrodes, and the separation membrane regions not corresponding to the outer periphery of the electrode are cut so as to be substantially parallel to the outer periphery of the electrode in a state where they are integrally joined, And the electrode assembly has a stable structure without deterioration of the electrode performance or quality due to foreign matter due to the absence of foreign substances in the electrode.

In one specific example, n, n-1, or n + 1 separators in the periphery of the junction may be bonded together.

In this structure, the edge portions of the electrodes located between the separators sharing the periphery of the junction can be supported while being surrounded by the periphery of the junction.

If the electrode assembly of the present invention is enlarged to the concept of a battery cell mounted on a battery case, the outer surface of the electrode assembly composed of the corner portions has a relatively small surface area, and a considerable pressure is applied when an impact is applied. The structure in which the n, n-1, or n + 1 separators are bonded to each other is a structure in which the periphery of the junction is in contact with the inner surface of the battery case The degree of friction of the edge portions of the first and second flanges can be reduced to solve the above-mentioned problems.

Alternatively, n, n-1, or n + 1 separators may be separated from each other around the junction.

The electrode assembly according to the present invention may have six or more polymodal structures on a flat surface, in which six or more polymodal electrodes are stacked on a plane, and two or more peripheral portions may be included so as to correspond to the polymodal structure.

In one specific example, the electrode assembly has a second electrode of a different polarity between the first electrode and the third electrode of the same polarity, and the shapes of the first electrode, the second electrode, and the third electrode may be the same . However, the sizes of these electrodes, for example, thickness or planarity, may be different from each other.

The first electrode and the third electrode may be an anode or a cathode, and the second electrode may have a polarity different from that of the first electrode and the third electrode.

Here, when n is 3 and the separation membrane is two, the electrode assembly may be stacked in the order of an electrode, a separator, an electrode, a separator, and an electrode.

Alternatively, when n is 3 and the separation membrane is three, the electrode assembly may have a structure in which the separation membrane, the electrode, the separation membrane, the electrode, the separation membrane, and the electrode are stacked in this order.

If n is 3 and the number of the separation membranes is four, the electrode assembly may have a structure in which the separation membrane, the electrode, the separation membrane, the electrode, the separation membrane, the electrode, and the separation membrane are stacked in this order.

Such an electrode laminate structure is generally referred to as a bi-cell, and more specifically, when the polarity of an electrode located in the intermediate layer is an anode, it can be broadly defined as an A-type bi- When the polarity of the electrode is a cathode, it can be defined as a C-type bi-cell in a broad sense.

In one specific example, each of the outer peripheries of the electrode may be interconnected to form an inner angle of 60 degrees or more and less than 270 degrees with the adjacent outer peripheries, and more specifically, an inner angle of 90 degrees or less and 180 degrees or less. have.

Meanwhile, the electrodes may include electrode tabs protruding outward from the outer periphery in the same direction.

In this case, if the electrode assembly has a structure in which the first electrode, the second electrode, and the third electrode are laminated, the first electrode terminal of the electrode assembly is formed in a state where the electrode tabs of the first electrode and the third electrode are vertically overlapped And the electrode tab of the second electrode forms a second electrode terminal of the electrode assembly at a position at least apart from the first electrode terminal.

That is, the electrode tabs of the first and second electrodes and the electrode tabs of the second electrode protrude outwardly from the outer periphery in the same direction, but they may be spaced apart from each other so as not to contact each other.

Alternatively, the first electrode and the third electrode may include electrode tabs protruding outward from the outer periphery of the first electrode and the third electrode, and the second electrode may have a different direction And an electrode tab protruding outward from the periphery of the electrode tab.

Therefore, in the structure in which the first electrode, the second electrode, and the third electrode are stacked, the first electrode terminal is formed at the same outer periphery of the electrode assembly with the electrode taps of the first electrode and the third electrode being overlapped vertically And the electrode tab of the second electrode may form a second electrode terminal of the electrode assembly at an outer periphery of a position different from the outer periphery where the first electrode terminal is located.

In this structure, the first electrode terminal and the second electrode terminal are spaced apart from each other, and by a device for applying a current to each of the first electrode terminal and the second electrode terminal in the activation process of the battery cell, that is, in the initial charge- They may not interfere with each other. The interference may be, for example, an interference due to a magnetic field formed when a current flows through the electrode terminal.

Moreover, in the above structure, since the first electrode terminal and the second electrode terminal are formed at the outer peripheries of different directions, the electrical connection structure for each of these terminals can be achieved in different directions, The connection structure with a circuit through which the electrode assembly can be electrically connected can be realized in various forms.

The electrode assembly of the present invention composed of such electrodes has a polygonal structure having N (N &gt; = 6) angles in plan view, and may have left and right and / or up and down symmetrical structures.

Alternatively, the electrode assembly may have a polygonal structure having N (N &gt; = 6) planes and may have a left-right and / or an up-down asymmetric structure.

The present invention also provides a secondary battery comprising at least one electrode assembly.

Specific examples of the secondary battery include a lithium ion (Li-ion) battery, a lithium polymer (Li-polymer) battery, and a lithium ion battery having advantages such as high energy density, discharge voltage, Or a lithium secondary battery such as a lithium ion polymer battery.

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

The positive electrode is prepared, for example, by coating a mixture of a positive electrode active material, a conductive material and a binder on a positive electrode current collector, and then drying the mixture. Optionally, a filler may be further added to the mixture.

The cathode current collector is generally made to have a thickness of 3 to 500 micrometers. Such a positive electrode current collector is not particularly limited as long as it has high conductivity without causing chemical change in the battery, and may be formed of a material such as stainless steel, aluminum, nickel, titanium, sintered carbon, or a surface of aluminum or stainless steel 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 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.

The negative electrode collector is generally made to have a thickness of 3 to 500 micrometers. Such an anode current collector is not particularly limited as long as it has conductivity without causing chemical change in the battery, and may be formed of a material such as copper, stainless steel, aluminum, nickel, titanium, fired carbon, 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.

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 electrolytic solution may be a non-aqueous electrolytic solution containing a lithium salt, and is composed of a non-aqueous electrolytic solution and a lithium salt. As the non-aqueous electrolyte, non-aqueous organic solvents, organic solid electrolytes, inorganic solid electrolytes, and the like are used, but the present invention is not limited thereto.

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 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 nonaqueous electrolytic solution is preferably a solution prepared by dissolving or dispersing in a solvent such as pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, glyme, hexaphosphoric triamide, 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 one specific _{example, 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 non-aqueous electrolyte.

 The present invention also provides a device comprising at least one battery cell.

The device may be, for example, an electronic device selected from the group consisting of a wearable electronic device, a mobile phone, a portable computer, a smart phone, a tablet PC, a smart pad, a netbook, a LEV (Light Electronic Vehicle) But is not limited thereto.

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

As described above, in the manufacturing method according to the present invention, the first and second separation membranes are not cut, but are in a state where they are laminated and fused to each other, that is, the fiber structures of the separation membranes are cut in a cured state The degree of occurrence of microscopic foreign matter due to cutting and cutting can be significantly reduced and the separation membrane in which the fibrous structure is cured can not be easily induced by the static electricity so that even if a small amount of foreign matter is generated, Can be mitigated.

In addition, the electrode assembly according to the present invention has six or more polygonal shapes in a plan view, and is formed in a shape that can be applied to a device such as a polygonal or geometric structure deviating from a general rectangular design, and further, a circular or curved surface.

Figures 1 and 2 are schematic diagrams of one exemplary non-rectangular electrode assembly;
3 is a flow diagram of a method of manufacturing according to one embodiment of the present invention;
Figures 4 and 5 are schematic diagrams of an electrode assembly according to one embodiment of the present invention;
Figure 6 is an enlarged vertical cross-sectional view of the L region of Figure 4;
7 is a schematic diagram of an electrode assembly according to another embodiment of the present invention;
8 is a schematic diagram of an electrode assembly according to another embodiment of the present invention;
9 is a schematic plan view of an electrode assembly according to another embodiment of the present invention;
10 is a schematic plan view of an electrode assembly according to another embodiment of the present invention;
11 is a schematic plan view of an electrode assembly according to another embodiment of the present invention.

Hereinafter, the present invention will be described in more detail with reference to the drawings according to embodiments of the present invention, but the scope of the present invention is not limited thereto.

FIG. 3 shows a flow chart of a manufacturing method according to one embodiment of the present invention.

In order to explain the manufacturing method according to the present invention based on the structure of the electrode assembly, the electrode assembly according to one embodiment of the present invention shown in Figs. 4 and 5 will be described with reference to Fig. 1, do.

Referring now to these drawings, a method 100 of the present invention for an electrode assembly 200 includes the steps of providing a first electrode 210 and a second electrode 220, The first separator 202 and the electrodes except for the portion protruding beyond the first electrode 210 and the second electrode 220 are laminated as a column through the first separator 202 having a large planar shape .

In the following step 120, a rectangular second separator 204 having a relatively large planar area is sandwiched between the second electrode 220 and the third electrode 230, and the second electrode 220, The second separator 204 and the electrodes except for the portion projecting beyond the third electrode 230 are laminated as a heat.

When the process 110 and the process 120 are completed, a lower end portion of the first separator 202 and the second separator 204 protrude more than the electrodes like the electrode assembly 200a shown in FIG. 5 .

In the present invention, an angle a of 30 to 60 degrees with respect to the outer periphery 208 of the adjacent electrode among the outer peripheries of the first and second separation membranes 202 and 204 is Are defined as outer peripheral surfaces 260 of the first separation membrane 202 and the second separation membrane 204 adjacent to the outer peripheries 251 and 252 which protrude.

In this state, the protruded first separator 202 and the outer circumferential surfaces 260, which are parts of the second separator 204, are laminated to each other with heat, thereby forming the outer circumferential surfaces 260 are integrally joined together.

In the process 140, the outer periphery 240, which is approximately 0 to 10 degrees with respect to the electrode outer periphery 208, is formed in the first and second separation membranes 202 and 204, And cut the laminated outer circumferential surfaces 260 along the imaginary cutting line C.

Although not shown in FIG. 3, in step 110, a third separation layer (not shown) may be further laminated on the surface of the first electrode 210 on which the first separation layer 202 is laminated, The process 130 may further include a process of further laminating the outer circumferential surface of the third separation membrane to the outer circumferential surfaces 260 of the first separation membrane 202 and the second separation membrane 204.

Also, in a state where the third separation membrane is further laminated, the third separation membrane can also be cut together with the first separation membrane 202 and the second separation membrane 204 through the process 140.

Similarly, a fourth separation layer (not shown) may be further laminated to the opposite surface of the second electrode 220 on which the second separation layer 204 is laminated. In this case, The outer circumferential surface of the separation membrane may be further laminated to the outer circumferential surfaces 260 of the first separation membrane 202 and the second separation membrane 204.

In addition, the fourth separation membrane may be cut together with the first separation membrane 202 and the second separation membrane 204 through the process 140, with the fourth separation membrane being further laminated.

As described above, in the manufacturing method of the present invention, the plurality of separation membranes are not cut, but are mutually laminated and fused, that is, the fiber structures of the separation membranes are cut in a cured state, and the degree of micro- It is possible to remarkably reduce the inevitable phenomenon that the foreign matter adsorbed on the electrode even if a small amount of foreign matter is generated due to the fact that the separation membrane in which the fiber structure is hardened is not easily induced by the static electricity.

FIGS. 4 and 5 are schematic diagrams of an electrode assembly according to an embodiment of the present invention, and FIG. 6 is a schematic vertical cross-sectional view of the L portion of FIG.

Referring to these drawings, the electrode assembly 200 includes a first electrode 210, a second electrode 220, a third electrode 230, and a first electrode 210, which are atypical electrodes having at least six outer peripheries on a plane. A second separation membrane 204 and a second separation membrane 204 and includes a first electrode 210, a first separation membrane 202, a second electrode 220, a second separation membrane 204, a third electrode 230, And stacked in this order.

The first electrode 210, the second electrode 220, and the third electrode 230 have an irregular structure having six outer peripheries and six inner angles, and their shapes are all the same.

The first electrode 210, the second electrode 220, and the third electrode 230 include electrode tabs 212, 222, and 232 protruding outward from the outer periphery of the first electrode 210, the second electrode 220, and the third electrode 230, respectively.

 The electrode tabs 212 and 232 of the first electrode 210 and the third electrode 230 are arranged vertically side by side in a state where the first electrode 210, the second electrode 220 and the third electrode 230 are laminated And the electrode tabs 212 and 232 of the same polarity superimposed in this manner form the first electrode terminal 206 of the electrode assembly 200.

The electrode tab 222 of the second electrode 220 forms a second electrode terminal of the electrode assembly 200 at a position apart from at least the first electrode terminal 206.

Although not shown in the drawing, the first electrode terminal 206 and the second electrode terminal 222 may be respectively coupled to a current carrying member such as an electrode lead by welding or soldering.

The first separation membrane 202 and the second separation membrane 204 have an area of about 130% of a plane area of any one of the first electrode 210, the second electrode 220 and the third electrode 230, The second electrode 220, and the third electrode 230. The second electrode 220 and the third electrode 230 have substantially the same shape.

The first separator 202 and the second separator 204 may have a rectangular structure and may have a first separator 202 and a second separator 204 in a state of being stacked together with the electrodes 210, 204 adjacent to the outer periphery 208 projecting at an angle (a, a ') of approximately 30 degrees to 60 degrees with respect to the outer periphery of the adjacent electrodes among the outer periphery of the separators 202, The outer circumferential surfaces 260 joined along the imaginary cutting line C forming 0 to 10 degrees with respect to the outer periphery 208 of the electrode are cut while the first and second outer circumferential surfaces 260 and 260 are joined to each other, The second electrode 220 and the third electrode 230 have substantially the same shape as the electrode 210, the second electrode 220, and the third electrode 230.

The portions of the first and second separation membranes 202 and 204 cut in the joined state are defined as the outer periphery of the junction 240 in the present invention. As shown in FIG. 5, the outer periphery of the joint 240 includes a cut line C (FIG. 5) of the outer peripheries of the outer periphery, which is the outermost periphery of the electrode assembly 200, ) Or a portion of the separation membrane from the cutting portion to the outer periphery of the adjacent electrode.

6 (i), the first separator 202 and the second separator 204 at the outer periphery of the junction 240a are separated from each other along the cutting line CC so that a part of the bonded outer circumferential surface remains, And they remain bonded to each other. In this structure, in the second electrode 220 positioned between the separators 202 and 204 sharing the outer periphery 240a of the bonding, the edge portions are supported in a state surrounded by the periphery 240 of the bonding.

Alternatively, as shown in FIG. 6 (ii), if the joined outer circumferential surfaces are cut along the cutting line CC, the first separator 202 and the second separator 204 are separated from each other .

As described above, the electrode assembly according to the present invention has six or more polygonal shapes in a plan view, and can be applied to devices of a polygonal or geometric structure deviating from a general rectangular design, and further applicable to devices such as a circle or a curved surface. have.

In addition, the separation membranes are cut so as to correspond to the shapes of the irregular electrodes, and the separation membrane regions not corresponding to the outer periphery of the electrode are cut so as to be substantially parallel to the outer periphery of the electrode in a state where they are integrally joined, And the electrode assembly has a stable structure without deterioration of the electrode performance or quality due to foreign matter due to the absence of foreign substances in the electrode.

7 is a schematic view of an electrode assembly according to another embodiment of the present invention.

Referring to FIG. 7, the electrode assembly 300 includes a first electrode 310, a second electrode 320, a third electrode 330, a first separator 330, A first separation layer 302 and a second separation layer 304. The first separation layer 302 and the second separation layer 304 are formed in the order of a first electrode 310, a first separation membrane 302, a second electrode 320, a second separation membrane 304, As shown in FIG.

The first electrode 310, the second electrode 320, and the third electrode 330 are each an amorphous structure having six outer peripheries and six inner angles, and their shapes are all the same.

The first electrode 310 and the third electrode 330 include electrode tabs 312 and 332 protruding outward from the periphery of the first electrode 310 and the third electrode 330. The second electrode 320 includes a first electrode 310, And electrode tabs 322 protruding outward from the outer periphery of the three electrodes 330 located in different directions with respect to the outer periphery of the electrode tabs 312 and 332.

Therefore, in the structure in which the first electrode 310, the second electrode 320 and the third electrode 330 are laminated, the electrode tabs 312 and 332 of the first electrode 310 and the third electrode 330 The first electrode terminal 306 is formed at the same outer periphery of the electrode assembly 300 while being overlapped vertically and horizontally while the electrode tab of the second electrode 320 is formed at the outer periphery where the first electrode terminal 306 is located The second electrode terminal 322 of the electrode assembly 300 is formed.

In this structure, the first electrode terminal 306 and the second electrode terminal 322 are spaced apart from each other and are electrically connected to the first electrode terminal 306 and the second electrode terminal 322 in the activation process of the battery cell, 322, respectively, they may not interfere with each other.

Moreover, since the first electrode terminal 306 and the second electrode terminal 322 are formed at the outer peripheries in different directions, the electrical connection structure for each of these terminals can be achieved in different directions, The connection structure of the electrode assembly 300 and the circuit that can be electrically connected to the electrode assembly 300 can be realized in various forms.

8 is a vertical cross-sectional view of three electrode assemblies according to further embodiments of the present invention.

Referring to FIG. 8, the electrode assembly 400 includes a third separator 406, a first electrode 410, a first separator 402, a second electrode 420, A separation membrane 404 and a third electrode 430 are sequentially stacked.

The electrode assembly 500 according to the second mode (ii) of FIG. 8 includes a first electrode 510, a first separator 502, a second electrode 520, a second separator 504, a third electrode 530 And a fourth separation membrane 508 are stacked in this order.

The electrode assembly 600 according to the third form (iii) of FIG. 8 includes a third separator 606, a first electrode 610, a first separator 602, a second electrode 620, a second separator 604 ), A third electrode 630, and a fourth separation layer 608 are sequentially stacked.

The electrode assemblies 400, 500 and 600 shown in the first, second and third forms (i), (ii) and (iii) are commonly provided with additional separators on the outermost electrodes When the needle-shaped conductor passes through the electrode assembly in the outermost electrode direction, the third separation membrane or the fourth separation membrane added to the outermost periphery may be extended along the needle-shaped conductor to cover the needle-shaped conductor surface. For this reason, electrodes of opposite polarity, for example, first and second electrodes, or second and third electrodes, can be cut off directly by the needle-shaped conductors through the needle-shaped conductors.

For this purpose, the third separator and the fourth separator, which are added to the outermost portion, may have a relatively thicker thickness than the first separator and the second separator. Specifically, the third separator and the fourth separator may have a thickness of about 1.5 to 3 It can have a thickness of double.

9 to 11 are schematic plan views of electrode assemblies according to further embodiments of the present invention.

When the electrode assemblies 700, 800, and 900 are viewed from the top or bottom, the outer peripheries of the separators 730, 830, and 930 forming the outermost peripheries of the electrode assemblies are connected to the electrode assembly The planar shape of the separator in the present invention is the same as that of the electrode, and the outer peripheries that determine the planar shape of the electrode assembly are understood as the outer peripheries of the electrode and can be fulfilled. Of course.

Referring to FIG. 9, the electrode assembly 700 has a polygonal structure including six outermost peripheries 701, 702, 703, 704, 705, and 706 that are linear in a plan view.

The outer peripheries 701, 702, 703, 704, 705, and 706 are connected to the adjacent outer peripheries at an angle of 90 degrees or more and less than 160 degrees, respectively, and they are connected in an irregular polygonal structure.

The electrode assembly 700 is also symmetrical with respect to a vertical axis P-P 'passing through the center thereof in a plan view and has a vertically asymmetric structure with respect to the horizontal axis H-H'.

The first electrode terminal 710 and the second electrode terminal 720 of the electrode assembly 700 protrude from the same outer periphery.

Fig. 10 schematically shows an electrode assembly according to another embodiment of the present invention.

Referring to FIG. 10, the electrode assembly 800 has a polygonal structure composed of eight outer peripheries (801, 802, 803, 804, 805, 806, 807, 808)

These outer peripheries 801, 802, 803, 804, 805, 806, 807, and 808 are connected to the adjacent outer peripheries at angles of 90 degrees to less than 150 degrees, and they are connected in an irregular polygonal structure .

The electrode assembly 800 is also horizontally and vertically symmetrical with respect to a vertical axis P-P 'and a horizontal axis H-H' via a central portion thereof in a plane.

The first electrode terminal 810 and the second electrode terminal 820 of the electrode assembly 800 protrude from the same outer periphery.

11 schematically shows an electrode assembly according to another embodiment of the present invention.

Referring to FIG. 11, the electrode assembly 900 has a polygonal structure composed of seven outer peripheries (901, 902, 903, 904, 905, 906, and 907)

The outer peripheries 901, 902, 903, 904, 905, 906, and 907 are connected to the adjacent outer peripheries at an angle of 90 degrees or more and less than 180 degrees, respectively, and they are connected in an irregular polygonal structure.

The electrode assembly 900 is also asymmetric with respect to a vertical axis P-P 'passing through the center of the electrode assembly 900 in a plan view, and has a vertically asymmetric structure with respect to a horizontal axis H-H'.

The first electrode terminal 910 and the second electrode terminal 920 of the electrode assembly 900 protrude outward from different outer circumferential surfaces.

Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims (19)

CLAIMS What is claimed is: 1. A method of fabricating an electrode assembly of an irregular structure consisting of at least six outer peripheries,
(a) a first separator interposed between the first electrode and the second electrode, the first separator having a plane area of 110% to 150% relative to any one of the electrodes, and a second separator interposed between the first electrode and the second electrode, A process of laminating the separator and electrodes;
(b) a second separator interposed between the second electrode and the third electrode having a plane area of 110% to 150% with respect to any one of the electrodes, and a second separator interposed between the second electrode and the third electrode, And laminating the electrodes;
(c) the outer peripheral surfaces of the first and second separation membranes adjacent to the outer periphery protruding from the outer peripheries of the first and second separation membranes at an angle of 30 to 60 degrees with respect to the outer periphery of the adjacent electrodes, Lamination process;
(d) cutting the laminated outer circumferential surfaces so that outer peripheries of 0 to 10 degrees with respect to the outer periphery of the electrode in step (c) are formed in the first and second separation membranes;
&Lt; / RTI &gt; The method of claim 1, wherein the first electrode is further laminated on the opposite surface of the laminated surface of the first separator, and the third separator is laminated on the outer surface of the third separator in step (c) Lt; RTI ID = 0.0 &gt; 1 &lt; / RTI &gt; separator and the second separator. The method of claim 1, wherein the third electrode is further laminated on the opposite side of the laminated surface of the third electrode in the step (b), and the outer peripheral surface of the fourth separator in the step (c) And further laminated to outer peripheral surfaces of the separator and the second separator. The method of claim 1, wherein the first electrode and the third electrode are an anode or a cathode, and the second electrode has a polarity different from that of the first electrode and the third electrode. The method of claim 1, wherein the first and second separation membranes have a rectangular planar shape in the steps (a) to (c), and the first separation membrane and the second separation membrane in the step (d) &Lt; / RTI &gt; As an electrode assembly,
(N &gt; = 3) composed of at least six outer peripheries on a plane are stacked together with n, n-1, or n + 1 separators, and each of the separators is adjacent Has an area of 110% to 150% of the area of the electrode so as to protrude outward beyond the outer peripheries of the electrode;
The outer peripheral surfaces of the separators adjacent to the outer periphery protruding from the outer peripheries of the respective separators at an angle of 30 to 60 degrees with respect to the outer perimeter of the adjacent electrodes are bonded to each other at an angle of 0 deg. And an outer periphery of the junction of the structure cut to have a degree of ten degrees. 7. The electrode assembly of claim 6, wherein each of the outer peripheries of the electrode is interconnected with an outer perimeter of the electrode at an angle of less than 90 degrees and less than 180 degrees. [7] The apparatus of claim 6, wherein the electrode assembly has a first electrode, a second electrode, and a third electrode having the same polarity between the first electrode and the third electrode having the same polarity, . The electrode assembly according to claim 6, wherein the electrode assembly has a polygonal structure having N (N &gt; = 6) angles in plan view, and has left and right and / or up and down symmetrical structures. [7] The electrode assembly of claim 6, wherein the electrode assembly has a polygonal structure having N internal angles (N &amp;ge; 6) in a plan view, and has left and right and / or asymmetric structures. 8. The electrode assembly of claim 7, wherein the electrodes each include an outwardly protruding electrode tab at an outer perimeter located in the same direction. [8] The apparatus of claim 7, wherein the first electrode and the third electrode include electrode tabs protruding outward from the periphery of the first electrode and the third electrode, And an electrode tab protruding outwardly from an outer periphery located in a different direction with respect to the electrode tab. The electrode assembly according to claim 6, wherein n, n-1, or n + 1 separators are bonded to each other at the periphery of the junction. 7. The electrode assembly of claim 6, wherein the electrode assembly comprises at least two of the outer periphery of the joint. The electrode assembly according to claim 6, wherein the electrode assembly has n of 3 and the separator has two electrodes, and the electrode assembly, the separator, the electrode, the separator, and the electrode are stacked in this order. The electrode assembly according to claim 6, wherein the electrode assembly has n of 3 and the separation membrane is three, and the separation membrane, the electrode, the separation membrane, the electrode, the separation membrane, and the electrode are stacked in this order. The electrode assembly according to claim 6, wherein the electrode assembly has n = 3 and the separation membrane is four, and the separation membrane, the electrode, the separation membrane, the electrode, the separation membrane, the electrode, and the separation membrane are stacked in this order. A secondary battery comprising at least one electrode assembly according to any one of claims 6 to 17. A device comprising a secondary cell according to claim 19.

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