KR20130095368A - Notching device for removal of scrap and secondary battery manufactured using the same - Google Patents

Abstract

PURPOSE: A notching device is provided to stably form a notch on an electrode sheet and to be able to smoothly discharge the scrap. CONSTITUTION: A notching device notches an electrode sheet at a unit electrode gap in order to manufacture multiple unit electrodes from a continuous electrode sheet (10) in which an electrode active material is coated on one side or both sides. A notching device comprises an unwinder in a roller shape on which the electrode sheet is rolled; a die cutter (100) cutting each notch on the upper end and the lower end of the electrode sheet in the state of being transferred from the unwinder and fixed on a die; and a rewinder in a roller shape rewinding the electrode sheet after cutting.

Description

Notching Device for Scrap Removal and Secondary Battery Manufactured Using the Same {Notching Device for Removal of Scrap and Secondary Battery Manufactured Using the Same}

The present invention relates to a notching device for scrap removal and a secondary battery produced using the same, and more particularly, to produce a plurality of unit electrodes from a continuous electrode sheet coated with an electrode active material, An apparatus for notching at unit electrode intervals, the apparatus comprising: a roller-shaped unwinder in which an electrode sheet is wound; A punching machine for punching the notches at the upper end and the lower end of the electrode sheet while being transported from the unwinder and fixed on the die; And a roller-shaped rewinder for rewinding the electrode sheet after the punching. The puncher includes: a punch for punching a notch and a die corresponding to the punch; It has a size corresponding to or smaller than the lower end surface of the punch, and the movement in the vertical direction to the close position (A) to the lower end of the punch and the separation position (B) from the lower end of the punch by the operation of the following drive cylinder Scrap removal plate; And mounted in the punch in a state interlocked with the scrap removing plate, and moving the scrap removing plate from the close contact position (A) to the separated position (B) to separate the punched scrap from the punch bottom surface and then close the close position. (A) the driving cylinder to the original position; It relates to a notching device comprising a.

BACKGROUND ART [0002] In recent years, rechargeable secondary batteries have been extensively used as an energy source or an auxiliary power device for wireless mobile devices. In addition, the secondary battery is an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (HEV), and the like, which are proposed as solutions for air pollution of existing gasoline vehicles and diesel vehicles using fossil fuels (Plug-In HEV) and the like.

Such a secondary battery is manufactured such that the electrode assembly is embedded in the battery case together with the electrolyte solution. The electrode assembly is classified into a stack type, a folding type, a stack-folding type, and the like according to a manufacturing method. In the case of the stacked or stacked-folded electrode assembly, the unit assembly has a structure in which an anode and a cathode are sequentially stacked with a separator interposed therebetween. To fabricate such an electrode assembly, it is necessary to first fabricate the anode and the cathode.

That is, in order to manufacture unit electrodes such as a positive electrode and a negative electrode, first, a process of notching a continuous electrode sheet coated with an electrode active material on one surface or both surfaces at unit electrode intervals is required. In the notching process, a method of notching a part of an electrode sheet using a punching machine is generally used.

The punching machine is a device for processing an electrode sheet, which is a punching object, in a predetermined form, and a continuous feeding method is widely used.

Referring to the operation of the punching machine with reference to Figure 1, the electrode sheet 10 includes a punch 20 for punching a notch of a predetermined shape and a die 30 located on the lower surface of the electrode sheet 10, In the lower portion of the die 30, a suction dust collector 40 is formed at a position facing the punch 20 (see (a)). Accordingly, while punch 20 is lowered and punches electrode sheet 10 (see (b)), suction dust collector 40 sucks scrap 15 from the bottom of die 30 and scrap 15 ) Will be removed.

However, in this punching process, the scrap 15 may be mixed into the punch 20 without exiting through the suction dust collector 40, and the scrap 15 mixed into the punch 20 may be sintered to the electrode surface. Symptoms (see (c)) may occur. In addition, since the space h between the conventional punch 20 and the die 30 is very narrow, about 5 μm or less, when the suction dust collector 40 is inhaled, air from the outside is scarce and the scrap is smoothly discharged. There is also a problem that is not achieved.

Therefore, there is a need for the development of a new notching device for solving the above problems.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-described problems of the prior art and the technical problems required from the past.

SUMMARY OF THE INVENTION An object of the present invention is to provide a notching apparatus which can stably form a notch on the electrode sheet and at the same time smoothly discharge the scrap.

Still another object of the present invention is to provide a secondary battery exhibiting excellent operating characteristics using the notching device as described above.

Therefore, the notching apparatus according to the present invention for achieving the above object, in order to manufacture a plurality of unit electrodes from a continuous electrode sheet is coated with an electrode active material on one side or both sides, the electrode sheet at unit electrode intervals As a notching device,

A roller-shaped unwinder in which an electrode sheet is wound;

A punching machine for punching the notches at the upper end and the lower end of the electrode sheet while being transported from the unwinder and fixed on the die; And

A roller-shaped rewinder for rewinding the electrode sheet after the punching;

To include, the punching machine,

A punch for punching a notch and a die corresponding to the punch;

It has a size corresponding to or smaller than the lower end surface of the punch, and the movement in the vertical direction to the close position (A) to the lower end of the punch and the separation position (B) from the lower end of the punch by the operation of the following drive cylinder Scrap removal plate; And

The scrap removal plate is mounted in the punch while being interlocked with the scrap removal plate, and the scrap removal plate is moved from the close contact position (A) to the separated position (B) to separate the punched scrap from the punch bottom surface, and then the close contact position ( Drive cylinder reverted to A);

.

That is, the notching device according to the present invention serves to prevent the mixing of the scrap after the punch by pushing the scrap scraped by the drive cylinder and the scrap removal plate to the lower end, and only performs the punching role in the conventional notching device In comparison, scrap can be effectively discharged.

As described above, the scrap removing plate may have a size corresponding to or smaller than the bottom surface of the punch, but if the size is too small, the scrap removing plate may not serve as a scrap removing plate. Thus, in the latter case, for example, it may have a size of 30% to 99% based on the width of the punch bottom surface.

The drive cylinder may preferably be an air hydraulic cylinder so as to perform mechanical reciprocating up and down movement by air pressure.

In the above structure, the drive cylinder can be opened and closed by, for example, an air sole valve.

In one preferred example, the scrap removal plate may have a structure that maintains the close contact position (A) at the time of the punching, and moves to a spaced position (B) during the lowering of the punch after the punching. Therefore, the scrap notched by the punching can be easily discharged to the bottom in the process of moving the scrap removal plate to the spaced position (B).

In this case, the scrap removal plate can be moved to its original position (A) in the process of raising the punch for subsequent punching.

In another preferred embodiment, the lower portion of the die may be a structure further including a suction dust collector in a position opposite the punch.

In one specific example, one or more vent holes in communication with the suction dust collector may be further formed in the punch.

In the above structure, the vent hole may be perforated to provide an air flow path in a shape in which outside air of the upper part of the punch may be introduced into the suction dust collector at the time of punching. Therefore, the dust collecting force by the outside air is strengthened by the vent hole, and the discharge of the scrap can be achieved very efficiently.

On the other hand, the electrode sheet after the punching may be made of a structure including an electrode tab.

The present invention also provides an electrode assembly manufactured using the notching device.

The electrode assembly has a structure in which the anode and the cathode are laminated with each other with a separator therebetween.

The positive electrode may be manufactured by, for example, applying a slurry prepared by mixing a positive electrode mixture with a solvent such as NMP onto a negative electrode current collector, followed by drying and rolling.

The positive electrode mixture may optionally include a conductive material, a binder, a filler, etc. in addition to the positive electrode active material.

The cathode active material is a lithium transition metal oxide capable of causing an electrochemical reaction, and includes two or more transition metals, for example, lithium cobalt oxide (LiCoO ₂ ) and lithium nickel oxide (substituted with one or more transition metals). Layered compounds such as LiNiO ₂ ); Lithium manganese oxide substituted with one or more transition metals; Formula _{LiNi 1-y M y O 2} ( where, M = Co, Mn, Al , Cu, Fe, Mg, B, Cr, Zn or Ga and Lim, 0.01≤y≤0.7 include one or more elements of the element) A lithium nickel-based oxide represented by the following formula: _{Li 1 + z Ni 1/3 Co 1/3} Mn 1/3 O 2, Li 1 + z Ni 0.4 Mn 0.4 Co 0.2 O 2 , such as _{Li 1 + z Ni b Mn c} Co 1- (b + c + d _{) M d O (2-e} ) A e ( where, -0.5≤z≤0.5, 0.1≤b≤0.8, 0.1≤c≤0.8, 0≤d≤0.2 , 0≤e≤0.2, b + c + d <1, M = Al, Mg, Cr, Ti, Si or Y, and A = F, P or Cl; lithium nickel cobalt manganese composite oxide; And the formula _{Li 1 + x M 1-y} M 'y PO 4-z X z ( wherein, M = a transition metal, preferably Fe, Mn, Co or Ni, M' = Al, Mg or Ti, X = F, S or N, and -0.5? X? +0.5, 0? Y? 0.5, and 0? Z? 0.1), but the present invention is not limited thereto.

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 whiskeys 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, and various copolymers.

The filler is optionally used as a component for suppressing the expansion of the electrode, and is not particularly limited as long as it is a fibrous material without causing any chemical change in the battery. Examples of the filler include olefin-based polymerizers such as polyethylene and polypropylene; Fibrous materials such as glass fibers and carbon fibers are used.

The cathode current collector is generally made to have a thickness of 3 to 500 mu m. Such a positive electrode collector is not particularly limited as long as it has conductivity without causing chemical change to the battery, and may be formed on the surface of stainless steel, aluminum, nickel, titanium, sintered carbon or aluminum or stainless steel 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 negative electrode is prepared, for example, by applying a negative electrode mixture containing a negative electrode active material on a negative electrode collector and then drying the same. The negative electrode mixture may contain a conductive material, a binder, a filler, May be included.

Examples of the negative electrode active material include carbon and graphite materials such as natural graphite, artificial graphite, expanded graphite, carbon fiber, non-graphitizable carbon, carbon black, carbon nanotube, fullerene and activated carbon; Metals such as Al, Si, Sn, Ag, Bi, Mg, Zn, In, Ge, Pb, Pd, Pt and Ti which can be alloyed with lithium and compounds containing these elements; Complexes of metals and their compounds and carbon and graphite materials; Lithium-containing nitrides, and the like. Among them, a carbon-based active material, a silicon-based active material, a tin-based active material, or a silicon-carbon based active material is more preferable, and these may be used singly or in combination of two or more.

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

The separation membrane is interposed between the anode and the cathode, and an insulating thin film having high ion permeability and mechanical strength is used. The pore diameter of the separator is generally 0.01 to 10 mu m and the thickness is generally 5 to 300 mu m. Such separation membranes include, for example, olefinic polymers such as polypropylene, which are chemically resistant and hydrophobic; A sheet or nonwoven fabric made of glass fiber, polyethylene or the like is used. When a solid electrolyte such as a polymer is used as an electrolyte, the solid electrolyte may also serve as a separation membrane.

The present invention also provides a secondary battery in which the electrode assembly is sealed inside a battery case together with a non-aqueous electrolyte solution containing a lithium salt.

The lithium salt-containing nonaqueous electrolyte solution is composed of an electrolyte solution and a lithium salt. As the electrolyte solution, a nonaqueous organic solvent, an organic solid electrolyte, and an inorganic solid electrolyte may be used.

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 propionate and ethyl propionate can be used.

Examples of the organic solid electrolyte include a polymer electrolyte such as a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, an agitation lysine, a polyester sulfide, a polyvinyl alcohol, a polyvinylidene fluoride, A polymer containing an ionic dissociation group and the like may be used.

As the inorganic solid electrolyte, for example, Li ₃ N, LiI, Li ₅ NI ₂ , Li ₃ N-LiI-LiOH, LiSiO ₄ , LiSiO _4- LiI-LiOH, Li ₂ SiS ₃ , Li ₄ SiO ₄ , Nitrides, halides, sulfates and the like of Li, such as Li ₄ SiO ₄ -LiI-LiOH, Li ₃ PO ₄ -Li ₂ S-SiS ₂ , and the like, may 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 electrolytic solution is preferably mixed with an organic solvent such as pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, glyme, Benzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N, N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrrole, 2-methoxyethanol, . In some cases, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride may be further added to impart nonflammability, or a carbon dioxide gas or the like may be further added to improve high-temperature storage characteristics.

The battery case may be in the form of a pouch obtained by heat-sealing a cylindrical can, a rectangular can, or a lamination sheet. Among these, pouch-type cases have been used in recent years because of their advantages such as low weight, low manufacturing cost, and easy deformation.

The laminate sheet is preferably made of a structure including an inner resin layer subjected to heat fusion, a barrier metal layer, and an outer resin layer exhibiting durability.

The outer resin layer must have excellent resistance to the external environment, and therefore, a tensile strength and weather resistance higher than a predetermined level are required. In this respect, the polymer resin of the outer coating layer may include polyethylene naphthalate (PEN), polyethylene terephthalate (PET), or stretched nylon having excellent tensile strength and weatherability.

The outer coating layer may be made of polyethylene naphthalate (PEN) and / or a polyethylene terephthalate (PET) layer may be provided on the outer surface of the outer coating layer.

The polyethylene naphthalate (PEN) has an excellent tensile strength and weatherability even at a thin thickness as compared with polyethylene terephthalate (PET), and thus is preferable for use as an outer coating layer.

The polymer resin of the internal resin layer may be a polymer resin having heat-sealability (thermal adhesiveness), low hygroscopicity to the electrolyte to suppress penetration of the electrolyte, and not swellable or eroded by the electrolyte. More preferably, it may be made of an unoriented polypropylene film (CPP).

In one preferred example, the laminate sheet according to the present invention is characterized in that the thickness of the outer coating layer is 5 to 40 占 퐉, the thickness of the barrier layer is 20 to 150 占 퐉, the thickness of the inner sealant layer is 10 to 50 占 퐉 Structure. When the thickness of each layer of the laminate sheet is too thin, it is difficult to expect a blocking function and strength improvement for the material. On the other hand, if it is too thick, the workability is deteriorated and the thickness of the sheet is increased.

The secondary battery as described above may not only be used in a battery cell used as a power source for a small device, but also includes a plurality of battery cells used as a power source for medium and large devices requiring high temperature stability, long cycle characteristics, and high rate characteristics. It can also be preferably used as a unit cell in the battery pack.

Preferred examples of the medium-to-large device include a power tool driven by a battery-based motor; An electric vehicle including an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and the like; An electric motorcycle including an electric bike (E-bike) and an electric scooter (E-scooter); An electric golf cart, and the like, but the present invention is not limited thereto.

As described above, the notching device according to the present invention pushes the scrap scraped by the drive cylinder and the scrap removing plate to the lower end, and serves to prevent the mixing of the scrap after the punching, thereby effectively discharging the scrap.

1 is a partial schematic view of a conventional notching apparatus;
2 is a block diagram of a notching apparatus according to one embodiment of the present invention;
3 to 6 are process schematic diagrams of the punching machine of FIG. 2.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited by the scope of the present invention.

2 is a block diagram of a notching device according to the present invention.

Referring to FIG. 2, an apparatus 200 for notching the electrode sheet 10 at unit electrode intervals in order to manufacture a plurality of unit electrodes from a continuous electrode sheet 10 coated with electrode active materials on both sides thereof is provided. The notch 50 is punched out of the roller-shaped unwinder 50 and the unwinder 50 in which the sheet 10 is wound to punch the notches at the upper and lower ends of the electrode sheet 10 in a state of being fixed on the die 130. The punching machine 100 and the roller-shaped winding machine 60 which rewind the electrode sheet 10 after a punching are included.

3 to 6 show process schematics of the punching machine of FIG. 2. Referring to these drawings in conjunction with FIG. 2, the punching machine 100 includes a punch 120 for punching a notch, a die 130, a scrap removing plate 140, and a driving cylinder 150 that is an air hydraulic cylinder. do.

The scrap removing plate 140 has a size of about 95% based on the width W of the bottom surface of the punch 120, and is in close contact with the bottom of the punch 120 by the operation of the driving cylinder 150. (A) and the movement in the up-down direction to the spaced position B from the lower end of the punch 120.

The driving cylinder 150 is mounted in the punch 120 in a state linked to the scrap removing plate 140, and is opened and closed by an air sole valve (not shown).

Referring to FIG. 3, in the process sequence of the notch, the scrap removing plate 140 maintains the close contact position A at the time of punching. Then, as shown in Figures 4 and 5, the punching 120 after the punching moves to the separation position (B) in the lowering process. Next, as shown in Figure 6, the scrap removal plate 140 is moved to the close position (A) in the process of raising the punch 120 for subsequent punching.

Meanwhile, a lower portion of the die 130 includes a suction dust collector 160 at a position opposite to the punch 120, and two vent holes 161 and 162 communicating with the suction dust collector 160 are disposed in the punch 120. Formed.

That is, the vent holes 161 and 162 are perforated to provide an air flow path in a shape such that outside air of the upper part of the punch can be introduced into the suction dust collector 160 at the time of punching (see FIG. 4), so that dust collection force by outside air is provided. Reinforcement allows for more efficient discharge of scrap.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.

Claims (14)

An apparatus for notching the electrode sheet at unit electrode intervals in order to manufacture a plurality of unit electrodes from a continuous electrode sheet coated with one or both electrode active materials,
A roller-shaped unwinder in which an electrode sheet is wound;
A punching machine for punching the notches at the upper end and the lower end of the electrode sheet while being transported from the unwinder and fixed on the die; And
A roller-shaped rewinder for rewinding the electrode sheet after the punching;
To include, the punching machine,
A punch for punching a notch and a die corresponding to the punch;
It has a size corresponding to or smaller than the lower end surface of the punch, and the movement in the vertical direction to the close position (A) to the lower end of the punch and the separation position (B) from the lower end of the punch by the operation of the following drive cylinder Scrap removal plate; And
The scrap removal plate is mounted in the punch while being interlocked with the scrap removal plate, and the scrap removal plate is moved from the close contact position (A) to the separated position (B) to separate the punched scrap from the punch bottom surface, and then the close contact position ( A drive cylinder reverting to A);
Notching device, characterized in that it comprises a. The notching apparatus of claim 1, wherein the scrap removing plate has a size of 30% to 99% based on a width of a punch bottom surface. 2. The notching device according to claim 1, wherein the drive cylinder is an air hydraulic cylinder. 4. The notching device according to claim 3, wherein the driving cylinder is opened and closed by an air sole valve. The notching apparatus according to claim 1, wherein the scrap removing plate maintains the close contact position (A) at the time of the punching and moves to a spaced position (B) during the lowering of the punch after the punching. 6. The notching device according to claim 5, wherein the scrap removing plate moves to the close position (A) in the process of raising the punch for subsequent punching. The notching apparatus of claim 1, further comprising a suction dust collector at a lower portion of the die at a position opposite to the punch. 8. The notching device according to claim 7, wherein at least one vent hole in communication with the suction dust collector is further formed in the punch. 9. The notching apparatus according to claim 8, wherein the vent hole is perforated to provide an air flow path in a shape in which outside air of the upper part of the punch can be introduced into the suction dust collector at the time of punching. The notching device according to claim 1, wherein the electrode sheet after the punching includes an electrode tab. An electrode assembly, which is produced using the apparatus according to any one of claims 1 to 10. The secondary battery according to claim 11, wherein the electrode assembly is sealed inside the battery case together with an electrolyte solution. A battery pack comprising two or more secondary batteries according to claim 12 as a unit cell. The battery pack as claimed in claim 13, wherein the battery pack is used as a power source for an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a power storage device.

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