KR102169839B1 - Battery Case Sealing Device Having Wrinkle Removal Function - Google Patents

Abstract

The present invention is a battery case sealing device that seals the outer periphery of the battery case in which the electrode assembly is embedded in the manufacturing process of the battery cell by heat-sealing, and the battery case is embedded and fixed with the outer periphery of the battery case protruding. Nest; A sealing tool for sealing by pressing and heating the upper and lower surfaces of the protruding outer periphery of the battery case up and down; And when the outer periphery of the battery case is sealed by the sealing tool to prevent wrinkles from being generated on the outer surface of the battery case after the degas process during the battery cell manufacturing process, the nest is moved toward the sealing tool. It provides a battery case sealing device comprising; a pusher to sequentially pressurize.

Description

Battery Case Sealing Device Having Wrinkle Removal Function {Battery Case Sealing Device Having Wrinkle Removal Function}

The present invention relates to a battery case sealing device having a wrinkle removal function.

Secondary batteries are widely used as power sources for mobile devices such as cell phones, laptops, and camcorders. In particular, the use of lithium secondary batteries is rapidly increasing due to the advantages of high operating voltage and high energy density per unit weight.

These lithium secondary batteries are also classified into lithium ion batteries, lithium ion polymer batteries, and lithium polymer batteries depending on the composition of the electrode and electrolyte, and among them, the use of lithium ion polymer batteries that are less likely to leak and are easy to manufacture. This is increasing.

Lithium-ion polymer battery (LiPB) is a structure in which an electrode assembly obtained by heat-sealing an electrode (anode and negative electrode) and a separator is impregnated with an electrolyte solution, and is mainly used in a form in which the electrode assembly is sealed in a pouch-shaped case of an aluminum laminate sheet. Therefore, lithium-ion polymer batteries are often referred to as pouch-type batteries.

1 schematically shows a general structure of a typical secondary battery including a stacked electrode assembly.

Referring to FIG. 1, the secondary battery 10 includes an electrode assembly 30 made of a positive electrode, a negative electrode, and a separator disposed therebetween in a pouch-shaped battery case 20, and the positive and negative electrodes thereof. The tabs 31 and 32 are welded to the two electrode leads 40 and 41, respectively, and are exposed to the outside of the battery case 20.

The battery case 20 is made of a flexible packaging material such as an aluminum laminate sheet, and includes a case body 21 including a concave-shaped storage unit 23 on which the electrode assembly 30 can be seated and the body 21 It consists of a cover 22 to which one side is connected.

The electrode assembly 30 used in the secondary battery 10 may have a jelly roll type structure or a stack/folding type structure in addition to the stack type structure as shown in FIG. 1. In the stacked electrode assembly 30, a plurality of positive electrode tabs 31 and a plurality of negative electrode tabs 32 are welded to electrode leads 40 and 41, respectively.

In the battery cell manufacturing process, such a secondary battery is sealed by heat-sealing the outer periphery of the battery case in which the electrode assembly is embedded using a sealing tool. Among the outer peripheries of the battery case that is heat-sealed and sealed, the outer periphery where the electrode lead is formed has a problem that wrinkles occur around the sealing portion due to the thickness of the electrode lead.

Moreover, the wrinkles generated as described above cause a problem in that the inside of the battery case is placed in a vacuum state while undergoing a degas process during the battery cell manufacturing process, and the wrinkles appear prominent, resulting in a problem of appearance defects.

Accordingly, there is a high need for a technology capable of fundamentally solving these problems and minimizing the wrinkles expressed in the battery case during the battery cell manufacturing process.

An object of the present invention is to solve the problems of the prior art and technical problems that have been requested from the past.

It is an object of the present invention to provide a battery case sealing device capable of minimizing appearance defects by removing wrinkles in a portion of the outer periphery of the battery case where electrode leads are formed in the sealing process of the battery case.

Battery case sealing device according to the present invention for achieving this object,

As a battery case sealing device that heats and seals the outer periphery of the battery case in which the electrode assembly is embedded in the battery cell manufacturing process,

A nest for installing and fixing the battery case with the outer periphery of the battery case protruding;

A sealing tool for sealing by pressing and heating the upper and lower surfaces of the protruding outer periphery of the battery case up and down; And

When the outer periphery of the battery case is sealed by the sealing tool, the nest is sequentially placed toward the sealing tool to prevent wrinkles from being generated on the outer surface of the battery case after the degas process during the battery cell manufacturing process. A pusher to pressurize;

It may be composed of a structure including.

Accordingly, the battery case sealing device according to the present invention includes a pusher that sequentially presses the nest toward the sealing tool when the outer periphery of the battery case is sealed by the sealing tool, thereby degasing the battery cell manufacturing process. After that, it is possible to minimize the appearance defect of the battery cell by preventing wrinkles from being generated on the outer surface of the battery case.

The battery case may be made of, for example, a laminate sheet including a metal layer and a resin layer suitable for a pouch type battery, and specifically, an upper layer of a first polymer resin, an intermediate layer of a barrier metal, and a second polymer resin. It can be made in the lower layer. Here, the first polymer resin layer may be specifically a heat-fusible polymer resin, for example, a non-stretched polypropylene resin. The barrier metal may be aluminum, for example, and the second polymer resin may be a resin having excellent weather resistance, such as nylon resin, polyethylene terephthalate resin, polyethylene naphthalate resin, or the like. However, it goes without saying that the type of material is not limited to the above examples.

In one embodiment of the present invention, the outer periphery of the battery case to be sealed may be one side in which the electrode terminals of the battery case are formed. Among the outer peripheries of the battery case sealed by the sealing tool, in particular, one side on which the electrode terminal is formed may be wrinkled in the direction of the center of the battery case by the thickness of the electrode terminal. Accordingly, the pusher may have a structure that sequentially presses the nest in a direction in which the electrode terminals of the battery case are formed.

As one specific example of the nest, the nest,

A fixing jig for mounting and fixing the battery case in a state in which the electrode assembly receiving part of the battery case is introduced; And

A top cover covering an upper surface of the battery case mounted on the fixing jig;

It may be composed of a structure including.

The fixing jig may have a mounting portion corresponding to the electrode assembly receiving portion of the battery case, and the top cover may have a flat structure corresponding to the upper surface of the battery case.

Specifically, the top cover may be coupled to one end of the fixing jig in a hinge structure, and may be rotated based on the hinge portion to cover the upper surface of the battery case.

In addition, the pusher may be configured to move toward the sealing tool while sequentially pressing the upper surface of the top cover from the hinge portion. That is, the pusher may have a structure that sequentially presses the upper surface of the battery case from an end opposite to the electrode terminal toward the electrode terminal.

As a specific example of the pusher, the pusher,

A pressing portion having a structure having a lower surface corresponding to the upper surface of the top cover, and moving in parallel while in contact with the upper surface of the top cover to rotate the top cover to the upper surface of the battery case and pressurizing; And

A fixing part coupled to one end of the pressing part and having a rail structure in which parallel movement of the pressing part is formed;

It may be composed of a structure including.

In addition, the upper surface of the top cover may have an inclined structure whose thickness decreases toward the hinge portion, and the lower surface of the pressing portion of the pusher may have a tapered structure corresponding to the upper surface of the top cover.

Accordingly, the pressing portion may be easily moved in parallel from the end opposite to the electrode terminal in the direction of the electrode terminal to press the top cover to the upper surface of the battery case.

The inclined structure of the top cover and the pressing portion may be changed and determined according to a pressure applied to the upper surface of the battery case, and specifically, the inclination angle may be formed within a range of 5 to 15 degrees.

The present invention also provides a battery cell manufactured using the battery case sealing device.

The type of the battery cell is not particularly limited, but as a specific example, it may be a lithium secondary battery such as a lithium ion battery or a lithium ion polymer battery having advantages such as high energy density, discharge voltage, and output stability.

In general, 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, followed by drying, and if necessary, a filler may be further added to the mixture.

The positive electrode active material may include a layered compound such as lithium cobalt oxide (LiCoO2) or lithium nickel oxide (LiNiO2), or a compound substituted with one or more transition metals; Lithium manganese oxides such as chemical formula Li1+xMn2-xO4 (wherein x is 0 to 0.33), LiMnO3, LiMn2O3, and LiMnO2; Lithium copper oxide (Li2CuO2); Vanadium oxides such as LiV3O8, LiFe3O4, V2O5, and Cu2V2O7; Ni site-type lithium nickel oxide represented by the formula LiNi1-xMxO2 (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, and x = 0.01 to 0.3); Formula LiMn2-xMxO2 (here, M = Co, Ni, Fe, Cr, Zn or Ta, x = 0.01 ~ 0.1) or Li2Mn3MO8 (where M = Fe, Co, Ni, Cu or Zn) Lithium manganese composite oxide; LiMn2O4 in which Li in the formula is partially substituted with alkaline earth metal ions; Disulfide compounds; Fe2(MoO4)3 etc. can be mentioned, but it is not limited only to these.

The conductive material is typically added in an amount of 1 to 30% by weight based on the total weight of the mixture including the positive electrode active material. Such a conductive material is not particularly limited as long as it has conductivity without causing a chemical change in the battery, and examples thereof include graphite such as natural graphite or artificial graphite; Carbon blacks such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; Conductive fibers such as carbon fibers and metal fibers; 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 may be used.

The binder is a component that aids in bonding of an active material and a conductive material and bonding to a current collector, and is typically added in an amount of 1 to 30% by weight based on the total weight of the mixture including the positive electrode active material. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, recycled cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene , Polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butylene rubber, fluorine rubber, and various copolymers.

The filler is selectively used as a component that suppresses the expansion of the positive electrode, and is not particularly limited as long as it is a fibrous material without causing chemical changes in the battery, and examples thereof include olivine polymers such as polyethylene and polypropylene; Fibrous materials such as glass fiber and carbon fiber are used.

The negative electrode is manufactured by coating and drying a negative electrode active material on a negative electrode current collector, and if necessary, components as described above may be optionally further included.

Examples of the negative active material include carbon such as non-graphitized carbon and graphite-based carbon; LixFe2O3 (0≤x≤1), LixWO2 (0≤x≤1), SnxMe1-xMe'yOz (Me: Mn, Fe, Pb, Ge; Me': Al, B, P, Si, Group 1 of the periodic table, Metal complex oxides such as Group 2 and Group 3 elements, halogen, 0<x≦1; 1≦y≦3; 1≦z≦8); Lithium metal; Lithium alloy; Silicon-based alloys; Tin-based alloys; Metal oxides such as SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, and Bi2O5; Conductive polymers such as polyacetylene; Li-Co-Ni-based materials and the like can be used.

The separator and the separation film are 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 μm, and the thickness is generally 5 to 130 μm. Examples of such separation membranes include olefin-based polymers such as polypropylene having chemical resistance and hydrophobicity; Sheets or non-woven fabrics made of glass fiber or polyethylene are used. When a solid electrolyte such as a polymer is used as the electrolyte, the solid electrolyte may also serve as a separator.

In addition, in one specific example, in order to improve the safety of the battery, the separator and/or the separation film may be an organic/inorganic composite porous SRS (Safety-Reinforcing Separators) separator.

The SRS separator is manufactured by using inorganic particles and a binder polymer as active layer components on a polyolefin-based separator substrate, and at this time, the pore structure included in the separator substrate itself and the interstitial volume between inorganic particles as the active layer component It has a uniform pore structure formed.

In the case of using such an organic/inorganic composite porous separator, compared to the case of using a conventional separator, there is an advantage in that it is possible to suppress an increase in the thickness of the battery due to swelling during the formation process. When a polymer that can be gelled when impregnated with a liquid electrolyte is used, it can be used as an electrolyte at the same time.

In addition, since the organic/inorganic composite porous separator can exhibit excellent adhesion characteristics by controlling the content of inorganic particles and binder polymers as active layer components in the separator, the battery assembly process can be easily performed.

The inorganic particles are not particularly limited as long as they are electrochemically stable. That is, the inorganic particles that can be used 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 (eg, 0 to 5V based on Li/Li+) of the applied battery. Particularly, in the case of using inorganic particles having ion transfer capability, it is possible to improve the performance by increasing the ionic conductivity in the electrochemical device, so it is preferable that the ion conductivity is as high as possible. In addition, when the inorganic particles have a high density, it is difficult to disperse during coating, as well as a problem of weight increase during battery manufacturing, so it is preferable that the density is as small as possible. Further, in the case of an inorganic material having a high dielectric constant, the ionic conductivity of the electrolyte may be improved by contributing to an increase in the degree of dissociation of an electrolyte salt, such as a lithium salt, in a liquid electrolyte.

The lithium salt-containing non-aqueous electrolyte is composed of a polar organic electrolyte and a lithium salt. As the electrolyte, a non-aqueous liquid electrolyte, an organic solid electrolyte, an inorganic solid electrolyte, or the like is used.

As the non-aqueous liquid electrolyte, for example, N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma -Butyl lactone, 1,2-dimethoxy ethane, tetrahydroxy franc (franc), 2-methyl tetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolone, formamide, dimethylformamide, dioxolone , Acetonitrile, nitromethane, methyl formate, methyl acetate, phosphoric acid tryster, trimethoxymethane, dioxolone derivative, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbo Aprotic organic solvents such as nate derivatives, tetrahydrofuran derivatives, ethers, methyl pyropionate and ethyl propionate may be used.

As the organic solid electrolyte, for example, a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, a poly agitation lysine, a polyester sulfide, a polyvinyl alcohol, a polyvinylidene fluoride, A polymer or the like containing an ionic dissociating group may be used.

Examples of the inorganic solid electrolyte include Li such as Li3N, LiI, Li5NI2, Li3N-LiI-LiOH, LiSiO4, LiSiO4-LiI-LiOH, Li2SiS3, Li4SiO4, Li4SiO4-LiI-LiOH, and Li3PO4-Li2S-SiS2. Nitrides, halides, sulfates, and the like can be used.

The lithium salt is a material that is soluble in the non-aqueous electrolyte, for example, LiCl, LiBr, LiI, LiClO4, LiBF4, LiB10Cl10, LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, (CF3SO2) 2NLi, lithium chloroborane, lithium lower aliphatic carboxylic acid, lithium tetraphenylborate, imide, and the like can be used.

In addition, non-aqueous electrolytes include pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylene diamine, n-glyme, and hexaphosphate triamide for the purpose of improving charge/discharge properties and flame retardancy. , Nitrobenzene derivative, sulfur, quinone imine dye, N-substituted oxazolidinone, N,N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxy ethanol, aluminum trichloride, etc. May be. In some cases, in order to impart non-flammability, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride may be further included, and carbon dioxide gas may be further included in order to improve high-temperature storage characteristics.

The present invention also provides a battery pack consisting of a structure including one or more of the battery cells.

The present invention also provides a device including the battery pack as a power source.

The device may be selected from a mobile phone, a wearable electronic device, a portable computer, a smart pad, a netbook, a light electronic vehicle (LEV), an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, and a power storage device.

Since the structure of these devices and a method of manufacturing them are known in the art, detailed descriptions thereof will be omitted in the present specification.

The present invention also provides a method of sealing a battery case using the battery case sealing device,

(a) mounting an electrode assembly having a positive electrode, a negative electrode, and a separator structure interposed between the positive electrode and the negative electrode in the receiving part of the battery case;

(b) the process of seating and fixing the battery case in which the electrode assembly is mounted on the nest;

(c) sealing the upper and lower surfaces of the outer periphery of the battery case protruding from the nest by pressing and heating up and down by a sealing tool; And

(d) performing the process (c) and simultaneously pressing the nest toward the sealing tool by a pusher;

It provides a battery case sealing method comprising a.

As described above, the battery case sealing apparatus according to the present invention includes a pusher that sequentially presses the nest toward the sealing tool when the outer periphery of the battery case is sealed by the sealing tool, thereby degassing during the battery cell manufacturing process. It is possible to minimize the appearance defect of the battery cell by preventing wrinkles from being generated on the outer surface of the battery case after the (degas) process.

1 is an exploded view of a conventional lithium secondary battery;
Figure 2 is a schematic diagram of a battery case sealing device according to an embodiment of the present invention;
3 is a flow chart of a method of sealing a battery case using the battery case sealing device according to an embodiment of the present invention.

Hereinafter, it will be described with reference to the drawings according to an embodiment of the present invention, but this is for an easier understanding of the present invention, and the scope of the present invention is not limited thereto.

Figure 2 is a schematic diagram of a battery case sealing device according to an embodiment of the present invention.

Referring to FIG. 2, the battery case sealing device 100 includes a nest 110, a sealing tool 120, and a pusher 130.

The nest 110 has a structure in which the battery case 200 is embedded and fixed in a state in which the outer periphery of the battery case 200 is drawn out.

Specifically, the nest 110 is made of a fixing jig 111 and a top cover 112.

The fixing jig 111 has a structure in which the battery case is seated and fixed in a state in which the electrode assembly receiving portion of the battery case 200 is introduced, and the top cover 112 covers the upper surface of the battery case mounted on the fixing jig 111. It consists of a covering structure.

The top cover 112 is coupled to the right end of the fixing jig 111 in a hinge 113 structure, and rotates based on the hinge 113 to cover the upper surface of the battery case 200.

The pusher 130 has a structure in which the upper surface of the top cover 112 is sequentially pressed from the hinge 113 portion and circumferentially navigates toward the sealing tool 120.

Specifically, the pusher 130 is composed of a pressing part 131 and a fixing part 132.

The pressing part 131 has a structure whose lower surface corresponds to the upper surface of the top cover 112, and moves in parallel while in contact with the upper surface of the top cover 112 to move the top cover 112 to the upper surface of the battery case 200. It consists of a structure that pressurizes while rotating.

The fixing part 132 is coupled to one end of the pressing part 131, and a rail 133 structure in which the pressing part 131 is moved in parallel is formed.

In addition, the upper surface of the top cover 112 has an inclined structure whose thickness decreases toward the hinge 113, and the lower surface of the pressing portion 131 of the pusher 130 is tapered corresponding to the upper surface of the top cover 112 It consists of a structure. The inclined structure of the top cover 112 and the pressing part 131 has an inclination angle of 10 degrees.

3 is a flowchart illustrating a method of sealing a battery case using the battery case sealing device according to an embodiment of the present invention.

Referring to FIG. 3, in step (a), an electrode assembly having a positive electrode, a negative electrode, and a separator structure interposed between the positive electrode and the negative electrode is mounted in the receiving part of the battery case (S100).

In step (b), the battery case in which the electrode assembly is mounted is seated and fixed to the nest (S200).

In step (c), the upper and lower surfaces of the outer periphery of the battery case protruding from the nest are pressed and heated up and down by a sealing tool to seal (S300).

In step (d), while performing step (c), the nest is sequentially pressed toward the sealing tool by a pusher to prevent wrinkles from being generated on the upper surface of the battery case (S400).

Although the above description has been made with reference to the drawings according to the embodiments of the present invention, a person of ordinary skill in the field to which the present invention belongs will be able to perform various applications and modifications within the scope of the present invention based on the above contents.

Claims (13)

As a battery case sealing device that heats and seals the outer periphery of the battery case in which the electrode assembly is embedded in the battery cell manufacturing process,
A nest for installing and fixing the battery case with the outer periphery of the battery case protruding;
A sealing tool for sealing by pressing and heating the upper and lower surfaces of the protruding outer periphery of the battery case up and down; And
When the outer periphery of the battery case is sealed by the sealing tool, the nest is sequentially placed toward the sealing tool to prevent wrinkles from being generated on the outer surface of the battery case after the degas process during the battery cell manufacturing process. A pusher to pressurize;
Including,
The nest is,
A fixing jig for mounting and fixing the battery case in a state in which the electrode assembly receiving part of the battery case is introduced; And
It includes a top cover (top cover) covering the upper surface of the battery case mounted on the fixing jig,
The pusher,
A pressing portion having a structure having a lower surface corresponding to the upper surface of the top cover, and moving in parallel while in contact with the upper surface of the top cover to rotate the top cover to the upper surface of the battery case and pressurizing; And
It is coupled to one end of the pressing portion, and includes a fixing portion having a rail structure in which parallel movement of the pressing portion is formed,
The top cover is coupled to one end of the fixing jig in a hinge structure, and is a structure capable of covering the upper surface of the battery case by rotating based on the hinge portion,
The upper surface of the top cover has an inclined structure whose thickness decreases toward the hinge, and the lower surface of the pressing part of the pusher has a tapered structure corresponding to the upper surface of the top cover,
The pusher is a battery case sealing device, characterized in that driving toward the sealing tool while sequentially pressing the upper surface of the top cover from the hinge portion. The battery case sealing device according to claim 1, wherein the battery case is made of a laminate sheet including a resin layer and a metal layer. The battery case sealing device according to claim 1, wherein the outer periphery of the battery case to be sealed is one side in which the electrode terminals of the battery case are formed. delete delete delete delete delete The battery case sealing device according to claim 1, wherein the inclined structure of the top cover and the pressing portion has an inclination angle of 5 to 15 degrees. delete delete delete A method of sealing a battery case using the battery case sealing device according to claim 1,
(a) mounting an electrode assembly having a positive electrode, a negative electrode, and a separator structure interposed between the positive electrode and the negative electrode in the receiving part of the battery case;
(b) the process of seating and fixing the battery case in which the electrode assembly is mounted on the nest;
(c) sealing the upper and lower surfaces of the outer periphery of the battery case protruding from the nest by pressing and heating up and down by a sealing tool; And
(d) performing the process (c) and simultaneously pressing the nest toward the sealing tool by a pusher;
Battery case sealing method comprising a.

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