KR20140000489A - Secondary battery and fabricating method of the same, and cell moudle with the same - Google Patents

Abstract

The present invention relates to a technique capable of performing the stable mold of a pouch structure. Especially, in a molding process of a secondary battery, a heating-pressure process and a cooling process are successively performed to obtain moldability and processing property. Therefore, a pluse process is realized. [Reference numerals] (AA) First sheet; (BB) Second sheet; (CC) Electrode assembly align; (DD) Pulse type molding process; (EE) Heating-pressure(60-100째); (FF) Cooling at room temperatures(60-100째)

Description

Secondary battery and method for manufacturing same, medium and large battery module including the same {SECONDARY BATTERY AND FABRICATING METHOD OF THE SAME, AND CELL MOUDLE WITH THE SAME}

The present invention relates to a technology capable of stable molding of a pouch structure and a secondary battery manufactured accordingly.

In recent years, lithium secondary batteries capable of charging and discharging, light weight, high energy density and high output density have been widely used as energy sources of wireless mobile devices. In addition, hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs) as alternatives to solve air pollution and greenhouse gas problems of existing internal combustion engine cars using fossil fuels such as gasoline and diesel vehicles. ), And electric vehicles (EVs), have been proposed, and lithium secondary batteries are attracting attention as a power source of such internal combustion engine replacement vehicles.

Lithium secondary batteries are classified into lithium ion batteries using liquid electrolytes and lithium polymer batteries using polymer electrolytes according to the type of electrolyte, and are classified into cylindrical, square or pouch types according to the shape of the exterior material in which the electrode assembly is accommodated.

Among them, the pouch type uses a pouch case composed of a metal layer (foil) and a multi-layered film of a synthetic resin layer coated on the upper and lower surfaces of the metal layer. It is possible to significantly reduce the weight of the battery is possible, there is an advantage that can be changed in various forms.

The pouch sheathing material is composed of an upper sheathing material and a lower sheathing material formed by folding the middle of the rectangular sheathing material in the longitudinal direction of one side thereof. The lower sheathing material has a space for accommodating the electrode assembly through a press process. . In the space portion of the lower housing member, various electrode assemblies having a structure in which a plate-shaped anode, a separator, and a cathode are stacked are accommodated. Then, the electrolyte is injected, and the edges around the lower facer space portion and the edges of the upper facer corresponding thereto are closely contacted with each other and heat-sealed to the close contact portion, thereby forming a sealed pouch type secondary battery.

FIG. 1 schematically shows a general structure of a typical conventional pouch-type secondary battery as an exploded perspective view.

Referring to FIG. 1, the pouch type secondary battery 1 includes an electrode assembly 10, electrode tabs 31 and 32 extending from the electrode assembly 10, and electrodes welded to the electrode tabs 31 and 32. And a battery case 20 accommodating the leads 51 and 52 and the electrode assembly 1.

The electrode assembly 10 is a power generator in which a positive electrode and a negative electrode are sequentially stacked in a state where a separator is interposed therebetween, and the electrode assembly 10 has a stack type or a stack / fold type structure. The electrode tabs 31, 32 extend from each pole plate of the electrode assembly 10, and the electrode leads 51, 52 are welded, for example, with a plurality of electrode tabs 31, 32 extending from each pole plate. Each is electrically connected to each other, and part of the battery case 20 is exposed to the outside. In addition, an insulating film 53 is attached to a portion of the upper and lower surfaces of the electrode leads 51 and 52 to increase the sealing degree with the battery case 20 and to secure an electrical insulating state.

In addition, since a plurality of positive and negative electrode tabs 31 and 32 are integrally coupled to form a welded portion, the inner upper end of the battery case 20 is spaced apart from the upper end surface of the electrode assembly 10 by a predetermined distance and is welded. The negative tabs 31 and 32 are bent in a substantially V-shape (also referred to as a V-forming part 41 and 42 where the coupling portion of the electrode tabs and the electrode leads is formed). The battery case 20 is made of an aluminum laminate sheet, provides a space for accommodating the electrode assembly 10, and has a pouch shape as a whole. The secondary battery includes the electrode assembly 10 embedded in the battery case 20, the electrolyte assembly (not shown) is injected, and then the outer peripheral surface of the battery case 20 is in contact with the upper laminate sheet and the lower laminate sheet. It is manufactured through a process of heat fusion.

However, in the case of the battery case consisting of aluminum lamination sheet in the above-described process, the electrode assembly 10 is disposed on the sheet divided into the upper and lower, and then the molding to give a constant shape to implement the final outer shape In general, the mold is pressed at room temperature to form a forming cup. However, in this process, a lot of stress is applied to the edge of the forming cup (forming cup), the strain of this portion is shown to be larger than other areas. In particular, when the thickness of the electrode assembly is increased in order to increase the capacity of the cell, the depth of the forming cup must be deepened. Such excessive deformation causes cracking of the polymer film at the edge of the pouch. Will occur. The occurrence of such cracks is a problem caused by excessive stress concentrated in the local portion, in particular, the destruction of the polymer layer of the upper and lower sheets forming the pouch leads to a problem of causing corrosion of the aluminum sheet to shorten the life of the final cell.

The present invention has been made in order to solve the above problems, an object of the present invention is to continuously heat the molding mold in the molding process of forming the upper and lower sheets forming the packaging material in the process of manufacturing a pouch type secondary battery after molding at room temperature continuously By introducing a process to cool in, it is possible to implement a reliable secondary battery by removing the occurrence of cracks due to deformation of the sheet material.

As a means for solving the above problems, the present invention implements a pulse type (pluse) process to ensure the formability and processability by continuously implementing the heat pressing and cooling process in the molding process of the pouch of the secondary battery do.

Specifically, the present invention is a pulse type molding for forming the first sheet and the second sheet by applying an alignment process and a heating condition and a cooling condition to accommodate the electrode assembly between the first sheet and the second sheet facing each other It is possible to provide a method for manufacturing a secondary battery comprising the step. In this case, the pulse type molding process, the heating conditions to mold the first sheet and the second sheet by heating the temperature of the mold to 60 ℃ ~ 200 ℃, after the heating conditions are performed, the first sheet And it may be implemented as a process of cooling (cooling) by applying a cooling condition of room temperature to the second sheet.

The secondary battery manufactured by the manufacturing process according to the present invention is a fusion of the first sheet and the second sheet is an outer portion of the receiving portion and the receiving portion of the electrode assembly disposed in a structure inserted between the first sheet and the second sheet. Although provided with a sealing portion as an area, the density of the polymer layer forming the side surface of the receiving portion may be implemented in a structure satisfying the range of 0.7 ~ 0.9 of the density of the sealing portion.

In this case, the first sheet and the second sheet in the above-described secondary battery, a structure in which at least two or more polymer layers are provided on one surface of the metal layer or the other surface facing the one surface, in particular, the metal layer of the polymer layer The polymer layer in contact with may be configured as a material having a higher melting point than other polymer layers.

According to the present invention, in the process of manufacturing a pouch-type secondary battery, in the forming process of forming the upper and lower sheets forming the packaging material, by introducing a process of heating the molding mold to cool continuously at room temperature after molding, cracks due to deformation of the sheet material Eliminating the occurrence of the has the effect of implementing a reliable secondary battery.

In particular, it is possible to improve the formability by forming by heating, and then to recover the state of the polymer layer constituting the flexible sheet through a cooling process to prevent the processability due to friction is also realized. .

1 is a principal part perspective view showing the structure of a conventional pouch type secondary battery.
2 is a block diagram illustrating a manufacturing process of a secondary battery according to the present invention.
3 is a cross-sectional conceptual view illustrating main parts of a secondary battery according to the present invention.
4 shows the configuration of a sheet constituting the pouch according to the present invention.
5 and 6 are a cross-sectional conceptual view and an exploded perspective view of the main portion showing the structure of the secondary battery according to the present invention.
Figure 7 shows the actual image of the edge portion of the pouch applying the manufacturing process according to the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and operation according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description with reference to the accompanying drawings, the same reference numerals denote the same elements regardless of the reference numerals, and redundant description thereof will be omitted. The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

2 is a process block diagram showing a manufacturing process of a secondary battery according to the present invention.

Referring to the drawings, the manufacturing process of the secondary battery according to the present invention is the first sheet by applying an heating process and a heating condition and cooling conditions to accommodate the electrode assembly between the first sheet and the second sheet facing each other And a pulsed molding process of molding the second sheet. Herein, the pulse type molding process is defined as a process of repeating heating and cooling, and in particular, in the present invention, the temperature of the mold is raised from the initial temperature of the process to a specific temperature for the molding process, and then, after forming the pouch, the normal temperature is again. By implementing a continuous process to perform the cooling to improve the fairness afterwards.

Specifically, first, the first sheet and the second sheet forming the pouch of the secondary battery are loaded, and the process of arranging and inserting the electrode assembly therebetween (alignment process) is performed. In this case, the first sheet and the second sheet may apply a structure in which a polymer is laminated on a metal layer. The metal layer maintains an appropriate thickness, prevents water vapor and gas from penetrating from the outside to the inside, and serves to prevent leakage of the electrolyte. The material constituting the metal layer is an alloy of iron (Fe), carbon (C), chromium (Cr) and manganese (Mn), iron (Fe), carbon (C), chromium (Cr) and nickel (Ni). Alloy, aluminum (Al), copper (Cu) or any one selected from the equivalents may be used, but is not limited thereto. However, when the metal layer is made of a material containing iron, mechanical strength is increased, and when the material is made of aluminum, flexibility is improved. Usually, an aluminum metal sheet is used preferably. The polymer layer may be applied to any one selected from PE, urethane, PET, PI, NY, PP, CPP, fluorine resin or a mixture of two or more materials.

Next, the molding process according to the present invention is performed by using a mold on the outer parts of the first sheet and the second sheet, that is, the outer parts of the region in which the electrode assembly is accommodated. In this case, the molding process according to the present invention is preferably performed by a pulsed molding process, that is, a heating pressing process in which a heat source is supplied to the mold to raise the temperature of the mold and then press the mold. In this case, the heating conditions for heating the mold is preferably performed to mold the first sheet and the second sheet by heating the temperature of the mold to 60 ℃ ~ 200 ℃. It is not possible to obtain the effect of heating during the molding process in the case of performing heat compression by forming at a temperature lower than 60 ° C., and when the heating condition is applied at a temperature higher than 200 ° C., the polymer layer formed on the sheet itself is This is because the moldability cannot be maintained by melting.

In particular, the pulse type molding process according to the present invention is characterized in that the molding is completed at the same time as the above-described heating conditions are applied, and then the process of performing cooling at room temperature can be continued continuously. In this case, the cooling conditions according to the cooling is performed by a process of cooling the molded first sheet and the second sheet in an environment of 15 ° C. to 25 ° C., or by lowering the temperature of the mold itself to 15 ° C. to 25 ° C. It can be carried out in the process.

In general, in the pulse type molding process according to the present invention, after arranging the electrode assembly between the first sheet and the second sheet, the electrode assembly is accommodated by performing heating and cooling using a mold on an outer portion of the region in which the electrode assembly is accommodated. It can be compressed in a process of forming a forming depth. This increases the flexibility (flexibility) of the polymer layer forming each sheet to facilitate deformation, thereby increasing the limit of the molding. This reduces the stress on the local area constituting the pouch, thereby preventing the pouch from being destroyed. In general, when the process is carried out by securing the ductility in a heated state, the polymer layer in the heated state is stretched, but the frictional force of the polymer layer of the pouch increases, and this increased frictional force is different after molding in the process When the transfer to the process does not slip, there is a problem that can not proceed after the process. To solve this problem, the temperature is lowered again to increase the fairness such as transportability to the pouch.

3 is a schematic cross-sectional view illustrating a schematic configuration of a secondary battery after a molding process manufactured by a manufacturing process according to the present invention.

As shown, the secondary battery manufactured according to the present invention described above, the receiving portion (X) of the electrode assembly 130 is arranged in a structure that is inserted between the first sheet 110 and the second sheet 120. And a sealing portion (Y) that is a fusion region of the first sheet and the second sheet, which is an outer surface of the accommodating portion, wherein the density of the polymer layer forming the side surface of the accommodating portion is 0.7 to 0.9 times the density of the sealing portion. It can be implemented with a satisfactory structure. In particular, as described above, the polymer layer density of the portion forming the bent portion (edge portions a1 and a2) among the portions forming the side surface is 0.7 to 0.9 times the range of the polymer layer density of the sealing portion (Y). More preferably, it is implemented with a satisfactory structure. Cracks generated by the molding is generated locally a lot of the above-described bent portion, according to the processing method according to the invention it is possible to eliminate this problem.

That is, in the molding of the pouch, the conventional molding technique has a very strong force applied to the local part, so that the strength or density of the stretched part is significantly lower than that of other parts, resulting in cracking of the metal layer inside the pouch. According to the process according to the invention, even if the side (A, B) of the receiving portion (X) in which the electrode assembly is accommodated is stretched, it is possible to maintain the thickness, strength, and density of the constant polymer layer, After stretching by the cooling process, it is possible to have a constant thickness and strength without being affected by external processes.

As described above, the first sheet or the second sheet according to the present invention may utilize a structure in which a polymer layer is formed on the metal layer, and more specifically, on one side or one side of the metal layer constituting the first sheet or the second sheet. It may be composed of a plurality of coating layers that are coated on the other side opposite.

4 illustrates a cross-sectional structure of the first sheet or the second sheet according to the present invention. In general, an outer resin layer 121 formed on one surface of the metal layer 122 and an inner resin layer 123 on the other surface of the first sheet or the second sheet. It may be implemented in a structure having a), not limited to this, each resin layer may be implemented in a plurality of layers.

In particular, in a structure such as an auxiliary resin layer 124 which is added on a resin layer in direct contact with the metal layer 122 such as the outer resin layer 121 or the inner resin layer 123, the layer directly faces the metal layer. Silver may be implemented to be configured as a material having a higher melting point of the remaining auxiliary resin layer. In the drawings, a structure stacked on the inner resin layer 123 will be described.

That is, in the case of the resin layer in contact with the metal layer 122, it can be configured as a material having a melting point of 20 ~ 30 ℃ higher than the sub-layer than the other auxiliary resin layer. In this case, in the hot pressing process according to the present invention, the layer having a lower melting point is first melted to increase the sealing property, and the layer directly facing the metal layer does not melt, so that the metal layers do not directly contact each other. Will not. That is, the insulating properties can be improved by suppressing contact between the metal layers.

In particular, in this case, it is preferable that the total thickness of the internal resin layer formed inside the metal layer is within a range of 20 to 100 μm. When the inner resin layer is thinner than 20 μm, a fatal defect that causes the resin layer to be pushed out during sealing and decreases in sealing strength or insulation property due to a decrease in thickness occurs. In addition, when the inner resin layer is thicker than 100 μm, there is a problem that the battery performance is lowered due to an increase in the moisture penetration area by the inner resin layer. The inner resin layer is at least one material selected from polyolefin resins, polyurethane resins, and polyimide resins, but polyethylene terephthalate (PET), Ny (nylon), peroxyacetyl nitrate (PAN), polypropylene (PP), and fluorine-based resins. Any one material selected from resins can be used.

5 and 6 illustrate an example of a structure in which a first cup and a second sheet which are applied to a medium-large module are formed simultaneously, rather than a single cup that forms only the second sheet described with reference to FIG. 4. That is, when the first sheet 110 and the second sheet 120 are molded, the above-described process according to the present invention can be applied as it is. That is, after arranging the first sheet 110 and the second sheet 120, by supplying a heat source to the mold to heat the temperature of the mold to 60 ℃ ~ 200 ℃ molding for the first sheet and the second sheet Is performed, and the molding is completed at the same time as the above-described heating conditions are applied, and then the first and second sheets are cooled in an environment of 15 ° C. to 25 ° C., or the temperature of the mold itself is Lower the temperature to 15 ℃ ~ 25 ℃ can be carried out by the process of cold pressing.

Of course, in the above double cup, the advantageous effects of the present invention, which can be realized in the molding of the above-described structure, can be realized.

That is, the side (C, D) of the receiving portion for receiving the electrode assembly 130 is different from the structure of Figure 3 in that both the first sheet and the second sheet is implemented, but the side of each receiving portion (X) The density of the polymer layer forming the edge portion (b1, b2) in the can be implemented in a structure that satisfies the range of 0.7 ~ 0.9 times the density of the sealing portion (Y), which is the crack of the edge portion generated by the molding Can be significantly reduced. This can be confirmed through the actual processing photo of FIG. 7 to be described later.

Thereafter, the electrode assembly 130 is disposed in the molded first sheet 110 and the second sheet 120, and thereafter, an accommodation groove between the molded first sheet 110 and the second sheet 120 is provided. The electrolyte is injected into the sealant and subjected to a sealing process.

FIG. 7 illustrates that when molding is performed by applying a pulse molding process to the first sheet 110 and the second sheet 120 according to the present invention, the molding depth is sequentially increased to 3 mm, 4 mm, 4.5 mm, and 5 mm. Even in the case of processing, the photo of the product after the actual process is shown in which the cracks do not occur in the above-described bent portion (edge portion) and the surfaces of the inner side and the outer side of the edge portion are smoothly formed. .

While one embodiment of the present invention has been described above with reference to the drawings, those skilled in the art to which the present invention pertains will be able to make various applications and modifications within the scope of the present invention.

Hereinafter, the present invention will be described in more detail with reference to the following Examples, but the present invention is not limited thereto.

Example

An aluminum foil metal foil layer was formed on an inner layer made of a CPP film having a thickness of 40 μm, and then a first layer of an inner resin having a thickness of 20 μm was formed on the aluminum metal layer by using a polyethylene terephthalate polymer. Then, an inner resin second layer having a thickness of 20 mu m was formed on the inner resin first layer by CPP (non-stretched polypropylene). Then, a pouch case was manufactured by laminating a nylon layer serving as an outer layer on the opposite side of the aluminum metal layer on which the inner resin first layer was formed.

Comparative Example

In the above embodiment, a pouch packaging material including a conventional inner layer / metal layer / outer layer that does not include a metal oxide film was manufactured, and a molding process was performed using a general mold.

Experimental Example

Using the pouch packaging material prepared in Examples and Comparative Examples, a conventional electrode assembly was placed therein, heated and molded in a range of 100 ° C., and then cooled at room temperature. Then, the failure rate due to the cracking of the insulating properties and pouches were evaluated as follows, and the results are shown in Table 1 below.

Total manufactured cells Insulation Batteries Cracked water A good battery Example 100 3 3 94 Comparative Example 100 25 20 55

Insulation Characteristics: The resistance between the aluminum of the packaging metal layer of the battery and the cathode of the battery was measured using a megaohmmeter, and the resistance value of 10 Mohm or less was evaluated as defective.

Crack occurrence: The defect was evaluated by the presence of microcracks generated through visual inspection.

As can be seen from the results of Table 1, in the case of the present invention it can be seen that the occurrence of cracks and the occurrence of poor insulation.

The electrode assembly to be applied in the present invention is a jelly-roll (wound) electrode assembly having a structure in which the long sheet-type anodes and cathodes are wound with a separator interposed therebetween, and a plurality of anodes and cathodes cut in units of a predetermined size. It is divided into a stack type (laminated) electrode assembly sequentially stacked with a separator interposed therebetween. The stacked structure and the stacked / folded structure are preferable. Since the stacked structure is well known in the art, a description thereof will be omitted herein. Details of the electrode assembly of the stack / foldable structure are disclosed in Korean Patent Application Publication Nos. 2001-0082058, 2001-0082059, and 2001-0082060 of the present applicant. Is incorporated by reference.

Hereinafter, specific materials and structural features of the components constituting the electrode assembly to be applied to the embodiment according to the present invention will be described.

Anode structure

In the present invention, the unit electrode is divided into an anode or a cathode, and the full cell and the bicell are manufactured by mutually bonding the anode and the cathode with a separator interposed therebetween. The positive electrode is prepared by, for example, applying a mixture of a positive electrode active material, a conductive material, and a binder onto a positive electrode current collector, followed by drying and pressing. If necessary, a filler may be further added to the mixture.

[Positive collector]

The cathode current collector generally has a thickness of 3 to 500 mu m. Such a positive electrode current collector is not particularly limited as long as it has high conductivity without causing chemical change in the battery. For example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel Surface-treated with carbon, nickel, titanium, silver or the like on the surface of 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.

[Positive electrode active material]

The cathode active material may be a lithium secondary battery, for example, a layered compound such as lithium cobalt oxide (LiCoO ₂ ) or 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 , Cu ₂ V ₂ O ₇ and the like; Ni-site type lithium nickel oxide represented by the formula LiNi _{1 - x} M _x O ₂ , wherein 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; and the like, but Fe ₂ (MoO _{4) 3,} but is not limited to these.

The conductive material is usually added in an amount of 1 to 50% 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 that 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 50 wt% 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 inhibiting expansion of the positive electrode, and is not particularly limited as long as it is a fibrous material without causing chemical change in the battery. Examples of the filler include olefinic polymers such as polyethylene and polypropylene; Fibrous materials such as glass fibers and carbon fibers are used.

Cathode structure

The negative electrode is manufactured by coating, drying, and pressing a negative electrode active material on a negative electrode current collector, and optionally, the conductive material, binder, filler, and the like as described above may be further included.

[Cathode collector]

The negative electrode current collector is generally made to have a thickness of 3 to 500 mu m. Such a negative electrode current collector is not particularly limited as long as it has conductivity without causing chemical change in the battery. For example, the surface of copper, stainless steel, aluminum, nickel, titanium, calcined 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.

[Cathode active material]

The negative electrode active material may include, for example, carbon such as non-graphitized carbon or 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 ≦ 1; 1 ≦ y ≦ 3; 1 ≦ z ≦ 8); 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.

[Separation membrane]

The full cells are placed on the separator sheet having a long length and then wound in a structure in which the separator sheet is interposed therebetween. Each full cell should be laminated so that the anode and the cathode face each other while the separator film is interposed therebetween. The separator sheet may have an extended length wrapping the electrode assembly once after winding up, and the outermost end of the separator sheet may be fixed by heat fusion or tape. For example, a thermal welder or a hot plate is brought into contact with the finished separator sheet so that the separator sheet itself is melted by heat and adhesively fixed. This allows the pressure to be maintained continuously, thereby enabling stable interfacial contact between the electrode and the separator sheet.

As long as the separator interposed between the anode and the cathode of the separator sheet or cell has an insulating property and a porous structure capable of moving ions, the material thereof is not particularly limited, and the separator and the separator sheet may or may not be the same material. It may be.

The separator or separator sheet may be a thin insulating film having high ion permeability and mechanical strength. The separator or separator sheet generally has a pore diameter of 0.01 to 10 mu m, 300 mu m. Examples of the separator or separator sheet include olefin polymers such as polypropylene, which is resistant to chemicals 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. Preferably, a multilayer film produced by a polyethylene film, a polypropylene film, or a combination of these films, or a film made of polyvinylidene fluoride, polyethylene oxide, polyacrylonitrile, or poly A polyvinylidene fluoride hexafluoropropylene copolymer or the like, or a polymer film for a gel-type polymer electrolyte.

It is preferable that the separator has an adhesive function by thermal fusion to form a full cell or a bicell, and the separator sheet does not necessarily have such a function, but an adhesive function is used to easily perform a winding process. It is desirable to.

In addition, in the present invention, an electrode is disposed on one separator to form a full cell or a bicell, and the structure is illustrated in a form in which it is wound in one direction or wound in a zigzag direction, but is not necessarily limited thereto. Of course, the lamination may be applied to a stacked structure in the form of a separate intervening electrode between the electrodes.

The secondary battery according to the present invention may be applied to a medium-large battery module having a unit cell as a unit cell, as well as a power tool when applied to a battery pack including a battery module; Electric vehicles selected from the group consisting of electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs); E-bikes; E-scooters; Electric golf cart; Electric truck; And it can be used as one or more power source selected from the medium-large device group consisting of electric commercial vehicles.

The medium-large battery module is configured to provide a high output capacity by connecting a plurality of unit cells in series or in series / parallel manner, which is well known in the art, and thus, description thereof is omitted herein.

In the foregoing detailed description of the present invention, specific examples have been described. However, various modifications are possible within the scope of the present invention. The technical idea of the present invention should not be limited to the embodiments of the present invention but should be determined by the equivalents of the claims and the claims.

110: first sheet
120: second sheet
121: outer resin layer
122: metal layer
123: inner resin layer
124: auxiliary resin layer
130: electrode assembly
X: receptacle
Y: sealing part
A, B: side part

Claims (16)

An alignment process for accommodating the electrode assembly between the first and second sheets facing each other; and
A pulse type molding process of molding the first sheet or the second sheet by applying heating and cooling conditions;
Wherein the secondary battery is manufactured by a method comprising the steps of:
The method according to claim 1,
The pulse forming process,
The heating condition is a method of manufacturing a secondary battery is a step of molding the first sheet or the second sheet by heating the temperature of the mold to 60 ℃ ~ 200 ℃.
The method according to claim 2,
The pulse forming process,
After the heating condition is performed,
A method of manufacturing a secondary battery, which is a step of cooling by applying cooling conditions at room temperature to the first sheet or the second sheet.
The method according to claim 3,
The first sheet and the second sheet,
A method of manufacturing a secondary battery applying a structure consisting of a lamination of a polymer layer and a metal layer.
The method of claim 4,
The polymer layer,
PE, urethane, PET, PI, NY, PP, CPP, fluorine resin of any one selected from the group consisting of or a mixture of two or more materials of the secondary battery manufacturing method.
The method of claim 4,
The step of applying the cooling conditions,
A method of manufacturing a secondary battery, which is a step of cooling and pressing the temperature of the mold to 15 ° C. to 25 ° C.
The method of claim 4,
The pulse forming process,
After the electrode assembly is aligned between the first sheet and the second sheet,
And forming a receiving depth of the electrode assembly by performing heating and cooling using a mold on an outer portion of the region in which the electrode assembly is accommodated.
The secondary battery manufactured by the manufacturing method of any one of Claims 1-7.
The method according to claim 8,
The secondary battery,
Receiving portion of the electrode assembly disposed in a structure inserted between the first sheet and the second sheet; And
And a sealing part that is a fusion region of the first sheet and the second sheet, which is an outer surface of the receiving part.
The secondary battery of which the density of the polymer layer forming the side of the receiving portion satisfies the range of 0.7 ~ 0.9 of the density of the sealing portion.
The method of claim 9,
The first sheet and the second sheet,
A secondary battery having a structure in which at least two polymer layers are provided on one surface of the metal layer or on the other surface of the metal layer.
The method of claim 10,
The polymer layer in contact with the metal layer of the polymer layer,
Secondary battery configured as a material having a higher melting point than other polymer layers.
The method of claim 11,
The polymer layer in contact with the metal layer of the polymer layer,
Secondary battery configured as a material having a melting point 20 ℃ ~ 30 ℃ higher than other polymer layers.
The method of claim 10,
The polymer layer has a total thickness of 20 to 100 ㎛ within the secondary battery.
The method according to claim 8,
The electrode assembly is a secondary battery consisting of any one of a wound type, a stack type, or a stack / fold type structure.
The method of claim 10,
The metal layer may include,
Alloys of iron (Fe), carbon (C), chromium (Cr) and manganese (Mn), alloys of iron (Fe), carbon (C), chromium (Cr) and nickel (Ni), aluminum (Al), copper (Cu) or a secondary battery selected from any of the equivalents.
Medium and large battery module comprising a secondary battery according to claim 9 as a unit cell.

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