Title of Invention: Secondary battery manufacturing method and manufacturing equipment thereof
technical field
[One]
Cross Citation with Related Applications
[2]
This application claims the benefit of priority based on Korean Patent Application No. 10-2019-0148932 dated November 19, 2019, and all contents disclosed in the literature of the Korean patent application are incorporated as a part of this specification.
[3]
technical field
[4]
The present invention relates to a method for manufacturing a secondary battery capable of simultaneously increasing process performance and lifetime performance, and a manufacturing facility thereof.
background
[5]
In general, a secondary battery refers to a battery capable of charging and discharging unlike a primary battery that cannot be charged, and such secondary batteries are widely used in high-tech electronic devices such as phones, notebook computers, and camcorders.
[6]
The secondary battery is classified into a can-type secondary battery and a pouch-type secondary battery, and the can-type secondary battery includes an electrode assembly, an electrolyte, a can accommodating the electrode assembly and the electrolyte, and a cap assembly mounted in the opening of the can. The pouch-type secondary battery includes an electrode assembly, an electrolyte, and a pouch accommodating the electrode assembly and the electrolyte.
[7]
Meanwhile, the secondary battery manufacturing method includes a process of manufacturing an electrode assembly, a process of laminating and bonding the manufactured electrode assembly, and a process of accommodating the bonded electrode assembly together with an electrolyte in a case assembly.
[8]
However, in the secondary battery manufacturing method described above, when lamination is strengthened when bonding the electrode assembly, the bonding force between the electrode and the separator is improved, so that the process performance can be improved, but there is a problem in that the battery performance is weakened. Conversely, when lamination is weakened, there is a problem in that the bonding force between the electrode and the separator is weakened and defects occur.
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[9]
The present invention was invented to solve the above problems, and the present invention is a secondary battery manufacturing method capable of simultaneously increasing process performance and battery performance by laminating an electrode assembly over a set pressure and then aging at a high temperature to heat treatment, and its The purpose is to provide manufacturing equipment.
means of solving the problem
[10]
A secondary battery manufacturing method of the present invention for achieving the above object includes the steps of (a) manufacturing an electrode assembly by alternately stacking an electrode and a separator; (b) laminating the electrode assembly at a pressure of 5 kgf/cm 2 or more to bond the electrode and the separator included in the electrode assembly; (c) accommodating the electrode assembly in a battery case, injecting an electrolyte into the battery case, and then sealing the battery case to manufacture a spare battery; (d) activating the preliminary battery by charging and discharging; and (e) heat-treating the preliminary battery by aging the preliminary battery at a high temperature in a range of 60° C. to 100° C. for 1 hour to 6 hours.
[11]
The high-temperature aging in step (e) may be performed for 1 hour to 3 hours.
[12]
The high temperature aging in step (e) may be performed in the range of 75 ℃ to 90 ℃.
[13]
Step (d) may include a process of charging and discharging the spare battery one or more times, and a process of degassing.
[14]
The degassing may be performed by aging.
[15]
The step (d) includes: (d1) the process of first charging the spare battery; (d2) a process of primary room temperature aging of the primary charged spare battery at 23° C. to 27° C., (d3) after the process (d2), a process of primary high-temperature aging of the preliminary battery at 50° C. to 80° C.; (d4) after the process (d3), a process of secondary room temperature aging of the spare battery at 23°C to 27°C, and (d5) a process of first discharging the spare battery after the process (d4) can
[16]
An additional degassing process may be further included between the process (d4) and the process (d5).
[17]
The additional degassing may include opening the battery case of the spare battery and sealing the battery case again.
[18]
The process (d1) may be performed up to SOC 10 to 100.
[19]
The process (d2) may be performed for 1 to 5 days.
[20]
The process (d3) may be performed for 10 to 30 hours.
[21]
The process (d4) may be performed for 10 hours to 30 days.
[22]
In the process (d5), the discharge may proceed at SOC 90 at 6.5 C for 1 minute.
[23]
On the other hand, the secondary battery manufacturing equipment of the present invention is an electrode assembly manufacturing apparatus for manufacturing an electrode assembly by alternately stacking an electrode and a separator; a lamination device for laminating the electrode assembly at a pressure of 5 kgf/cm 2 or more to bond the electrode and the separator included in the electrode assembly; a spare battery manufacturing apparatus for manufacturing a spare battery by accommodating the electrode assembly and the electrolyte in a battery case; an activation device for activating the spare battery by charging and discharging; and a heat treatment device for manufacturing the secondary battery by aging the preliminary battery at a high temperature in a range of 60° C. to 100° C. for 1 hour to 6 hours.
Effects of the Invention
[24]
The secondary battery manufacturing method of the present invention includes (a) manufacturing an electrode assembly, (b) laminating the electrode assembly at a pressure of 5 kgf/cm 2 or more, (c) manufacturing a spare battery, (d) spare battery It is characterized in that it comprises the steps of activating, and (e) heat-treating the preliminary battery by high-temperature aging. Due to such a feature, it is possible to improve the ionic conductivity through deformation of the separator, and thus, it is possible to inhibit the increase in resistance by inducing a decrease in the OCV at the discharge end, and as a result, it is possible to prevent deterioration of the battery and improve the lifespan characteristics. can In particular, it is possible to non-destructively prevent deterioration of battery performance due to strong lamination. That is, the process performance and the battery performance can be improved at the same time.
[25]
That is, in the secondary battery manufacturing method of the present invention, the bonding strength between the electrode and the separator can be greatly increased by lamination at a pressure of 5 kgf/cm 2 or more, and aging at a high temperature in the range of 60°C to 100°C for 1 hour to 6 hours. By doing so, the concentration polarization resistance hindered by lamination can be improved, so that the battery performance can be improved.
[26]
In addition, in the secondary battery manufacturing method of the present invention, the high-temperature aging of step (e) is characterized in that it is performed in the range of 75°C to 90°C for 1 hour to 3 hours. Due to these characteristics, it is possible to effectively heat-treat the laminated electrode assembly at a pressure of 5 kgf/cm 2 or more, and as a result, the battery performance can be greatly improved.
[27]
Meanwhile, in the method for manufacturing a secondary battery of the present invention, step (d) includes a process of charging and discharging the spare battery one or more times, and a process of degassing. Due to these characteristics, it is possible to effectively charge and discharge the spare battery to activate it.
[28]
That is, in the secondary battery manufacturing method of the present invention, step (d) includes, (d1) the process of primary charging the preliminary battery, (d2) primary aging of the primary charged secondary battery at 23°C to 27°C at room temperature. process, (d3) after the process (d2), the preliminary high temperature aging of the spare battery at 50° C. to 80° C., (d4) after the step (d3), the preliminary battery is heated at 23° C. to 27° C. 2 A fourth step of aging at room temperature (S34), and (d5) after the step (d4), a step of first discharging the preliminary battery is characterized. Due to these characteristics, it is possible to significantly increase the charge/discharge efficiency of the spare battery.
[29]
Meanwhile, in the method for manufacturing a secondary battery of the present invention, an additional degassing process is further included between the process (d4) and the process (d5). can be discharged quickly, thereby increasing the charging and discharging efficiency.
Brief description of the drawing
[30]
1 is a view showing a secondary battery manufacturing equipment of the present invention.
[31]
2 is a flowchart illustrating a method for manufacturing a secondary battery of the present invention.
[32]
3 is a graph showing cycle characteristics according to Experimental Examples 1 and 2.
[33]
4 to 6 are graphs showing cycle characteristics according to Experimental Example 3.
[34]
7 is a discharge capacity graph that can confirm the concentration polarization resistance of the SOC section according to Experimental Example 4;
[35]
8 is a graph showing high temperature aging according to Experimental Example 5;
Best mode for carrying out the invention
[36]
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art can easily carry out the present invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.
[37]
[Secondary battery manufacturing apparatus of the present invention]
[38]
As shown in FIG. 1, the secondary battery manufacturing apparatus 100 of the present invention includes an electrode assembly manufacturing apparatus 110 for manufacturing an electrode assembly 10 by alternately stacking electrodes and a separator, and the electrode assembly 10. Lamination device 120 for bonding the electrode and the separator by laminating at a pressure of 5 kgf/cm 2 or more, the electrode assembly 10 and the electrolyte 20 are accommodated in the battery case 30 to prepare a spare battery 1a Aging the battery manufacturing device 130, the activation device 140 for activating by charging and discharging the spare battery 1a, and the spare battery 1a at a high temperature in the range of 60°C to 100°C for 1 hour to 6 hours to include a heat treatment device 150 for manufacturing the secondary battery (1).
[39]
Electrode assembly manufacturing device
[40]
The electrode assembly manufacturing apparatus 110 is for manufacturing an electrode assembly, and an electrode supply roller 111 for supplying an electrode 11 and a separator supply roller for supplying a separator 12 interposed between the electrode 11 . (112), a first cutter 113 for cutting the electrode 11 to a predetermined size, and a matching roller 114 for matching the cut electrode 11 and the separator 12 to be stacked alternately.
[41]
The electrode assembly manufacturing apparatus 110 having such a configuration manufactures the electrode assembly 10 by alternately stacking electrodes and separators.
[42]
lamination device
[43]
The lamination device 120 is for increasing the bonding strength of the electrode assembly, and a heating unit 121 that heats the electrode assembly 10 to raise it to a set temperature, and the electrode assembly 10 heated to a set temperature by rolling the electrode assembly ( A second cutter ( 123).
[44]
Here, the rolling roller 122 bonds the electrode 11 and the separator 12 by laminating the electrode assembly 10 at a pressure of 5 kgf/cm 2 or more.
[45]
That is, the secondary battery manufacturing facility 100 of the present invention can improve the concentration polarization resistance between the electrode and the separator, which was disturbed due to lamination, by aging the activated electrode assembly 10 at a high temperature, and accordingly, the electrode assembly ( 10) can be laminated at a pressure of 5 kgf/cm 2 or more, preferably 7 kgf/cm 2 or more, and as a result, the lifespan performance of the electrode assembly 10 can be greatly improved.
[46]
Spare battery manufacturing device
[47]
The preliminary battery manufacturing apparatus 130 includes an injection part 131 for injecting the electrolyte 20 into the battery case 30 in which the electrode assembly 10 is accommodated, and a sealing part 132 for sealing the opening of the battery case 30 . ), and thus the spare battery 1a can be manufactured.
[48]
activation device
[49]
The activation device 140 repeatedly activates charging and discharging of the spare battery 1a at a set voltage, thereby activating the spare battery 1a.
[50]
heat treatment device
[51]
The heat treatment device 150 heats the spare battery 1a by aging it at a high temperature in a range of 60° C. to 100° C. for 1 hour to 6 hours, and thus the secondary battery 1 can be manufactured.
[52]
Hereinafter, the secondary battery manufacturing method of the present invention will be described in detail with reference to the accompanying drawings.
[53]
[Method for manufacturing secondary battery of the present invention]
[54]
As shown in FIGS. 3 to 8, the secondary battery manufacturing method of the present invention includes the steps of (a) manufacturing an electrode assembly 10 by alternately stacking an electrode 11 and a separator 12, (b) bonding the electrode 11 and the separator 12 provided in the electrode assembly 10 by laminating the electrode assembly 10 at a pressure of 5 kgf/cm 2 or more, (c) the electrode assembly 10 in a battery case (30), and after injecting the electrolyte 20 into the battery case 30, sealing the battery case 20 to manufacture a spare battery 1a, (d) the spare battery 1a ) by charging and discharging to activate it, and (e) heat-treating the preliminary battery 1a by aging the preliminary battery 1a at a high temperature in a range of 60° C. to 100° C. for 1 hour to 6 hours. includes
[55]
(a) step
[56]
In step (a), the electrode assembly 10 is manufactured by alternately stacking the electrode 11 and the separator 12 through the electrode assembly manufacturing apparatus 110 . Here, the electrode 11 includes an anode and a cathode.
[57]
On the other hand, the positive electrode is manufactured by coating an electrode mixture, which is a mixture of a positive electrode active material, a conductive material, and a binder, on a positive electrode current collector and then drying the mixture, and if necessary, further adding a filler to the mixture.
[58]
The positive active material may include, for example, a layered compound such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), or a compound substituted with one or more transition metals; lithium manganese oxides of the formula Li1+xMn2-xO4 (where x is 0 to 0.33), LiMnO3, LiMn2O3, LiMnO2, and the like; 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 (wherein M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, and x = 0.01 to 0.3); represented by the formula LiMn2-xMxO2 (where M = Co, Ni, Fe, Cr, Zn or Ta, and x = 0.01 to 0.1) or Li2Mn3MO8 (where M = Fe, Co, Ni, Cu or Zn) lithium manganese composite oxide; lithium manganese composite oxide having a spinel structure represented by LiNixMn2-xO4; LiMn2O4 in which a part of Li in the formula is substituted with an alkaline earth metal ion; disulfide compounds; Fe2(MoO4)3 and the like may be included, but are not limited thereto.
[59]
The positive electrode current collector is generally made to have a thickness of 3 to 500 μm. 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. Carbon, nickel, titanium, silver, etc. surface-treated on the surface of the can be used. The current collector may increase the adhesion of the positive electrode active material by forming fine irregularities on the surface thereof, and various forms such as a film, sheet, foil, net, porous body, foam body, and nonwoven body are possible.
[60]
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. 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 fibers and metal fibers; 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; A conductive material such as a polyphenylene derivative may be used. Specific examples of commercially available conductive materials include acetylene black-based Chevron Chemical Company, Denka Singapore Private Limited, Gulf Oil Company, etc.), Ketjenblack, EC series (products of the Armak Company), the Vulcan XC-72 (products of the Cabot Company) and the Super P (products of the Timcal Company).
[61]
The binder is a component that assists in bonding between the active material and the conductive material and bonding to the 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 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 butyrene rubber, fluororubber, various copolymers, and the like.
[62]
The filler is optionally used as a component for inhibiting the expansion of the positive electrode, and is not particularly limited as long as it is a fibrous material without causing a chemical change in the battery. A fibrous material such as glass fiber or carbon fiber is used.
[63]
The negative electrode is manufactured by coating, drying and pressing the negative electrode active material on the negative electrode current collector, and may optionally further include a conductive material, a binder, a filler, and the like as described above as necessary.
[64]
The negative active material is one selected from the group consisting of crystalline artificial graphite, crystalline natural graphite, amorphous hard carbon, low crystalline soft carbon, carbon black, acetylene black, Ketjen black, super P, graphene, and fibrous carbon or more carbon-based materials, Si-based materials, LixFe2O3 (0≤x≤1), LixWO2 (0≤x≤1), SnxMe1-xMe'yOz(Me: Mn, Fe, Pb, Ge; Me': Al, B, metal complex oxides such as P, Si, elements of Groups 1, 2, and 3 of the periodic table, halogen;0
[69]
Preparation of anode
[70]
0.5Li2MnO3·0.5Li(Ni0.45Mn0.35Ni0.20)O2 was used as the cathode active material, and NMP (N-methyl-2) was used in a weight ratio of 90: 5: 4 with a conductive material (carbon black) and a binder (PVdF). -pyrrolidone) and mix to prepare a positive electrode mixture. Next, the positive electrode mixture is coated on an aluminum foil having a thickness of 20 μm to a thickness of 80 μm, then rolled and dried to prepare a positive electrode.
[71]
Preparation of the cathode
[72]
Artificial graphite is used as an anode, and a conductive material (carbon black), a conductive material (carbon black), and a binder (PVdF) are mixed in NMP (N-methyl-2-pyrrolidone) in a weight ratio of 95:3:2. A negative electrode mixture is prepared. Next, the negative electrode mixture is coated on a copper foil having a thickness of 20 μm to a thickness of 80 μm, then rolled and dried to prepare a negative electrode.
[73]
Preparation of electrode assembly
[74]
The electrode 11 and the separator 12 (DB0901, BA1 SRS composition, thickness: 18 μm, fabric 9 μm, SRS coated with a thickness of 4.5 μm per side of the SRS total 9 μm) including the positive and negative electrodes prepared as described above were applied to the electrode. The electrode assembly 10 is manufactured by supplying it through the assembly manufacturing apparatus 110 and alternately stacking it.
[75]
(b) step
[76]
In step (b), the electrode assembly 10 is laminated using a lamination device 120 at a pressure of 5 kgf/cm 2 or more, preferably 7 kgf/cm 2 or more, and the electrode 11 included in the electrode assembly 10 and The separation membrane 12 is bonded.
[77]

[78]
The change in the gap and the adhesive force between the electrode 11 and the separator 12 included in the electrode assembly 10 by laminating the electrode assembly 10 at a pressure of 3 kgf/cm 2 is shown in the graph of FIG. 3 .
[79]

[80]
The change in the gap and the adhesive force between the electrode 11 and the separator 12 included in the electrode assembly 10 by laminating the electrode assembly 10 at a pressure of 5 kgf/cm 2 or more is shown in the graph of FIG. 3 .
[81]

[82]
3 shows a change in the gap between the electrode 11 and the separator 12 included in the electrode assembly 10 in a state where the electrode assembly 10 is not laminated.
[83]
As a result, referring to FIG. 3, in the present invention, when the electrode assembly 10 is subjected to lamination at a pressure of 5 kgf/cm 2 or more and when lamination is not performed, it can be seen that the gap between the electrode and the separator is greatly reduced. have. At this time, the adhesive force (gf/20mm) of Comparative Example 1 is 0, the adhesive force (gf/20mm) of Experimental Example 1 is 6.7, and the adhesive force (gf/20mm) of Experimental Example 2 is 70.8. That is, when the process performance is significantly improved, it can be confirmed that the life performance is significantly reduced.
[84]
(c) step
[85]
In step (c), the electrode assembly 10 is accommodated in the battery case 30 using the preliminary battery manufacturing apparatus 130 , and the electrolyte 20 is injected into the battery case 30 , and then the battery case ( 20) is sealed to prepare a spare battery 1a.
[86]
On the other hand, the electrolyte uses a non-aqueous electrolyte, and the non-aqueous electrolyte consists of a liquid electrolyte and a lithium salt, and a non-aqueous organic solvent is used as the liquid electrolyte.
[87]
Examples of the non-aqueous organic solvent include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma -Butyl lactone, 1,2-dimethoxy ethane, tetrahydroxy franc, 2-methyl tetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane , acetonitrile, nitromethane, methyl formate, methyl acetate, phosphoric acid triester, trimethoxymethane, dioxolane derivative, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbo An aprotic organic solvent such as a nate derivative, a tetrahydrofuran derivative, ether, methyl pyropionate, or ethyl propionate can be used.
[88]
The lithium salt is a material readily 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 carboxylate, lithium tetraphenyl borate, imide, and the like can be used.
[89]
In addition, for the purpose of improving charge/discharge characteristics, flame retardancy, etc. in the electrolyte, for example, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, n-glyme, hexaphosphate triamide, nitro Benzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N,N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrrole, 2-methoxyethanol, aluminum trichloride, etc. may be added. . In some cases, in order to impart incombustibility, a halogen-containing solvent such as carbon tetrachloride and ethylene trifluoride may be further included, and carbon dioxide gas may be further included to improve high-temperature storage characteristics, and FEC (Fluoro-Ethylene) carbonate), propene sultone (PRS), and fluoro-ethlene carbonate (FEC) can be further included.
[90]
That is, in step (c), the electrode assembly is housed in a pouch-type battery case, and ethyl carbonate, dimethyl carbonate, and ethylmethyl carbonate are mixed in a volume ratio of 1:1:1, and 1M of LiPF6 is included as a lithium salt. A spare battery 1a is manufactured by adding the non-aqueous electrolyte.
[91]
(d) step
[92]
Step (d) is for activating the spare battery by charging and discharging, (d1) the process of primary charging the preliminary battery 1a, and (d2) the primary charged spare battery 1a at 23° C. to 27° C. In the process of primary room temperature aging, (d3) after the process (d2), the process of primary high temperature aging of the spare battery 1a at 50° C. to 80° C., (d4) after the process (d3), the preliminary Secondary room temperature aging of the battery 1a at 23° C. to 27° C., and (d5) a process of first discharging the spare battery 1a after the process (d4). Through this process, the spare battery 1a may be activated.
[93]
Here, the aging process is performed to improve the ionic conductivity of the separator through sufficient impregnation with an electrolyte.
[94]
Meanwhile, step (d) may include a process of charging and discharging the spare battery 1a one or more times, and a process of degassing, and the degassing may be performed by aging.
[95]
In addition, an additional degassing process may be further included between the process (d4) and the process (d5), wherein the additional degassing is for opening the battery case of the spare battery and sealing the battery case again. process may be included.
[96]
That is, according to the charging according to the activation process, the electrode active material is activated and the electrolyte is decomposed, so that gas is generated inside the battery. Therefore, a step of removing such a gas, that is, a degassing process is required. At this time, even by the aging process in which the spare battery is left unattended, the generated gas may be substantially removed.
[97]
Meanwhile, the degassing may also be performed by the aging process in which the spare battery is left unattended.
[98]
Meanwhile, the process (d1) is performed up to SOC 10 to 100. Specifically, it may be performed up to SOC 25 to 35. This is because the initial charge for activation does not need to be fully charged, and it is preferable in terms of process efficiency as well as forming a sufficiently stable passivation film even in the above range, and inducing initial gas generation.
[99]
On the other hand, the aging performed for stabilization of the passivation film formed by electrolyte impregnation, initial gas generation, and initial charging, the (d2) process is performed for 1 to 5 days, and the (d3) process is 10 hours to 30 hours is carried out, the process (d4) is performed for 10 hours to 30 days, and the process (d5) proceeds to discharge at SOC 90 at 6.5 C for 1 minute.
[100]
When the aging process is completed, the spare battery performs a primary discharge, in which case the primary discharge is completely discharged to near SOC 0.
[101]
In summary, in step (d), the preliminary battery 1a is first charged with SOC 30, and aged at room temperature for 3 days at 25°C. Next, after high temperature aging at 60 ° C. for 24 hours, and aging at room temperature for 20 days at 25 ° C., part of the pouch-type battery case is opened and degassed, and then SOC 0 is 1 Discharge the car. Thereafter, the process of charging to SOC 100 and discharging to SOC 0 is repeated two more times to complete the activation process.
[102]

[103]
A secondary battery is manufactured by charging the activated spare battery 1a to SOC 30, which is in the shipping state, and aging it at a high temperature for 1 hour at a temperature of 80°C.
[104]

[105]
A secondary battery is manufactured by charging the activated spare battery 1a to SOC 30, which is in the shipping state, and aging it at a high temperature for 3 hours at a temperature of 80°C.
[106]

[107]
A secondary battery is manufactured by charging the activated spare battery 1a to SOC 30, which is in the shipping state, and aging it at a high temperature for 6 hours at a temperature of 80°C.
[108]

[109]
A secondary battery was manufactured by charging the activated spare battery 1a to SOC 30, which is in the shipping state, and no separate treatment was performed.
[110]

[111]
Cycle characteristics of each of the secondary batteries prepared in Examples 1 to 3 and Comparative Example 2 were evaluated and shown in the graphs of FIGS. 4 to 6 .
[112]
Cycle characteristics, capacity retention rate according to the cycle, OCV change in voltage (E0D) maintained during rest after discharging, and resistance increase rate were measured. Repeat the process 100 times and measure.
[113]
Looking at the cycle characteristics of FIG. 4 , it can be seen that Examples 1 to 3 maintain capacity retention according to the cycle than Comparative Example 2.
[114]
Looking at the cycle characteristics of FIG. 5 , it can be seen that the OCV change in the voltage (E0D) maintained during rest after discharging is reduced.
[115]
Looking at the cycle characteristics of FIG. 6 , when high-temperature aging is performed in the activation step, it can be seen that the resistance is reduced as a result of comparison with the case where it is not, and thus, it can be confirmed that the lifespan characteristics are remarkably improved.
[116]
On the other hand, of course, although there is a difference in the OCV value, it can be confirmed that, in actuality, the change value does not show a significant difference in the capacity retention rate according to the cycle or the resistance increase when stored for 1 to 6 hours.
[117]
Therefore, even with an aging time of about 1 hour, the lifespan characteristics can be improved.
[118]

[119]
After confirming the difference in concentration polarization resistance by measuring the change in discharge capacity while discharging the secondary batteries prepared in Example 3 and Comparative Example 1 at 6.5 C for 1 minute for each interval of 10 changes from SOC 90 to SOC 10 , the result is shown in the graph of FIG. 7 below.
[120]
Referring to FIG. 7 , it can be confirmed that high discharge capacity is exhibited when high-temperature aging is performed. It is considered that this is because the concentration polarization resistance is improved by improving the ionic conductivity of the separator.
[121]
(e) step
[122]
In step (e), the preliminary battery 1a is heat-treated by aging the preliminary battery 1a at a high temperature in a range of 60° C. to 100° C. for 1 hour to 6 hours. Accordingly, the secondary battery 1 can be manufactured.
[123]
Meanwhile, the high-temperature aging of step (e) may be performed for 1 hour to 5 hours, more specifically, 1 hour to 3 hours.
[124]
When carried out for too little time, the intended effect of the present invention cannot be obtained, but when carried out for too long, the intended effect of the present invention can be achieved only by carrying out for 1 hour or more, and there is a significant difference On the other hand, since the process time is increased, it is not preferable.
[125]
Therefore, it can be carried out for 1 hour to 6 hours, and in consideration of fairness, it is more preferable to carry out for 1 hour to 3 hours.
[126]
On the other hand, the high temperature aging of step (e) may be performed in the range of 60 ℃ to 100 ℃, preferably 75 ℃ to 90 ℃.
[127]
When the temperature is lower than the above temperature, the time is too long or the temperature is not high enough to apply a deformation to the separator, so it is difficult to achieve the intended effect of the present invention. On the other hand, if it is too high, the active material and the like may be affected, and the battery performance may be deteriorated, which is not preferable.
[128]
In other words, according to the present invention, the intended effect can be achieved only by high-temperature aging of the secondary battery after the activation process has been completed in the state of SOC 25 to 35, which is shipping and charging, and can be caused by strong lamination when manufacturing the secondary battery. Battery performance degradation can be recovered non-destructively.
[129]

[130]
The preliminary battery 1a including the electrode assembly laminated at a pressure of 5 kgf/cm 2 is aged at 75° C. for 3 hours at a high temperature, and the cycle change is shown in the graph of FIG. 8 .
[131]

[132]
A separate treatment is not performed on the spare battery 1a including the electrode assembly laminated at a pressure of 5 kgf/cm 2 .
[133]
As a result, referring to FIG. 8 , it can be seen that the cycle degraded due to lamination is recovered when high-temperature aging is performed.
[134]
The scope of the present invention is indicated by the claims to be described later rather than the above detailed description, and various embodiments derived from the meaning and scope of the claims and their equivalent concepts are possible.
Claims
[Claim 1]
(a) manufacturing an electrode assembly by alternately stacking an electrode and a separator; (b) laminating the electrode assembly at a pressure of 5 kgf/cm 2 or more to bond the electrode and the separator included in the electrode assembly; (c) accommodating the electrode assembly in a battery case, injecting an electrolyte into the battery case, and then sealing the battery case to manufacture a spare battery; (d) activating the preliminary battery by charging and discharging; and (e) heat-treating the preliminary battery by aging the preliminary battery at a high temperature in a range of 60°C to 100°C for 1 hour to 6 hours.
[Claim 2]
The method according to claim 1, wherein the high-temperature aging in step (e) is performed for 1 hour to 3 hours.
[Claim 3]
The method according to claim 1, wherein the high-temperature aging in step (e) is performed in the range of 75 ℃ to 90 ℃ secondary battery manufacturing method.
[Claim 4]
The method according to claim 1, wherein step (d) comprises charging and discharging the spare battery one or more times, and degassing the secondary battery.
[Claim 5]
The method according to claim 4, wherein the degassing is performed by aging.
[Claim 6]
The method according to claim 1, wherein step (d) comprises: (d1) the process of first charging the spare battery; (d2) a process of primary room temperature aging of the primary charged spare battery at 23° C. to 27° C., (d3) after the process (d2), a process of primary high-temperature aging of the preliminary battery at 50° C. to 80° C.; (d4) after the step (d3), a step of secondary room temperature aging of the spare battery at 23°C to 27°C, and (d5) a step of first discharging the spare battery after the step (d4) Secondary battery manufacturing method.
[Claim 7]
The method according to claim 6, further comprising an additional degassing process between the process (d4) and the process (d5).
[Claim 8]
The method according to claim 7, wherein the additional degassing comprises the steps of opening the battery case of the spare battery and sealing the battery case again.
[Claim 9]
The method according to claim 6, wherein step (d1) is performed up to SOC 10 to 100.
[Claim 10]
The method according to claim 6, wherein step (d2) is performed for 1 to 5 days.
[Claim 11]
The method according to claim 6, wherein step (d3) is performed for 10 to 30 hours.
[Claim 12]
The method according to claim 6, wherein step (d4) is performed for 10 hours to 30 days.
[Claim 13]
The method according to claim 6, wherein in the step (d5), discharging is performed at SOC 90 at 6.5 C for 1 minute.
[Claim 14]
an electrode assembly manufacturing apparatus for manufacturing an electrode assembly by alternately stacking electrodes and separators; a lamination device for laminating the electrode assembly at a pressure of 5 kgf/cm 2 or more to bond the electrode and the separator included in the electrode assembly; a spare battery manufacturing apparatus for manufacturing a spare battery by accommodating the electrode assembly and the electrolyte in a battery case; an activation device for activating the spare battery by charging and discharging; and a heat treatment device for manufacturing the secondary battery by aging the preliminary battery at a high temperature in the range of 60°C to 100°C for 1 hour to 6 hours.