KR102027421B1 - Radiation gel-type electrolyte precursor composition, secondary battery and manufacturing method of the same - Google Patents

Abstract

The present invention relates to a radiation gel electrolyte precursor composition comprising an organic electrolyte solution containing an ionic salt and an organic solvent, and a vinyl monomer and a polyfunctional vinyl crosslinking agent; The present invention relates to a secondary battery and a method of manufacturing the same.

Description

Radiation Gel Electrolyte Precursor Composition, Secondary Battery and Manufacturing Method Thereof {RADIATION GEL-TYPE ELECTROLYTE PRECURSOR COMPOSITION, SECONDARY BATTERY AND MANUFACTURING METHOD OF THE SAME}

The present invention relates to a radiation gel electrolyte precursor composition, a secondary battery and a method of manufacturing the same.

Secondary battery refers to an energy storage device that can be repeatedly used while converting electrical energy into chemical energy (charging) and chemical energy into electrical energy (discharging) by electrochemical oxidation / reduction reaction. The secondary battery is composed of an electrode, a separator and an electrolyte, and in particular, the electrolyte is a key element of battery safety.

 At present, the biggest problem of the secondary battery using the liquid electrolyte is the risk of explosion due to impact and heat. In order to solve this problem, development of a secondary battery using a gel electrolyte has been attempted.

In the secondary battery manufacturing method using the gel electrolyte developed to date, a method of manufacturing a gel electrolyte using heat and light (UV) and then assembling the secondary battery and 2) using a gel electrolyte precursor composition After assembly, there is a method of manufacturing a secondary battery to which a gel electrolyte is applied through heat and light (UV).

In the case of the electronic method, the design and development of a new manufacturing process are required for low performance and industrial application due to the increase in interfacial resistance between the electrode and the electrolyte, which makes it difficult to apply a commercial manufacturing process. On the other hand, the latter method has the advantage that it can be directly applied to the secondary battery manufacturing process that is currently applied, unlike the former, thermal and light (UV) -based gel formation method has the following problems in actual industrial applications There is a limit.

 The heat-based gel formation method requires an initiator, has low productivity at high temperatures (≥ 70 ° C.) for a long time (≥ 30 minutes), has a problem of volume expansion of the battery due to volatilization of the electrolyte, and In this case, a photoinitiator is required for rapid gel formation, and a long time is required when there is no photoinitiator, and there is a limit that is applied only to a cell having a thickness of less than millimeter (≤ mm) due to the low permeability of the UV light source.

 Therefore, in order to overcome this problem, a creative and new technical approach is needed to manufacture secondary batteries using gel electrolyte having high performance and high safety without changing the commercial manufacturing process. It is true.

Korean Patent Publication No. 10-0131460 (December 1, 1997)

The present invention utilizes radiation having high permeability and energy, and uses a radiation gel electrolyte having both high gelation and ion conductivity at the same time for a short time at a room temperature (≤ seconds) without changing a commercial manufacturing process and using a separate initiator. In order to be prepared in-situ, to provide an organic electrolyte solution containing an ionic salt and an organic solvent, and a radiation gel electrolyte precursor composition comprising a vinyl monomer and a polyfunctional vinyl crosslinking agent.

However, the technical problem to be achieved by the present invention is not limited to the above-mentioned problem, another task that is not mentioned will be clearly understood by those skilled in the art from the following description.

The present invention provides a radiation gel electrolyte precursor composition comprising an organic electrolyte solution containing an ionic salt and an organic solvent, and a vinyl monomer and a polyfunctional vinyl crosslinking agent.

In one embodiment of the present invention, an electrode assembly including a positive electrode, a negative electrode and a separator; And a radiation gel electrolyte formed from an organic electrolyte solution containing an ionic salt and an organic solvent, and a radiation gel electrolyte precursor composition comprising a vinyl monomer and a polyfunctional vinyl crosslinking agent.

In another embodiment, (a) preparing a radiation gel electrolyte precursor composition comprising an organic electrolyte containing an ionic salt and an organic solvent, and a vinyl monomer and a polyfunctional vinyl crosslinking agent; (b) an anode; Injecting an electrode assembly including a negative electrode and a separator into a battery case; (c) injecting the radiation gel electrolyte precursor composition of step (a) into the battery case of step (b), and then sealing and assembling a secondary battery precursor; And (d) provides a method for manufacturing a secondary battery comprising the step of irradiating the secondary battery precursor of step (c).

The secondary battery to which the gel electrolyte according to the present invention is applied comprises an organic electrolyte containing an ionic salt and an organic solvent, and a radiation gel electrolyte formed from a radiation gel electrolyte precursor composition comprising a vinyl monomer and a polyfunctional vinyl crosslinking agent. A secondary battery using a radiation gel type electrolyte having both high gelation and ion conductivity at the same time can be used for a short time at room temperature by utilizing radiation having high permeability and energy, and without changing a commercial manufacturing process and using a separate initiator. <Several seconds) in-situ. Therefore, the secondary battery is characterized by high safety while maintaining the same level of performance as the secondary battery to which the conventional liquid electrolyte is applied.

Furthermore, in the manufacture of the secondary battery, as a result of proving productivity by irradiating radiation by employing a radiation continuous process facility (processing capacity: 1 M x 1 M area per 3 seconds) to a secondary battery precursor assembled in a commercial manufacturing process, It was confirmed that 480,000 and 360,000 cylindrical secondary batteries and portable secondary batteries could be produced per hour, respectively, and thus, despite the application of irradiation technology, it is expected that there will be no effect on the productivity of commercial manufacturing processes.

In the future, the present invention is not only commercially available lithium-graphite secondary battery having low safety, but also has a low life due to dissolution of sulfur during charging and discharging secondary battery in the research and development stage of lithium-sulfur, lithium-air, etc., which is slow commercialization As it can be applied up to, the technical impact is expected to be very large.

1 is a view schematically showing a method of manufacturing a secondary battery to which a radiation gel electrolyte according to an embodiment of the present invention is applied.
Figure 2 is a photograph showing the gel formation of the electrolyte prepared in Example 1 (vs Comparative Example 3) and Example 6 (vs Comparative Example 4).
3 is a graph showing the discharge capacity of the lithium secondary battery prepared in Examples 1 and 2.

The present inventors are studying a method for manufacturing a secondary battery using a gel electrolyte by utilizing radiation having high permeability and energy, and an organic electrolyte solution containing an ionic salt and an organic solvent, a vinyl monomer, and a polyfunctional vinyl system. When using a radiation gel electrolyte precursor composition containing a crosslinking agent, a secondary battery to which a radiation gel electrolyte having high gelation and ion conductivity at the same time is applied for a short time (≤ several seconds) without having to change a commercial manufacturing process and use a separate initiator. While confirming that it can be prepared in-situ, the present invention was completed.

Hereinafter, the present invention will be described in detail.

radiation Gel type  Electrolyte Precursor Composition

The present invention provides a radiation gel electrolyte precursor composition comprising an organic electrolyte solution containing an ionic salt and an organic solvent, and a vinyl monomer and a polyfunctional vinyl crosslinking agent.

As used herein, the term "radiation gel electrolyte precursor composition" refers to a precursor (previous step) material in which a colloidal solution (sol) is thickened to a predetermined concentration or more, thereby forming a solid electrolyte and forming a solid electrolyte. In order to do so, it means a state in which irradiation is required.

First, the radiation gel electrolyte precursor composition according to the present invention includes an organic electrolyte containing an ionic salt and an organic solvent.

The ionic salts are Li ^+, Na ^+, ClO ₄ and the selected cation from the group consisting of K ⁺ and _{^{NH 4 + -, PF 6 -}} , Cl -, I -, Br -, SCN -, CF 3 SO 3 -, _{^{BF 4 -, CF 3 CCl 3}} -, C 4 F 9 SO 3 -, AlO 2 -, AlCl 4 -, N (C x F 2x + 1 SO 2) (C y F 2y + 1 SO 2) (x and y is a natural _{^{number) -, 2 B (C 2}} O 4) - it may comprise a negative ion selected from the group consisting of. For example, the ionic salt is LiClO ₄ , LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiAsF ₆ , LiC ₄ F ₉ SO ₃ , LiAlO ₂ , LiAlCl ₄ , LiN (C _x F _{2x + 1} SO ₂ ) (C _y F _{2y + 1} SO ₂ ) (x and y is a natural number), LiCl, LiI and LiB (C ₂ O ₄ ) ₂ One or more selected from the group consisting of, but is not limited to these.

The organic solvent is ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylene carbonate (VC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), Methylformate (MF), gamma-butyrolactone (? -BL; butyrolactone), sulfolane (sulfolane), methylacetate (MA; methylacetate), and methylpropionate (MP; methylpropionate) It may be one or more, but is not limited thereto.

On the other hand, the concentration of the ionic salt in the organic electrolyte may be 0.1 M to 5.0 M, by using an organic electrolyte in this concentration range, while producing a radiation gel electrolyte having an appropriate viscosity, the ion in the organic electrolyte It is possible to sufficiently dissolve and dissociate the salt, to enable the effective movement of the cation, and to optimize the ionic conductivity of the radiation gel type saline. At this time, when the concentration of the ionic salt in the organic electrolyte solution is less than 0.1 M, there is a problem that the ionic salt dissolved and dissociated in the organic electrolyte solution is not sufficient, when the concentration of the ionic salt in the organic electrolyte solution exceeds 5.0 M, the organic electrolyte solution There is a problem that does not dissolve and dissociate all the ionic salts. As a result, there is a problem of lowering the ion conductivity of the radiation gel-type electrolyte.

The vinyl monomer may be viewed as a precursor (previous step) material for interacting with the ionic salt in the organic electrolyte solution and for crosslinking through the multifunctional vinyl-based crosslinking agent upon irradiation.

Specifically, the vinyl monomer is N-vinylpyrrolidone (N-vinylpyrrolidone), N, N'-dimethylacrylamide (N, N'-dimethylacrylamide), acrylonitrile (acrylonitrile), methyl methacrylate ( methyl methacrylate, vinyl acetate, acrylic acid, butyl acrylate, dimethylamino ethyl acrylate (2- (dimethylamino) ethyl acrylate) and glycidyl methacrylate It may be one or more selected from the group consisting of.

Moreover, the vinyl monomer may include a polar functional group for interacting with the ionic salt, and the polar functional group is preferably a nitrogen-containing functional group including an amide group or a cyano group, but is not limited thereto. At this time, the amide group or cyano group may be regarded as a highly polar functional group due to nitrogen having a high electronegativity, and by intensively interacting with the ionic salt, the ion conductivity of the radiation gel-type electrolyte may be optimized.

Specifically, the vinyl monomer is one selected from the group consisting of N-vinylpyrrolidone, N, N'-dimethylacrylamide and acrylonitrile. It is preferable that it is above, but it is not limited to this.

The polyfunctional vinyl-based crosslinking agent is a material that acts as a crosslinking agent for forming a gel having a three-dimensional network structure when irradiated with radiation, and when a monofunctional vinyl-based crosslinking agent is used instead of the polyfunctional vinylic crosslinking agent, irradiation When a single functional group does not have a sufficient crosslinking role, there is a problem in that it does not properly form a gel having a three-dimensional network structure.

Specifically, as the multifunctional vinyl-based crosslinking agent, polyethylene glycol diacrylate, poly propylene glycol diacrylate, tetraethylene glycol diacrylate, 1, 4-butanediol diacrylate (1,4-butanediol diacrylate), 1,6-hexanediol diacrylate (1,6-hexandiol diacrylate), trimethylolpropane triacrylate, trimethylol propane ethoxylate Triacrylate, trimethylolpropane ethoxylate triacrylate, trimethylolpropane propoxylate triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol tetraacrylate, pentaerythritol Ethoxylate tetra One selected from the group consisting of pentaerythritol ethoxylate tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate and triallyl isocyanurate (TAIC) The above can be used.

More specifically, the multifunctional vinyl-based crosslinking agent may include two or more acrylate groups, and the multifunctional vinyl-based crosslinking agent is preferably a compound represented by Chemical Formula 1, but is not limited thereto.

[Formula 1]

R is an ethylene group or a propylene group, and n is an integer of 10-1,000. In this case, when n is less than 10, there is a problem of low performance of the secondary battery due to low ion conductivity of the gel, and when n is more than 1,000, there is a problem that the viscosity is too high and is limited to application to the actual process of the secondary battery.

Meanwhile, the weight ratio of the organic electrolyte and the vinyl monomer and the polyfunctional vinyl crosslinking agent is preferably 70:30 to 95: 5, but preferably 85:15 to 95: 5, but is not limited thereto. In this case, when the relative content of the organic electrolyte is too low, there is a problem that the ion conductivity is lowered due to excessive crosslinking, leading to a decrease in the performance of the secondary battery, and gel is not formed properly when the relative content of the organic electrolyte is too high. There is a problem.

In addition, the weight ratio of the vinyl monomer and the polyfunctional vinyl-based crosslinking agent may be 10:90 to 85:15, preferably 55:45 to 85:15, but is not limited thereto. In this case, when the relative content of the polyfunctional vinyl-based crosslinking agent is too high, there is a problem in that the ion conductivity is lowered due to excessive crosslinking, resulting in a decrease in the performance of the secondary battery, and when the relative content of the polyfunctional vinyl-based crosslinking agent is too low. There is a problem that the gel is not formed properly.

Secondary battery

The present invention includes an electrode assembly including a positive electrode, a negative electrode and a separator; And a radiation gel electrolyte formed from an organic electrolyte solution containing an ionic salt and an organic solvent, and a radiation gel electrolyte precursor composition comprising a vinyl monomer and a polyfunctional vinyl crosslinking agent.

The secondary battery may be a lithium secondary battery, and specifically, the lithium secondary battery may be a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, a lithium ion polymer secondary battery, a lithium air secondary battery, and a lithium sulfur secondary battery. Preferably, but not limited to.

In addition, it is possible to provide a medium-large battery module or a battery pack including a plurality of the secondary battery electrically connected. The medium-large battery module or battery pack includes a power tool; Electric vehicles including electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs); Electric trucks; Electric commercial vehicles; Or it can be used as a power source for any one or more of the system for power storage.

First, the secondary battery according to the present invention includes an electrode assembly including a positive electrode, a negative electrode, and a separator.

The electrode assembly includes a positive electrode, a negative electrode, and a separator, and the positive electrode includes a positive electrode current collector and a positive electrode active material. Specifically, a lithium-containing transition metal oxide may be preferably used as the cathode active material, for example, LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , Li (Ni _a Co _b Mn _c ) O ₂ ( 0 <a <1, 0 <b <1, 0 <c <1, a + b + c = 1), LiNi _{1 -y} Co _y O ₂ , LiCo _{1 - y} Mn _y O ₂ , LiNi _{1 - y} Mn _y O ₂ (O <y <1), Li (Ni _a Co _b Mn _c ) O ₄ (0 <a <2, 0 <b <2, 0 <c <2, a + b + c = 2), LiMn _{2 − z Ni z O4, LiMn 2 -} z CozO 4 can be used (0 <z <2), LiCoPO 4 , and at least one selected from the group consisting of LiFePO _4. In addition to such lithium-containing transition metal oxides, sulfides, selenides, and halides may be used.

The negative electrode includes a negative electrode current collector and a negative electrode active material. Specifically, the cathode active material is typically a carbon material, lithium-containing titanium composite oxide (LTO) that can store and release lithium ions; Metals (Me) which are Si, Sn, Li, Zn, Mg, Cd, Ce, Ni, Fe; Alloys composed of the metals (Me); Oxides of the metals (Me) (MeOx); And a composite of the metals (Me) and carbon, and the like, and it is preferable to use a carbon material such as low crystalline carbon and high crystalline carbon, but is not limited thereto. For example, soft crystalline carbon and hard carbon are typical low crystalline carbon, and high crystalline carbon is natural graphite, Kish graphite, pyrolytic carbon, liquid crystal pitch. High-temperature calcined carbon such as mesophase pitch based carbon fiber, meso-carbon microbeads, mesophase pitches, and petroleum or coal tar pitch derived cokes are typical. Meanwhile, the negative electrode may include a binder, and the binder may include polyvinylidene fluoride, polyacrylonitrile, vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), poly Various kinds of binder polymers such as methyl methacrylate may be used.

The separator may be manufactured using fibers such as nonwoven fabric made of polyolefin, such as polyethylene, polypropylene, polyvinylidene fluoride, and the like for chemical preparation, thermal bonding, airlay, wet, needle punching, and spun. A well-known method, such as a threadless, spun bond, melt blown, stitch, electrospinning, can be used. Meanwhile, the separator may be a single layer film or a multilayer film of two or more layers.

Next, the secondary battery according to the present invention includes an organic electrolyte containing an ionic salt and an organic solvent, and a radiation gel electrolyte formed from a radiation gel electrolyte precursor composition comprising a vinyl monomer and a polyfunctional vinyl crosslinking agent.

The radiation gel electrolyte is formed by radiation from the radiation gel electrolyte precursor composition. Since the radiation gel electrolyte precursor composition has been described above, duplicate descriptions will be omitted.

The radiation gel electrolyte may have a gelation rate of 90% or more represented by Equation 1 below:

[Equation 1]

Where W _dry is the initial dry weight of the radiation gel electrolyte and W _dissolved is the dry weight after extraction of the radiation gel gel electrolyte with an organic solvent at 50 ° C. for 1 week.

When the gelation rate of the radiation gel electrolyte is 90% or more, unlike the secondary battery to which the existing liquid electrolyte is applied, by solving the risk of explosion due to impact and heat, it has the advantage of manufacturing a secondary battery with high safety.

In addition, the radiation gel electrolyte may have an ion conductivity σ of 10 ⁻⁴ mS / cm to 10 ⁻² mS / cm, and 10 ⁻³ mS / cm to 10 ⁻² mS / cm Is preferably, but is not limited to:

[Equation 2]

Where R is the bulk resistance measured by EIS, A is the area of SUS in contact with the radiation gel electrolyte, and l is the thickness of the radiation gel electrolyte.

The radiation gel electrolyte has good ion conductivity in the range of 10 ⁻⁴ mS / cm to 10 ⁻² mS / cm (particularly very good ion conductivity in the range of 10 ⁻³ mS / cm to 10 ⁻² mS / cm), It is manufactured through an actual commercial manufacturing process, and has the advantage of manufacturing a secondary battery having the same level of performance as a secondary battery to which a conventional liquid electrolyte is applied.

Manufacturing method of secondary battery

The present invention comprises the steps of preparing a radiation gel electrolyte precursor composition comprising (a) an organic electrolyte solution containing an ionic salt and an organic solvent, and a vinyl monomer and a polyfunctional vinyl crosslinking agent; (b) an anode; Injecting an electrode assembly including a negative electrode and a separator into a battery case; (c) injecting the radiation gel electrolyte precursor composition of step (a) into the battery case of step (b), and then sealing and assembling a secondary battery precursor; And (d) provides a method for manufacturing a secondary battery comprising the step of irradiating the secondary battery precursor of step (c).

1 is a view schematically showing a method of manufacturing a secondary battery to which a radiation gel electrolyte according to an embodiment of the present invention is applied.

As shown in FIG. 1, a secondary battery to which a radiation gel electrolyte according to an embodiment of the present invention is applied may be prepared by preparing the radiation gel electrolyte precursor composition; Injecting the radiation gel electrolyte precursor composition into a battery case into which an electrode assembly including a positive electrode, a negative electrode, and a separator is injected, and then sealing and assembling a secondary battery precursor; It is produced by irradiating a secondary battery precursor with radiation.

First, a method of manufacturing a secondary battery according to the present invention comprises the steps of preparing a radiation gel electrolyte precursor composition comprising an organic electrolyte containing an ionic salt and an organic solvent, and a vinyl monomer and a polyfunctional vinyl crosslinking agent [(a) Step].

Since the radiation gel electrolyte precursor composition has been described above, redundant description will be omitted.

Next, a method of manufacturing a secondary battery according to the present invention is a positive electrode; Injecting an electrode assembly including a negative electrode and a separator into a battery case [step (b)] and injecting the radiation gel electrolyte precursor composition into the battery case and then sealing and assembling a secondary battery precursor [(c) Step].

Since the electrode assembly has been described above, duplicate descriptions will be omitted.

The battery case may have various shapes such as a cylindrical shape, a square shape, or a coin shape, and the secondary battery precursor is in a state in which the radiation gel electrolyte precursor composition is injected and sealed, and before the irradiation is performed. Assembly of the precursor has the advantage that it can be assembled in a commercial manufacturing process.

Next, the method of manufacturing a secondary battery according to the present invention includes the step of (i) irradiating the secondary battery precursor with radiation.

The radiation has a high permeability and energy, and by utilizing the radiation, a secondary battery using a radiation gel-type electrolyte having a high gelation degree and ion conductivity at the same time for a short time at room temperature without changing the commercial manufacturing process and using a separate initiator (≤ several seconds) can be prepared in-situ.

Specifically, the radiation may include one or more selected from the group consisting of electron beams, gamma rays and X-rays, preferably in the short term irradiation electron beam, but is not limited thereto. In this case, the total radiation dose may be 0.1 kGy to 20 kGy.

More specifically, when using an electron beam as the radiation, an electron beam of 300 keV to 10 MeV may be used depending on the penetration depth of the secondary battery. At this time, less than 300 keV, there is a problem in that the formation of the gel is difficult due to the limited depth of penetration, and more than 10 MeV may cause a problem that the organic material is changed to a completely different material.

In addition, the electron beam is preferably irradiated at a dose rate of 0.1 to 30 kGy / sec so that the total irradiation amount of the electron beam is 1 kGy to 20 kGy, but is not limited thereto. At this time, less than 1 kGy has a problem that a sufficient gel is not formed, and more than 20 kGy has a problem due to the rapid decrease in ion conductivity due to excessive gel formation.

On the other hand, when gamma rays are used as the radiation, the gamma rays are irradiated at a dose rate of 0.1 to 10 kGy / sec, so that the total irradiation amount of the gamma rays is 0.1 kGy to 10 kGy, but is not limited thereto. Do not. At this time, less than 0.1 kGy has a problem that a sufficient gel is not formed, and more than 10 kGy has a problem due to the rapid decrease in ion conductivity due to excessive gel formation.

On the other hand, when X-rays are used as the radiation, the X-rays are irradiated at a dose rate of 0.1 to 10 kGy / sec, so that the total dose of X-rays is 0.1 kGy to 10 kGy, but It is not limited. At this time, less than 0.1 kGy has a problem that a sufficient gel is not formed, and more than 10 kGy has a problem due to the rapid decrease in ion conductivity due to excessive gel formation.

Therefore, the secondary battery to which the gel electrolyte according to the present invention is applied includes an organic electrolyte containing an ionic salt and an organic solvent, and a radiation gel electrolyte formed from a radiation gel electrolyte precursor composition comprising a vinyl monomer and a polyfunctional vinyl crosslinking agent. A secondary battery using a radiation gel type electrolyte having both high gelation and ionic conductivity at room temperature may be utilized by utilizing radiation having high permeability and energy, and without changing a commercial manufacturing process and using a separate initiator. It can be prepared in-situ for a short time (≦ several seconds). Therefore, the secondary battery is characterized by high safety while maintaining the same level of performance as the secondary battery to which the conventional liquid electrolyte is applied.

Furthermore, in the manufacture of the secondary battery, as a result of proving productivity by irradiating radiation by employing a radiation continuous process facility (processing capacity: 1 M x 1 M area per 3 seconds) to a secondary battery precursor assembled in a commercial manufacturing process, It was confirmed that 480,000 and 360,000 cylindrical secondary batteries and portable secondary batteries could be produced per hour, respectively, and thus, despite the application of irradiation technology, it is expected that there will be no effect on the productivity of commercial manufacturing processes.

In the future, the present invention is not only commercially available lithium-graphite secondary battery having low safety, but also has a low life due to dissolution of sulfur during charging and discharging secondary battery in the research and development stage of lithium-sulfur, lithium-air, etc., which is slow commercialization As it can be applied up to, the technical impact is expected to be very large.

Hereinafter, preferred examples are provided to aid in understanding the present invention. However, the following examples are merely provided to more easily understand the present invention, and the contents of the present invention are not limited by the following examples.

[ Example ]

Example  One

(1) electron beam Gel type  Preparation of Electrolyte Precursor Composition

An organic electrolyte was prepared by dissolving LiClO ₄ in an ethylene carbonate (EC): diethyl carbonate (DEC) having a volume ratio of 1: 1 as an organic solvent so as to have a concentration of 1M as an ionic salt. Prepared organic electrolyte: vinyl monomer, N-vinylpyrrolidone: polyfunctional vinyl-based crosslinking agent, polyethylene glycol diacrylate (poly (glycol) diacrylate; PEGDA) in a weight ratio of 90: 8: 2 To prepare an electron beam gel electrolyte precursor composition.

(2) Preparation of Lithium Secondary Battery Precursor

Using the electron beam gel electrolyte precursor composition prepared in (1), a lithium secondary battery precursor was prepared in the form of a coin cell.

Specifically, the positive electrode active material (LiCoO ₂ ): conductive material (Denka black): binder (PVDF) is uniformly mixed in a solvent of N-methyl-2-pyrrolidone in a weight ratio of 92.5: 3.5: 4.0, and then in aluminum foil After applying evenly and compressing in a roll press, vacuum was dried for 12 hours in a vacuum oven of 100 to prepare a positive electrode. Next, a negative electrode active material (carbon powder, graphite): conductive material (carbon black): binder (PVDF) was uniformly mixed in an N-methyl-2-pyrrolidone solvent at a weight ratio of 92.5: 3.5: 4.0, and then copper Evenly applied to the foil and pressed in a roll press, and vacuum dried for 12 hours in a vacuum oven of 100 to prepare a negative electrode.

As the prepared anode, the prepared cathode and the separator, a nonwoven fabric (namyang nonwoven fabric, OCP22, thickness of 50 um) made of polyethylene polypropylene was used, respectively, and the electron beam gel electrolyte precursor composition prepared in (1) was injected. It was prepared in the form of a coin cell (coin cell) according to a conventional manufacturing method.

On the other hand, in order to measure the ionic conductivity, except that the prepared positive electrode and the prepared negative electrode was replaced with a SUS material, it was additionally manufactured in the coin cell form in the same manner.

(3) Fabrication of lithium secondary battery by electron beam irradiation

The lithium secondary battery precursor prepared in (2) was irradiated with a dose rate of 2.5 mA, 20 m / min, and 1 kGy / 3 sec using a 2.5 MeV electron beam to prepare a lithium secondary battery. At this time, the total irradiation amount of the electron beam was 1 kGy.

Example  2 ~ 20

A lithium secondary battery was manufactured in the same manner as in Example 1, except that the type of the ionic salt, the type of the vinyl monomer, and the total irradiation amount of the electron beam were changed as shown in Table 1 below.

Comparative example  One

Same as in Example 1, except that the vinyl monomer and the polyfunctional vinyl crosslinking agent were omitted from the electron beam gel electrolyte precursor composition, the separator was changed to a polyethylene nonwoven fabric (NR420, 20 um), and the electron beam irradiation was omitted. A lithium secondary battery was manufactured by the method.

Comparative example  2

Comparative example except that the organic electrolyte solution was changed to ethylene carbonate (EC): diethyl carbonate (DEC) having a volume ratio of 1: 1 by using an organic electrolyte solution in which LiPF ₆ was dissolved at a concentration of 1 M as an ionic salt. A lithium secondary battery was manufactured in the same manner as in 1.

Comparative example  3

A lithium secondary battery was manufactured in the same manner as in Example 1, except that electron beam irradiation was omitted.

Comparative example  4

A lithium secondary battery was manufactured in the same manner as in Example 6 except that the electron beam irradiation was omitted.

Comparative example  5

A lithium secondary battery was manufactured in the same manner as in Example 11 except that the electron beam irradiation was omitted.

Comparative example  6

A lithium secondary battery was manufactured in the same manner as in Example 16, except that electron beam irradiation was omitted.

Comparative example  7

A lithium secondary battery was manufactured in the same manner as in Example 1, except that the weight ratio of the prepared organic electrolyte solution: vinyl monomer: polyfunctional vinyl crosslinking agent was changed to 80: 16: 4.

Comparative example  8

A lithium secondary battery was manufactured in the same manner as in Example 5, except that the weight ratio of the prepared organic electrolyte solution: vinyl monomer: polyfunctional vinyl crosslinking agent was changed to 90: 90: 1.

Comparative example  9

A lithium secondary battery was manufactured in the same manner as in Example 1, except that the weight ratio of the prepared organic electrolyte solution: vinyl monomer: polyfunctional vinyl crosslinking agent was changed to 90: 5: 5.

Electrolyte Precursor Composition anode cathode Separator Total dose of electron beam
(kGy) Organic electrolyte Vinyl monomers Multifunctional vinyl type crosslinking agent
(PEGDA) Kinds content
(wt%) Kinds content
(wt%) content
(wt%) Example 1 1 M LiClO ₄ in EC / DEC (1/1, v / v) 90 N-vinylpyrrolidone 8 2 LiCoO ₂ Graphite Non-woven
(0CP22, 50 um) One Example 2 90 8 2 2 Example 3 90 8 2 4 Example 4 90 8 2 8 Example 5 90 8 2 16 Example 6 1 M LiPF ₆ in EC / DEC
(1/1, v / v) 90 N, N’-dimethylacrylamide 8 2 LiCoO ₂ Graphite Non-woven
(0CP22, 50 um) One Example 7 90 8 2 2 Example 8 90 8 2 4 Example 9 90 8 2 8 Example 10 90 8 2 16 Example 11 1 M LiPF ₆ in EC / DEC
(1/1, v / v) 90 acrylonitrile 8 2 LiCoO ₂ Graphite Non-woven
(0CP22, 50 um) One Example 12 90 8 2 2 Example 13 90 8 2 4 Example 14 90 8 2 8 Example 15 90 8 2 16 Example 16 1 M LiPF ₆ in EC / DEC
(1/1, v / v) 90 methylacrylate 8 2 LiCoO ₂ Graphite Non-woven
(0CP22, 50 um) One Example 17 90 8 2 2 Example 18 90 8 2 4 Example 19 90 8 2 8 Example 20 90 8 2 16 Comparative Example 1 1 M LiClO ₄ in EC / DEC (1/1, v / v) 100 - - - LiCoO ₂ Graphite Separator
(NR420, 20 um) - Comparative Example 2 1 M LiPF ₆ in EC / DEC
(1/1, v / v) 100 - - - LiCoO ₂ Graphite Separator
(NR420, 20 um) - Comparative Example 3 1 M LiClO ₄ in EC / DEC (1/1, v / v) 90 N-vinylpyrrolidon 8 2 LiCoO ₂ Graphite Non-woven
(0CP22, 50 um) - Comparative Example 4 1 M LiPF ₆ in EC / DEC
(1/1, v / v) 90 N, N’-dimethylacrylamide 8 2 LiCoO ₂ Graphite Non-woven
(0CP22, 50 um) - Comparative Example 5 1 M LiPF ₆ in EC / DEC
(1/1, v / v) 90 acrylonitrile 8 2 LiCoO ₂ Graphite Non-woven
(0CP22, 50 um) - Comparative Example 6 1 M LiPF ₆ in EC / DEC
(1/1, v / v) 90 methylacrylaten 8 2 LiCoO ₂ Graphite Non-woven
(0CP22, 50 um) - Comparative Example 7 1 M LiClO ₄ in EC / DEC (1/1, v / v) 80 N-vinylpyrrolidon 16 4 LiCoO ₂ Graphite Non-woven
(0CP22, 50 um) One Comparative Example 8 1 M LiClO ₄ in EC / DEC (1/1, v / v) 90 N-vinylpyrrolidon 9 One LiCoO ₂ Graphite Non-woven
(0CP22, 50 um) 16 Comparative Example 9 1 M LiClO ₄ in EC / DEC (1/1, v / v) 90 N-vinylpyrrolidon 5 5 LiCoO ₂ Graphite Non-woven
(0CP22, 50 um) One

* At this time, the organic electrolyte, vinyl monomer and polyfunctional vinyl crosslinking agent used in Table 1 were all purchased from Aldrich, and both positive and negative electrodes were purchased from MTI Korea.

Experimental Example  1: electron beam Gel type  Electrolyte Gelation rate  And ion conductivity measurement

(1) electron beam Gel type  Electrolyte Gelation rate  Measure

In order to measure the gelation rate of the electrolytes prepared in Examples 1 to 20 and Comparative Examples 1 to 9, the electrolytes prepared in Examples 1 to 20 and Comparative Examples 1 to 9 were used in a volume ratio of 1: 1 for 1 week at 50 ° C. Ethylene carbonate (EC) having a: diethyl carbonate (DEC) to extract the unreacted material was extracted, and then observed the formation of the gel, the gelation rate represented by the following equation 1 through the dry weight change was measured, The results are shown in Table 2 and FIG. 2 below:

[Equation 1]

Where W _dry is the initial dry weight of the radiation gel electrolyte and W _dissolved is the dry weight after extraction of the radiation gel gel electrolyte with an organic solvent at 50 ° C. for 1 week.

Gel Formation Gelation degree
( wt% ) Example  One ○ 95 Example  2 ○ 97 Example  3 ○ 100 Example  4 ○ 100 Example  5 ○ 100 Example  6 ○ 97 Example  7 ○ 100 Example  8 ○ 100 Example  9 ○ 100 Example  10 ○ 100 Example  11 ○ 90 Example  12 ○ 93 Example  13 ○ 98 Example  14 ○ 100 Example  15 ○ 100 Example  16 ○ 90 Example  17 ○ 95 Example  18 ○ 97 Example  19 ○ 100 Example  20 ○ 100 Comparative example  One × 0 Comparative example  2 × 0 Comparative example  3 × 0 Comparative example  4 × 0 Comparative example  5 × 0 Comparative example  6 × 0 Comparative example  7 ○ 100 Comparative example  8 × 0 Comparative example  9 ○ 100

As shown in Table 2, unlike Comparative Examples 1 to 6 and 8, the electrolyte prepared in Examples 1 to 20 was found to have a gelation rate of 90% or more even without a separate initiator at a total electron beam irradiation of at least 1 kGy.

On the other hand, the electrolyte prepared in Comparative Examples 1 to 6 is confirmed that no gel was formed due to the electron beam non-irradiation. In addition, the electrolyte prepared in Comparative Example 8 was prepared with a weight ratio of the organic electrolyte solution, the vinyl monomer, and the polyfunctional vinyl crosslinking agent at 90: 9: 1, and the gel was relatively low because the relative content of the polyfunctional vinyl agent was too small. It is confirmed that this is not formed.

In addition, as shown in FIG. 2, unlike Comparative Examples 3 and 4, the electrolytes prepared in Examples 1 and 6 clearly confirm that a complete gel did not flow.

(2) electron beam Gel type  Ionic Conductivity Measurement of Electrolyte

In order to measure the ionic conductivity of the electrolytes prepared in Examples 1-20 and Comparative Examples 1-9, electrochemical impedance spectroscopy (EIS) was performed on the lithium secondary batteries prepared in Examples 1-20 and Comparative Examples 1-9. After the bulk resistance was measured using), the ion conductivity was calculated through Equation 2.

[Equation 2]

Where R is the bulk resistance measured by EIS, A is the area of SUS in contact with the radiation gel electrolyte, and l is the thickness of the radiation gel electrolyte.

Ion conductivity
( mS / cm) Example  One 1.65 Example  2 1.50 Example  3 1.39 Example  4 1.17 Example  5 1.11 Example  6 1.58 Example  7 1.43 Example  8 1.25 Example  9 1.10 Example  10 1.06 Example  11 1.55 Example  12 1.42 Example  13 1.24 Example  14 1.09 Example  15 1.03 Example  16 0.160 Example  17 0.147 Example  18 0.121 Example  19 0.109 Example  20 0.103 Comparative example  One 0.11 Comparative example  2 0.14 Comparative example  3 1.81 Comparative example  4 1.69 Comparative example  5 1.71 Comparative example  6 1.73 Comparative example  7 0.12 Comparative example  8 1.11 Comparative example  9 0.32

As shown in Table 3, the electrolytes prepared in Examples 1 to 20 were found to have excellent ion conductivity within the range of 10 ⁻⁴ mS / cm to 10 ⁻² mS / cm while having a gelation rate of 90% or more. In particular, the electrolyte prepared in Examples 1 to 15 was prepared using a vinyl monomer containing a polar functional group (amide group or cyano group) for interacting with an organic electrolyte solution, an ionic salt, and a polyfunctional vinyl based crosslinking agent. It is characterized by having a very good ion conductivity in the range of 10 ⁻³ mS / cm to 10 ⁻² mS / cm.

On the other hand, the electrolyte prepared in Comparative Example 7 was prepared using a weight ratio of the organic electrolyte solution, the vinyl monomer and the polyfunctional vinyl crosslinking agent as 80: 16: 4. Since the relative content of the organic electrolyte solution is too low, the ion conductivity is lowered. It is confirmed. In addition, the electrolyte prepared in Comparative Example 9 was prepared using a weight ratio of the organic electrolyte solution, the vinyl monomer, and the polyfunctional vinyl crosslinking agent at 90: 5: 5, and since the relative content of the polyfunctional vinyl crosslinking agent was too high, It is confirmed that the conductivity is lowered. Therefore, the electrolytes prepared in Comparative Examples 7 and 9 have a gelation rate of 90% or more, but are difficult to be applied to lithium secondary batteries due to too low ionic conductivity.

Experimental Example  2: Evaluation of discharge capacity of lithium secondary battery

In order to evaluate the discharge capacity of the lithium secondary batteries prepared in Examples 1 and 2, the discharge capacity was evaluated under a charge and discharge current rate of 0.1 C at room temperature using a charge and discharge tester (wonAtech), and the results 3 is shown.

As shown in FIG. 3, Examples 1 and 2 exhibited a discharge capacity (143 mAh / g) equivalent to that of a lithium secondary battery (liquid electrolyte applied) in the form of a coin cell manufactured through an actual commercial manufacturing process. . That is, the lithium secondary batteries prepared in Examples 1 and 2 can be seen that very fast performance in a few seconds at room temperature even without the initiator, even if the gel electrolyte is applied. Although not shown, the lithium secondary batteries prepared in Examples 3 to 20 (particularly, Examples 3 to 15) were also confirmed to have excellent discharge capacity.

The foregoing description of the present invention is intended for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

Claims (16)

delete delete delete delete delete delete delete delete delete delete delete delete delete (a) a radiation gel electrolyte precursor composition comprising an organic electrolyte solution containing an ionic salt and an organic solvent, a vinyl monomer having an amide group or a cyano group for interacting with the ionic salt, and a polyfunctional vinyl crosslinking agent; Manufacturing;
(b) an anode; Injecting an electrode assembly including a negative electrode and a separator into a battery case;
(c) injecting the radiation gel electrolyte precursor composition of step (a) into the battery case of step (b), and then sealing and assembling a secondary battery precursor; And
(d) irradiating the secondary battery precursor of step (c) with radiation;
The weight ratio of the organic electrolyte and the vinyl monomer and the polyfunctional vinyl crosslinking agent is from 85:15 to 95: 5, and the weight ratio of the vinyl monomer and the polyfunctional vinyl crosslinking agent is from 55:45 to 85:15. The radiation gel electrolyte precursor composition does not include a separate initiator
Method of manufacturing a secondary battery.
The method of claim 14,
In the step (d) the radiation comprises one or more selected from the group consisting of electron beam, gamma ray and X-ray
Method of manufacturing a secondary battery.
The method of claim 14,
Total radiation dose in step (d) is 0.1 kGy to 20 kGy
Method of manufacturing a secondary battery.

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