KR20140144583A - Electrochemical device including a porous core element - Google Patents

Abstract

The present invention relates to an electrochemical device including a wound porous core element, and, more specifically, to an electrochemical device, in which an electrode assembly manufactured by winding a cathode, an anode, and a separator interposed between the cathode and the anode is mounted in a battery case, and a wound porous core element absorbing the impacts applied to the electrochemical device is inserted into the wound core of the electrode assembly. According to an embodiment of the present invention, the gas generated by the inner reaction in charging/discharging and operating the electrochemical device is efficiently discharged to the outside of the electrochemical device through the wound porous core element existing in the wound core of the electrochemical device so as to prevent explosion due to the inner gas, improve the safety of the electrochemical device, prevent the circuit shortage within the electrochemical device through the impact absorption of the wound core element even though an external impact is applied to the electrochemical device, and improve the mechanical strength of the electrochemical device.

Description

[0001] The present invention relates to an electrochemical device including a porous core member,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrochemical device including a porous core member, and more particularly, to an electrochemical device including a porous core member for preventing external damage to an electrode assembly by absorbing an external impact, ≪ / RTI >

Recently, interest in energy storage technology is increasing. As the application fields of cell phones, camcorders, notebook PCs and even electric vehicles are expanding, efforts for research and development of electrochemical devices are becoming more and more specified. The electrochemical device has received the most attention in this respect. Of these, the development of a rechargeable secondary battery has become a focus of attention. Recently, in developing such a battery, Research and development on the design of electrodes and batteries are underway.

Among the currently applied secondary batteries, the lithium secondary battery developed in the early 1990s has advantages such as higher operating voltage and higher energy density than conventional batteries such as Ni-MH, Ni-Cd and sulfuric acid-lead batteries using an aqueous electrolyte solution .

According to the shape of the battery case, the electrochemical device is classified into a cylindrical battery and a prismatic battery in which an electrode assembly is embedded in a cylindrical or rectangular metal can, and a pouch-type battery in which an electrode assembly is embedded in a pouch-shaped case of an aluminum laminate sheet do.

In addition, the electrode assembly contained in the battery case is a chargeable / dischargeable power generation element having a cathode, an anode, and a separator interposed between the cathode and the anode. The electrode assembly includes a long sheet-like cathode coated with an electrode active material, A jelly-roll type in which a separator is interposed between a cathode and an anode, and a stacked type in which a plurality of cathodes and anodes of a predetermined size are sequentially stacked with a separator interposed therebetween. Among them, the jelly-roll type electrode assembly has an advantage of being easy to manufacture and having a high energy density per weight.

The jelly-roll type electrode assembly is mainly used for a cylindrical battery or a prismatic battery. The cylindrical battery includes a jelly-roll type electrode assembly housed in a cylindrical battery case, a non-aqueous electrolyte injected into a cylindrical battery case, And a top cap in which an electrode terminal is formed at an open upper end.

A cylindrical core member is generally inserted into the core of the jelly-roll type electrode assembly. Such a core member is generally made of a metal material in order to impart a predetermined strength and has a hollow cylindrical structure having a structure in which the plate member is bent in a round shape and the horizontal end portion is not in contact with the end. These core members act as passages for fixing and supporting the electrode assembly and for releasing gas generated by internal reactions during charging, discharging and operation.

However, the conventional core member is liable to be deformed in the hollow internal structure when an external impact such as dropping and pressing of the electrochemical device is applied. By such deformation, the non-contact end of the core member penetrates the separator, Contact may cause an internal short circuit.

In particular, when a cylindrical secondary battery is used in, for example, a notebook PC, most of the batteries are subjected to a safety test such as an impact test. As a result, a strong impact is applied to the battery, Which is a serious problem.

Accordingly, a problem to be solved by the present invention is to provide a passage through which gases generated by an internal reaction during charging, discharging and operation of an electrochemical device are efficiently discharged, thereby improving the safety of an electrochemical device, There is provided an electrochemical device including a porous core member in which an internal short circuit is prevented by minimizing an impact applied to an electrode assembly through shock absorption of a core member even if an external impact is applied to the device, and the mechanical strength of the electrochemical device is improved, .

According to an aspect of the present invention, there is provided an electrochemical device embedded in a battery case, the electrode assembly being manufactured by winding a cathode, an anode, and a separator interposed between the cathode and the anode, There is provided an electrochemical device in which a porous core member for absorbing an impact applied to an electrochemical device is inserted in the core of the electrode assembly.

At this time, the porosity of the porous core member may be 20 to 80%.

The diameter of the porous core member may be 1 to 10 mm.

The porous core member may be formed of any one selected from the group consisting of metals, ceramics, and polymers, or a mixture of two or more thereof.

The metal may be any one selected from the group consisting of Al, In, Sn, Pb, Cu, Ag, Au, Fe, Co, Ni, Pt, Cr, Mn, Zn and Ti, Lt; / RTI >

The ceramic may be any one selected from the group consisting of Al ₂ O ₃ -SiO ₂ ceramics, oxide ceramics, carbide ceramics and nitride ceramics, or a mixture of two or more thereof.

The polymer may be at least one selected from the group consisting of acrylonitrile butadiene styrene copolymer (ABS), acrylonitrile ethyl acrylate styrene copolymer (AES), polycarbonate (PC), acrylonitrile styrene copolymer (SAN) (PE), polyethylene carbonate (PEC), polyphthalamide (PPA), polyamide (PA), polybutylene terephthalate (PA), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyurethane (PU), thermoplastic polyester elastomer (TPEE), polysulfone (PSU), polyphenylene oxide (PPO) and polyvinylidene fluoride Or a mixture of two or more thereof.

The electrochemical device may be a lithium secondary battery.

According to one embodiment of the present invention, even if an external impact is applied to the electrochemical device, the internal short-circuit of the electrochemical device is prevented through shock absorption of the core member, and the mechanical strength of the electrochemical device is improved.

The gas generated by the internal reaction during charging, discharging and operation of the electrochemical device is efficiently discharged to the outside of the electrochemical device through the porous core member existing in the core of the electrode assembly, thereby preventing the explosion by the internal gas Thereby improving the safety of the electrochemical device.

Hereinafter, the present invention will be described in detail. The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms and the inventor may appropriately define the concept of the term in order to best describe its invention It should be construed as meaning and concept consistent with the technical idea of the present invention.

Therefore, it should be understood that the embodiments described herein are merely the most preferred embodiments of the present invention, and are not intended to represent all of the technical ideas of the present invention. Accordingly, various equivalents and variations And the like.

An electrochemical device of the present invention is an electrochemical device in which an electrode assembly manufactured by winding a cathode, an anode, and a separator interposed between the cathode and the anode is embedded in a battery case, and an impact Is inserted into the core of the electrode assembly.

The core member used in the electrochemical device according to the present invention is made of a porous structure absorbing impacts and can be used as an impact test or a crush test for an external impact, particularly a cylindrical electrochemical device for a notebook PC, The pores in the core member serve as a discharge channel for the gas generated by the internal reaction during charging and discharging and operation, and the high-temperature to high-pressure It is possible to prevent the electrode assembly from igniting or exploding in a harsh environment such as the environment, and ultimately the safety of the electrochemical device can be improved.

Here, the porous core member may be formed in a shape corresponding to the winding core of the electrode assembly. In the case of a cylindrical electrochemical device, the porous core member may be formed in the form of a rod having a substantially circular, elliptical or polygonal cross- In the case of a square or pouch type electrochemical device, it is formed in a plate-like shape to prevent deformation of the electrode assembly.

At this time, the porosity of the porous core member may be 20 to 80%. When the numerical range is satisfied, the movement of the electrolyte and gas in the electrochemical device is facilitated, which is advantageous for improving the stability of the battery.

The diameter of the porous core member may be 1 to 10 mm. If the diameter of the core member is too large, the capacity of the electrochemical device becomes small. If the core member is too small, the mechanical rigidity of the core member becomes small.

Meanwhile, the porous core member may be composed of any one selected from the group consisting of metals, ceramics, and polymers, or a mixture of two or more thereof.

The metal is selected from the group consisting of Al, In, Sn, Pb, Cu, Ag, Au, Fe, Co, Ni, Pt, Cr, Mn, Zn, and Ti with no or low reactivity with the electrolyte Any one or a mixture of two or more thereof may be used. When a metal is used as the core member, appropriate mechanical properties (such as malleability, ductility, rigidity, etc.) are imparted and a large amount of impact can be absorbed.

The ceramic may be any one selected from the group consisting of Al ₂ O ₃ -SiO ₂ ceramics, oxide ceramics, carbide ceramics and nitride ceramics, or a mixture of two or more thereof. The ceramic is a porous material having strength, which facilitates the movement of the electrolytic solution and gas in the electrochemical device, absorbs external impacts, and maintains the shape of the electrode assembly.

The polymer may be at least one selected from the group consisting of acrylonitrile butadiene styrene copolymer (ABS), acrylonitrile ethyl acrylate styrene copolymer (AES), polycarbonate (PC), acrylonitrile styrene copolymer (SAN) (PE), polyethylene carbonate (PEC), polyphthalamide (PPA), polyamide (PA), polybutylene terephthalate (PA), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyurethane (PU), thermoplastic polyester elastomer (TPEE), polysulfone (PSU), polyphenylene oxide (PPO) and polyvinylidene fluoride Or a mixture of two or more thereof. When the polymer is used, the electrode assembly can be prevented from being damaged by absorbing impact applied to the electrode assembly.

Meanwhile, the cathode according to the present invention has a structure in which a cathode layer including a cathode active material, a conductive material, and a binder is supported on one or both surfaces of a current collector.

The cathode active material may include a lithium-containing oxide, and a lithium-containing transition metal oxide may be preferably used. For example, Li _x CoO ₂ (0.5 <x <1.3), Li _x NiO ₂ (0.5 <x <1.3), Li _x MnO ₂ (0.5 <x <1.3), Li _x Mn ₂ O _{4 1.3), Li x (Ni a} Co b Mn c) O 2 (0.5 <x <1.3, 0 <a <1, 0 <b <1, 0 <c <1, a + b + c = 1), Li _{x Ni 1 -y Co y O 2} (0.5 <x <1.3, 0 <y <1), Li x Co 1 -y Mn y O 2 (0.5 <x <1.3, 0≤y <1), Li x Ni _{1 -y} Mn _y O ₂ (0.5 <x <1.3, 0≤y <1), Li _x (Ni _a Co _b Mn _c ) O ₄ (0.5 <x <1.3, 0 <a < 2, 0 <c <2, a + b + c = 2), Li x Mn 2 -z Ni z O 4 (0.5 <x <1.3, 0 <z <2), Li x Mn 2 -z Co z O _{4 (0.5 <x <1.3,} 0 <z <2), Li x CoPO 4 (0.5 <x <1.3) and 2 out of any one or combinations selected from the group consisting of _{Li x FePO 4 (0.5 <x} <1.3) And the lithium-containing transition metal oxide may be coated with a metal such as aluminum (Al) or a metal oxide. In addition to the lithium-containing transition metal oxide, sulfide, selenide and halide may also be used.

The conductive material is not particularly limited as long as it is an electron conductive material that does not cause a chemical change in an electrochemical device. In general, carbon black, graphite, carbon fiber, carbon nanotube, metal powder, conductive metal oxide, organic conductive material and the like can be used. Commercially available products as the conductive material include acetylene black series (manufactured by Chevron Chemical Co., (Chevron Chemical Company or Gulf Oil Company products), Ketjen Black EC series (Armak Company), Vulcan XC-72 (Cabot Company) and Super P (MM (MMM)). For example, acetylene black, carbon black and graphite.

The anode has a structure in which the anode layer including the anode active material and the binder is supported on one or both surfaces of the current collector.

As the anode active material, a lithium metal, a carbonaceous material, a metal compound, or a mixture thereof may be used, in which lithium ions can be occluded and released.

Concretely, as the carbon material, both low-crystalline carbon and highly-crystalline carbon may be used. Examples of the low crystalline carbon include soft carbon and hard carbon. Examples of highly crystalline carbon include natural graphite, Kish graphite, pyrolytic carbon, liquid crystal pitch carbon fiber high temperature sintered carbon such as mesophase pitch based carbon fiber, meso-carbon microbeads, mesophase pitches and petroleum or coal tar pitch derived cokes.

Examples of the metal compound include metal elements such as Si, Ge, Sn, Pb, P, Sb, Bi, Al, Ga, In, Ti, Mn, Fe, Co, Ni, Cu, Zn, Ag, Mg, , And the like. These metal compounds may be a single substance, an alloy, an oxide (TiO ₂ , SnO ₂ Or the like), a nitride, a sulfide, a boride, an alloy with lithium, or the like, but an alloy with a single substance, an alloy, an oxide, and lithium can be increased in capacity. Among them, it may contain at least one element selected from Si, Ge and Sn, and it may further increase the capacity of the battery including at least one element selected from Si and Sn.

The binder used for the cathode and the anode has a function of holding the cathode active material and the anode active material in the current collector and also connecting the active materials, and a commonly used binder may be used without limitation.

For example, polyvinylidene fluoride-hexafluoropropylene (PVDF-co-HFP), polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethyl methacrylate various kinds of binders such as polymethyl methacrylate, styrene butadiene rubber (SBR), and carboxyl methyl cellulose (CMC) can be used.

The current collector used for the cathode and the anode may be any metal having a high conductivity and a metal which can easily adhere to the slurry of the active material and is not reactive in the voltage range of the battery. Specifically, examples of the current collector for a cathode include aluminum, nickel, or a combination thereof. Examples of the current collector for an anode include copper, gold, nickel, or a copper alloy or a combination thereof And the like. In addition, the current collector may be used by laminating the substrates made of the above materials.

The cathode and the anode are kneaded using an active material, a conductive material, a binder, and a high boiling point solvent to form an electrode mixture, and then the mixture is applied to a copper foil or the like of the current collector and dried and press- Respectively, for 2 hours under a vacuum.

The thickness of the electrode layer of the cathode (per one current collector) may be 30 to 120 占 퐉, or 50 to 100 占 퐉, and the thickness of the anode electrode layer may be 1 to 100 占 퐉, or 3 to 70 占 퐉. When the cathode and the anode satisfy such a thickness range, the amount of the active material in the electrode material layer is sufficiently secured, the battery capacity can be prevented from being reduced, and the cycle characteristics and rate characteristics can be improved.

As the separator according to the present invention, any porous substrate used for an electrochemical device can be used. For example, a polyolefin porous membrane or a nonwoven fabric may be used, but the present invention is not limited thereto.

Examples of the polyolefin-based porous film include polyolefin-based polymers such as polyethylene, polypropylene, polybutylene, and polypentene, such as high-density polyethylene, linear low-density polyethylene, low-density polyethylene and ultra-high molecular weight polyethylene, One membrane can be mentioned.

The nonwoven fabric may include, in addition to the polyolefin nonwoven fabric, for example, polyethylene terephthalate, polybutylene terephthalate, polyester, polyacetal, polyamide, polycarbonate ), Polyimide, polyetheretherketone, polyethersulfone, polyphenylene oxide, polyphenylenesulfide, and polyethylene naphthalene, which may be used alone or in combination, And nonwoven fabrics formed by mixing these polymers. The structure of the nonwoven fabric may be a spun bond nonwoven fabric or a meltblown nonwoven fabric composed of long fibers.

The thickness of the porous substrate is not particularly limited, but may be 5 to 50 μm, and the pore size and porosity present in the porous substrate are also not particularly limited, but may be 0.01 to 50 μm and 10 to 95%, respectively.

On the other hand, in order to improve the mechanical strength of the separator composed of the porous substrate and to prevent a short circuit between the cathode and the anode, a porous coating layer containing inorganic particles and a polymeric binder may be further provided on at least one surface of the porous substrate.

In the porous coating layer, the polymer binder binds the inorganic particles together (that is, the polymer binder binds and fixes the inorganic particles) so that the inorganic particles can remain bonded to each other, and the porous coating layer binds the porous substrate with the polymer binder . The inorganic particles of the porous coating layer exist in a closely packed state in a state of being substantially in contact with each other, and the interstitial volume generated when the inorganic particles are in contact becomes the pores of the porous coating layer.

At this time, the inorganic particles used are not particularly limited as long as they are electrochemically stable. That is, the inorganic particles are not particularly limited as long as the oxidation and / or reduction reaction does not occur in the operating voltage range of the applied electrochemical device (for example, 0 to 5 V based on Li / Li ⁺ ). Particularly, when inorganic particles having ion transfer ability are used, the ion conductivity in the electrochemical device can be increased to improve the performance.

When inorganic particles having a high dielectric constant are used as the inorganic particles, dissociation of an electrolyte salt, for example, a lithium salt, in the liquid electrolyte is also increased, and ion conductivity of the electrolyte can be improved.

For the reasons stated above, the inorganic particles may include high-permittivity inorganic particles having a dielectric constant of 5 or more, or 10 or more, inorganic particles having lithium ion-transporting ability, or a mixture thereof.

Nonlimiting examples of inorganic particles having a dielectric constant of 5 or more include BaTiO ₃ , Pb (Zr _x Ti _{1 -x} ) O ₃ (PZT, where 0 <x <1), Pb _{1 - x} La _x Zr _{1 - y} Ti _y O ₃ (PLZT, where, 0 <x <1, 0 <y <1 Im), (1-x) Pb (Mg 1/3 Nb 2/3) O 3 -xPbTiO 3 (PMN-PT, where 0 < xO, x <1), hafnia (HfO ₂ ), SrTiO ₃ , SnO ₂ , CeO ₂ , MgO, NiO, CaO, ZnO, ZrO ₂ , Y ₂ O ₃ , Al ₂ O ₃ , SiC, TiO ₂ May be used alone or in combination of two or more.

In particular, the above-described _{BaTiO 3, Pb (Zr x Ti} 1 -x) O 3 (PZT, where 0 <x <1), Pb 1 - x La x Zr 1 -y Ti y O 3 (PLZT, where 0 < x <1, 0 <y < 1 Im), (1-x) Pb (Mg 1/3 Nb 2/3) O 3 - x PbTiO 3 (PMN-PT, where 0 <x <1), hafnia ( HfO ₂ ) exhibits a high dielectric constant with a dielectric constant of 100 or more, as well as a piezoelectricity in which a potential difference is generated between both surfaces due to the generation of charge when a certain pressure is applied to the piezoelectric element by being stretched or compressed. It is possible to prevent internal short-circuiting of both electrodes due to the impact, thereby improving the safety of the electrochemical device. Further, when the above-mentioned high-permittivity inorganic particles and inorganic particles having lithium ion transferring ability are mixed, their synergistic effect can be doubled.

The inorganic particles having the lithium ion transferring ability refer to inorganic particles that contain a lithium element but do not store lithium but have a function of transferring lithium ions. The inorganic particles having lithium ion transferring ability exist in the particle structure Since lithium ions can be transferred and transferred due to a kind of defect, the lithium ion conductivity in the battery can be improved and the battery performance can be improved. Examples of the inorganic particles having lithium ion transferring ability include lithium phosphate (Li ₃ PO ₄ ), lithium titanium phosphate (Li _x Ti _y (PO ₄ ) ₃ , 0 <x <2, 0 <y < (Li _x Al _y Ti _z (PO ₄ ) ₃ , 0 <x <2, 0 <y <1, 0 <z <3), 14Li ₂ O-9Al ₂ O ₃ -38TiO ₂ -39P ₂ O ₅ as such (LiAlTiP) _x O _y series glass (0 <x <4, 0 <y <13), lithium lanthanum titanate _{(Li x La y TiO 3,} 0 <x <2, 0 <y <3 ), Li _{3 .25} Ge _{0 .25} P _{0 .75} S ₄ Lithium, such as germanium Mani help thiophosphate lithium nitro, such as _{(Li x Ge y P z S} w, 0 <x <4, 0 <y <1, 0 <z <1, 0 <w <5), Li 3 N fluoride _{(Li x N y, 0 <} x <4, 0 <y <2), Li 3 PO 4 -Li 2 S-SiS 2 SiS 2 based glass, such as _{(Li x Si y S z,} 0 <x <3 , 0 <y <2, 0 <z <4), LiI-Li ₂ SP ₂ S ₅ There is P ₂ S ₅ based glass _{(Li x P y S z,} 0 <x <3, 0 <y <3, 0 <z <7) or a mixture thereof as such.

As the polymer binder used for forming the porous coating layer, a polymer commonly used in the formation of the porous coating layer in the art can be used. In particular, a polymer having a glass transition temperature (T _g ) of -200 to 200 ° C can be used because it can improve mechanical properties such as flexibility and elasticity of a finally formed porous coating layer. Such a polymer binder faithfully performs a binder function to connect and stably fix inorganic particles, thereby contributing to prevention of degradation of mechanical properties of the separator into which the porous coating layer is introduced.

Further, the polymer binder does not necessarily have ion conductivity, but when the polymer having ion conductivity is used, the performance of the electrochemical device can be further improved. Therefore, a polymer binder having a high permittivity constant can be used. Actually, the dissociation degree of the salt in the electrolytic solution depends on the permittivity constant of the solvent of the electrolyte. Therefore, the higher the permittivity constant of the polymer, the better the salt dissociation degree in the electrolyte. The permittivity constant of such a polymeric binder may be in the range of 1.0 to 100 (measurement frequency = 1 kHz), in particular, 10 or more.

In addition to the functions described above, the polymeric binder may be characterized by being capable of exhibiting a high degree of swelling of the electrolyte due to gelation upon impregnation with a liquid electrolyte. Accordingly, the solubility parameter of the polymeric binder is from 15 to 45 MPa ^1/2 or 15 to 25 MPa ^1/2, and 30 to 45 MPa ^1/2 range. Therefore, hydrophilic polymers having many polar groups can be used more than hydrophobic polymers such as polyolefins. If the solubility is more than ^1/2 and less than 15 MPa 45 MPa ^1/2, because it can be difficult to swell (swelling) by conventional liquid electrolyte batteries.

Non-limiting examples of such polymeric binders include polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichlorethylene, poly But are not limited to, polymethylmethacrylate, polybutylacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, polyethylene-co- polyvinyl acetate, vinyl acetate, polyethylene oxide, polyarylate, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, Cyanoethylpullulan, cyanoethylpolybi Cyanoethylpolyvinylalcohol, cyanoethylcellulose, cyanoethylsucrose, pullulan, and carboxyl methyl cellulose can be given.

The weight ratio of the inorganic particles to the polymeric binder may be 50:50 to 99: 1, or 60:40 to 90:10, or 70:30 to 80:20.

The thickness of the porous coating layer composed of the inorganic particles and the polymer binder is not particularly limited, but may be in the range of 0.01 to 20 占 퐉. The pore size and porosity are also not particularly limited, but the pore size may be in the range of 0.01 to 10 mu m, and the porosity may be in the range of 5 to 90%.

The separator according to an aspect of the present invention may further include other additives in addition to the inorganic particles and the polymer binder described above as the porous coating layer component.

Meanwhile, the electrochemical device according to an embodiment of the present invention includes all devices that perform an electrochemical reaction, and specific examples thereof include capacitors such as all types of secondary cells, fuel cells, solar cells, or super- ). Particularly, a lithium secondary battery including a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, or a lithium ion polymer secondary battery among the above secondary batteries is preferable.

On the other hand, the electrochemical device of the present invention is manufactured by inserting an electrode assembly into a battery case, injecting a non-aqueous electrolyte into the battery case, and then joining a top cap having electrode terminals formed at the open upper end of the battery case.

Here, the non-aqueous electrolyte may include an electrolyte salt and an organic solvent, and the electrolyte salt is a lithium salt. The lithium salt may be any of those conventionally used for non-aqueous electrolytes for lithium secondary batteries. For example is the above lithium salt anion ^{F -, Cl -, Br -} , I -, NO 3 -, N (CN) 2 -, BF 4 -, ClO 4 -, PF 6 -, (CF 3) 2 PF _{^{4 -, (CF 3) 3}} PF 3 -, (CF 3) 4 PF 2 -, (CF 3) 5 PF -, (CF 3) 6 P -, CF 3 SO 3 -, CF 3 CF 2 SO 3 - _{, (CF 3 SO 2) 2} N -, (FSO 2) 2 N -, CF 3 CF 2 (CF 3) 2 CO -, (CF 3 SO 2) 2 CH -, (SF 5) 3 C -, ( CF ₃ SO ₂ ) ₃ C ^- , CF ₃ (CF ₂ ) ₇ SO ₃ ^- , CF ₃ CO ₂ ^- , CH ₃ CO ₂ ^- SCN ^- and (CF ₃ CF ₂ SO ₂ ) ₂ N ^- .

Examples of the organic solvent included in the non-aqueous electrolyte include those commonly used in non-aqueous electrolytes for lithium secondary batteries, such as ether, ester, amide, linear carbonate, cyclic carbonate, etc., Or more.

Among them, a carbonate compound which is typically a cyclic carbonate, a linear carbonate, or a mixture thereof may be included.

Specific examples of the cyclic carbonate compound include ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, Propylene carbonate, 2,3-pentylene carbonate, vinylene carbonate, vinylethylene carbonate, and halides thereof, or a mixture of two or more thereof. Examples of such halides include, but are not limited to, fluoroethylene carbonate (FEC) and the like.

Specific examples of the linear carbonate compound include any one selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, ethyl methyl carbonate (EMC), methyl propyl carbonate and ethyl propyl carbonate And mixtures of two or more of them may be used as typical examples, but the present invention is not limited thereto.

In particular, ethylene carbonate and propylene carbonate, which are cyclic carbonates in the carbonate-based organic solvent, are high-viscosity organic solvents having a high dielectric constant and can dissociate the lithium salt in the electrolyte more easily. In addition, such cyclic carbonates can be used as dimethyl carbonate and diethyl carbonate When a low viscosity, low dielectric constant linear carbonate is mixed in an appropriate ratio, an electrolyte having a higher electric conductivity can be produced.

As the ether in the organic solvent, any one selected from the group consisting of dimethyl ether, diethyl ether, dipropyl ether, methyl ethyl ether, methyl propyl ether and ethyl propyl ether or a mixture of two or more thereof may be used , But is not limited thereto.

Examples of the ester in the organic solvent include methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate,? -Butyrolactone,? -Valerolactone,? -Caprolactone,? -Valerolactone, ε-caprolactone, or a mixture of two or more thereof, but the present invention is not limited thereto.

The injection of the nonaqueous electrolyte solution can be performed at an appropriate stage of the manufacturing process of the electrochemical device according to the manufacturing process and required properties of the final product. That is, it can be applied before assembling the electrochemical device or in the final stage of assembling the electrochemical device.

The outer shape of the electrochemical device is not particularly limited, but may be a cylindrical shape, a square shape, a pouch shape, or the like using a can.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

Claims (8)

An electrode assembly manufactured by winding a cathode, an anode, and a separator interposed between the cathode and the anode, is an electrochemical device embedded in a battery case,
Wherein a porous core member for absorbing an impact applied to the electrochemical device is inserted into the core of the electrode assembly. The method according to claim 1,
Wherein the porosity of the porous core member is 20 to 80%. The method according to claim 1,
And the diameter of the porous core member is 1 to 10 mm. The method according to claim 1,
Wherein the porous core member is made of any one selected from the group consisting of metals, ceramics and polymers, or a mixture of two or more thereof. 5. The method of claim 4,
The metal may be any one selected from the group consisting of Al, In, Sn, Pb, Cu, Ag, Au, Fe, Co, Ni, Pt, Cr, Mn, Zn and Ti or a mixture of two or more thereof Characterized in that the electrochemical device. 5. The method of claim 4,
Wherein the ceramic is any one selected from the group consisting of Al ₂ O ₃ -SiO ₂ ceramics, oxide ceramics, carbide ceramics and nitride ceramics, or a mixture of two or more thereof. 5. The method of claim 4,
The polymer may be selected from the group consisting of acrylonitrile butadiene styrene copolymer (ABS), acrylonitrile ethyl acrylate styrene copolymer (AES), polycarbonate (PC), acrylonitrile styrene copolymer (SAN), acrylonitrile (PE), polyethylene carbonate (PEC), polyphthalamide (PPA), polyamide (PA), polybutylene terephthalate (PBT), polyethylene terephthalate ) Selected from the group consisting of polyethylene terephthalate (PET), polyurethane (PU), thermoplastic polyester elastomer (TPEE), polysulfone (PSU), polyphenylene oxide (PPO) and polyvinylidene fluoride Or a mixture of two or more thereof. The method according to claim 1,
Wherein the electrochemical device is a lithium secondary battery.