Case for lithium rechargeable battery and lithium rechargeable battery including same

Abstract

The present invention relates to a case for a lithium rechargeable battery and a lithium rechargeable battery comprising same. The case for a lithium rechargeable battery comprises: a laminate sheet in which an inner layer, an intermediate layer, and an outer layer are sequentially laminated; and a first polymer film positioned on the outer layer of the laminate sheet and containing a first polyurethane resin.

Description

Case for lithium secondary battery and lithium secondary battery including same

[0001] The present invention relates to a case for a lithium secondary battery and a lithium secondary battery including the same.

[0002]

[0003] Lithium secondary batteries are rechargeable and have an energy density per unit weight that is three times higher than that of conventional lead-acid batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries, and they are capable of fast charging. Therefore, they are commercialized for use in laptops, cell phones, power tools, and electric bicycles, and active research and development is being conducted to further improve energy density.

[0004] Lithium secondary batteries currently on the market are lithium-ion batteries that use electrolytes containing flammable organic solvents. This poses safety concerns, as they can explode or cause fire in the event of collisions or penetrations. Therefore, all-solid-state batteries, which utilize solid electrolytes instead of the electrolytes, are being proposed. Among lithium secondary batteries, all-solid-state batteries are comprised entirely of solid materials, specifically those that utilize solid electrolytes.

[0005] A lithium secondary battery, regardless of its form, includes a case for a lithium secondary battery; and an electrode assembly built into the case for the lithium secondary battery. In addition, the electrode assembly includes a positive electrode, a negative electrode, and an electrolyte positioned between the positive electrode and the negative electrode. However, when a metallic foreign substance (e.g., a nail) penetrates from the outside of the case for the lithium secondary battery, an electron conductive path is formed between the positive electrode and the negative electrode by the penetrated metallic foreign substance, causing electricity to flow, and the electrical energy is converted into thermal energy.

[0006]

[0007] One embodiment provides a case for a lithium secondary battery that can suppress short circuit and heat generation even when a foreign metal substance or the like penetrates the inside of the battery from the outside.

[0008]

[0009] One embodiment provides a case for a lithium secondary battery, comprising: a laminate sheet in which an inner layer, a middle layer, and an outer layer are sequentially laminated; and a first polymer film positioned on the outer layer of the laminate sheet and including a first polyurethane resin.

[0010]

[0011] A case for a lithium secondary battery according to an embodiment can ensure the safety of a lithium secondary battery by suppressing short circuit and heat generation phenomena even when a foreign metal substance or the like penetrates the inside of the battery from the outside.

[0012]

[0013] Figure 1 is a cross-sectional view schematically illustrating a nail penetration test of a lithium secondary battery using a conventional lithium secondary battery case.

[0014] Figures 2 and 3 are cross-sectional views schematically illustrating a nail penetration test of a lithium secondary battery using a lithium secondary battery case of one embodiment.

[0015] Figures 4 and 5 are cross-sectional views schematically illustrating an all-solid-state battery according to one embodiment.

[0016]

[0017] Hereinafter, embodiments of the present invention will be described in detail. However, these are presented as examples and are not intended to limit the present invention. The present invention is defined solely by the scope of the claims set forth below.

[0018] Unless otherwise specified herein, when a part such as a layer, film, region, plate, etc. is said to be “on” another part, this includes not only cases where it is “directly on” the other part, but also cases where there is another part in between.

[0019] Unless otherwise specified herein, the singular may also include the plural. Furthermore, unless otherwise specified, "A or B" may mean "including A, including B, or including A and B."

[0020] As used herein, “combination thereof” may mean mixtures, laminates, composites, copolymers, alloys, blends, and reaction products of the components.

[0021] Unless otherwise defined herein, the particle size may be the average particle size. In addition, the particle size refers to the average particle size (D50), which means the diameter of particles with a cumulative volume of 50% by volume in a particle size distribution. The average particle size (D50) can be measured by a method well known to those skilled in the art, for example, by measuring with a particle size analyzer, or by measuring with a transmission electron microscope (TEM) photograph or a scanning electron microscope (SEM) photograph. Alternatively, the average particle size (D50) value can be obtained by measuring with a measuring device that utilizes dynamic light-scattering, performing data analysis to count the number of particles for each particle size range, and calculating from the counted number. Alternatively, the average particle size (D50) value can be obtained by measuring with a laser diffraction method. When measuring by laser diffraction, more specifically, after the particles to be measured are dispersed in a dispersion medium, they are introduced into a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000) and irradiated with ultrasonic waves of approximately 28 kHz at an output of 60 W, and the average particle size (D50) based on 50% of the particle size distribution in the measuring device can be calculated.

[0022] In this specification, “weight average molecular weight” is a value measured by gel permeation chromatography (GPC: gel permeation chromatography, PL GPC220, Agilent Technologies) and corrected with a third-order function using polystyrene.

[0023]

[0024] (Case for lithium secondary battery)

[0025] One embodiment provides a case for a lithium secondary battery, comprising: a laminate sheet in which an inner layer, a middle layer, and an outer layer are sequentially laminated; and a first polymer film positioned on the outer layer of the laminate sheet and including a first polyurethane resin.

[0026] A case for a lithium secondary battery according to one embodiment may further include a second polymer film positioned on an inner layer of the laminate sheet and including a second polyurethane resin.

[0027] A case for a lithium secondary battery according to an embodiment can ensure the safety of a lithium secondary battery by suppressing short circuit and heat generation phenomena even when a foreign metal substance or the like penetrates the inside of the battery from the outside.

[0028]

[0029] Figure 1 is a cross-sectional view schematically illustrating a nail penetration test of a lithium secondary battery using a conventional lithium secondary battery case.

[0030] Conventional lithium secondary battery cases are made only of laminated sheets in which inner, middle, and outer layers are sequentially laminated, so that the outer layer is exposed to the outside as is.

[0031] However, the outer layer is typically composed of low-friction materials such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or nylon. Therefore, if a nail penetrates the exterior of a conventional lithium secondary battery case, the outer layer fails to elongate beyond a certain level and is severed. As a result, the nail penetrating the outer layer forms a direct conductive path between the positive and negative electrodes.

[0032]

[0033] Figures 2 and 3 are cross-sectional views schematically illustrating a nail penetration test of a lithium secondary battery using a case of one embodiment.

[0034] A case for a lithium secondary battery according to one embodiment further includes a first polymer film on an outer layer of a conventional case for a lithium secondary battery, so that the outer layer is protected by the first polymer film.

[0035] In addition, the case for a lithium secondary battery according to the above embodiment may further optionally include a second polymer film on the inner layer of a conventional case for a lithium secondary battery, so that the inner layer may be protected by the second polymer film.

[0036] The first polymer film and the second polymer film each include a polyurethane resin, which is an insulating material having high frictional force, elongation, and tensile strength.

[0037] Accordingly, when a nail penetrates from the outside of the case for a lithium secondary battery of one embodiment, the first polymer film and the second polymer film are not cut but are stretched and pushed into the inside of the lithium secondary battery together with the nail, thereby suppressing the formation of a direct conductive path between the positive electrode and the negative electrode.

[0038] The synergistic effect resulting from the simultaneous presence of the first polymer film and the second polymer film may be higher than the effect of the first polymer film alone.

[0039]

[0040] Below, a case for a lithium secondary battery according to an embodiment is described in detail.

[0041]

[0042] First polymer film and second polymer film

[0043] As mentioned above, the first polymer film and the second polymer film each include polyurethane resin, which is an insulating material having high frictional force, elongation, and tensile strength.

[0044]

[0045] Weight average molecular weight

[0046] The first polyurethane resin and the second polyurethane resin may each independently have a weight average molecular weight measured by the GPC method of 10,000 to 3,000,000 g / mol, specifically 20,000 to 2,000,000 g / mol, and more specifically 70,000 to 100,000 g / mol. Within this range, the first polymer film and the second polymer film having an appropriate friction coefficient may each be formed, but are not limited thereto.

[0047]

[0048] coefficient of friction

[0049] The first polymer film and the second polymer film may each independently have a coefficient of friction of 0.4 μ to 0.8 μ. Within this range, the first polymer film and the second polymer film can each provide a large frictional force that pushes in together with the metal foreign substance, thereby excellently exhibiting the above-described effect.

[0050] The above coefficient of friction can be measured using a static friction coefficient measurement method. Specifically, the stress at the point where the object begins to move is calculated and measured by increasing the angle of the slope using equipment that measures the coefficient of static friction.

[0051]

[0052] Elongation

[0053] The first polymer film and the second polymer film may each independently have an elongation of 200 to 700%, specifically 200 to 650%, and more specifically 400 to 650%, according to the ASTM D638 measurement method. Within this range, the first polymer film and the second polymer film may each be sufficiently elongated to be pushed in together with the metal foreign substance, thereby excellently exhibiting the above-described effect.

[0054]

[0055] tensile strength

[0056] The first polymer film and the second polymer film each independently have a tensile strength of 250 to 600 kgf / mm according to the ISO527 measurement method. 2 , specifically 300 to 500 kgf / mm 2 , more specifically 330 to 450 kgf / mm 2 It can be. In this range, the first polymer film and the second polymer film can each exhibit the above-described effect excellently without being cut by a metal foreign substance.

[0057]

[0058] thickness

[0059] The first polymer film and the second polymer film may each independently have a thickness of 10 to 300 μm, specifically 50 to 300 μm, and more specifically 100 to 250 μm. Within this range, since the thicknesses of the first polymer film and the second polymer film, which are pushed in together with the metal foreign substance, are sufficiently secured, the above-described effect can be excellently exhibited.

[0060] The above thickness can be measured by a thickness measuring instrument (Digimatic Thickness Gauge: MIYUTOYO).

[0061]

[0062] Method for manufacturing polymer film

[0063] The first polymer film and the second polymer film can each be independently manufactured from a composition for a polymer film containing a polyurethane resin.

[0064] The composition for the above polymer film can be prepared from a composition for the polymer film including a urethane-based binder, a curing agent, and a plasticizer.

[0065]

[0066] Urethane binder

[0067] The above urethane-based binder can be cured by the above curing agent to form the above polyurethane resin.

[0068] The above urethane-based binder may have one or more urethane bonds and one or more hydroxyl groups (-OH). The above urethane-based binder may be included in an amount of 60 to 100 wt % of the above urethane-based binder.

[0069] The above urethane-based binder may have a number average molecular weight of 30,000 to 150,000 g / mol, specifically 50,000 to 70,000 g / mol.

[0070]

[0071] The above urethane-based binder can be manufactured by reacting one or more polyols and one or more isocyanate compounds.

[0072] Specifically, the urethane-based binder can be manufactured by polymerizing an isocyanate-based compound based on 100 parts by weight of a polyol including a polyether-based triol, a polyether-based diol, and a polyester-based diol. Here, the polymerization can be thermal polymerization.

[0073]

[0074] The above polyol may include at least one of a polyether polyol, a polyester polyol, a polyacrylic polyol, a polycaprolactone polyol, and a polycarbonate polyol. Specifically, the polyol may include at least one polyether polyol, and may further include at least one polyester polyol.

[0075] Accordingly, the urethane-based binder may be a random copolymer having units derived from the polyol. Specifically, the urethane-based binder may include units derived from a polyether-based polyol and may further include units derived from a polyester-based polyol.

[0076]

[0077] The above polyether polyol may be a polyether polyol having two or more hydroxyl groups, such as a bifunctional polyether polyol (polyether diol) such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc., a trifunctional polyether polyol (polyether triol), a trifunctional polyether polyol of a glycerin alkylene oxide adduct (polyether triol), etc., which has an alkylene oxide group. Through this, the urethane binder becomes a hyperbranched binder, so that the urethane binder has a structure that is more structured than a linear form, so that the effects of the present invention can be more easily implemented. The 'hyperbranched' refers to a polymer having many terminal functional groups and a branched structure of the aqueous phase.

[0078] The above polyether polyol may be used alone or in combination of two or more when manufacturing a urethane binder. Specifically, the polyether polyol may include a mixture of a polyether diol and a polyether triol.

[0079] The polyether polyol may have a number average molecular weight of 400 to 10,000 g / mol, specifically 1,000 to 7,000 g / mol. Specifically, the polyether triol may have a number average molecular weight of 400 to 10,000 g / mol, specifically 2,000 to 8,000 g / mol. In addition, the polyether diol may have a number average molecular weight of 400 to 10,000 g / mol, specifically 1,000 to 6,000 g / mol.

[0080]

[0081] The above polyester polyol may include a polyol obtained by an esterification reaction between one or more polyols and one or more acid components.

[0082] The polyol used at this time may include at least one of ethylene glycol, propylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 2-ethyl-1,3-hexanediol, 1,8-octanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 1,8-decanediol, octadecane diol, glycerin, trimethylolpropane, pentaerythritol, and hexanetriol, but is not limited thereto. Acid components used at this time include, but are not limited to, succinic acid, methylsuccinic acid, adipic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, 1,14-tetradecanedioic acid, dimer acid, 2-methyl-1,4-cyclohexanedicarboxylic acid, 2-ethyl-1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, or acid anhydrides thereof.

[0083] The above polyester polyols may be used alone or in combination of two or more when manufacturing a urethane binder.

[0084] The above polyester polyol may include a polyester polyol having two or more hydroxyl groups, including at least one of a bifunctional polyester polyol (polyester diol) or a trifunctional polyester polyol (polyester triol). Through this, the urethane binder becomes a hyperbranched binder, thereby facilitating the implementation of the effects of the present invention. Specifically, a polyester diol may be used as the polyester polyol.

[0085] The above polyester diol may have a number average molecular weight of 1,000 to 5,000 g / mol, specifically 2,000 to 3,000 g / mol. Within the above range, it may be advantageous to achieve the peel strength and modulus of the present invention.

[0086]

[0087] The above isocyanate compound may include a polyisocyanate compound having multiple isocyanate groups (-NCO). The polyisocyanate compound may be a known polyisocyanate compound, and may include at least one of an aliphatic polyisocyanate, an alicyclic polyisocyanate, an aromatic polyisocyanate, and an aromatic aliphatic polyisocyanate. Among them, an aliphatic polyisocyanate may be preferable.

[0088] The above aliphatic polyisocyanate compound may include at least one of hexamethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate, but is not limited thereto.

[0089]

[0090] Specifically, the urethane-based binder can be manufactured by polymerizing 1 to 10 parts by weight of an isocyanate-based compound based on 100 parts by weight of a polyol containing 50 to 90% by weight of a polyether-based triol, 5 to 40% by weight of a polyether-based diol, and 5 to 40% by weight of a polyester-based diol.

[0091] Specifically, the polymerization can be performed by adding a catalyst to a mixture containing one or more polyols and one or more polyisocyanate compounds and then reacting at a predetermined temperature.

[0092] The catalyst may include, but is not limited to, tin compounds such as dibutyl tin dilaurate (DBTDL), tin 2-ethylhexanoate, and the like.

[0093] The above urethane-based binder can be produced by placing a polyol mixture in a reactor and polymerizing it at 50 to 100°C for 3 to 7 hours under nitrogen purging.

[0094]

[0095] hardener

[0096] The above curing agent can produce a polyurethane resin by curing the above urethane-based binder.

[0097] The above curing agent can react with a urethane-based binder by having one or more isocyanate groups (-NCO).

[0098] The above isocyanate-based curing agent is a polyfunctional isocyanate-based curing agent having multiple isocyanate groups, and may include a conventional isocyanate-based curing agent known to those skilled in the art.

[0099] The above isocyanate-based curing agent may include at least one of an aliphatic isocyanate, an alicyclic isocyanate, an aromatic isocyanate, an aromatic aliphatic isocyanate, or a polyol adduct thereof, a biuret thereof, or an isocyanurate thereof. For example, the aliphatic isocyanate-based compound may include at least one of hexamethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate, but is not limited thereto. For example, the aromatic isocyanate compound may include, but is not limited to, one or more of toluene diisocyanate, xylylene diisocyanate, and phenylene diisocyanate.

[0100] The above-mentioned hardener can be used in an amount of 1 to 10 parts by weight, specifically 2 to 6 parts by weight, per 100 parts by weight of the above-mentioned urethane-based binder.

[0101]

[0102] plasticizer

[0103] The above plasticizer is an additive that reduces the viscosity or plasticity of a material.

[0104] The plasticizer may be used in an amount of 1 to 30 parts by weight, 5 to 30 parts by weight, or 10 to 30 parts by weight, based on 100 parts by weight of the urethane-based binder. Within the above range, as the content of the plasticizer increases, the coefficient of friction of the polymer film may increase.

[0105] The plasticizer may be, but is not limited to, isopropyl myristate, isopropyl palmitate, isotridecyl isononanoate, 1,2-cyclohexane dicarboxylic acid diisononyl ester, isostearyl palmitate, isostearyl laurate, diisostearyl adipate, diisocetyl sebacate, or a combination thereof.

[0106]

[0107] Other additives

[0108] The composition for the polymer film may further include a leveling agent, an antistatic agent, an antioxidant, a catalyst, a retardant, or a combination thereof.

[0109]

[0110] The above leveling agent can improve the leveling property of the polymer film. The leveling agent may include an acrylic leveling agent, a fluorine leveling agent, a silicone leveling agent, a silicone-acrylate leveling agent, etc.

[0111] The above leveling agent can be used in an amount of 0.1 to 5 parts by weight, specifically 0.2 to 1 part by weight, per 100 parts by weight of the urethane-based binder.

[0112]

[0113] The above-mentioned antistatic agent can prevent damage to the adherend by suppressing the generation of static electricity during the process of attaching and then peeling the polymer film from the adherend. The antistatic agent may include any conventional antistatic agent known to those skilled in the art. For example, the antistatic agent may include an ionic liquid.

[0114] The above-mentioned antistatic agent can be used in an amount of 0.01 to 5 parts by weight, specifically 0.02 to 1 part by weight, based on 100 parts by weight of the above-mentioned urethane-based binder.

[0115]

[0116] The antioxidant described above can secure peel strength by blocking the adhesive film from being affected by the external environment and thereby inhibiting its release. The antioxidant may include conventional antioxidants known to those skilled in the art. For example, the antioxidant may include cinnamate-based, phenol-based, sulfur-based, phosphorus-based, or HALS-based antioxidants.

[0117] The above antioxidant can be used in an amount of 0.01 to 5 parts by weight, specifically 0.02 to 1 part by weight, based on 100 parts by weight of the urethane-based binder.

[0118]

[0119] The catalyst may be a reaction catalyst between a urethane-based binder and a curing agent. The catalyst may include at least one metal-based catalyst. The metal-based catalyst may include at least one tin-based catalyst or a non-tin-based catalyst. The tin-based catalyst and the non-tin-based catalyst may each employ a common type known to those skilled in the art. For example, the tin-based catalyst may include, but is not limited to, dibutyl tin dichloride, dibutyl tin oxide, dibutyl tin dilaurate, dibutyl tin sulfide, dibutyl tin diacetate, dibutyl tin maleate, and the like.

[0120] The above catalyst can be used in an amount of 0.005 to 0.5 parts by weight, specifically 0.01 to 0.1 parts by weight, per 100 parts by weight of the urethane-based binder.

[0121]

[0122] The above retarder may include a conventional retarder known to those skilled in the art. For example, the retarder may include acetylacetone or a complex thereof.

[0123] The above-mentioned delay agent can be used in an amount of 0.01 to 5 parts by weight, specifically 1.5 to 3 parts by weight, per 100 parts by weight of the above-mentioned urethane-based binder.

[0124]

[0125] laminate sheet

[0126] The above laminate sheet may have the same structure as a conventional case for a lithium secondary battery.

[0127] Specifically, the laminate sheet may have a structure in which an inner layer, a middle layer, and an outer layer are sequentially laminated.

[0128]

[0129] The outer layer may include a polymer to protect the electrode assembly from the external environment.

[0130] Specifically, the outer layer may include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), nylon, or a combination thereof.

[0131]

[0132] The above-mentioned layer may include a metal layer that improves the strength of the case while preventing the inflow / outflow of gas.

[0133] Specifically, the inner layer may include aluminum (Al), iron (Fe), copper (Cu), tin (Sn), nickel (Ni), cobalt (Co), silver (Ag), stainless steel, carbon (C), chromium (Cr), manganese (Mn), titanium (Ti), or a combination thereof.

[0134]

[0135] The inner layer may include a polymer having thermal fusion properties while suppressing leakage of the electrolyte.

[0136] Specifically, the outer layer may include a polyolefin-based resin. More specifically, the outer layer may include a polypropylene (PP) resin.

[0137]

[0138] The above lamination sheet may further include, but is not limited to, an adhesive layer between different layers.

[0139]

[0140] pouch-type case

[0141] A case for a lithium secondary battery of one embodiment may be a pouch-type case, and the safety of the pouch-type case can be improved by applying the polymer film.

[0142]

[0143] (lithium secondary battery)

[0144] In another embodiment, a lithium secondary battery is provided, comprising: a case for a lithium secondary battery according to the above-described embodiment; and an electrode assembly built into the case for the lithium secondary battery.

[0145] A lithium secondary battery using the above lithium secondary battery case may be an all-solid-state battery, a semi-solid-state battery, a lithium metal battery, or a lithium ion battery.

[0146]

[0147] Nail penetration test of all-solid-state batteries

[0148] A lithium secondary battery using the above lithium secondary battery case is an all-solid-state battery, and when subjected to a nail penetration test under the conditions of SOC 100%, nail diameter 3 mm, and penetration speed 25 mm / sec, the heat generation may be 100 to 1,000 J / g, 200 to 800 J / g, or 300 to 750 J / mol. In contrast, in the case of an all-solid-state battery using the conventional lithium secondary battery case, the heat generation exceeds 2,700 J / g when subjected to a nail penetration test under the same conditions as above.

[0149] This effect is the same not only in all-solid-state batteries, but also in semi-solid-state batteries, lithium metal batteries, or lithium ion batteries.

[0150] Therefore, a case for a lithium secondary battery according to one embodiment can ensure the safety of a lithium secondary battery by suppressing short circuit and heat generation phenomena even when a foreign metal substance or the like penetrates the inside of the battery from the outside.

[0151]

[0152] All-solid-state batteries

[0153] For example, the lithium secondary battery may be an all-solid-state battery. The all-solid-state battery may also be expressed as an all-solid-state secondary battery, or an all-solid-state lithium secondary battery.

[0154] FIG. 4 is a cross-sectional view of an all-solid-state battery according to an embodiment. Referring to FIG. 4, the all-solid-state battery (100) may have a structure in which an electrode assembly in which a negative electrode (400) including a negative electrode collector (401) and a negative electrode active material layer (403), a solid electrolyte layer (300), and a positive electrode (200) including a positive electrode active material layer (203) and a positive electrode collector (201) are laminated is housed in a case such as a pouch. The all-solid-state battery (100) may further include an elastic layer (500) on the outer side of at least one of the positive electrode (200) and the negative electrode (400). Although FIG. 4 illustrates one electrode assembly including a negative electrode (400), a solid electrolyte layer (300), and a positive electrode (200), an all-solid-state battery may be manufactured by laminating two or more electrode assemblies.

[0155] An all-solid-state battery according to one embodiment can be manufactured by sequentially stacking a positive electrode, a solid electrolyte, and a negative electrode to prepare a laminate, and then pressurizing the laminate.

[0156] The pressurization may be performed at a temperature of, for example, 25°C to 90°C, and at a pressure of 550 MPa or less, or 500 MPa or less, for example, 400 MPa to 500 MPa. The pressurization may be, for example, an isostatic press, a roll press, or a plate press.

[0157] The above-mentioned all-solid-state battery may be a unit battery having a structure of positive electrode / solid electrolyte layer / negative electrode, a bi-cell having a structure of positive electrode / solid electrolyte layer / negative electrode / solid electrolyte layer / positive electrode, or a laminated battery in which the structure of the unit battery is repeated.

[0158] The shape of the above-mentioned all-solid-state battery is not particularly limited, and may be, for example, coin-shaped, button-shaped, sheet-shaped, stacked, cylindrical, flat, etc. In addition, the above-mentioned all-solid-state battery can be applied to medium- to large-sized batteries used in electric vehicles, etc. For example, the above-mentioned all-solid-state battery can be used in hybrid vehicles such as plug-in hybrid electric vehicles (PHEVs). In addition, it can be applied to energy storage systems (ESS) that require a large amount of power storage, and can also be applied to electric bicycles or power tools, etc.

[0159]

[0160] positive electrode active material

[0161] A compound capable of reversible intercalation and deintercalation of lithium (a lithiated intercalation compound) can be used as a cathode active material. Specifically, one or more of a composite oxide of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof can be used.

[0162] The above composite oxide may be a lithium transition metal composite oxide, and specific examples thereof include lithium nickel-based oxide, lithium cobalt-based oxide, lithium manganese-based oxide, lithium iron phosphate-based compound, cobalt-free nickel-manganese-based oxide, or a combination thereof.

[0163] As an example, a compound represented by any one of the following chemical formulas may be used: Li a A 1-b X b O 2-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Mn 2-b X b O 4-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Ni1-b-c Co b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Mn b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b Co c L 1 d G e O2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); Li a NiG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-b G b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn2G b O4(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-g G g PO4(0.90≤a≤1.8, 0≤g≤0.5); Li (3-f) Fe2(PO4)3(0≤f≤2); Li a FePO4(0.90≤a≤1.8).

[0164] In the above chemical formula, A is Ni, Co, Mn, or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; L 1 is Mn, Al or a combination thereof.

[0165] For example, the cathode active material may be a high-nickel cathode active material in which the nickel content is 80 mol% or more, 85 mol% or more, 90 mol% or more, 91 mol% or more, or 94 mol% or more and 99 mol% or less, based on 100 mol% of metals excluding lithium in the lithium transition metal composite oxide. The high-nickel cathode active material can realize high capacity and thus can be applied to high-capacity, high-density lithium secondary batteries.

[0166] The cathode active material may include, for example, a lithium nickel-based oxide represented by the following chemical formula 11, a lithium cobalt-based oxide represented by the following chemical formula 12, a lithium iron phosphate-based compound represented by the following chemical formula 13, a cobalt-free lithium nickel-manganese-based oxide represented by the following chemical formula 14, or a combination thereof.

[0167] [Chemical Formula 11]

[0168] Li a1 Ni x1 M 1 y1 M 2 z1 O 2-b1 X b1

[0169] In the above chemical formula 11, 0.9≤a1≤1.8, 0.3≤x1≤1, 0≤y1≤0.7, 0≤z1≤0.7, 0.9≤x1+y1+z1≤1.1, and 0≤b1≤0.1, and M 1 and M 2 are each independently one or more elements selected from the group consisting of Al, B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, and Zr, and X is one or more elements selected from the group consisting of F, P, and S.

[0170] In the above chemical formula 1, 0.6≤x1≤1, 0≤y1≤0.4, and 0≤z1≤0.4, or 0.8≤x1≤1, 0≤y1≤0.2, and 0≤z1≤0.2.

[0171] [Chemical Formula 12]

[0172] Li a2 Co x2 M 3 y2 O 2-b2 X b2

[0173] In the above chemical formula 12, 0.9≤a2≤1.8, 0.7≤x2≤1, 0≤y2≤0.3, 0.9≤x2+y2≤1.1, and 0≤b2≤0.1, and M 3 is one or more elements selected from the group consisting of Al, B, Ba, Ca, Ce, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Se, Si, Sn, Sr, Ti, V, W, Y, Zn and Zr, and X is one or more elements selected from the group consisting of F, P and S.

[0174] [Chemical Formula 13]

[0175] Li a3 Fe x3 M 4 y3 PO 4-b3 X b3

[0176] In the above chemical formula 13, 0.9≤a3≤1.8, 0.6≤x3≤1, 0≤y3≤0.4, and 0≤b3≤0.1, and M 4 is one or more elements selected from the group consisting of Al, B, Ba, Ca, Ce, Co, Cr, Cu, Mg, Mn, Mo, Ni, Se, Si, Sn, Sr, Ti, V, W, Y, Zn and Zr, and X is one or more elements selected from the group consisting of F, P and S.

[0177] [Chemical Formula 14]

[0178] Li a4 Ni x4 Mn y4 M 5 z4 O 2-b4 X b4

[0179] In the above chemical formula 14, 0.9≤a2≤1.8, 0.8≤x4<1, 0 <y4≤0.2, 0≤z4≤0.2, 0.9≤x4+y4+z4≤1.1, 및 0≤b4≤0.1이고 M 5 is one or more elements selected from the group consisting of Al, B, Ba, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sn, Sr, Ti, V, W, and Zr, and X is one or more elements selected from the group consisting of F, P, and S.

[0180] The average particle diameter (D50) of the positive electrode active material may be 1 μm to 25 μm, for example, 3 μm to 25 μm, 1 μm to 20 μm, 1 μm to 18 μm, 3 μm to 15 μm, or 5 μm to 15 μm. For example, the positive electrode active material may include small particles having an average particle diameter (D50) of 1 μm to 9 μm and large particles having an average particle diameter (D50) of 10 μm to 25 μm. A positive electrode active material having such a particle diameter range can be harmoniously mixed with other components within a positive electrode active material layer and can realize high capacity and high energy density. Here, the average particle diameter may be obtained by selecting 20 or so random particles from a scanning electron microscope image of the positive electrode active material, measuring their particle diameters (diameter, major axis, or major axis length), obtaining a particle size distribution, and then taking the diameter (D50) of particles having a cumulative volume of 50% by volume from the particle size distribution as the average particle diameter.

[0181] The above-mentioned positive electrode active material may be in the form of a secondary particle formed by agglomeration of a plurality of primary particles, or may be in the form of a single particle. In addition, the above-mentioned positive electrode active material may be spherical or nearly spherical in shape, or may be polyhedral or irregular in shape.

[0182] Meanwhile, the positive electrode active material may include a buffer layer on the particle surface. The buffer layer may be expressed as a coating layer, a protective layer, etc., and may play a role in lowering the interfacial resistance between the positive electrode active material and the sulfide-based solid electrolyte particles. For example, the buffer layer may include a lithium-metal-oxide, wherein the metal may be one or more elements selected from the group consisting of Al, B, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sn, Sr, Ta, V, W, and Zr. The lithium-metal-oxide is excellent in lowering the interfacial resistance between the positive electrode active material and the solid electrolyte particles while improving the performance of the positive electrode active material by facilitating the movement of lithium ions and electron conduction.

[0183]

[0184] anode

[0185] A positive electrode for an all-solid-state battery includes a current collector and a positive electrode active material layer positioned on the current collector, wherein the positive electrode active material layer includes a positive electrode active material and may optionally include a solid electrolyte, a binder, and / or a conductive material.

[0186] For example, the anode may further include an additive that can act as a sacrificial anode.

[0187] The content of the positive electrode active material may be 90 wt% to 99.5 wt% with respect to 100 wt% of the positive electrode active material layer, and the contents of the binder and conductive material may be 0.5 wt% to 5 wt%, respectively, with respect to 100 wt% of the positive electrode active material layer.

[0188] The above binder serves to adhere the positive electrode active material particles well to each other and also to adhere the positive electrode active material well to the current collector. Representative examples of the binder include, but are not limited to, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylic resin, polyester resin, nylon, etc.

[0189] The conductive material is used to provide conductivity to the electrode, and any material that does not cause chemical changes and is electronically conductive can be used in the battery. Examples of the conductive material include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, and carbon nanotube; metal-based materials containing copper, nickel, aluminum, silver, etc. in the form of metal powder or metal fiber; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0190] The positive electrode active material layer may optionally further include a solid electrolyte. The solid electrolyte may include, for example, a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a halide-based solid electrolyte, or a combination thereof, and a detailed description thereof will be provided later in the section on the solid electrolyte layer.

[0191] With respect to 100 wt% of the positive electrode active material layer, the solid electrolyte may be included in an amount of 0.1 wt% to 35 wt%, for example, 1 wt% to 35 wt%, 5 wt% to 30 wt%, 8 wt% to 25 wt%, or 10 wt% to 20 wt%.

[0192] In the positive electrode active material layer, the positive electrode active material may be comprised in an amount of 65 to 99 wt% and the solid electrolyte in an amount of 1 to 35 wt%, based on 100 wt% of the total of the positive electrode active material and the solid electrolyte, for example, the positive electrode active material may be comprised in an amount of 80 to 90 wt% and the solid electrolyte in an amount of 10 to 20 wt%. When the solid electrolyte is comprised in the positive electrode in such an amount, the efficiency and life characteristics of the all-solid-state secondary battery can be improved without reducing the capacity.

[0193] Al may be used as the above current collector, but is not limited thereto.

[0194]

[0195] Negative active material

[0196] The negative electrode active material includes a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0197] The material capable of reversibly intercalating / deintercalating the lithium ions may include a carbon-based negative electrode active material, for example, crystalline carbon, amorphous carbon, or a combination thereof. Examples of the crystalline carbon include graphite such as natural graphite or artificial graphite in an amorphous, plate-like, flake-like, spherical, or fibrous form, and examples of the amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, and the like.

[0198] As the above lithium metal alloy, an alloy of lithium and a metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn can be used.

[0199] As the material capable of doping and dedoping the lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material may be used. The Si-based negative electrode active material may be silicon, a silicon-carbon composite, SiOx (0 < x < 2), a Si-Q alloy (wherein Q is selected from alkali metals, alkaline earth metals, Group 13 elements, Group 14 elements (excluding Si), Group 15 elements, Group 16 elements, transition metals, rare earth elements, and combinations thereof), or a combination thereof. The Sn-based negative electrode active material may be Sn, SnO2, a Sn-based alloy, or a combination thereof.

[0200] The silicon-carbon composite may be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite may be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles. For example, the composite may include secondary particles (cores) in which silicon primary particles are assembled and an amorphous carbon coating layer (shell) positioned on the surface of the secondary particles. The amorphous carbon may also be positioned between the silicon primary particles, such that, for example, the silicon primary particles may be coated with amorphous carbon. The secondary particles may be dispersed and present in an amorphous carbon matrix.

[0201] The silicon-carbon composite may further comprise crystalline carbon. For example, the silicon-carbon composite may comprise a core comprising crystalline carbon and silicon particles and an amorphous carbon coating layer positioned on the surface of the core.

[0202] The above Si-based negative electrode active material or Sn-based negative electrode active material can be used in a mixture with a carbon-based negative electrode active material.

[0203]

[0204] cathode

[0205] An anode for an all-solid-state battery may include, for example, a current collector and a negative electrode active material layer positioned on the current collector. The negative electrode active material layer includes a negative electrode active material and may further include a binder, a conductive material, and / or a solid electrolyte.

[0206] For example, the negative electrode active material layer may include 90 to 99 wt% of the negative electrode active material, 0.5 to 5 wt% of the binder, and 0 to 5 wt% of the conductive material.

[0207] The above binder serves to adhere the negative electrode active material particles well to each other and also to adhere the negative electrode active material well to the current collector. The binder may be a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof.

[0208] Examples of the non-aqueous binder include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, or combinations thereof.

[0209] The above-mentioned aqueous binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluoroelastomer, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0210] When using an aqueous binder as the above-mentioned negative electrode binder, a cellulose-based compound capable of imparting viscosity may be further included. The cellulose-based compound may be a mixture of one or more of carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, or an alkali metal salt thereof. The alkali metal may be Na, K, or Li.

[0211] The above dry binder is a polymeric material capable of being fiberized, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

[0212] The conductive material is used to provide conductivity to the electrode, and any material that does not cause chemical changes and is electronically conductive can be used in the battery. Specific examples include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, carbon nanofibers, and carbon nanotubes; metal-based materials in the form of metal powder or metal fibers, including copper, nickel, aluminum, and silver; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0213] The negative electrode current collector may be selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and a combination thereof.

[0214]

[0215] precipitation cathode

[0216] Meanwhile, as an example, the above-mentioned all-solid-state battery negative electrode may be a precipitation-type negative electrode. The precipitation-type negative electrode refers to a negative electrode that does not have a negative electrode active material when the battery is assembled, but in which lithium metal or the like is precipitated when the battery is charged, and this acts as a negative electrode active material.

[0217] Fig. 5 is a schematic cross-sectional view of an all-solid-state battery including a precipitation-type negative electrode. Referring to Fig. 5, the precipitation-type negative electrode (400') may include a current collector (401) and a negative electrode coating layer (405) positioned on the current collector. An all-solid-state battery including such a precipitation-type negative electrode (400') starts initial charging in a state in which no negative electrode active material is present, and upon charging, high-density lithium metal or the like is precipitated between the current collector (401) and the negative electrode coating layer (405) to form a lithium metal layer (404), which may function as a negative electrode active material. Accordingly, in an all-solid-state battery that has been charged at least once, the precipitation-type negative electrode (400') may include a current collector (401), a lithium metal layer (404) positioned on the current collector, and a negative electrode coating layer (405) positioned on the metal layer. The above lithium metal layer (404) refers to a layer in which lithium metal, etc. is precipitated during the charging process of the battery, and may be referred to as a metal layer or a negative electrode active material layer.

[0218] The above cathode coating layer (405) may include a metal and / or carbon material that acts as a catalyst.

[0219] The metal may include, for example, gold, platinum, palladium, silicon, silver, aluminum, bismuth, tin, zinc, or a combination thereof, and may be composed of one kind of these or may be composed of several kinds of alloys. The average particle diameter (D50) of the metal may be about 4 μm or less, and may be, for example, 10 nm to 4 μm, 10 nm to 2 μm, or 10 nm to 1 μm.

[0220] The carbon material may be, for example, crystalline carbon, non-graphitic carbon, or a combination thereof. The crystalline carbon may be, for example, at least one selected from natural graphite, artificial graphite, mesophase carbon microbeads, and combinations thereof. The non-graphitic carbon may be at least one selected from carbon black, activated carbon, acetylene black, Denka black, Ketjen black, furnace black, graphene, and combinations thereof.

[0221] When the above-described negative electrode coating layer (405) includes both the metal and the carbon material, the mixing ratio of the metal and the carbon material may be, for example, a weight ratio of 1:10 to 1:2, 1:10 to 2:1, 5:1 to 1:1, or 4:1 to 2:1. In this case, the precipitation of lithium metal can be effectively promoted and the characteristics of the all-solid-state battery can be improved. The above-described negative electrode coating layer (405) may include, for example, a carbon material supported with a catalytic metal, or may include a mixture of metal particles and carbon material particles.

[0222] The above cathode coating layer (405) may further include a binder, and the binder may be, for example, a conductive binder. In addition, the above cathode coating layer (405) may further include general additives such as fillers, dispersants, and ionic conductive agents.

[0223] The thickness of the negative electrode coating layer (405) may be, for example, 1 μm to 20 μm, 2 μm to 10 μm, or 3 μm to 7 μm. In addition, the thickness of the negative electrode coating layer (405) may be 50% or less, 20% or less, or 5% or less of the thickness of the positive electrode active material layer. If the thickness of the negative electrode coating layer (405) is too thin, it may be collapsed by the lithium metal layer (404), and if the thickness is too thick, the density of the all-solid-state battery may decrease and the internal resistance may increase.

[0224] The above-described precipitated negative electrode (400') may further include, for example, a thin film on the surface of the current collector, i.e., between the current collector and the negative electrode coating layer. The thin film may include an element capable of forming an alloy with lithium. The element capable of forming an alloy with lithium may be, for example, gold, silver, zinc, tin, indium, silicon, aluminum, bismuth, etc., and may be composed of one type thereof or may be composed of multiple types of alloys. The thin film may further flatten the precipitated form of the lithium metal layer (404) and further improve the characteristics of the all-solid-state battery. The thin film may be formed by, for example, a vacuum deposition method, a sputtering method, a plating method, etc. The thickness of the thin film may be, for example, 1 nm to 800 nm, or 100 nm to 500 nm.

[0225] The lithium metal layer (404) may include lithium metal or a lithium alloy. The lithium alloy may be, for example, a Li-Al alloy, a Li-Sn alloy, a Li-In alloy, a Li-Ag alloy, a Li-Au alloy, a Li-Zn alloy, a Li-Ge alloy, or a Li-Si alloy.

[0226] The thickness of the lithium metal layer (404) may be 1 μm to 500 μm, 1 μm to 200 μm, 1 μm to 100 μm, or 1 μm to 50 μm. If the thickness of the lithium metal layer (404) is too thin, it may be difficult to perform the role of a lithium storage, and if it is too thick, the battery volume may increase and performance may deteriorate.

[0227] When such a precipitation-type cathode is applied, the cathode coating layer (405) can play a role in protecting the lithium metal layer (404) and suppressing the precipitation growth of lithium deadlight. Accordingly, short-circuiting and capacity reduction of the all-solid-state battery can be suppressed, and the life characteristics can be improved.

[0228]

[0229] solid electrolyte layer

[0230] The solid electrolyte layer contains a solid electrolyte.

[0231] The above solid electrolyte may be a type of inorganic solid electrolyte, and may include, for example, a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a halide-based solid electrolyte, or a combination thereof.

[0232] Sulfide-based solid electrolyte

[0233] Sulfide-based solid electrolytes include, for example, Li2S-P2S5, Li2S-P2S5--LiX (where X is a halogen element, for example, I or Cl), Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z. m S n (m, n are integers, Z is Ge, Zn or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p, q are integers, and M is P, Si, Ge, B, Al, Ga or In), or a combination thereof.

[0234] A sulfide-based solid electrolyte can be obtained, for example, by mixing Li2S and P2S5 in a molar ratio of 50:50 to 90:10, or 50:50 to 80:20, and optionally heat-treating them. Within the above mixing ratio range, a sulfide-based solid electrolyte having excellent ionic conductivity can be produced. The ionic conductivity can be further improved by further including other components such as SiS2, GeS2, and B2S3.

[0235] Methods for mixing sulfur-containing raw materials for producing sulfide-based solid electrolytes include mechanical milling or the solution method. Mechanical milling involves placing raw materials in a ball mill reactor and vigorously stirring them to finely atomize and mix them. Using the solution method, the raw materials are mixed in a solvent to obtain a solid electrolyte as a precipitate. Furthermore, heat treatment after mixing can solidify the crystals of the solid electrolyte and improve ionic conductivity. For example, a sulfide-based solid electrolyte can be produced by mixing sulfur-containing raw materials and heat-treating them twice or more, resulting in a sulfide-based solid electrolyte with high ionic conductivity and robustness.

[0236] According to one embodiment, sulfide-based solid electrolyte particles can be manufactured through, for example, a first heat treatment in which sulfur-containing raw materials are mixed and calcined at 120°C to 350°C, and a second heat treatment in which the first heat treatment result is mixed and calcined at 350°C to 800°C. The first heat treatment and the second heat treatment can each be performed in an inert gas or nitrogen atmosphere. The first heat treatment can be performed for 1 to 10 hours, and the second heat treatment can be performed for 5 to 20 hours. The first heat treatment can have the effect of milling small raw materials, and the second heat treatment can synthesize the final solid electrolyte. Through two or more such heat treatments, a high-performance sulfide-based solid electrolyte with high ionic conductivity and robustness can be obtained, and such a solid electrolyte can be said to be suitable for mass production. The temperature of the first heat treatment may be, for example, 150°C to 330°C, or 200°C to 300°C, and the temperature of the second heat treatment may be, for example, 380°C to 700°C, or 400°C to 600°C.

[0237] For example, the sulfide-based solid electrolyte particles may include argyrodite-type sulfides. The argyrodite-type sulfide-based solid electrolyte particles may have an ionic conductivity of 10, which is the ionic conductivity of a typical liquid electrolyte at room temperature. -4 10 inland -2 It has a high ionic conductivity approaching the S / cm range, can form a close bond between a positive electrode active material and a solid electrolyte without causing a decrease in ionic conductivity, and further can form a close interface between an electrode layer and a solid electrolyte layer. An all-solid-state secondary battery including this can have improved battery performance, such as rate characteristics, Coulombic efficiency, and cycle life characteristics.

[0238] The argyrodite-type sulfide-based solid electrolyte particles may include, for example, a compound represented by the chemical formula 21 below.

[0239] [Chemical Formula 21]

[0240] (Li a M 1 b M 2 c )(P d M 3 e )(S f M 4 g )X h

[0241] In the above chemical formula 21, 4≤a≤8, and M 1 is Mg, Cu, Ag, or a combination thereof, and 0≤b<0.5, and M 2 is Na, K, or a combination thereof, 0≤c<0.5, and M 3 is Sn, Zn, Si, Sb, Ge, or a combination thereof, and 0 <d<4, 0≤e<1 이고, M 4 is O, SO n , or a combination thereof, and 1.5≤n≤5, 3≤f≤12, 0≤g<2, and X is F, Cl, Br, I, or a combination thereof, and 0≤h≤2.

[0242] For example, in chemical formula 21, a halide element (X) may be included as an essential element, in which case 0 <h≤2로 표시될 수 있다. 일 예로 화학식 21에 M 1 Elements may be required, in which case 0 <b<0.5로 표시될 수 있다. 화학식 21에서 M 3 can be understood as an element substituted in place of P and 0 <e<1일 수 있다. 화학식 21에서 M 4 is substituted in the S position, for example, 0 <g<2일 수 있으며 S의 비율인 f는 예를 들어 3≤f≤7일 수 있다. M 4 Go SO n If SO n It can be, for example, S4O6, S3O6, S2O3, S2O4, S2O5, S2O6, S2O7, S2O8, SO4, or SO5, and can be, for example, SO4.

[0243] For example, in chemical formula 21, a+b+c+h=7, d+e=1, and f+g+h=6.

[0244] As a specific example, argyrodite-type sulfide-based solid electrolyte particles include Li3PS4 and Li7P3S. 11 , Li7PS6, Li6PS5Cl, Li6PS5Br, Li 5.8 PS 4.8 Cl 1.2 , Li 6.2 PS 5.2 Br 0.8 , Li 5.75 PS 4.75 Cl 1.25 , (Li 5.69 Cu 0.06 )PS 4.75 Cl 1.25 , (Li 5.72 Cu 0.03 )PS 4.75 Cl 1.25 , (Li 5.69 Cu 0.06 )P(S 4.70 (SO4) 0.05 )Cl 1.25 , (Li 5.69 Cu0.06 )P(S 4.60 (SO4) 0.15 )Cl 1.25 , (Li 5.72 Cu 0.03 )P(S 4.725 (SO4) 0.025 )Cl 1.25 , (Li 5.72 Na 0.03 )P(S 4.725 (SO4) 0.025 )Cl 1.25 , Li 5.75 P(S 4.725 (SO4) 0.025 )Cl 1.25 , or combinations thereof, but are not limited thereto.

[0245] An argyrodite-type sulfide-based solid electrolyte can be manufactured, for example, by mixing lithium sulfide and phosphorus sulfide, and optionally, lithium halide. After mixing these, a heat treatment may be performed. The heat treatment may include, for example, two or more heat treatment steps. Here, manufacturing an argyrodite-type sulfide-based solid electrolyte may include, for example, a first heat treatment of mixing raw materials and calcining at 120°C to 350°C, and a second heat treatment of mixing the resultant of the first heat treatment again and calcining at 350°C to 800°C.

[0246] The average particle size (D50) of the sulfide-based solid electrolyte particles may be, for example, 0.1 ㎛ to 5.0 ㎛ or 0.1 ㎛ to 3.0 ㎛, and may be small particles of 0.1 ㎛ to 1.9 ㎛ or large particles of 2.0 ㎛ to 5.0 ㎛. The sulfide-based solid electrolyte particles may be a mixture of small particles having an average particle size of 0.1 ㎛ to 1.9 ㎛ and large particles having an average particle size of 2.0 ㎛ to 5.0 ㎛. The average particle size of the sulfide-based solid electrolyte particles may be measured from an electron microscope image, and for example, a particle size distribution may be obtained by measuring the size (diameter or major axis length) of about 20 particles in a scanning electron microscope image, and D50 may be calculated from this.

[0247]

[0248] Oxide-based solid electrolyte

[0249] Oxide-based solid electrolytes include, for example, Li 1+x Ti 2-x Al(PO4)3(LTAP)(0≤x≤4), Li 1+x+y Al x Ti 2-x Si y P 3-y O 12 (0 <x<2, 0≤y<3), BaTiO3, Pb(Zr,Ti)O3(PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT)(0≤x<1, 0≤y<1), PB(Mg3Nb 2 / 3 )O3-PbTiO3(PMN-PT), HfO2, SrTiO3, SnO2, CeO2, Na2O, MgO, NiO, CaO, BaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiO2, lithium phosphate (Li3PO4), lithium titanium phosphate (Li x Ti y (PO4)3, 0 <x<2, 0<y<3), Li 1+x+y (Al, Ga) x (Ti, Ge) 2-x Siy P 3-y O 12 (0≤x≤1, 0≤y≤1), lithium lanthanum titanate (Li x La y TiO3, 0 <x<2, 0<y<3), Li2O, LiAlO2, Li2O-Al2O3-SiO2-P2O5-TiO2-GeO2계 세라믹스, 가넷(Garnet)계 세라믹스 Li 3+x La3M2O 12 (M= Te, Nb, or Zr; x is an integer from 1 to 10), or mixtures thereof.

[0250]

[0251] Halide-based solid electrolyte

[0252] The solid electrolyte layer may further include, for example, a halide-based solid electrolyte. The halide-based solid electrolyte contains a halogen element as a main component, and may mean that the ratio of the halide element to all elements constituting the solid electrolyte is 50 mol% or more, 70 mol% or more, 90 mol% or more, or 100 mol%. For example, the halide-based solid electrolyte may not contain a sulfur element.

[0253] The halide-based solid electrolyte may contain lithium element, a metal element other than lithium, and a halogen element. The metal element other than lithium may be Al, As, B, Bi, Ca, Cd, Co, Cr, Fe, Ga, Hf, In, Mg, Mn, Ni, Sb, Sc, Sn, Ta, Ti, Y, Zn, Zr, or a combination thereof. The halogen element may be F, Cl, Br, I, or a combination thereof, and may be Cl, Br, or a combination thereof. The halide-based solid electrolyte may contain, for example, Li aM1X6 (M is Al, As, B, Bi, Ca, Cd, Co, Cr, Fe, Ga, Hf, In, Mg, Mn, Ni, Sb, Sc, Sn, Ta, Ti, Y, Zn, Zr, or a combination thereof, X is F, Cl, Br, I, or a combination thereof, and 2≤a≤3) can be represented. The halide-based solid electrolyte is, for example, Li2ZrCl6, Li 2.7 Y 0.7 Zr 0.3 Cl6, Li 2.5 Y 0.5 Zr 0.5 Cl6, Li 2.5 In 0.5 Zr 0.5 Cl6, Li2In 0.5 Zr 0.5 Cl6, Li3YBr6, Li3YCl6, Li3YBr2Cl4, Li3YbCl6, Li 2.6 Hf 0.4 Yb 0.6 Cl6, or combinations thereof, but is not limited thereto.

[0254]

[0255] bookbinder

[0256] The solid electrolyte layer may further include a binder. Binders include, for example, nitrile-butadiene rubber, hydrogenated nitrile-butadiene rubber, styrene-butadiene rubber, acrylated styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylic rubber, butyl rubber, fluoroelastomer, natural rubber, polydimethylsiloxane, polyethylene oxide, polyvinylpyrrolidone, polyvinylpyridine, chlorosulfonated polyethylene, polyvinyl alcohol, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, polyamideimide, polyimide, poly(meth)acrylate, polyacrylonitrile, polystyrene, polyurethane resin, and the like. copolymers, or combinations thereof.

[0257] The binder may be included in an amount of 0.1 wt% to 3 wt% based on 100 wt% of the solid electrolyte layer, for example, 0.5 wt% to 2 wt%, or 0.5 wt% to 1.5 wt%. When the binder is included in the above range, the components within the solid electrolyte layer can be well combined without lowering the ionic conductivity of the solid electrolyte, thereby improving the durability and reliability of the battery.

[0258]

[0259] Other ingredients

[0260] The solid electrolyte layer may optionally further comprise an alkali metal salt, and / or an ionic liquid, and / or a conductive polymer.

[0261] The above alkali metal salt may be, for example, a lithium salt. The content of the lithium salt in the solid electrolyte layer may be 1 M or more, for example, 1 M to 4 M. In this case, the lithium salt may improve ion conductivity by enhancing the lithium ion mobility of the solid electrolyte layer.

[0262] The lithium salt may be applied without limitation on type, and may include, for example, LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiAlO2, LiAlCl4, LiPO2F2, LiCl, LiI, LiSCN, LiN(CN)2, lithium bis(oxalato)borate (LiBOB), lithium difluoro(oxalato)borate (LiDFOB), lithium difluorobis(oxalato)phosphate (LiDFBP), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(pentafluoroethanesulfonyl)imide (LiBETI), lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, or a combination thereof.

[0263] For example, the lithium salt may be an imide-based lithium salt such as LiTFSI, LiFSI, LiBETI, or a combination thereof. The imide-based lithium salt can maintain or improve ionic conductivity by appropriately maintaining chemical reactivity with the ionic liquid.

[0264] Ionic liquids are salts or molten salts that are composed only of ions and are liquid at room temperature, with a melting point below room temperature.

[0265] The ionic liquid comprises a) one or more cations selected from ammonium, pyrrolidinium, pyridinium, pyrimidinium, imidazolium, piperidinium, pyrazolium, oxazolium, pyridazinium, phosphonium, sulfonium, trizolium, and mixtures thereof, and b) BF4. - , PF6 - , AsF6 - , SbF6 - , AlCl4 - , HSO4 - , ClO4 - , CH3SO3 - , CF3CO2 - , Cl - , Br - , I- , BF4 - , SO4 - , CF3SO3 - , (FSO2)2N - , (C2F5SO2)2N - , (C2F5SO2)(CF3SO2)N - , and (CF3SO2)2N - It may be a compound containing one or more anions selected from among.

[0266] The ionic liquid may be at least one selected from the group consisting of, for example, N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide, N-butyl-N-methylpyrrolidinium bis(3-trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide.

[0267] In the solid electrolyte layer, the weight ratio of the solid electrolyte to the ionic liquid may be 0.1:99.9 to 90:10, for example, 10:90 to 90:10, 20:80 to 90:10, 30:70 to 90:10, 40:60 to 90:10, or 50:50 to 90:10. A solid electrolyte layer satisfying the above range can maintain or improve ionic conductivity by improving the electrochemical contact area with the electrode. Accordingly, the energy density, discharge capacity, rate characteristics, etc. of the all-solid-state secondary battery can be improved.

[0268]

[0269] A lithium secondary battery according to one embodiment of the present invention can be applied to automobiles, mobile phones, and / or various types of electrical devices, but the present invention is not limited thereto.

[0270]

[0271] Hereinafter, examples and comparative examples of the present invention will be described. However, the following examples are merely examples of the present invention, and the present invention is not limited to the following examples.

[0272]

[0273] Example 1-1

[0274] (1) Preparation of composition for polymer film

[0275] To 100 parts by weight of a mixture containing 68 wt% of a polyether triol (product name: PPG-3020, manufacturer: Kumho Petrochemical, solid content: 100%, number average molecular weight: approximately 3,000 g / mol), 16 wt% of a polyether diol (PPG-6000, manufacturer: Kumho Petrochemical, solid content: 100%, number average molecular weight: approximately 6,000 g / mol), and 16 wt% of a polyester polyol (product name: P-2010, manufacturer: Kuraray, number average molecular weight: 2,000 g / mol), 4 parts by weight of hexamethylene diisocyanate as an isocyanate compound was added, and thermal polymerization was performed at 70°C for 5 hours to obtain a urethane binder (number average molecular weight: 6,013 g / mol ± 5% ) was obtained.

[0276] Based on 100 parts by weight of the obtained urethane binder, 4.5 parts by weight of coronate HX as a hardener, 0.23 parts by weight of BYK-Silclean3700 as a leveling agent, 10 parts by weight of isopropyl myristate as a plasticizer, 0.25 parts by weight of FC4400 as an antistatic agent, 0.25 parts by weight of Irganox1010 as an antioxidant, 0.01 parts by weight of DBTDL as a catalyst, and 1.5 parts by weight of acetylacetone as a retarder are mixed with MEK (Methyl Ethyl Ketone) to prepare a composition for a polymer film.

[0277] (2) Manufacturing of cases for lithium secondary batteries

[0278] A laminate sheet (pouch film, manufacturer: DNP) in which an inner layer, a middle layer, and an outer layer were sequentially laminated was prepared. Using a slip casting method, the polymer film composition was cast onto the outer layer of the laminate sheet to a thickness of 100 μm, dried at 130°C for 4 minutes, and then left at 45°C for 3 days. Accordingly, a lithium secondary battery case was obtained in which a first polymer film (thickness: 100 μm) including a first polyurethane resin (weight average molecular weight: 78,480 g / mol) was formed on the outer layer of the laminate sheet.

[0279] (3) Manufacturing of solid electrolyte layer

[0280] An argyrodite-type solid electrolyte Li6PS5Cl (D50=3㎛) is added to a binder solution in which an acrylic binder (SX-A334, Zeon) is dissolved in an isobutylyl isobutylate (IBIB) solvent, and the solution is stirred in a sinky mixer to adjust the viscosity to an appropriate level. After adjusting the viscosity, 2 mm zirconia balls are added and stirred again in a sinky mixer to prepare a slurry. The slurry contains 98 wt% of the solid electrolyte and 2 wt% of the binder. The slurry is applied on a release PET film using a bar coater and dried at room temperature to prepare a solid electrolyte layer.

[0281] (4) Manufacturing of anode

[0282] LiNi 0.9 Co 0.05 Mn 0.0585 wt% of O2 positive electrode active material, 13.5 wt% of lithium argyrodite-type solid electrolyte Li6PS5Cl, 1.0 wt% of polyvinylidene fluoride binder, and 0.5 wt% of carbon nanotube conductive agent are prepared, and added to a dispersion medium in which octyl acetate (OA) and pentyl propionate (PPP) are mixed in a weight ratio of 1:1. This is placed in a thinky mixer, 2 mm zirconia balls are added, and stirred to prepare a positive electrode composition. The content of the dispersion medium is 30 parts by weight based on 100 parts by weight of solid content. The solid content represents the sum of the positive electrode active material, solid electrolyte, binder, and conductive agent.

[0283] The prepared positive electrode composition is coated on a positive electrode current collector using a bar coater, and dried in a convection oven at 80°C for 10 minutes, thereby manufacturing a positive electrode in which a positive electrode active material layer is formed on the current collector.

[0284] (5) Manufacturing of cathode

[0285] A catalyst is prepared by mixing carbon black having a primary particle size (D50) of about 30 nm and silver (Ag) having an average particle size (D50) of about 60 nm in a weight ratio of 3:1, and 0.25 g of the catalyst is added to 2 g of an NMP solution containing 7 wt% of polyvinylidene fluoride binder and mixed to prepare a cathode coating layer composition. This is applied to a nickel foil current collector using a bar coater and vacuum-dried to prepare a deposition-type cathode in which a cathode coating layer is formed on the current collector.

[0286] (6) Manufacturing of all-solid-state batteries

[0287] An electrode assembly is manufactured by cutting a positive electrode, a negative electrode, and a solid electrolyte layer, laminating a solid electrolyte layer on the positive electrode, and then laminating a negative electrode thereon. Using the lithium secondary battery case, the electrode assembly is sealed in a pouch shape and subjected to a warm isostatic press (WIP) at a high temperature of 85°C and 500 MPa for 30 minutes to manufacture an all-solid-state battery. In a pressurized state, the thickness of the positive electrode active material layer is about 100 μm, the thickness of the negative electrode coating layer is about 7 μm, and the thickness of the solid electrolyte layer is about 60 μm.

[0288]

[0289] Example 1-2

[0290] A polyurethane resin and an all-solid-state battery are manufactured in the same manner as in Example 1-1, except that 15 parts by weight of isopropyl myristate is used as a plasticizer.

[0291]

[0292] Example 1-3

[0293] A polyurethane resin and an all-solid-state battery are manufactured in the same manner as in Example 1-1, except that 20 parts by weight of isopropyl myristate is used as a plasticizer.

[0294]

[0295] Example 1-4

[0296] A polyurethane resin and an all-solid-state battery are manufactured in the same manner as in Example 1-1, except that 25 parts by weight of isopropyl myristate is used as a plasticizer.

[0297]

[0298] Example 1-5

[0299] A polyurethane resin and an all-solid-state battery are manufactured in the same manner as in Example 1-1, except that 30 parts by weight of isopropyl myristate is used as a plasticizer.

[0300]

[0301] Example 1-6

[0302] A polyurethane resin and an all-solid-state battery are manufactured in the same manner as in Example 1, except that the thickness of the first polymer film is changed to 150 μm.

[0303]

[0304] Example 1-7

[0305] A polyurethane resin and an all-solid-state battery are manufactured in the same manner as in Example 1, except that the thickness of the first polymer film is changed to 250 μm.

[0306]

[0307] Example 2-1

[0308] A polyurethane resin and an all-solid-state battery are manufactured in the same manner as in Example 1, except that a second polymer film including a second polyurethane resin is further formed on the inner layer of the laminate sheet as follows.

[0309] A laminate sheet (pouch film, manufacturer: DNP) in which an inner layer, a middle layer, and an outer layer were sequentially laminated was prepared. Using a slip casting method, the polymer film composition was cast onto the outer layer and the inner layer of the laminate sheet to a thickness of 100 μm, respectively, and dried at 130°C for 4 minutes and then left at 45°C for 3 days. Accordingly, a first polymer film (thickness: 100 μm) including a first polyurethane resin (weight average molecular weight: 78,480 g / mol) was formed on the outer layer of the laminate sheet, and a first polymer film (thickness: 100 μm) including a second polyurethane resin (weight average molecular weight: 78,480 g / mol) was formed on the inner layer of the laminate sheet, thereby obtaining a case for a lithium secondary battery.

[0310]

[0311] Example 2-2

[0312] A polyurethane resin and an all-solid-state battery are manufactured in the same manner as in Example 2-1, except that 15 parts by weight of isopropyl myristate is used as a plasticizer.

[0313]

[0314] Example 2-3

[0315] A polyurethane resin and an all-solid-state battery are manufactured in the same manner as in Example 2-1, except that 20 parts by weight of isopropyl myristate is used as a plasticizer.

[0316]

[0317] Example 2-4

[0318] A polyurethane resin and an all-solid-state battery are manufactured in the same manner as in Example 2-1, except that 25 parts by weight of isopropyl myristate is used as a plasticizer.

[0319]

[0320] Example 2-5

[0321] A polyurethane resin and an all-solid-state battery are manufactured in the same manner as in Example 2-1, except that 30 parts by weight of isopropyl myristate is used as a plasticizer.

[0322]

[0323] Example 2-6

[0324] A polyurethane resin and an all-solid-state battery are manufactured in the same manner as in Example 2-1, except that the thickness of each of the first polymer film and the second polymer film is changed to 150 μm.

[0325]

[0326] Example 2-7

[0327] A polyurethane resin and an all-solid-state battery are manufactured in the same manner as in Example 2-1, except that the thickness of each of the first polymer film and the second polymer film is changed to 250 μm.

[0328]

[0329] Comparative Example 1

[0330] An all-solid-state battery is manufactured in the same manner as in Example 1, except that the first polymer film is not formed.

[0331]

[0332] Evaluation Example 1: Evaluation of physical properties of polymer films

[0333] As evaluated as follows, the coefficient of friction, elongation, tensile strength, and thickness of each first polymer film of the example are shown in Table 1 below.

[0334] For reference, the coefficient of friction was evaluated in the state in which the polymer film was formed on the outer layer of the laminate sheet, and the elongation, tensile strength, and thickness were evaluated after the polymer film was removed from the outer layer of the laminate sheet.

[0335] Coefficient of friction: This can be measured using the static friction coefficient measurement method. Using equipment that measures the coefficient of static friction, the angle of the slope is increased, and the stress at the point where the object begins to move is calculated and measured.

[0336] Elongation: According to the ASTM D638 method, a universal testing machine (Instron Model 4466) is used to pull the specimen at a crosshead speed of 200 mm / min, and the point where the specimen breaks is measured. The elongation (%) can then be calculated as follows.

[0337] Elongation (%) = Length after elongation / Initial length × 100

[0338] Tensile strength: Can be measured using a universal testing machine (Zwick Z020) according to ISO527.

[0339] Thickness: Can be measured by a thickness gauge (Digimatic Thickness Gauge: MIYUTOYO).

[0340]

[0341] Coefficient of friction (μ) Elongation (%) Tensile strength (kgf / mm) 2 ) Thickness (㎛)Example 1-1, 2-10.4430330100Example 1-2, 2-20.5450460100Example 1-3, 2-30.6445430100Example 1-4, 2-40.7440380100Example 1-5, 2-50.8440390100Example 1-6, 2-60.5480410150Example 1-7, 2-70.5650450250

[0342]

[0343] Evaluation Example 2: Nail Penetration Test

[0344] For each all-solid-state battery of the examples and comparative examples, the cell was clamped under a pressure of 4 MPa and charged at a 0.1 C-rate charge / discharge rate in a 45°C chamber to a state of charge (SOC) of 100%. After removing the clamping plate, a nail penetration test was performed under GB / T conditions (nail diameter 3 mm, penetration speed 25 mm / sec). Thereafter, the temperature change of the all-solid-state battery was measured to evaluate the degree of heat generation, and the results are shown in Table 2 below.

[0345]

[0346] Heat generation (J / g) during nail penetration test Example 1-1724 Example 1-2632 Example 1-3541 Example 1-4512 Example 1-5482 Example 1-6544 Example 1-7346 Example 2-1654 Example 2-2531 Example 2-3494 Example 2-4464 Example 2-5443 Example 2-6486 Example 2-7286 Comparative Example 12786

[0347]

[0348] According to Table 2 above, the all-solid-state batteries of Examples 1-1 to 1-7 using a case in which a first polymer film was formed on the outer layer of a laminate sheet exhibited a heat generation of only 300 to 750 J / mol in a nail penetration test under the conditions of SOC 100%, a nail diameter of 3 mm, and a penetration speed of 25 mm / sec. In contrast, the all-solid-state battery of Comparative Example 1 using a laminate sheet as a case in which a polymer film was not formed exhibited a heat generation of over 2,700 J / g in a nail penetration test under the same conditions as above.

[0349] It is expected that this effect will be the same not only in all-solid-state batteries, but also in semi-solid-state batteries, lithium metal batteries, or lithium ion batteries.

[0350] Therefore, a case for a lithium secondary battery according to one embodiment can ensure the safety of a lithium secondary battery by suppressing short circuit and heat generation phenomena even when a foreign metal substance or the like penetrates the inside of the battery from the outside.

[0351]

[0352] Meanwhile, the all-solid-state batteries of Examples 2-1 to 2-7, which used cases in which a first polymer film was formed on the outer layer of a laminate sheet and a second polymer film was further formed on the inner layer, exhibited lower heat generation when subjected to a nail penetration test under the same conditions as above. Therefore, the synergistic effect resulting from the simultaneous presence of the first polymer film and the second polymer film is higher than the effect of the first polymer film alone.

[0353]

[0354] Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the patent claims, the detailed description of the invention, and the attached drawings, and it is obvious that this also falls within the scope of the present invention.

[0355]

[0356] [Explanation of symbols]

[0357] 100: All-solid-state battery 200: Cathode

[0358] 201: Cathode current collector 203: Cathode active material layer

[0359] 300: solid electrolyte layer 400: cathode

[0360] 401: Negative current collector 403: Negative active material layer

[0361] 400': Precipitation type cathode 404: Lithium metal layer

[0362] 405: Cathode coating layer 500: Elastic layer

Claims

1. A laminate sheet in which inner, middle, and outer layers are sequentially laminated; and A first polymer film positioned on the outer layer of the laminate sheet and including a first polyurethane resin, Case for lithium secondary batteries.

2. In paragraph 1, Further comprising a second polymer film positioned on the inner layer of the laminate sheet and including a second polyurethane resin, Case for lithium secondary batteries.

3. In paragraph 1 or 2, A case for a lithium secondary battery, wherein the first polymer film and the second polymer film each independently have a coefficient of friction of 0.4 to 0.8 μ.

4. In paragraph 1 or 2, A case for a lithium secondary battery, wherein the first polymer film and the second polymer film each independently have an elongation of 200 to 700% according to the ASTM D638 measurement method.

5. In paragraph 1 or 2, The first polymer film and the second polymer film each independently have a tensile strength of 250 to 600 kgf / mm according to the ISO527 measurement method. 2 Case for lithium secondary battery.

6. In paragraph 1 or 2, A case for a lithium secondary battery, wherein the first polymer film and the second polymer film each independently have a thickness of 10 to 300 ㎛.

7. In paragraph 1 or 2, A case for a lithium secondary battery, wherein the first polyurethane resin and the second polyurethane resin each independently have a weight average molecular weight of 10,000 to 3,000,000 g / mol as measured by the GPC method.

8. In paragraph 1 or 2, A case for a lithium secondary battery, wherein the first polymer film and the second polymer film are each independently manufactured from a composition for a polymer film containing a urethane-based binder, a curing agent, and a plasticizer.

9. In paragraph 8, A case for a lithium secondary battery, wherein the composition for the polymer film comprises 1 to 30 parts by weight of a plasticizer based on 100 parts by weight of the urethane-based binder.

10. In paragraph 8, A case for a lithium secondary battery, wherein the plasticizer comprises isopropyl myristate, isopropyl palmitate, isotridecyl isononanoate, 1,2-cyclohexanedicarboxylic acid diisononyl ester, isostearyl palmitate, isostearyl laurate, diisostearyl adipate, diisocetyl sebacate, or a combination thereof.

11. In paragraph 8, The above urethane binder, Based on 100 parts by weight of a polyol comprising 50 to 90 wt% of a polyether triol, 5 to 40 wt% of a polyether diol, and 5 to 40 wt% of a polyester diol, Manufactured by polymerizing 1 to 10 parts by weight of an isocyanate compound, Case for lithium secondary batteries.

12. In paragraph 8, A case for a lithium secondary battery, wherein the composition for the polymer film further comprises a leveling agent, an antistatic agent, an antioxidant, a catalyst, a retardant, or a combination thereof.

13. In paragraph 1, The above case is a pouch-type case for lithium secondary batteries.

14. Cases under paragraph 1 or 2; and A lithium secondary battery comprising an electrode assembly built into the above case.

15. In paragraph 14, The above lithium secondary battery is a lithium secondary battery that is an all-solid-state battery, a semi-solid-state battery, a lithium metal battery, or a lithium ion battery.

16. In paragraph 14, The above lithium secondary battery is an all-solid-state battery, and has a calorific value of 100 to 1,000 J / g in a nail penetration test under the conditions of SOC 100%, nail diameter 3 mm, and penetration speed 25 mm / sec.

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