Elastic pad for all-solid-state battery, all-solid-state battery comprising same, and manufacturing method therefor

Abstract

The present invention relates to an elastic pad for an all-solid-state battery, the all-solid-state battery comprising same, and a manufacturing method therefor, and, more specifically, comprises: a matrix including a first acrylic resin and / or a urethane resin; and an impact modifier in the matrix, wherein the impact modifier includes: a core including a first polymer; and a shell including a second polymer, the first polymer being an elastomer, and the second polymer being a polymer that includes at least one selected from the group consisting of polymethacrylate-based polymers and polystyrene acrylonitrile-based polymers.

Description

Elastic pad for all-solid-state battery, all-solid-state battery including same, and method for manufacturing same

[0001] The present invention relates to an elastic pad for an all-solid-state battery, an all-solid-state battery including the same, and a method for manufacturing the same.

[0002] Recent industrial demands have led to the active development of batteries with high energy density and safety. For example, lithium-ion batteries are being used not only in information and communication devices, but also in the automotive sector. Safety is particularly important in the automotive sector, as it is directly related to life.

[0003] Recently, all-solid-state batteries, which replace the electrolyte with a solid electrolyte, have been proposed. By eliminating the use of flammable organic dispersion media, all-solid-state batteries significantly reduce the risk of fire or explosion in the event of a short circuit. Therefore, these all-solid-state batteries can significantly improve safety compared to lithium-ion batteries that use electrolytes.

[0004] The problem to be solved by the present invention is to provide an elastic pad for an all-solid-state battery having excellent restoring force and excellent shock absorption rate and a method for manufacturing the same.

[0005] Another problem that the present invention seeks to solve is to provide an all-solid-state battery that maintains excellent performance and is lightweight.

[0006] An elastic pad for an all-solid-state battery according to one embodiment of the present invention comprises: a matrix comprising at least one of a first acrylic resin or a urethane resin; and an impact modifier within the matrix; wherein the impact modifier comprises: a core comprising a first polymer; and a shell comprising a second polymer; wherein the first polymer is an elastomer, and the second polymer may be a polymer comprising at least one selected from the group consisting of polymethacrylate-based polymers and polystyrene acrylonitrile-based polymers.

[0007] An all-solid-state battery according to one embodiment of the present invention comprises a plurality of battery cells and at least one elastic pad, wherein the elastic pad may be the elastic pad for the all-solid-state battery described above.

[0008] According to one embodiment of the present invention, a method for manufacturing an elastic pad for an all-solid-state battery comprises: forming an impact modifier comprising a core and a shell, wherein the core comprises a first polymer, and the shell comprises a second polymer; UV curing a first mixture comprising a first monomer, a second monomer, a third monomer, and a first initiator to form a third polymer; and UV curing a second mixture comprising the impact modifier, the third polymer, a second initiator, and a crosslinking agent; wherein the first polymer is an elastomer, the second polymer is a polymer comprising at least one selected from the group consisting of polymethacrylates and polystyrene acrylonitriles, and the first monomer is an aliphatic (meth)acrylate having a temperature of C1 to C20, the second monomer is an alicyclic (meth)acrylate having a Tg of 50°C or higher, and the third monomer may be a hydrophilic monomer.

[0009] An elastic pad for an all-solid-state battery according to one embodiment of the present invention can have excellent resilience and excellent shock absorption. As a result, the yield in the all-solid-state battery manufacturing process can be improved.

[0010] An all-solid-state battery according to one embodiment of the present invention can maintain performance and be lightweight.

[0011] A method for manufacturing an elastic pad for an all-solid-state battery according to one embodiment of the present invention can manufacture an elastic pad for an all-solid-state battery having the above-described effects.

[0012] Figure 1 is a cross-sectional view of a cell according to one embodiment of the present invention.

[0013] Figure 2 is a cross-sectional view of a cell according to one embodiment of the present invention.

[0014] FIG. 3 and FIG. 4 are a plan view and a cross-sectional view of a cell according to one embodiment of the present invention, respectively.

[0015] Figure 5 is a cross-sectional view of a cell according to one embodiment of the present invention.

[0016] FIG. 6 is a cross-sectional view of a cell including a gasket structure according to one embodiment of the present invention.

[0017] Figure 7 is a cross-sectional view of a cell according to one embodiment of the present invention.

[0018] Figure 8 is a cross-sectional view of a cell according to one embodiment of the present invention.

[0019] Figure 9 is a cross-sectional view of an elastic pad for an all-solid-state battery according to embodiments of the present invention.

[0020] Figure 10 is a cross-sectional view of an impact modifier according to embodiments of the present invention.

[0021] Figure 11 is a cross-sectional view of an all-solid-state battery according to one embodiment of the present invention.

[0022] Figure 12 is a cross-sectional view of an all-solid-state battery according to one embodiment of the present invention.

[0023] Figure 13 is a flow chart of a method for manufacturing an elastic pad for an all-solid-state battery according to embodiments of the present invention.

[0024] Figure 14 is a stress-strain curve of examples and comparative examples.

[0025] Figure 15 is a stress-strain curve of Example 1.

[0026] To fully understand the structure and effects of the present invention, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various forms and subject to various modifications. However, the description of these embodiments is provided solely to ensure a complete disclosure of the present invention and to fully inform those skilled in the art of the invention of the scope of the invention.

[0027] In this specification, when a component is referred to as being on another component, it means that it can be formed directly on the other component, or a third component may be interposed between them. Furthermore, in the drawings, the thicknesses of the components are exaggerated for the sake of clarity. Parts designated by the same reference numerals throughout the specification represent the same components.

[0028] Embodiments described herein will be described with reference to cross-sectional and / or plan views, which are ideal illustrations of the present invention. In the drawings, the thicknesses of films and regions are exaggerated for the purpose of effectively explaining the technical contents. Accordingly, the regions illustrated in the drawings have a schematic nature, and the shapes of the regions illustrated in the drawings are intended to illustrate specific shapes of regions of the device and are not intended to limit the scope of the invention. Although terms such as first, second, and third are used to describe various components in various embodiments of the present specification, these components should not be limited by such terms. These terms are used only to distinguish one component from another. The embodiments described and illustrated herein also include complementary embodiments thereof.

[0029] The terminology used herein is for the purpose of describing embodiments and is not intended to limit the present invention. In this specification, the singular also includes the plural unless specifically stated otherwise. As used herein, the words "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components.

[0030] As used herein, “combination thereof” may mean mixtures, laminates, composites, copolymers, alloys, blends, and reaction products of the components.

[0031] 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.

[0032]

[0033] FIG. 1 is a cross-sectional view of a cell (CEL) according to one embodiment of the present invention.

[0034] Referring to FIG. 1, a cell (CEL) according to one embodiment includes a positive electrode layer (100), a negative electrode layer (200) facing the positive electrode layer (100), and a solid electrolyte layer (300) disposed between the positive electrode layer (100) and the negative electrode layer (200). However, the present invention is not limited thereto, and the cell (CEL) may further include an additional functional layer, such as an adhesion enhancing layer, disposed between the positive electrode layer (100) and the solid electrolyte layer (300) or between the negative electrode layer (200) and the solid electrolyte layer (300).

[0035] The positive electrode layer (100) of one embodiment includes a positive electrode current collector (110) and a positive electrode active material layer (120) disposed on the positive electrode current collector (110). The positive electrode active material layer (120) may include a positive electrode active material, a solid electrolyte, a conductive material, and a binder.

[0036] The cathode current collector (110) can provide a reference surface on which the cathode active material layer (120) is arranged. The cathode current collector (110) can include a plate or foil including, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), or an alloy thereof.

[0037] Meanwhile, unlike that illustrated in FIG. 1, in one embodiment of the present invention, the positive electrode current collector (110) may be omitted. Although not illustrated, a carbon layer having a thickness of 0.1 μm to 4 μm may be additionally disposed between the positive electrode current collector (110) and the positive electrode active material layer (120) to increase the bonding strength between the positive electrode current collector (110) and the positive electrode active material layer (120).

[0038] A cathode active material is a material that can reversibly absorb and desorb lithium ions. The cathode active material may include, but is not necessarily limited to, lithium transition metal oxides such as lithium cobalt oxide (LCO), lithium nickel oxide, lithium nickel cobalt oxide, lithium nickel cobalt aluminum oxide (NCA), lithium nickel cobalt manganese oxide (NCM), lithium manganate, and lithium iron phosphate, nickel sulfide, copper sulfide, lithium sulfide, iron oxide, or vanadium oxide. The cathode active materials may be used alone or as a mixture of two or more.

[0039] Lithium transition metal oxides include, for example, Li a A 1-b B b D2(0.90≤a≤1, 0≤b≤0.5), Li a E 1-b B b O 2-c D c (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05), LiE 2-b B b O 4-c D c (0≤b≤0.5, 0≤c≤0.05), Li a Ni 1-b-c Co b B c D α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2), Li a Ni 1-b-c Co b B c O 2-α F α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2), Li a Ni 1-b-c Mn b B c D α(0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α≤2), Li a Nor 1-b-c Mn b B c O 2-α F α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2), Li a Nor b E c G d O2(0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0.001≤d≤0.1), Li a Nor b Co c Mn d GeO2(0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0.001≤e≤0.1), Li a NiG b O2(0.9≤a≤1, 0.001≤b≤0.1), Li a CoG b O2(0.90≤a≤1, 0.001≤b≤0.1), Li a MnG b O2(0.90≤a≤1, 0.001≤b≤0.1), Li a Mn2GbO4(0.90≤a≤1, 0.001≤b≤0.1), QO2, QS2, LiQS2, V2O5, LiV2O5, LiIO2, LiNiVO4, Li 3-f J2(PO4)3(0≤f≤2), Li 3-fA compound represented by any one of Fe2(PO4)3(0≤f≤2), LiFePO4. In these compounds, the capital letter “A” is Ni, Co, Mn, or a combination thereof, the capital letter “B” is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof, the capital letter “D” is O, F, S, P, or a combination thereof, the capital letter “E” is Co, Mn, or a combination thereof, the capital letter “F” is F, S, P, or a combination thereof, the capital letter “G” is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof, the capital letter “Q” is Ti, Mo, Mn, or a combination thereof, the capital letter “I” is Cr, V, Fe, Sc, Y, or a combination thereof, and the capital letter “J” is V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

[0040] The cathode active material may include, for example, a lithium salt of a transition metal oxide having a layered rock salt type structure among the lithium transition metal oxides described above. The "layered rock salt type structure" is, for example, a cubic rock salt type structure. <111> It is a structure in which oxygen atomic layers and metal atomic layers are alternately and regularly arranged in a direction, and thereby each atomic layer forms a two-dimensional plane. The "cubic rock salt structure" refers to a sodium chloride type (NaCl type) structure, which is a type of crystal structure, and specifically refers to a structure in which face-centered cubic lattices (fcc) formed by cations and anions respectively are arranged with a displacement of half of the ridge of the unit lattice. Lithium transition metal oxides having this layered rock salt structure include, for example, LiNi x Co y Al z O2(NCA) or LiNi x Co y Mn zO2(NCM) (0 <x<1,0<y<1, 0<z<1, x+y+z=1) 등의 삼원계 리튬전이금속산화물일 수 있다. 양극활물질(121)이 층상암염형 구조를 갖는 삼원계 리튬전이금속산화물을 포함하는 경우, 셀(CEL)의 에너지 밀도가 커지고 열안정성이 향상될 수 있다.

[0041] The above-described compound included in the positive electrode active material may be covered by a coating layer (not shown). The positive electrode active material may also be a mixture of the above-described compound and a compound to which a coating layer is added. Meanwhile, the coating layer added to the surface of the positive electrode active material may include, for example, an oxide, a hydroxide, an oxyhydroxide, an oxycarbonate, or a hydroxycarbonate of the coating elements below. The compound forming the coating layer may be amorphous or crystalline. The coating elements included in the coating layer may include Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or mixtures thereof. The coating layer may include, for example, Li2O-ZrO2 (LZO). The method of forming the coating layer is selected within a range that does not adversely affect the physical properties of the positive electrode active material. The method of forming the coating layer includes, for example, spray coating, dipping, etc.

[0042] When the cathode active material is a ternary lithium transition metal oxide such as NCA or NCM and contains nickel (Ni), it is possible to increase the capacity density of the cell (CEL) and reduce metal dissolution of the cathode active material in a charged state. As a result, the cycle characteristics of the cell (CEL) in a charged state are improved. Meanwhile, the “cycle characteristics” are characteristics indicating the degree to which the cell (CEL) is deteriorated due to charge / discharge of the cell (CEL). A cell (CEL) with high cycle characteristics may have a small degree of cell (CEL) deterioration due to charge / discharge, and a cell (CEL) with low cycle characteristics may have a large degree of cell (CEL) deterioration due to charge / discharge.

[0043] The shape of the cathode active material may include particle shapes such as a sphere or an ellipsoid, for example. The particle size and content of the cathode active material are not particularly limited.

[0044] The solid electrolyte may have a particle shape. The solid electrolyte may be dispersed between the positive electrode active materials. The solid electrolyte may include a sulfide-based solid electrolyte having excellent lithium ion conductivity characteristics. Examples of the sulfide-based solid electrolyte include Li2S-P2S5, Li2S-P2S5-LiX (X is a halogen element), 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 positive numbers, capital letter “Z” represents Ge, Zn or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p, q are positive numbers, capital letter “M” is one of P, Si, Ge, B, Al, Ga In), Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2), and Li 7-x PS 6-x I x It may include at least one selected from (0≤x≤2).

[0045] Sulfide-based solid electrolytes include, for example, Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2), and Li 7-x PS 6-x Ix It may be an argyrodite-type compound including at least one selected from (0≤x≤2). In particular, the sulfide-based solid electrolyte may be an argyrodite-type compound including at least one selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0046] Alternatively, the sulfide-based solid electrolyte is Li 7-a M a PS 6-c X c It may be an argyrodite-type compound containing (0≤a≤2, (0≤c≤2)), where X may be F, Br, Cl, or a combination thereof. M can be candium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), bismuth (Bi), or a combination thereof.

[0047] The density of the argyrodite-type solid electrolyte may be 1.5 g / cc to 2.0 g / cc. Since the argyrodite-type solid electrolyte has a density of 1.5 g / cc or more, the internal resistance of the all-solid-state battery is reduced, and the defect of the solid electrolyte membrane being penetrated and short-circuited due to the formation of lithium dendrites can be prevented. The elastic modulus of the solid electrolyte (122-1) may be, for example, 15 GPa to 35 GPa.

[0048] The solid electrolyte included in the positive electrode active material layer (120) may have a smaller median particle size (D50) than the solid electrolyte included in the solid electrolyte layer (300). For example, the median particle size (D50) of the solid electrolyte included in the positive electrode active material layer (120) may be 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, or 20% or less of the median particle size (D50) of the solid electrolyte included in the solid electrolyte layer (300). Meanwhile, the median particle size (D50) may be a median diameter measured using a laser particle size distribution meter.

[0049] The cathode active material layer (120) may include a conductive material. The conductive material may be conductive without causing chemical changes in the cell (CEL), thereby increasing the conductivity of the cathode active material and the solid electrolyte. The conductive material may include a carbon-based material. For example, the conductive material may include one or more selected from graphite, carbon black, acetylene black, carbon nanofibers, and carbon nanotubes.

[0050] The positive electrode active material layer (120) may further include a binder. The binder may include a material for binding the positive electrode active material, solid electrolyte, and conductive material included in the positive electrode active material layer (120) and improving bonding strength with the positive electrode current collector (110). The binder may include, for example, polyvinylidene fluoride, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate.

[0051] Based on 100 parts by weight of the total of the positive electrode active material, the solid electrolyte, the conductive material, and the binder, the positive electrode active material layer (120) may include 85 parts by weight or more and 92 parts by weight or less of the positive electrode active material. Based on 100 parts by weight of the total of the positive electrode active material, the solid electrolyte, the conductive material, and the binder, the positive electrode active material layer (120) may include 0.5 parts by weight or more and 1.5 parts by weight or less of the binder.

[0052] Based on 100 parts by weight of the solid electrolyte, the positive electrode active material layer (120) may include 1 part by weight or more and 50 parts by weight or less of a conductive material. If the conductive material is included in the positive electrode active material layer (120) in an amount of less than 1 part by weight based on 100 parts by weight of the solid electrolyte, the proportion of the conductive material may decrease, thereby lowering the electrical conductivity of the positive electrode active material layer (120). If the conductive material is included in the positive electrode active material layer (120) in an amount of more than 50 parts by weight based on 100 parts by weight of the solid electrolyte, the proportion of the conductive material may be excessively high, so that a covering layer covering the surface of the solid electrolyte may not be properly formed.

[0053] The cathode active material layer (120) may further include additives such as fillers, coating agents, dispersants, and ion conductive aids in addition to the cathode active material, solid electrolyte, conductive agent, and binder described above.

[0054] Referring to FIG. 1, the solid electrolyte layer (300) is disposed between the positive electrode layer (100) and the negative electrode layer (200) and includes a sulfide-based solid electrolyte having excellent lithium ion conductivity characteristics. The solid electrolyte included in the solid electrolyte layer (300) may be the same as or different from any one of the materials that may be included in the solid electrolyte included in the positive electrode active material layer (120) described above.

[0055] The solid electrolyte layer (300) of one embodiment may include a sulfide-based solid electrolyte. The sulfide-based solid electrolyte may be manufactured by treating starting materials such as Li2S and P2S5 by a melting rapid cooling method or a mechanical milling method. In addition, a heat treatment may be performed after the treatment. The solid electrolyte may be amorphous, crystalline, or a mixture thereof. In addition, the solid electrolyte may include, for example, at least sulfur (S), phosphorus (P), and lithium (Li) as constituent elements among the above-described sulfide-based solid electrolyte materials. For example, the solid electrolyte may be a material including Li2S-P2S5. When using a sulfide-based solid electrolyte material including Li2S-P2S5 to form the solid electrolyte, the mixing molar ratio of Li2S and P2S5 is, for example, in the range of Li2S:P2S5=50:50 to 90:10.

[0056] Sulfide-based solid electrolytes include, for example, Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2), and Li 7-x PS 6-It may be an argyrodite-type compound including at least one selected from xIx(0≤x≤2). In particular, the sulfide-based solid electrolyte may be an argyrodite-type compound including at least one selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I. The density of the argyrodite-type solid electrolyte may be 1.5 g / cc to 2.0 g / cc. Since the argyrodite-type solid electrolyte has a density of 1.5 g / cc or more, the internal resistance of the all-solid-state battery is reduced, and the defect of the solid electrolyte membrane being penetrated and short-circuited due to the formation of lithium dendrites can be prevented. The elastic modulus of the solid electrolyte is, for example, 15 GPa to 35 GPa.

[0057] The solid electrolyte layer (300) may further include a binder. The binder included in the solid electrolyte layer (300) may be, for example, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, etc., but is not limited thereto. The binder of the solid electrolyte layer (300) may be the same as or different from the binder included in the positive electrode active material layer (120) or the binder included in the negative electrode active material layer (220).

[0058] Referring to FIG. 1, the negative electrode layer (200) includes a negative electrode current collector (210) and a negative electrode active material layer (220) disposed on the negative electrode current collector (210). The negative electrode active material layer (220) may include a negative electrode active material and a binder.

[0059] The negative electrode current collector (210) can provide a reference surface on which the negative electrode active material layer (220) is arranged. The negative electrode current collector (210) can include, for example, a material that does not react with lithium, i.e., does not form an alloy or compound with lithium. The material constituting the negative electrode current collector (210) is not necessarily limited to, for example, copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), and nickel (Ni), and any material that can be used as an electrode current collector can be used. The thickness of the negative electrode current collector can be 1 to 20 μm, for example, 5 to 15 μm, for example, 7 to 10 μm.

[0060] The negative electrode current collector (210) may be composed of one of the above-described metals, or may include an alloy or coating material of two or more metals. The negative electrode current collector (210) is, for example, in the form of a plate or foil. Meanwhile, in one embodiment, the negative electrode current collector (210) may be omitted.

[0061] The negative electrode active material included in the negative electrode active material layer (220) may have a particle form. The median particle size average particle diameter (D50) of the negative electrode active material having a particle form may be, for example, 4 μm or less, 2 μm or less, 1 μm or less, or 900 nm or less. The median particle size average particle diameter (D50) of the negative electrode active material may be, for example, 10 nm to 4 μm, 10 nm to 2 μm, or 10 nm to 900 nm. When the negative electrode active material has a median particle size average diameter (D50) in this range, reversible absorption and / or desorption of lithium may be facilitated during charge and discharge. Meanwhile, the median particle size average diameter (D50) may be a median diameter measured using a laser particle size distribution meter.

[0062] The negative electrode active material may include, for example, at least one selected from a carbon-based negative electrode active material and a metal or metalloid negative electrode active material.

[0063] The carbon-based negative electrode active material may be amorphous carbon, in particular. Examples of amorphous carbon include, but are not limited to, carbon black (CB), acetylene black (AB), furnace black (FB), ketjen black (KB), and graphene. Amorphous carbon is carbon that has no crystallinity or very low crystallinity, and is distinguished from crystalline carbon or graphitic carbon.

[0064] The metal or metalloid negative electrode active material includes, but is not necessarily limited to, one or more selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn), and may be a metal negative electrode active material or a metalloid negative electrode active material that forms an alloy or compound with lithium. On the other hand, nickel (Ni) does not form an alloy with lithium and therefore is not a metal negative electrode active material.

[0065] The negative electrode active material layer (220) includes one type of negative electrode active material among these negative electrode active materials, or includes a mixture of multiple different negative electrode active materials. For example, the negative electrode active material layer (220) may include only amorphous carbon, or may include one or more selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn).

[0066] In one embodiment, the negative electrode active material layer (220) may include a mixture of amorphous carbon and one or more selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn). The mixing ratio of the mixture of amorphous carbon and gold (Au), etc., may be, for example, 10:1 to 1:2, 5:1 to 1:1, or 4:1 to 2:1 by weight, but is not necessarily limited to this range and may be selected according to the characteristics of the required cell (CEL). When the negative electrode active material has this composition, the cycle characteristics of the cell (CEL) can be further improved.

[0067] The binder included in the negative electrode active material layer (220) may be, for example, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, polymethyl methacrylate, etc., but is not necessarily limited thereto. The binder may include a single binder or a plurality of different binders.

[0068] Since the negative electrode active material layer (220) includes a binder, the negative electrode active material layer (220) can be stably formed on the negative electrode current collector (210). That is, the bonding strength between the negative electrode active material layer (220) and the negative electrode current collector (210) can be increased. In addition, cracking of the negative electrode active material layer (220) is suppressed despite changes in the volume and / or relative positions of the negative electrode active material layer (220) during the charge and discharge process. If the negative electrode active material layer (220) does not include a binder, the negative electrode active material layer (220) can be easily separated from the negative electrode current collector (210). As the negative electrode active material layer (220) is detached from the negative electrode current collector (210), the negative electrode current collector (210) can come into contact with the solid electrolyte layer at the exposed portion, thereby increasing the possibility of a short circuit occurring.

[0069] The negative electrode active material layer (220) is manufactured, for example, by providing a mixture in which the materials constituting the negative electrode active material layer (220) are dispersed onto the negative electrode current collector (210). Since a binder is included in the materials constituting the negative electrode active material layer (220), stable dispersion of the negative electrode active material in the mixture is possible. For example, when applying the mixture onto the negative electrode current collector (210) by screen printing, it is possible to suppress clogging of the screen (e.g., clogging by aggregates of the negative electrode active material) by the binder.

[0070] The negative electrode active material layer (220) may further include other additives in addition to the negative electrode active material and binder. The negative electrode active material layer (220) may further include, for example, fillers, coating agents, dispersants, ion conductive additives, etc.

[0071] The negative electrode active material layer (220) may have a smaller thickness than the positive electrode active material layer (120). The thickness of the negative electrode active material layer (220) may be, for example, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, or 5% or less of the thickness of the positive electrode active material layer (120). The thickness of the negative electrode active material layer (220) may be, for example, 1 um to 20 um, 2 um to 10 um, or 3 um to 7 um. If the thickness of the negative electrode active material layer (220) is too thin, lithium dendrites formed between the negative electrode active material layer (220) and the negative electrode current collector (210) may collapse the negative electrode active material layer (220), thereby deteriorating the cycle characteristics of the all-solid-state battery (10). If the thickness of the negative electrode active material layer (220) increases excessively, the energy density of the cell (CEL) may decrease and the internal resistance of the cell (CEL) due to the negative electrode active material layer (220) may increase, thereby deteriorating the cycle characteristics of the cell (CEL).

[0072] If the thickness of the negative electrode active material layer (220) decreases, the charge capacity of the negative electrode active material layer (220) may also decrease, for example. The charge capacity of the negative electrode active material layer (220) is, for example, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, 5% or less, or 2% or less than the charge capacity of the positive electrode active material layer (120). The charge capacity of the negative electrode active material layer (220) is, for example, 0.1% to 50%, 0.1% to 40%, 0.1% to 30%, 0.1% to 20%, 0.1% to 10%, 0.1% to 5%, or 0.1% to 2% than the charge capacity of the positive electrode active material layer (120). If the charge capacity of the negative electrode active material layer (220) is excessively small, the thickness of the negative electrode active material layer (220) becomes very thin, and the same defects as the defects described above that occur when the thickness of the negative electrode active material layer (220) becomes excessively thin may occur. If the charge capacity of the negative electrode active material layer (220) increases excessively, the same defects as the defects described above that occur when the thickness of the negative electrode active material layer (220) increases excessively may occur.

[0073] The charge capacity of the positive electrode active material layer (120) can be obtained by multiplying the charge capacity density (mAh / g) of the positive electrode active material by the mass of the positive electrode active material of the positive electrode active material layer (120). When the positive electrode active material layer (120) includes several types of positive electrode active materials, the [charge capacity density Х mass] value is calculated for each positive electrode active material, and the sum of these values ​​of the positive electrode active materials is the charge capacity of the positive electrode active material layer (120). The charge capacity of the negative electrode active material layer (220) can also be calculated in the same way. That is, the charge capacity of the negative electrode active material layer (220) is obtained by multiplying the charge capacity density (mAh / g) of the negative electrode active material by the mass of the negative electrode active material in the negative electrode active material layer (220). When the negative electrode active material layer (220) includes several types of negative electrode active materials, the [charge capacity density Х mass] value is calculated for each negative electrode active material, and the sum of these values ​​of the negative electrode active materials is the capacity of the negative electrode active material layer (220). Here, the charge capacity density of the positive electrode active material and the negative electrode active material may be an estimated capacity using an all-solid-state half-cell using lithium metal as a counter electrode. The charge capacity of the positive electrode active material layer (120) and the negative electrode active material layer (220) can be directly measured by measuring the charge capacity using the all-solid-state half-cell. The charge capacity density can be obtained by dividing the measured charge capacity by the mass of each active material. Meanwhile, in the present specification, the “charge capacity” of the positive electrode active material layer (120) and the negative electrode active material layer (220) means the initial charge capacity measured at the time of the first cycle charge.

[0074] Meanwhile, although not shown, a carbon layer may be further included to improve adhesion between the negative electrode active material layer (220) and the solid electrolyte layer (300).

[0075]

[0076] FIG. 2 is a cross-sectional view of a cell (CEL) according to another embodiment of the present invention.

[0077] Referring to FIG. 2, the solid electrolyte layer (300) may include a first solid electrolyte layer (310) and a second solid electrolyte layer (320). The first solid electrolyte layer (310) may be adjacent to the positive electrode layer (100), and the second solid electrolyte layer (320) may be adjacent to the negative electrode layer (200).

[0078] The first solid electrolyte layer (310) and the second solid electrolyte layer (320) may have different thicknesses. The first solid electrolyte layer (310) may have a first thickness (TK1), and the second solid electrolyte layer (320) may have a second thickness (TK2). The first thickness (TK1) may be greater than the second thickness (TK2). For example, the first thickness (TK1) may be 2 to 100 times greater than the second thickness (TK2).

[0079]

[0080] Fig. 3 is a plan view of a cell (CEL) according to another embodiment of the present invention. Fig. 4 is a cross-sectional view taken along line A-A' of Fig. 3. In this embodiment, detailed descriptions of technical features that overlap with those previously described with reference to Figs. 1 and 2 will be omitted, and differences will be described in detail.

[0081] Referring to FIGS. 3 and 4, the area of ​​the anode layer (100) and the area of ​​the cathode layer (200) may be different from each other. Specifically, the area of ​​the cathode layer (200) may be larger than the area of ​​the anode layer (100). The anode layer (100) may be completely overlapped within the cathode layer (200).

[0082] In one embodiment of the present invention, the first solid electrolyte layer (310) may have substantially the same area as the positive electrode layer (100). The second solid electrolyte layer (320) may have substantially the same area as the negative electrode layer (200).

[0083] Specifically, the first solid electrolyte layer (310) may have a first width (WI1) in a first direction (D1). The second solid electrolyte layer (320) may have a second width (WI2) in the first direction (D1). The first width (WI1) may be smaller than the second width (WI2). The first solid electrolyte layer (310) may have a third width (WI3) in the second direction (D2). The second solid electrolyte layer (320) may have a fourth width (WI4) in the second direction (D2). The third width (WI3) may be smaller than the fourth width (WI4).

[0084] A cell (CEL) according to the present embodiment can be manufactured by forming a first laminate of an anode layer (100) and a first solid electrolyte layer (310), forming a second laminate of an cathode layer (200) and a second solid electrolyte layer (320), and then laminating the first laminate and the second laminate.

[0085]

[0086] FIG. 5 is a cross-sectional view taken along line A-A' of FIG. 3 to explain a cell (CEL) according to another embodiment of the present invention.

[0087] Referring to FIG. 5, the negative electrode layer (200) of the cell (CEL) may further include a lithium metal layer (400) between the negative electrode current collector (210) and the negative electrode active material layer (220). The thickness of the lithium metal layer (400) may further increase when the cell (CEL) is charged. The negative electrode active material layer (220) serves as a protective layer for the lithium metal layer (400), and at the same time, may suppress the growth of lithium dendrites from the lithium metal layer (400).

[0088] The lithium metal layer (400) may be a metal thin film containing lithium or a lithium alloy. The lithium alloy may include, but is not limited to, 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, a Li-Si alloy, etc., and any lithium alloy may be used. The lithium metal layer (400) may contain one of these alloys or lithium. Alternatively, the lithium metal layer (400) may contain various types of alloys.

[0089] The lithium metal layer (400) may have a fifth width (WI5) in the first direction (D1). The fifth width (WI5) may be equal to or greater than the first width (WI1). The fifth width (WI5) may be equal to or less than the second width (WI2). For example, the fifth width (WI5) may be greater than the first width (WI1) and less than the second width (WI2).

[0090]

[0091] FIG. 6 is a cross-sectional view illustrating a cell (CEL) according to another embodiment of the present invention.

[0092] Referring to FIG. 6, the cell (CEL) may include a gasket structure (500). The gasket structure (500) may fill in the step difference in the side surface of the cell (CEL) caused by the difference in area between the first laminate and the second laminate. The gasket structure (500) may surround the side surfaces of the first laminate of the cell (CEL) along the first and second directions (D1, D2). For example, the thickness of the gasket structure (500) may be substantially the same as the thickness of the first laminate. Accordingly, even when the first and second laminates having different areas are laminated and pressed, damage to the step difference in the side surface of the all-solid-state battery can be prevented. The term “substantially the same thickness” may be defined as a thickness that can prevent damage to the step difference in the side surface of the all-solid-state battery even when the first and second laminates having different areas are laminated and pressed.

[0093]

[0094] FIG. 7 and FIG. 8 are cross-sectional views illustrating a cell (CEL) according to another embodiment of the present invention.

[0095] Referring to FIG. 7, the cell (CEL) may include a bi-cell. For example, the bi-cell may be a stacked form of the mono-cells of FIGS. 1 to 7.

[0096] Referring to FIG. 8, the cell (CEL) may include a gasket structure (500). The gasket structure (500) may be as described above.

[0097]

[0098] elastic pad

[0099] Figure 9 is a cross-sectional view illustrating an elastic pad according to embodiments of the present invention.

[0100] Referring to FIG. 9, the elastic pad (EPD) may include a matrix (MTR) and an impact modifier (IMM).

[0101] The thickness of the elastic pad (TK3) can be 0.1 mm to 3 mm.

[0102] The elastomeric pad (EPD) may be composed of elastically deformable materials, and more specifically, may be composed of materials having a lower elastic modulus than the positive and negative current collectors. The elastomeric pad (EPD) may include, for example, an insulating material.

[0103] The elastic pad (EPD) may include at least one of a first acrylic resin or a urethane resin.

[0104] The first acrylic resin may be a ternary copolymer of a mixture of a first monomer, a second monomer, and a third monomer. The first monomer, the second monomer, and the third monomer are described below with reference to FIG. 13.

[0105] The first acrylic resin may be a solid. The first acrylic resin may be prepared by UV curing the third polymer described below. The first acrylic resin may be an acrylic resin having a weight average molecular weight (Mw) greater than that of the third polymer described below. For example, the weight average molecular weight (Mw) of the first acrylic resin may be greater than 1,500,000. That is, in the present invention, the solid acrylic resin may be defined as a resin having a weight average molecular weight (Mw) greater than 1,500,000.

[0106] Urethane resins can be polyurethanes. Polyurethanes can be defined as homopolymers or copolymers containing urethane groups formed by the combination of polyols and isocyanates.

[0107] For example, the urethane resin may be derived from a polyether polyol. The polyether polyol may have a functional group number of 2 to 4 and a number average molecular weight of 2000 to 4000. In addition to the polyether polyol, the urethane resin may also be derived from a polyester polyol. For example, the polyester polyol may include one obtained by condensation of a low molecular weight polyol such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, hexanediol, glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, diglycerin, sorbitol, sucrose, and the like with succinic acid, adipic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, succinic anhydride, maleic anhydride, phthalic anhydride, and the like. In addition, the polyester polyol may include a polyol that is a ring-opening condensate of caprolactone and methyl valerolactone, which are classified as lactone esters. The polycarbonate polyol may include one obtained by a dealcoholization reaction of a polyhydric alcohol such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, pentanediol, or hexanediol with a dialkyl carbonate, dialkylene carbonate, or diphenyl carbonate. The polycarbonate polyol may have a functional group number of 2 to 3 and a number average molecular weight of 500 to 1000 (or a hydroxyl number of 112 mgKOH / g or more and 224 mgKOH / g or less). The above isocyanate may include at least one of methylene diphenyl diisocyanate (MDI) and toluene diisocyanate (TDI).

[0108] An impact modifier (IMM) may be included within the matrix (MTR). The content of the impact modifier (IMM) may be 3 wt% to 15 wt% relative to the total weight of the elastic pad (EPD). When the content of the impact modifier (IMM) satisfies the above-described range, the elastic pad (EPD) can maintain the internal pressure of the all-solid-state battery during charge and discharge, and can have excellent impact absorption. The impact modifier (IMM) will be described in detail below with reference to FIG. 10.

[0109]

[0110] shock absorber

[0111] Figure 10 is a cross-sectional view illustrating an impact modifier according to embodiments of the present invention.

[0112] Referring to FIG. 10, the impact modifier (IMM) may include a core (COR) and a shell (SHL).

[0113] The core (COR) may include a first polymer. The first polymer may be an elastomer. For example, the elastomer may include rubber. For example, the elastomer may include at least one selected from the group consisting of silicone rubber, butadiene rubber, and acrylic rubber.

[0114] The core (COR) may include a first polymer in which a fourth monomer, a fifth monomer, and a sixth monomer are graft polymerized.

[0115] The fourth monomer may include a (meth)acrylic acid alkyl ester monomer. For example, the fourth monomer may include at least one selected from the group consisting of methyl acrylic acid ester, ethyl acrylic acid ester, and butyl acrylic acid ester.

[0116] The fifth monomer may include an unsaturated nitrile monomer. For example, the fifth monomer may include at least one selected from the group consisting of acrylonitrile, 3-butenenitrile, 4-pentenenitrile, and 5-hexenenitrile.

[0117] The sixth monomer may include an aromatic vinyl monomer. For example, the sixth monomer may include at least one selected from the group consisting of alpha-methylstyrene, beta-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, and the like.

[0118] The shell (SHL) may be a polymer including at least one selected from the group consisting of polymethacrylate and polystyrene acrylonitrile. For example, the polymer constituting the shell may be polymethyl methacrylate (PMMA).

[0119] The thickness of the shell (SHL) can be 20 nm to 100 nm.

[0120] The average particle size of the impact modifier may be between 100 nm and 500 nm. For example, the average particle size of the impact modifier may be between 150 nm and 300 nm, or between 200 nm and 250 nm. In one embodiment, the average particle size may be measured using a particle size analyzer. The average particle size may refer to the diameter (D50) of particles having a cumulative volume of 50% by volume in the particle size distribution.

[0121] When the impact modifier (IMM) has the structure and components described above, the elastic pad (EPD) can maintain the internal pressure of the all-solid-state battery during charging and discharging, and can have excellent shock absorption. The impact modifier (IMM) is described in detail below with reference to FIG. 10.

[0122]

[0123] All-solid-state battery (stack cell)

[0124] FIGS. 11 and 12 are cross-sectional views illustrating an all-solid-state battery according to one embodiment of the present invention. Referring to FIGS. 11 and 12 , the all-solid-state battery may include a plurality of battery cells and at least one elastic pad. That is, the all-solid-state battery may include a stack cell.

[0125] Each of the plurality of battery cells may include at least one of a monocell or a bicell. For example, each of the plurality of battery cells may include a cell (CEL) of FIGS. 1 to 8. For example, referring to FIG. 11, each of the plurality of battery cells may be a monocell of FIG. 1. For example, referring to FIG. 12, each of the plurality of battery cells may be a bicell of FIG. 4.

[0126] An elastic pad (EPD) can maintain the internal pressure of an all-solid-state battery during charging and discharging, and can exhibit excellent shock absorption. Specifically, the EPD can buffer the volume expansion of an all-solid-state battery during charging, and furthermore, exhibit excellent resilience during discharge. This can maintain the performance of the all-solid-state battery and improve yield in the all-solid-state battery manufacturing process. Furthermore, by reducing the number of washer springs used to maintain the internal pressure of the all-solid-state battery, the weight of the all-solid-state battery can be reduced.

[0127]

[0128] An elastic pad (EPD) according to embodiments of the present invention and an all-solid-state battery including the same can have the following effects.

[0129] An elastic pad (EPD) can have excellent restoring force. In a stress-strain curve of the elastic pad (EPD), the EPD has a first stress at a first strain and a second stress at a second strain, the first stress is an internal pressure when SOC is 0, the second stress is an internal pressure when SOC is 100, and a ratio of a difference between the first stress and the second stress may be 0.6 or less, or 0.5 to 0.6, in comparison to the difference between the first strain and the second strain. The internal pressure when SOC is 0 may be 1 MPa to 3 MPa. For example, the internal pressure when SOC is 0 may be 1 MPa to 1.5 MPa. The internal pressure when SOC is 100 may be 3 MPa to 5 MPa. For example, when the SOC is 100, the internal pressure can be 4 MPa. This reduces the volume change of the all-solid-state battery during charging and discharging, and maintains the internal pressure of the all-solid-state battery. Furthermore, the performance of the all-solid-state battery can be maintained, and the number of washer springs used to maintain the internal pressure of the all-solid-state battery can be reduced, thereby reducing the weight of the all-solid-state battery.

[0130] Elastomeric pads (EPDs) can have excellent shock absorption. The shock absorption of the elastomeric pad can be greater than 50%. The shock absorption of the elastomeric pad can range from 50% to 100%, or from 50% to 60%. This can improve yield in the all-solid-state battery manufacturing process.

[0131]

[0132] Method for manufacturing elastic pads

[0133] Figure 13 is a flowchart illustrating a method for manufacturing an elastic pad for an all-solid-state battery according to embodiments of the present invention. The elastic pad for an all-solid-state battery may include a matrix including a first acrylic resin; and an impact modifier within the matrix.

[0134] Referring to FIG. 13, a method for manufacturing an elastic pad for an all-solid-state battery according to embodiments of the present invention may include forming an impact modifier (S100); forming a third polymer (S300); and mixing and curing the impact modifier, the third polymer, an initiator, and a crosslinking agent (S500).

[0135]

[0136] First, the above-described impact modifier can be formed (S100) (see FIG. 10). That is, the impact modifier includes a core (COR) and a shell (SHL), wherein the core (COR) includes a first polymer, and the shell (SHL) includes a second polymer. The first polymer may be an elastomer, and the second polymer may be a polymer including at least one selected from the group consisting of polymethacrylates and polystyrene acrylonitrile. As an example, the second polymer may be polymethyl methacrylate (PMMA).

[0137] The first polymer may be a graft polymerization of the fourth monomer, the fifth monomer, and the sixth monomer. The first polymer may constitute a core (COR) of an impact modifier (IMM).

[0138] The fourth monomer may include a (meth)acrylic acid alkyl ester monomer. For example, the fourth monomer may include at least one selected from the group consisting of methyl acrylic acid ester, ethyl acrylic acid ester, and butyl acrylic acid ester.

[0139] The fifth monomer may include an unsaturated nitrile monomer. For example, the fifth monomer may include at least one selected from the group consisting of acrylonitrile, 3-butenenitrile, 4-pentenenitrile, and 5-hexenenitrile.

[0140] The sixth monomer may include an aromatic vinyl monomer. For example, the sixth monomer may include at least one selected from the group consisting of alpha-methylstyrene, beta-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, and the like.

[0141] The second polymer may be a polymer comprising at least one selected from the group consisting of polymethacrylates and polystyrene acrylonitriles. The second polymer may be polymethyl methacrylate (PMMA). The second polymer may constitute the shell (SHL) of the impact modifier (IMM).

[0142]

[0143] The first mixture can be UV-cured to form a third polymer (S300). The first mixture can include a first monomer, a second monomer, a third monomer, and a first initiator.

[0144] The first monomer may be an aliphatic (meth)acrylate having a carbon number of C1 to C20. For example, the first monomer may include at least one selected from the group consisting of 2-ethylhexyl (meth)acrylate, 2-ethylpentyl (meth)acrylate, 2-ethylheptyl (meth)acrylate, 2-ethylnonyl (meth)acrylate, 2-propylhexyl (meth)acrylate, and 2-propyloctyl (meth)acrylate.

[0145] The content of the first monomer in the first mixture may be 20 to 60 parts by weight based on 100 parts by weight of the total weight of the first to third monomers.

[0146] The second monomer may be an alicyclic (meth)acrylate having a Tg of 50°C or higher. For example, the second monomer may include at least one selected from the group consisting of isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, and cyclopentyl (meth)acrylate.

[0147] The content of the second monomer in the first mixture may be 5 to 25 parts by weight based on 100 parts by weight of the total weight of the first to third monomers.

[0148] The third monomer may be a hydrophilic monomer. For example, the third monomer may include a polar functional group. For example, the third monomer may include a hydroxyl group. For example, the third monomer may include at least one selected from the group consisting of 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate.

[0149] The content of the third monomer in the first mixture may be 15 to 50 parts by weight based on 100 parts by weight of the total weight of the first to third monomers. When the content of the third monomer satisfies the above-described range, the third polymer may have adhesiveness and may sufficiently disperse the impact modifier in step S500 described below.

[0150] The first initiator can initiate the polymerization of the monomers by absorbing energy from UV light. The first initiator may include an initiator typically used in UV curing. For example, the first initiator may include Irgacure 651.

[0151] UV curing is, for example, 10 mw / cm under nitrogen atmosphere. 2 It can be carried out for several minutes using a lamp having a power of 10 mW / cm2. For example, UV curing is carried out under a nitrogen atmosphere using a lamp having a power of 10 mW / cm2. 2 It can be done for 1 to 5 minutes using a lamp with a century.

[0152] The third polymer may be a copolymer of the first mixture. For example, the third polymer may be a copolymer of the first mixture comprising the first monomer, the second monomer, and the third monomer. For example, the third polymer may comprise an acrylic resin and may be a prepolymer of the first acrylic resin described above. For example, the weight average molecular weight (Mw) of the third polymer may be from 500,000 to 1,500,000.

[0153] For example, the third polymer may be a liquid. For example, the viscosity of the third polymer may be from 1,000 cPs to 10,000 cPs.

[0154]

[0155] The second mixture can be UV-cured to form an elastic pad for an all-solid-state battery (S500). The second mixture can include the impact modifier, the third polymer, the second initiator, and the crosslinking agent.

[0156] The impact modifier and the third polymer may be formed in the S100 step and the S300 step, respectively.

[0157] The content of the impact modifier in the second mixture may be 3 to 15 parts by weight based on 100 parts by weight of the third polymer. For example, the content of the impact modifier in the second mixture may be 10 parts by weight based on 100 parts by weight of the third polymer. When the content of the impact modifier satisfies the above-described range, the elastic pad (EPD) can maintain the internal pressure of the all-solid-state battery during charging and discharging, and can have excellent impact absorption.

[0158] The second initiator can initiate the polymerization of the monomers by absorbing energy from UV light. The second initiator may include an initiator typically used in UV curing.

[0159] Crosslinking agents can link polymer chains together through chemical bonds. Crosslinking agents can include those commonly used in UV curing. For example, crosslinking agents can include 1,6-hexanediol diacrylate.

[0160] UV curing is, for example, 10 mw / cm under nitrogen atmosphere. 2 It can be carried out for several minutes using a lamp having a power of 10 mW / cm2. For example, UV curing is carried out under a nitrogen atmosphere using a lamp having a power of 10 mW / cm2. 2 The process can be carried out for 5 to 30 minutes using a lamp having a century of power. As a result, the third polymer can be cured, and a film-formed first acrylic resin can be produced.

[0161] In this way, an elastic pad (EPD) including a matrix (MTR) and an impact modifier (IMM) can be manufactured. The elastic pad (EPD) can include a first acrylic resin. The first acrylic resin can be a terpolymer of a mixture of a first monomer, a second monomer, and a third monomer. The first acrylic resin can be a solid. The first acrylic resin can be manufactured by UV curing the above-described third polymer.

[0162]

[0163] Hereinafter, the present invention will be described in more detail through examples. However, these examples are intended to exemplify the present invention and the scope of the present invention is not limited to these examples.

[0164]

[0165] Example 1: Manufacturing of an elastic pad

[0166] An elastic pad containing a shock-absorbing agent was manufactured.

[0167] An impact modifier (M210, Kaneka Co., average particle size 220 nm) comprising a core and a shell was prepared (S100). The core contained a butyl acrylate polymer (first polymer), and the shell contained polymethyl methacrylate (second polymer).

[0168] A first mixture comprising 2-ethylhexyl acrylate (EHA, a first monomer), isobornyl acrylate (IBOA, a second monomer), 4-hydrobutylacrylate (HBA, a third monomer), and Igacure 651 (a first initiator) can be UV-cured to form a third polymer (S300). The first mixture contained 25 parts by weight of the first monomer, 25 parts by weight of the second monomer, and 50 parts by weight of the third monomer. The content of Igacure 651 in the first mixture was 1 wt% based on the total weight of the first mixture. The first mixture was cured under a nitrogen atmosphere at a temperature of 10 mw / cm 2 UV was irradiated for 3 minutes using a lamp having a UV intensity of . As a result, a third polymer having a weight average molecular weight (Mw) of 500,000 and a viscosity of 3,000 cps was formed.

[0169] A second mixture containing a third polymer, an impact modifier, Igacure 651 (a second initiator), and 1,6-hexanediol diacrylate (HDDA, a crosslinker) was UV-cured to produce an elastic pad for an all-solid-state battery (S500). The second mixture contained 10 parts by weight of the impact modifier, 0.35 parts by weight of the second initiator, and 1 part by weight of the crosslinker, per 100 parts by weight of the third polymer. The second mixture was cured under a nitrogen atmosphere at a temperature of 10 mw / cm. 2 UV was irradiated for 10 minutes using a lamp having a UV intensity of . Thus, an all-solid-state battery elastic pad including a matrix and an impact modifier was manufactured. The elastic pad had a thickness of 0.2 mm. The matrix included a solid first acrylic resin. The impact modifier was uniformly dispersed within the matrix. The content of the impact modifier within the elastic pad was approximately 9 wt% based on the total weight of the elastic pad.

[0170]

[0171] Example 2

[0172] The second mixture was prepared in the same manner as in Example 1, except that in step S500, the second mixture contained 10 parts by weight of an impact modifier per 100 parts by weight of the third polymer. Thus, the content of the impact modifier in the elastic pad was approximately 5% by weight based on the total weight of the elastic pad.

[0173]

[0174] Comparative Example 1

[0175] The second mixture was prepared in the same manner as in Example 1, except that at step S500, the second mixture did not contain any impact modifier.

[0176]

[0177] Comparative Example 2

[0178] The second mixture was prepared in the same manner as in Example 1, except that in step S500, the second mixture contained 1 part by weight of an impact modifier per 100 parts by weight of the third polymer. Thus, the content of the impact modifier in the elastic pad was approximately 1% by weight based on the total weight of the elastic pad.

[0179]

[0180] Comparative Example 3

[0181] The second mixture was prepared in the same manner as in Example 1, except that in step S500, the second mixture contained 20 parts by weight of an impact modifier per 100 parts by weight of the third polymer. Thus, the content of the impact modifier in the elastic pad was approximately 16% by weight based on the total weight of the elastic pad.

[0182]

[0183] Experimental example: Investigation of elastic pads

[0184] The restoring force and shock absorption rate of elastic pads according to examples and comparative examples were investigated. The restoring force and shock absorption rate were evaluated using the stress-strain curve of the elastic pad. The compressive strength of the elastic pad was 30x30mm. 2 The elastic pads were laminated to a thickness of 10 mm, and the laminated elastic pads were compressed at 10 μm / sec using a universal testing machine (UTM) and measured. The results are shown in Figs. 14 and 15 and Table 1. Fig. 14 shows the results of the elastic pads according to Examples 1 and 2 and Comparative Examples 1, 2, and 3. Fig. 15 shows the results of the elastic pad according to Example 1 among Fig. 14.

[0185] Regarding the stress-strain diagram of the elastic pad, the elastic pad follows the behavior of the return curve when the cell is charged and discharged. The y-axis of the return curve represents the “force that rebounds against compression.” The restoring force was evaluated as the ratio (i.e., slope) of the difference between the first stress and the second stress compared to the difference between the first and second strains. The first strain was defined as having the first stress (stress1), and the second strain was defined as having the second stress (stress2). The first stress (stress1) was defined as the internal pressure (1.5 MPa) when the SOC was approximately 0, and the second stress (stress2) was defined as the internal pressure (4 MPa) when the SOC was 100. The gentler the slope, the better the restoring force of the elastic pad is evaluated to be.

[0186] The pressure at SOC 100 (SOC100) was measured using a surface pressure pad during cell operation. At SOC100 pressure (4 MPa), lithium metal is desorbed and the elastic pad moves 12 μm / sheet. The pressure at SOC 0 (SOC0) was defined as the stress value when the strain was restored by 6% compared to SOC100.

[0187] Shock absorption rate is 30x30mm 2The elastic pad was placed on a Ball Drop measuring device, and a 7g SUS ball was dropped from a height of 20cm from the elastic pad to evaluate the shock absorption rate. The shock absorption rate was expressed as the change in the amount of shock received by the floor after dropping the SUS ball compared to the state before dropping the SUS ball.

[0188] Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Matrix EHA / IBOA / HBA = 25:25:50, Crosslinker: HDDA 1% Content of impact modifier (wt%) 10 50 120 Return curve Strain 1 @ 1.5 MPa 3 7.44 4 1.67 5 4.78 5 3.95 5 2.24 Return curve Strain 2 @ 4 MPa 4 2.17 4 6.00 5 7.47 5 7.42 5 5.06 1.5 - 4 MPa Slope 0.53 4 0.58 3 0.88 5 0.92 8 0.72 1 SOC 0 Pressure 1.24 1.18 0.77 0.91 0.79 Impact absorption rate 5 2.43 5 0.74 4 2.81 43.87 4 3.81

[0189] Referring to FIG. 14, FIG. 15 and Table 1, the elastic pads according to Examples 1 and 2 had superior restoring force and shock absorption rate compared to the elastic pads according to Comparative Examples 1 to 3.

[0190]

[0191] While embodiments of the present invention have been described with reference to the attached drawings, the present invention may be implemented in other specific forms without altering the technical spirit or essential features thereof. Therefore, it should be understood that the embodiments described above are exemplary in all respects and are not limiting.

Claims

1. A matrix comprising at least one of a first acrylic resin or a urethane resin; and Including an impact modifier within the above matrix; The above shock absorber is: a core comprising a first polymer; and a shell comprising a second polymer; The above first polymer is an elastomer, The second polymer is a polymer including at least one selected from the group consisting of polymethacrylate and polystyrene acrylonitrile. Elastic pad for all-solid-state batteries.

2. In paragraph 1, The average particle diameter of the above impact modifier is 100 nm to 500 nm. Elastic pad for all-solid-state batteries.

3. In paragraph 1, The content of the above shock-absorbing agent is 3 wt% to 15 wt% based on the total weight of the elastic pad. Elastic pad for all-solid-state batteries.

4. In paragraph 1, The above elastomer comprises at least one selected from the group consisting of silicone rubber, butadiene rubber and acrylic rubber. Elastic pad for all-solid-state batteries.

5. In paragraph 1, The second polymer comprises polymethyl methacrylate, Elastic pad for all-solid-state batteries.

6. In paragraph 1, The thickness of the above shell is 20 nm to 100 nm, Elastic pad for all-solid-state batteries.

7. In paragraph 1, The thickness is 0.1mm to 3mm, Elastic pad for all-solid-state batteries.

8. Including a plurality of battery cells and at least one elastic pad, The above elastic pad is an elastic pad for an all-solid-state battery as described in claim 1. All-solid-state battery.

9. In paragraph 8, Each of the plurality of battery cells includes at least one of a monocell or a bicell. All-solid-state battery.

10. In paragraph 8, In the stress-strain curve of the above elastic pad, In the first strain diagram, the first stress is present, In the second deformation, there is a second stress, The first stress is the internal pressure when SOC is 0, The second stress is the internal pressure when the SOC is 100. The ratio of the difference between the first stress and the second stress to the difference between the first strain and the second strain is 0.6 or less. All-solid-state battery.

11. In paragraph 8, When the SOC is 0, the internal pressure is 1 MPa to 3 MPa, All-solid-state battery.

12. In paragraph 8, When the SOC is 100, the internal pressure is 3 MPa to 5 MPa, All-solid-state battery.

13. In paragraph 8, The shock absorption rate of the above elastic pad is 50% or more, All-solid-state battery.

14. An impact modifier comprising a core and a shell, wherein the core comprises a first polymer and the shell comprises a second polymer; UV curing a first mixture comprising a first monomer, a second monomer, a third monomer, and a first initiator to form a third polymer; and UV curing a second mixture comprising the above impact modifier, the third polymer, the second initiator and the crosslinking agent; The above first polymer is an elastomer, The second polymer is a polymer including at least one selected from the group consisting of polymethacrylate and polystyrene acrylonitrile, The first monomer is an aliphatic (meth)acrylate having C1 to C20, The above second monomer is an alicyclic (meth)acrylate having a Tg of 50°C or higher, The third monomer is a hydrophilic monomer, Method for manufacturing an elastic pad for an all-solid-state battery.

15. In paragraph 14, The content of the impact modifier in the second mixture is 3 to 15 parts by weight based on 100 parts by weight of the third polymer. Method for manufacturing an elastic pad for an all-solid-state battery.

16. In paragraph 14, The third monomer comprises a hydroxyl group, Method for manufacturing an elastic pad for an all-solid-state battery.

17. In paragraph 14, The third monomer comprises at least one selected from the group consisting of 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Method for manufacturing an elastic pad for an all-solid-state battery.

18. In paragraph 14, The content of the third monomer in the first mixture is 15 to 50 parts by weight based on 100 parts by weight of the total weight of the first to third monomers. Method for manufacturing an elastic pad for an all-solid-state battery.

19. In paragraph 14, The above second polymer is a graft polymerization of the fourth monomer, the fifth monomer, and the sixth monomer, The fourth monomer comprises a (meth)acrylic acid alkyl ester monomer, The fifth monomer comprises an unsaturated nitrile monomer, The sixth monomer comprises an aromatic vinyl monomer, Method for manufacturing an elastic pad for an all-solid-state battery.

20. In paragraph 14, The above third polymer is an acrylic resin, Method for manufacturing an elastic pad for an all-solid-state battery.

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