Device and method for measuring pressure density of powder material for all-solid rechargeable battery

Abstract

Provided is a device and method for measuring the pressure density of a powder material for an all-solid rechargeable battery. The device for measuring the pressure density of a powder material for an all-solid rechargeable battery according to an embodiment comprises: an upper plate; an intermediate plate which is provided below the upper plate, and has a central pressing portion and a flange outside of the pressing portion; a lower plate which ascends and descends below the intermediate plate and presses, against the intermediate plate, a pellet die on which is placed a powder material to be measured for pressure; a first length sensor which is installed on the upper plate and connected to the lower plate, and which measures longitudinal deformation according to pressure and applies the measurement result to a controller; and a second length sensor which is installed on the lower plate and connected to the intermediate plate, and which measures longitudinal deformation according to pressure and applies the measurement result to the controller.

Description

Device and method for measuring the compressed density of powder materials of all-solid-state secondary batteries

[0001] The present disclosure relates to a device and method for measuring the compression density of a powder material of an all-solid-state secondary battery.

[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] Lithium-ion batteries currently on the market use electrolytes containing flammable organic solvents, which poses a risk of overheating and fire in the event of a short circuit. To address this issue, all-solid-state secondary batteries using solid electrolytes are being proposed.

[0004] All-solid-state secondary batteries do not use flammable organic solvents, significantly reducing the risk of fire or explosion even if a short circuit occurs. Therefore, these all-solid-state batteries significantly improve safety compared to lithium-ion batteries that use electrolytes.

[0005] The above-described information disclosed in the background technology of this invention is only intended to improve understanding of the background of the present disclosure and may therefore include information that does not constitute prior art.

[0006] One embodiment provides a device for measuring the compression density of a powder material of an all-solid-state secondary battery, which reflects the deformation of a measuring device when pressurizing the powder material of an all-solid-state secondary battery.

[0007] One embodiment provides a method for measuring the compressed density of a powder material of an all-solid-state secondary battery, which reflects the deformation of a measuring device when pressurizing the powder-type material of the all-solid-state secondary battery.

[0008] According to one embodiment, a device for measuring the compression density of a powder material of an all-solid-state secondary battery includes an upper plate, a middle plate provided below the upper plate and having a central pressing portion and a flange at the outer edge of the pressing portion, a lower plate that operates to rise and fall below the middle plate to press a pellet die on which a pressure measurement target of the powder material is placed against the middle plate, a first length sensor installed on the upper plate and connected to the lower plate to measure a length deformation according to pressure and to apply the measurement to a control unit, and a second length sensor installed on the lower plate and connected to the middle plate to measure a length deformation according to pressure and to apply the measurement to the control unit.

[0009] It further includes a cylinder for pressurizing the upper plate and the lower plate, and the cylinder can be connected to a center of gravity of at least one side of the upper plate and the lower plate.

[0010] The first length sensors are provided in plurality and are respectively arranged corresponding to the vertex positions of an equilateral triangle forming the centers of gravity of the upper plate and the lower plate, and the second length sensors are provided in plurality and form the centers of gravity of the flange of the middle plate and the lower plate, and can be respectively arranged corresponding to the inside of the vertex positions so that the second center of gravity coincides with the first center of gravity.

[0011] The pellet die is deformed by the pressure of the upper plate and the lower plate, and the control unit calculates an overall average value using the first average value of the first length sensor and the second average value of the second length sensor, and can use the overall average value as a pressure compensation value of the pellet die.

[0012] The above powder material can be formed into one of an aerogel powder, a block, and a sheet.

[0013] According to one embodiment, a device for measuring the compression density of a powder material of an all-solid-state secondary battery includes an upper plate, a lower plate that operates to elevate below the upper plate to press a pellet die on which a pressure measurement target of the powder material is placed against the upper plate, and a length sensor that is installed on the upper plate and connected to the lower plate to measure a length deformation according to pressure and apply the measured length to a control unit.

[0014] It further includes a cylinder for pressing the upper plate and the lower plate, and the cylinder can be connected to the center of gravity of at least one side of the upper plate and the lower plate.

[0015] The above first length sensors may be provided in multiple numbers and arranged to correspond to the vertex positions of an equilateral triangle forming the centers of gravity of the upper and lower plates.

[0016] The pressure measurement object is deformed by the pressure of the upper plate and the lower plate, and the control unit can use the average value of the length sensor as a pressure correction value of the pressure measurement object.

[0017] A method for measuring the compression density of a powder material of an all-solid-state secondary battery according to one embodiment includes a first step of pressing a pellet die having a pressure measurement target of a powder material placed on a lower plate that moves up and down below an intermediate plate, a 21st step of measuring a first length deformation according to pressure by a first length sensor installed on an upper plate and connected to the lower plate, and a 22nd step of measuring a second length deformation according to pressure by a second length sensor installed on the lower plate and connected to the intermediate plate; and a third step of using a control unit that receives measurement value signals of the first and second length sensors to utilize the measurement values ​​as pressure correction values ​​of the pellet die.

[0018] The above first step can pressurize a pressure measurement object formed of one of aerogel powder, a block, and a sheet using the above powder material.

[0019] The third step calculates a first average value measured by the first length sensor, calculates a second average value measured by the second length sensor, calculates an overall average value using the first average value and the second average value, and can utilize the overall average value as the pressure correction value.

[0020] A method for measuring the compression density of a powder material of an all-solid-state secondary battery according to one embodiment includes a first step of pressing a pellet die having a pressure measurement target of a powder material placed on a lower plate that moves up and down below an upper plate, to the upper plate, a second step of measuring a length deformation according to pressure by a length sensor installed on the upper plate and connected to the lower plate, and a third step of using a control unit that receives a measurement value signal of the length sensor as a pressure correction value of the pellet die.

[0021] The third step above calculates an average value measured by the length sensor, and can use the average value as a pressure correction value of the pressure measurement object.

[0022] One embodiment measures the compression density of a powder material by pressurizing a pellet die in which a measurement object is placed between an upper plate and a lower plate, and measures the length deformation according to the pressure change with a length sensor connected to the upper plate and the lower plate, so that deformation of the pellet die can be taken into account.

[0023] Therefore, one embodiment can accurately measure density changes according to applied pressure using only small amounts (e.g., 0.5 g) of powder material. For example, using a pellet die with a diameter of 13 mm, the compressed density of a powder material can be measured in real time at a resolution of 0.1 μm at pressures of up to 400 MPa, and the data can be stored in the control unit.

[0024] Figure 1 is a cross-sectional view showing an all-solid-state secondary battery according to one embodiment of the present invention.

[0025] FIG. 2 is a cross-sectional view showing the formation of a lithium metal layer of an all-solid-state secondary battery according to one embodiment.

[0026] Figure 3 is a plan view of a device for measuring the compression density of a powder material of an all-solid-state secondary battery according to the first embodiment of the present invention.

[0027] Figure 4 is a front view of a pellet die compressed on the press plate of Figure 3.

[0028] Figure 5 is a front view of Figure 3.

[0029] Figure 6 is a front view of the pressing plate before compressing the pellet die without deformation.

[0030] Figure 7 is a front view of the pressing plate deformed by compressing the pellet die.

[0031] Figure 8 is a graph showing the relationship between pressure and displacement.

[0032] Figure 9 is a flowchart of a method for measuring the compression density of a powder material of an all-solid-state secondary battery according to a first embodiment of the present invention.

[0033] Figure 10 is a graph showing the relationship between pressure and density measured using the compression density measurement method of the comparative example and the first embodiment.

[0034] Fig. 11 is a plan view of a device for measuring the compression density of a powder material of an all-solid-state secondary battery according to a second embodiment of the present invention.

[0035] Figure 12 is a front view of Figure 11.

[0036] Figure 13 is a flowchart of a method for measuring the compression density of a powder material of an all-solid-state secondary battery according to a second embodiment of the present invention.

[0037] Figure 14 is a graph showing the compression density of a cathode measured using an embodiment of the device and method according to the present invention.

[0038] Figure 15 is a graph showing the compression density of an aerogel powder measured using an apparatus and method according to an embodiment of the present invention.

[0039] Figure 16 is a graph showing the compression density of a solid electrolyte measured using an embodiment of the device and method according to the present invention.

[0040] Figure 17 is a graph showing the compression density of a positive electrode measured using an embodiment of the device and method according to the present invention.

[0041] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. The present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0042] Additionally, throughout the specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0043] To clearly illustrate various layers and regions in the drawings, their thicknesses are enlarged, and similar parts are designated by the same drawing reference numerals throughout the specification. When an element such as a layer, film, region, or plate is said to be "over" or "on" another element, this includes not only the case where it is "directly over" the other element, but also the case where there is another element in between. Conversely, when an element is said to be "directly over" another element, it means that there is no other element in between.

[0044] Furthermore, the term "layer" here includes not only shapes formed on the entire surface when observed in a plan view, but also shapes formed on a portion of the surface. Here, "or" is not interpreted in an exclusive sense; for example, "A or B" is interpreted to include A, B, A+B, etc.

[0045] Cathode for all-solid-state secondary batteries

[0046] In one embodiment, a positive electrode for an all-solid-state secondary battery is provided, comprising a current collector and a positive electrode active material layer positioned on the current collector, wherein the positive electrode active material layer comprises at least one of a positive electrode active material, a sulfide-based solid electrolyte, a binder, and a conductive material. However, without limitation thereto, the positive electrode for an all-solid-state secondary battery may comprise more or less components than the components described above.

[0047] In one embodiment, the positive electrode for the all-solid-state secondary battery is manufactured by applying a positive electrode composition including at least one of a positive electrode active material, a sulfide-based solid electrolyte, a binder, and a conductive agent to a current collector, followed by drying and rolling.

[0048] positive electrode active material

[0049] The above-mentioned positive electrode active material can be applied without limitation as long as it is generally used in all-solid-state secondary batteries. For example, the above-mentioned positive electrode active material may be a compound capable of reversible intercalation and deintercalation of lithium, and may include a compound represented by any one of the following chemical formulas.

[0050] Li a A 1-b X b D2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5);

[0051] 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);

[0052] Li a E 1-b X b O 2-c D c (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05);

[0053] Li a HAVE BEEN 2-b X b O 4-c D c (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05);

[0054] Li a Ni 1-b-c Co b X c D α (0.90 ≤ a ≤1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.5, 0 <α ≤ 2);

[0055] Li a Ni 1-b-c Co b X c O 2-α T α (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2);

[0056] Li a Ni 1-b-c Co b X c O 2-α T2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2);

[0057] Li a Ni 1-b-c Mr b X c D α (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α ≤ 2);

[0058] Li a Ni 1-b-c Mr b X c O 2-α T α (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2);

[0059] Li a Ni 1-b-c Mr b X cO 2-α T2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 <α < 2);

[0060] The a Nor b E c G d O2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0.001 ≤ d ≤ 0.1);

[0061] The a Nor b Co c Mn d G e O2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤0.5, 0.001 ≤ e ≤ 0.1);

[0062] The a NiG b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0063] The a CoG b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0064] The a Mn 1-b G b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0065] The a Mn2G b O4(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0066] The a Mn 1-g G g PO4(0.90 ≤ a ≤ 1.8, 0 ≤ g ≤ 0.5);

[0067] QO2; QS2; LiQS2;

[0068] V2O5; LiV2O5;

[0069] LiZO2;

[0070] LiNiVO4;

[0071] Li (3-f) J2(PO4)3(0 ≤ f ≤ 2);

[0072] Li (3-f) Fe2(PO4)3(0 ≤ f ≤ 2);

[0073] Li a FePO4(0.90 ≤ a ≤ 1.8).

[0074] In the above chemical formulas, A is selected from the group consisting of Ni, Co, Mn, and combinations thereof; X is selected from the group consisting of Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements, and combinations thereof; D is selected from the group consisting of O, F, S, P, and combinations thereof; E is selected from the group consisting of Co, Mn, and combinations thereof; T is selected from the group consisting of F, S, P, and combinations thereof; G is selected from the group consisting of Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, and combinations thereof; Q is selected from the group consisting of Ti, Mo, Mn, and combinations thereof; Z is selected from the group consisting of Cr, V, Fe, Sc, Y, and combinations thereof; J is selected from the group consisting of V, Cr, Mn, Co, Ni, Cu, and combinations thereof.

[0075] The above-mentioned positive electrode active material may be, for example, lithium cobalt oxide (LCO), lithium nickel oxide (LNO), lithium nickel cobalt oxide (NC), lithium nickel cobalt aluminum oxide (NCA), lithium nickel cobalt manganese oxide (NCM), lithium nickel manganese oxide (NM), lithium manganese oxide (LMO), or lithium iron phosphate (LFP).

[0076] The above positive electrode active material may include a lithium nickel-based oxide represented by the following chemical formula 1, a lithium cobalt-based oxide represented by the following chemical formula 2, a lithium iron phosphate-based compound represented by the following chemical formula 3, or a combination thereof.

[0077] [Chemical Formula 1]

[0078] Li a1 Ni x1 M 1 y1 M 2 1-x1-y1 O2

[0079] In the above chemical formula 1, 0.9≤a1≤1.8, 0.3≤x1≤1, 0≤y1≤0.7, and M 1 and M 2 is one or more elements independently selected from the group consisting of Al, B, Ba, Ca, Ce, Co, Cr, Cu, F, Fe, Mg, Mn, Mo, Nb, P, S, Si, Sr, Ti, V, W, and Zr.

[0080] [Chemical Formula 2]

[0081] Li a2 Co x2 M 3 1-x2 O2

[0082] In the above chemical formula 2, 0.9≤a2≤1.8, 0.6≤x2≤1, and M 3 is one or more elements selected from the group consisting of Al, B, Ba, Ca, Ce, Cr, Cu, F, Fe, Mg, Mn, Mo, Nb, P, S, Si, Sr, Ti, V, W, and Zr.

[0083] [Chemical Formula 3]

[0084] Li a3 Fe x3 M 4 (1-x3) PO4

[0085] In the above chemical formula 3, 0.9≤a3≤1.8, 0.6≤x3≤1, and M 4is one or more elements selected from the group consisting of Al, B, Ba, Ca, Ce, Co, Cr, Cu, F, Fe, Mg, Mn, Mo, Nb, P, S, Si, Sr, Ti, V, W, and Zr.

[0086] 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, 5 μm to 25 μm, 5 μm to 20 μm, 8 μm to 20 μm, or 10 μm to 18 μm. A positive electrode active material having such a particle diameter range can be harmoniously mixed with other components within the positive electrode active material layer and can realize high capacity and high energy density.

[0087] 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.

[0088] Sulfide-based solid electrolyte

[0089] 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.

[0090] Such sulfide-based solid electrolytes 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. Here, the ionic conductivity can be further improved by further including other components such as SiS2, GeS2, and B2S3.

[0091] Methods for mixing sulfur-containing raw materials for producing sulfide-based solid electrolytes include mechanical milling or the solution method. Mechanical milling involves placing the starting raw materials in a reactor and vigorously stirring them with a ball mill or similar device to finely atomize and mix them. Using the solution method, the starting 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.

[0092] For example, the sulfide-based solid electrolyte particles may include argyrodite-type sulfides. The argyrodite-type sulfides may include, for example, Li a M b P c S d A e (wherein a, b, c, d and e are all 0 or more and 12 or less, M is a metal other than Li or a combination of multiple metals other than Li, and A is F, Cl, Br, or I) and a specific example is Li 7-x PS6-x A x (x is 0.2 or more and 1.8 or less, and A is F, Cl, Br, or I) can be expressed by the chemical formula. The above argyrodite-type sulfide is specifically Li3PS4, Li7P3S 11 , Li7PS6, Li6PS5Cl, Li6PS5Br, Li 5.8 PS 4.8 Cl 1.2 , Li 6.2 PS 5.2 Br 0.8 It could be the back.

[0093] Sulfide-based solid electrolyte particles containing these argyrodite-type sulfides 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 can further form a close interface between an electrode layer and a solid electrolyte layer. An all-solid-state battery including this can have improved battery performance, such as rate characteristics, Coulombic efficiency, and cycle life characteristics.

[0094] An argyrodite-type sulfide-based solid electrolyte can be prepared, for example, by mixing lithium sulfide, phosphorus sulfide, and optionally, a lithium halide. After mixing, a heat treatment may be performed. The heat treatment may include, for example, two or more heat treatment steps.

[0095] According to one embodiment, the average particle diameter (D50) of the sulfide-based solid electrolyte particles may be 5.0 ㎛ or less, for example, 0.1 ㎛ to 5.0 ㎛, 0.1 ㎛ to 4.0 ㎛, 0.1 ㎛ to 3.0 ㎛, 0.5 ㎛ to 2.0 ㎛, or 0.1 ㎛ to 1.5 ㎛. Alternatively, the sulfide-based solid electrolyte particles may be small particles having an average particle diameter (D50) of 0.1 ㎛ to 1.0 ㎛, or may be large particles having an average particle diameter (D50) of 1.5 ㎛ to 5.0 ㎛, depending on the location or purpose of use. The sulfide-based solid electrolyte particles having such a particle diameter range can effectively penetrate between solid particles in a battery, and have excellent contact with an electrode active material and connectivity between solid electrolyte particles. The average particle size of the sulfide-based solid electrolyte particles may be measured from a microscope image, for example, by measuring the sizes of about 20 particles in a scanning electron microscope image to obtain a particle size distribution and calculating D50 from this.

[0096] The content of the solid electrolyte in the positive electrode for the all-solid-state battery may be 0.5 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%. This is the content relative to the total weight of components in the positive electrode, and specifically, it can be said to be the content relative to the total weight of the positive electrode active material layer.

[0097] In one embodiment, the positive electrode active material layer may include 50 wt% to 99.35 wt% of the positive electrode active material, 0.5 wt% to 35 wt% of the sulfide-based solid electrolyte, 0.1 wt% to 10 wt% of the fluorine-based resin binder, and 0.05 wt% to 5 wt% of the vanadium oxide, based on 100 wt% of the positive electrode active material layer. When this content range is satisfied, the positive electrode for an all-solid-state secondary battery can implement high capacity and high ionic conductivity while maintaining high adhesiveness, and the viscosity of the positive electrode composition can be maintained at an appropriate level, thereby improving processability.

[0098] bookbinder

[0099] The 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, and representative examples thereof 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, acrylated styrene-butadiene rubber, epoxy resin, nylon, etc.

[0100] Challenge

[0101] The above-described positive electrode active material layer may further include a conductive material. The conductive material is used to impart conductivity to the electrode, and may include, for example, carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, and carbon nanotubes; metal-based materials containing copper, nickel, aluminum, silver, and the like in the form of metal powder or metal fibers; conductive polymers such as polyphenylene derivatives; or combinations thereof.

[0102] The conductive material may be included in an amount of 0.1 wt% to 5 wt%, or 0.1 wt% to 3 wt%, based on the total weight of each component of the positive electrode for the all-solid-state battery, or based on the total weight of the positive electrode active material layer. Within the above content range, the conductive material can improve electrical conductivity without degrading battery performance.

[0103] When the positive electrode active material layer further includes a conductive material, the positive electrode active material layer may include 45 wt% to 99.25 wt% of the positive electrode active material, 0.5 wt% to 35 wt% of the sulfide-based solid electrolyte, 0.1 wt% to 10 wt% of the fluorine-based resin binder, 0.05 wt% to 5 wt% of the vanadium oxide, and 0.1 wt% to 5 wt% of the conductive material, based on 100 wt% of the positive electrode active material layer.

[0104] Meanwhile, the positive electrode for the lithium secondary battery may further include an oxide-based inorganic solid electrolyte in addition to the above-described solid electrolyte. The oxide-based inorganic solid electrolyte may be, 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 Si y 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 a combination thereof.

[0105] All-solid-state secondary battery

[0106] In one embodiment, an all-solid-state secondary battery is provided, which includes the aforementioned positive electrode and negative electrode and a solid electrolyte layer positioned between the positive electrode and negative electrode. The all-solid-state secondary battery may also be referred to as an all-solid-state battery or an all-solid-state lithium secondary battery.

[0107] Fig. 1 is a cross-sectional view of an all-solid-state secondary battery according to one embodiment. Referring to Fig. 1, the all-solid-state secondary 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 secondary 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. 1 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.

[0108] cathode

[0109] An anode for an all-solid-state battery may include, for example, a current collector and a layer of anode active material positioned on the current collector. The layer of anode active material includes a cathode active material and may further include a binder, a conductive material, and / or a solid electrolyte.

[0110] The above negative active material may include 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.

[0111] 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.

[0112] As the above lithium metal alloy, an alloy of lithium and one or more metals 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.

[0113] 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 can be used, and the Si-based negative electrode active material may be silicon, a silicon-carbon composite, or SiO. x(0<x<2), Si-Q 합금(상기 Q는 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소, 15족 원소, 16족 원소, 전이금속, 희토류 원소 및 이들의 조합으로 이루어진 군에서 선택되는 원소이며, Si은 아님), 상기 Sn계 음극 활물질로는 Sn, SnO2, Sn-R 합금(상기 R은 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소, 15족 원소, 16족 원소, 전이금속, 희토류 원소 및 이들의 조합으로 이루어진 군에서 선택되는 원소이며, Sn은 아님) 등을 들 수 있고, 또한 이들 중 적어도 하나와 SiO2를 혼합하여 사용할 수도 있다. 상기 원소 Q 및 R로는 Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Tl, Ge, P, As, Sb, Bi, S, Se, Te, Po, 및 이들의 조합으로 이루어진 군에서 선택되는 것을 사용할 수 있다.

[0114] The silicon-carbon composite may be, for example, a silicon-carbon composite including a core comprising crystalline carbon and silicon particles and an amorphous carbon coating layer positioned on the surface of the core. The crystalline carbon may be artificial graphite, natural graphite, or a combination thereof. As the amorphous carbon precursor, coal pitch, mesophase pitch, petroleum pitch, coal oil, petroleum heavy oil, or a polymer resin such as a phenol resin, a furan resin, or a polyimide resin may be used. At this time, the content of silicon may be 10 wt% to 50 wt% with respect to the total weight of the silicon-carbon composite. In addition, the content of the crystalline carbon may be 10 wt% to 70 wt% with respect to the total weight of the silicon-carbon composite, and the content of the amorphous carbon may be 20 wt% to 40 wt% with respect to the total weight of the silicon-carbon composite. In addition, the thickness of the amorphous carbon coating layer may be 5 nm to 100 nm.

[0115] The average particle diameter (D50) of the above silicon particles may be 10 nm to 20 μm, for example, 10 nm to 500 nm. The silicon particles may exist in an oxidized form, and at this time, the atomic content ratio of Si:O in the silicon particles, which indicates the degree of oxidation, may be 99:1 to 33:67. The silicon particles may be SiO x It can be a particle, in which case SiO x In the range of x, it can be greater than 0 and less than 2. Here, the average particle diameter (D50) is measured by a particle size analyzer using laser diffraction and means the diameter of particles having a cumulative volume of 50% by volume in the particle size distribution.

[0116] The above Si-based negative electrode active material or Sn-based negative electrode active material can be used in combination with a carbon-based negative electrode active material. The mixing ratio of the Si-based negative electrode active material or Sn-based negative electrode active material and the carbon-based negative electrode active material can be 1:99 to 90:10 by weight.

[0117] The content of the negative active material in the above negative active material layer may be 95 wt% to 99 wt% with respect to the total weight of the negative active material layer.

[0118] In one embodiment, the negative electrode active material layer further includes a binder and may optionally further include a conductive material. The content of the binder in the negative electrode active material layer may be 1 wt% to 5 wt% based on the total weight of the negative electrode active material layer. In addition, when the negative electrode active material layer further includes a conductive material, the negative electrode active material layer may include 90 wt% to 98 wt% of the negative electrode active material, 1 wt% to 5 wt% of the binder, and 1 wt% to 5 wt% of the conductive material.

[0119] The above binder serves to adhere the negative active material particles well to each other and also to adhere the negative active material well to the current collector. The binder may include an insoluble binder, a water-soluble binder, or a combination thereof.

[0120] The above-described non-aqueous binder may include, for example, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, a polymer comprising ethylene oxide, an ethylene propylene copolymer, polystyrene, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, or a combination thereof.

[0121] The water-soluble binder may be a rubber-based binder or a polymer resin binder. The rubber-based binder may be selected from styrene-butadiene rubber, acrylated styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylic rubber, butyl rubber, fluororubber, and combinations thereof. The polymer resin binder may be selected from polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, polyacrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0122] When a water-soluble binder is used as the negative electrode binder, a thickener capable of imparting viscosity may be used together, and the thickener may include, for example, a cellulose-based compound. The cellulose-based compound may include carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, an alkali metal salt thereof, or a combination thereof. Na, K, or Li may be used as the alkali metal. The amount of the thickener used may be 0.1 to 3 parts by weight based on 100 parts by weight of the negative electrode active material.

[0123] The conductive material is used to provide conductivity to the electrode, and may include, for example, carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, 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.

[0124] 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.

[0125] As another example, the negative electrode for the all-solid-state battery may be a precipitation-type negative electrode. The precipitation-type negative electrode refers to a negative electrode that does not include 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.

[0126] FIG. 2 is a schematic cross-sectional view of an all-solid-state secondary battery including a precipitation-type negative electrode according to one embodiment. Referring to FIG. 2, 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.

[0127] The above cathode coating layer (405) may include a metal, a carbon material, or a combination thereof that acts as a catalyst.

[0128] 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 type of these or may be composed of an alloy of several types. When the metal is present in the form of particles, the average particle diameter (D50) thereof may be about 4 μm or less, for example, 10 nm to 4 μm.

[0129] The carbon material may be, for example, crystalline carbon, amorphous carbon, or a combination thereof. The crystalline carbon may be, for example, natural graphite, artificial graphite, mesophase carbon microbeads, or a combination thereof. The amorphous carbon may be, for example, carbon black, activated carbon, acetylene black, Denka black, Ketjen black, or a combination thereof.

[0130] 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 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.

[0131] The above cathode coating layer (405) may include, for example, the metal and amorphous carbon, in which case it can effectively promote the precipitation of lithium metal.

[0132] The above cathode coating layer (405) may further include a binder, and the binder may be a conductive binder. In addition, the above cathode coating layer (405) may further include general additives such as fillers, dispersants, and ionic conductive agents.

[0133] The thickness of the cathode coating layer (405) may be, for example, 100 nm to 20 ㎛, or 500 nm to 10 ㎛, or 1 ㎛ to 5 ㎛.

[0134] 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 500 nm.

[0135] solid electrolyte layer

[0136] The solid electrolyte layer (300) may include a sulfide-based solid electrolyte, an oxide-based solid electrolyte, etc. The specific details of the sulfide-based solid electrolyte and the oxide-based solid electrolyte are as described above.

[0137] In one example, the solid electrolyte included in the positive electrode (200) and the solid electrolyte included in the solid electrolyte layer (300) may include the same compound or different compounds. For example, when both the positive electrode (200) and the solid electrolyte layer (300) include an argyrodite-type sulfide-based solid electrolyte, the overall performance of the all-solid-state secondary battery may be improved. In addition, for example, when both the positive electrode (200) and the solid electrolyte layer (300) include the above-described coated solid electrolyte, the all-solid-state secondary battery may implement high capacity and high energy density while implementing excellent initial efficiency and lifespan characteristics.

[0138] Meanwhile, the average particle diameter (D50) of the solid electrolyte included in the positive electrode (200) may be smaller than the average particle diameter (D50) of the solid electrolyte included in the solid electrolyte layer (300). In this case, the energy density of the all-solid-state battery can be maximized while increasing the mobility of lithium ions, thereby improving the overall performance. For example, the average particle diameter (D50) of the solid electrolyte included in the positive electrode (200) may be 0.1 ㎛ to 1.0 ㎛, or 0.1 ㎛ to 0.8 ㎛, and the average particle diameter (D50) of the solid electrolyte included in the solid electrolyte layer (300) may be 1.5 ㎛ to 5.0 ㎛, or 2.0 ㎛ to 4.0 ㎛, or 2.5 ㎛ to 3.5 ㎛. When this particle size range is satisfied, the energy density of the all-solid-state secondary battery can be maximized while lithium ion transport is facilitated, resistance is suppressed, and the overall performance of the all-solid-state secondary battery can be improved. Here, the average particle diameter (D50) of the solid electrolyte can be measured using a particle size analyzer using laser diffraction. Alternatively, the particle size can be measured by selecting 20 or so random particles from a microscope image such as a scanning electron microscope, obtaining a particle size distribution, and calculating the D50 value from this.

[0139] The above solid electrolyte layer may further include a binder in addition to the solid electrolyte. At this time, the binder may be styrene butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, an acrylate polymer, or a combination thereof, but is not limited thereto, and any binder used in the relevant technical field may be used. The acrylate polymer may be, for example, butyl acrylate, polyacrylate, polymethacrylate, or a combination thereof.

[0140] The above solid electrolyte layer can be formed by adding a solid electrolyte to a binder solution, coating the same on a base film, and drying the same. The solvent of the binder solution may be isobutyryl isobutyrate, xylene, toluene, benzene, hexane, or a combination thereof. Since the solid electrolyte layer formation process is widely known in the art, a detailed description thereof will be omitted.

[0141] The thickness of the solid electrolyte layer may be, for example, 10 ㎛ to 150 ㎛.

[0142] The above solid electrolyte layer may further include an alkali metal salt, and / or an ionic liquid, and / or a conductive polymer.

[0143] 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.

[0144] The above lithium salts include, for example, LiSCN, LiN(CN)2, Li(CF3SO2)3C, LiC4F9SO3, LiN(SO2CF2CF3)2, LiCl, LiF, LiBr, LiI, LiB(C2O4)2, LiBF4, LiBF3(C2F5), lithium bis(oxalato)borate (LiBOB), lithium oxalyldifluoroborate (LIODFB), lithium difluoro(oxalato)borate (LiDFOB), lithium bis(trifluoro methanesulfonyl)imide (LiTFSI, LiN(SO2CF3)2), lithium bis(fluorosulfonyl)imide (LiFSI, It may include LiN(SO2F)2), LiCF3SO3, LiAsF6, LiSbF6, LiClO4 or mixtures thereof.

[0145] In addition, the lithium salt may be an imide-based one, and for example, the imide-based lithium salt may include lithium bis(trifluoro methanesulfonyl)imide (LiTFSI, LiN(SO2CF3)2), lithium bis(fluorosulfonyl)imide (LiFSI, LiN(SO2F)2). The lithium salt may maintain or improve ionic conductivity by appropriately maintaining chemical reactivity with an ionic liquid.

[0146] The above ionic liquid has a melting point below room temperature and is a salt or room-temperature molten salt that is liquid at room temperature and consists only of ions.

[0147] The above ionic liquid may be a compound including a) one or more cations selected from ammonium-based, pyrrolidinium-based, pyridinium-based, pyrimidinium-based, imidazolium-based, piperidinium-based, pyrazolium-based, oxazolium-based, pyridazinium-based, phosphonium-based, sulfonium-based, triazolium-based, and mixtures thereof, and b) one or more anions selected from 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-.

[0148] 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.

[0149] In the above solid electrolyte layer, the weight ratio of the solid electrolyte and 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 battery can be improved.

[0150] 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.

[0151] 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 large-scale 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 used in fields requiring large amounts of power storage, and for example, it can be used in electric bicycles or power tools.

[0152] A limitation of current compressive property evaluation methods is that pressure application and measurement are separated, making accurate measurement difficult. One embodiment of the device enables simultaneous pressure application and measurement. When high pressure (e.g., below 500 MPa) is applied, the pellet die containing the sample deforms.

[0153] One embodiment enables accurate measurements by reflecting deformation of the pellet die. The device of one embodiment enables pressure application and measurement of samples of various shapes, including powder, plates, and cylinders, and enables precise measurements with a resolution of 0.1 μm while applying a compressive load of up to 5 tons.

[0154] The device of one embodiment can store measurement data in real time in the control unit. Purchasing equipment with similar functionality to that of the embodiment would require significantly more money than the actual development cost. This will be explained in detail below.

[0155] A device for measuring the compression density of a powder material of an all-solid-state secondary battery according to one embodiment enables accurate measurement of the physical properties of a product composed of a powder-type material, such as an all-solid-state secondary battery.

[0156] FIG. 3 is a plan view of a device for measuring the compression density of a powder material of an all-solid-state secondary battery according to a first embodiment of the present invention, FIG. 4 is a front view of a pellet die compressed on a pressing plate of FIG. 3, and FIG. 5 is a front view of FIG. 3.

[0157] Referring to FIGS. 3 to 5, the compression density measuring device (1) of the first embodiment includes an upper plate (10), a lower plate (20), a middle plate (30), a first length sensor (40), and a second length sensor (50).

[0158] The upper plate (10) forms the upper part on which the measurement object (71) is placed in the compression density measuring device (1). The lower plate (20) forms the lower part on which the measurement object (71) is placed in the compression density measuring device (1).

[0159] A cylinder (60) for pressurizing a measurement object (71) may be installed on at least one side of the upper plate (10) and the lower plate (20). The first embodiment exemplifies that the cylinder (60) is installed on each of the upper plate (10) and the lower plate (20).

[0160] And the cylinder (60) is connected to the first center of gravity of the upper and lower plates (10, 20). Therefore, the pressing force of the cylinder (60) is stably applied to the upper and lower plates (10, 20), and the measurement object (71) and the pellet die (70) on which the measurement object (71) is installed are stably applied.

[0161] The middle plate (30) is provided below the upper plate (10) and has a central pressing portion (31) and a flange (32) on the outer side of the pressing portion (31). The middle plate (30) applies a downward compressive force to the measurement object (71) and the pellet die (70) by the pressing force of the upper plate (10).

[0162] The lower plate (20) is positioned below the middle plate (30) and moves up and down below the middle plate (30) to pressurize a pellet die (70) on which a pressure measurement object (71) made of powder material is placed, against the middle plate (30). The powder material may be formed as an aerogel powder or a block. By the compression operation of the cylinder (60), the pellet die (70) installed between the middle plate (30) and the lower plate (20) and the pressure measurement object (71) placed thereon are pressurized.

[0163] The first length sensor (40) is installed on the upper plate (10) and connected to the lower plate (20). Accordingly, when pressure is applied between the upper plate (10) and the lower plate (20) in response to the pressure of the cylinder (60), the first length sensor (40) causes a length deformation according to the pressure, measures the length deformation, and applies it to a control unit (not shown). The control unit may include a computer and a storage device for storing data.

[0164] Fig. 8 is a graph illustrating the relationship between pressure and displacement. Referring to Figs. 3, 5, and 8, in a balanced pressurized state of the upper plate (10) and the lower plate (20), the first length sensor (40) is provided in multiples, i.e., three, so as to accurately measure the length deformation according to pressure.

[0165] The three first length sensors (40) are respectively arranged at the vertex positions of an equilateral triangle forming the first center of gravity of the upper plate (10) and the lower plate (20), and measure the length deformation at each position. That is, the arrangement of the three first length sensors (40) is such that each measurement point is at the first center of gravity. The control unit calculates the first average value (AV1) using the measurement values ​​of the three first length sensors (40).

[0166] Figure 6 is a front view of the pressing plate before compressing the pellet die without deformation, and Figure 7 is a front view of the pressing plate after compressing the pellet die and with deformation.

[0167] Referring to FIGS. 5 to 7, the second length sensor (50) is installed on the lower plate (20) and connected to the middle plate (30). Accordingly, when pressure (P) is applied between the middle plate (30) and the lower plate (20) in response to the pressure of the cylinder (6), the second length sensor (50) causes a length deformation according to the pressure, measures the length deformation, and applies it to the control unit.

[0168] In order for the pressing force of the cylinder (60) to be applied to the pellet die (70) in a balanced manner without being biased to one side, the middle plate (30) is formed in a circular shape with a flange portion (32) disposed on the inside of the three first length sensors (40). That is, the second centers of gravity of the lower plate (20) and the middle plate (30) are aligned with the first centers of gravity of the upper plate (10) and the lower plate (20) and are disposed on the same center line.

[0169] Referring to FIGS. 3, 5 and 8, in a state of balanced pressurization of the upper plate (10) and the lower plate (20) and simultaneously in a state of balanced pressurization of the middle plate (30) and the lower plate (20), the second length sensors (50) are provided in multiples, i.e., three, so that they can accurately measure the length deformation according to the pressure.

[0170] Three second length sensors (50) are respectively arranged in correspondence with the inner side of the vertex position so as to form a second center of gravity of the flange (32) of the lower plate (20) and the middle plate (30), and measure the length deformation at each position. The arrangement of the three second length sensors (50) is such that the measurement point is at the second center of gravity. The control unit calculates a second average value (AV2) using the measurement values ​​of the three second length sensors (50).

[0171] At this time, the flange (32) of the middle plate (30) is bent by the pressure applied through the second length sensor (50), and the second length sensor (50) measures the deformation amount of the flange (32) as the length is deformed. The amount of bending of the flange (32) is a part that must be corrected.

[0172] In addition, the control unit calculates an overall average value (AV) using the first average value (AV1) of the first length sensor (40) measured from the center of gravity and the second average value (AV2) of the second length sensor (50), and utilizes the overall average value (AV) as a pressure correction value of the pellet die (70). That is, by utilizing the pressure correction value of the pellet die (70), it is possible to calculate the deformation amount of only the pressure measurement target (71) of the powder material.

[0173] Figure 9 is a flowchart of a method for measuring the compressed density of a powder material of an all-solid-state secondary battery according to a first embodiment of the present invention. Referring to Figures 3, 5, and 9, the method for measuring the compressed density of the first embodiment includes a first step (ST1), a second step (ST2), and a third step (ST3). The second step (ST2) further includes a twenty-first step (ST21) and a twenty-second step (ST22).

[0174] In the first stage (ST1), a pellet die (70) having a pressure measurement target (71) made of powder material placed on a lower plate (20) that operates upwardly below the middle plate (30) is pressed against the middle plate (30). That is, in the first stage (ST1), the cylinder (60) is operated to raise the lower plate (20), thereby pressing the pellet die (70) against the middle plate (30).

[0175] In the second step (ST2), the twenty-first step (ST21) measures the first length deformation according to pressure by the first length sensor (40) installed on the upper plate (10) and connected to the lower plate (20). In the twenty-second step (ST22), the second length sensor (50) installed on the lower plate (20) and connected to the middle plate (30) measures the second length deformation according to pressure.

[0176] In the third step (ST3), the control unit, which has received the measurement value signals from the first length sensor (40) and the second length sensor (50), utilizes the measurement values ​​as pressure compensation values ​​of the pellet die (70). That is, the third step (ST3) calculates the first average value measured by the first length sensor (40), calculates the second average value measured by the second length sensor (50), calculates the overall average value using the first average value and the second average value, and utilizes the overall average value as the pressure compensation value of the pellet die (70).

[0177] Fig. 10 is a graph showing the relationship between pressure and density measured by the compression density measurement method of the comparative example and the first embodiment. Referring to Fig. 10, the relationship between the density (G / CC) and pressure (MPA) of the fillet die (70) for argyrodite, which is a pressure measurement target (71) of a powder material, is shown for the comparative example and the first embodiment.

[0178] Since the first embodiment (L1) utilizes the measurement values ​​of the first length sensor (40) and the second length sensor (50) as the pressure compensation value of the pellet die (70), the density (G / CC) of the fillet die (70) appears lower for the same pressure (MPA) range compared to the comparative example (L2) that does not utilize the measurement values. Therefore, even at low pressures, the density (G / CC) of the fillet die (70) is prevented from reaching the impossible area (IPB) from the possible area (PA), and the density (G / CC) of the fillet die (70) can be measured even at high pressures. The boundary between the possible area (PA) and the impossible area (IPB) can be set as an estimated value of the true density of argyrodite.

[0179] In this way, the length deformation according to the pressure change is measured by the first and second length sensors (40, 50) connected to the upper plate (10), the lower plate (20), and the middle plate (30), and by considering the deformation of the pellet die (70) in the measured value, the pellet die (70) in which the measurement object (71) is placed between the upper plate (10) and the lower plate (20) can be pressed to accurately measure the compressed density of the powder material.

[0180] Referring to Figure 10, it can be seen that as the pressure increases, the density of the powder material, which is the pressure measurement object (71), increases, and at the same time, deformation of the measuring device also occurs. It can be seen that, in order to accurately measure the density, deformation of the measuring device, the pellet die (70), must be taken into account.

[0181] For example, it can be seen that a metal pellet die (70) deforms by approximately 0.1 mm under a pressure of 300 MPa. Failure to compensate for the deformation of the pellet die (70) can result in a physically impossible measurement. It is important to know the density under actual pressure conditions.

[0182] The device and method of the first embodiment are possible because they simultaneously apply pressure and measure the thickness of the measurement object (71) and the pellet die (70). Measurement of the length deformation of the first and second length sensors (40, 50) enables simultaneous thickness measurement of the measurement object (71) and the pellet die (70).

[0183] Hereinafter, a second embodiment of the present invention will be described. By comparing the second embodiment with the first embodiment, descriptions of the same components will be omitted, and descriptions of the different components will be provided.

[0184] Fig. 11 is a plan view of a compression density measuring device of a powder material of an all-solid-state secondary battery according to a second embodiment of the present invention, and Fig. 12 is a front view of Fig. 11. Referring to Figs. 11 and 12, the compression density measuring device (2) of the second embodiment includes an upper plate (10), a lower plate (20), and a length sensor (40).

[0185] The upper plate (10) forms the upper part on which the measurement object (271) is placed in the compression density measuring device (2). The lower plate (20) forms the lower part on which the measurement object (271) is placed in the compression density measuring device (1).

[0186] A cylinder (60) for pressurizing a measurement object (271) may be installed on at least one side of the upper plate (10) and the lower plate (20). The second embodiment exemplifies that the cylinder (60) is installed on each of the upper plate (10) and the lower plate (20).

[0187] And the cylinder (60) is connected to the center of gravity of the upper and lower plates (10, 20). Therefore, the pressing force of the cylinder (60) is stably applied to the upper and lower plates (10, 20), and the measurement object (271) and the pellet die (270) on which the measurement object (271) is installed are stably applied.

[0188] The upper plate (10) applies a downward compressive force to the measurement object (271) and the pellet die (270). The pellet die (270) can be formed by modifying the pellet die (70) of the first embodiment to correspond to the length sensor (40).

[0189] The lower plate (20) is positioned below the upper plate (10) and operates to move up and down below the lower plate (20) to pressurize a pellet die (270) on which a pressure measurement object (271) made of powder material is placed, against the upper plate (10). The powder material may be formed as an aerogel powder or a block. By the compression operation of the cylinder (60), the pellet die (270) installed between the upper plate (10) and the lower plate (20) and the pressure measurement object (271) placed thereon are pressurized.

[0190] The length sensor (40) is installed on the upper plate (10) and connected to the lower plate (20). Accordingly, when pressure is applied between the upper plate (10) and the lower plate (20) in response to the pressure of the cylinder (60), the length sensor (40) causes a length deformation according to the pressure, measures the length deformation, and applies it to a control unit (not shown). The control unit may include a computer and a storage device for storing data.

[0191] Referring to FIG. 11, FIG. 12 and FIG. 8, in a balanced pressurized state of the upper plate (10) and the lower plate (20), a plurality of length sensors (40) are provided, i.e., three, so that the length sensors can accurately measure the length deformation according to the pressure.

[0192] Three length sensors (40) are arranged corresponding to the vertex positions of an equilateral triangle forming the centers of gravity of the upper plate (10) and the lower plate (20), and measure the length deformation at each position. That is, the arrangement of the three length sensors (40) is such that each measurement point is at the center of gravity. The control unit calculates an average value (AV) using the measurement values ​​of the three length sensors (40).

[0193] In addition, the control unit calculates the average value (AV) of the length sensor (40) measured from the center of gravity and uses the average value (AV) as a pressure correction value of the pellet die (270). That is, by using the average value (AV) as a pressure correction value of the pellet die (270), it is possible to calculate the deformation amount of only the pressure measurement target (271) of the powder material.

[0194] Fig. 13 is a flowchart of a method for measuring the compressed density of a powder material of an all-solid-state secondary battery according to a second embodiment of the present invention. Referring to Figs. 11 to 13, the method for measuring the compressed density of the second embodiment includes a first step (ST1'), a second step (ST2'), and a third step (ST3').

[0195] In the first step (ST1'), a pellet die (270) having a pressure measurement target (271) made of powder material is placed on a lower plate (20) that moves upward and downward from the upper plate (10) and presses the pellet die (270) against the upper plate (10). That is, in the first step (ST1'), the cylinder (60) is operated to move the lower plate (20) upward and press the pellet die (270) against the upper plate (10).

[0196] In the second step (ST2'), a length sensor (40) installed on the upper plate (10) and connected to the lower plate (20) measures length deformation according to pressure.

[0197] In the third step (ST3'), the control unit, which has received the measurement value signal from the length sensor (40), uses the measurement value as a pressure compensation value of the pellet die (270). That is, the third step (ST3) calculates the average value measured by the length sensor (40) and uses the average value as a pressure compensation value of the pellet die (270).

[0198] The devices (1, 2) of the first and second embodiments and the methods of the first and second embodiments using the same can measure the compression density of the negative electrode, the aerogel powder, the solid electrolyte, and the positive electrode among the components of an all-solid-state secondary battery.

[0199] Fig. 14 is a graph showing the measurement of the compression density of a cathode using an embodiment of the device and method according to the present invention. Referring to Fig. 14, it can be seen that the relationship between the packing density and pressure of the first and second cathode materials (141, 142) can be measured. The maximum compression points (P11, P21) and the recovery points (P12, P22) after 1 minute of the first and second cathode materials (141, 142) are measured.

[0200] Fig. 15 is a graph showing the measurement of the compressed density of an aerogel powder using an apparatus and method according to an embodiment of the present invention. Referring to Fig. 15, it can be seen that the relationship between the pellet die density and pressure of the first, second, and third aerogel powders (151, 152, 153) can be measured. The compression and relaxation of the first, second, and third aerogel powders (151, 152, 153) are measured.

[0201] Fig. 16 is a graph showing the measurement of the compression density of a solid electrolyte using an embodiment of the device and method according to the present invention. Referring to Fig. 16, it can be seen that the relationship between the pellet die density and pressure of the first, second, third, and fourth solid electrolytes (161, 162, 163, and 164) can be measured. The compression and relaxation of the first, second, third, and fourth solid electrolytes (161, 162, 163, and 164) are measured.

[0202] Fig. 17 is a graph showing the compression density of a positive electrode measured using an embodiment of the device and method according to the present invention. Referring to Fig. 17, it can be seen that the relationship between the pellet die density and pressure of the first, second, third, fourth, and fifth positive electrode materials (171, 172, 173, 174, and 175) can be measured. The compression and relaxation of the first, second, third, fourth, and fifth positive electrode materials (171, 172, 173, 174, and 175) are measured.

[0203] The above description is only one embodiment for implementing the all-solid-state secondary battery according to the present disclosure, and the present disclosure is not limited to the above-described embodiment, and as claimed in the following claims, it will be understood that the technical spirit of the present disclosure encompasses a range in which various modifications can be implemented without departing from the gist of the present disclosure by anyone having ordinary skill in the art to which the invention pertains.

[0204] - Explanation of symbols -

[0205] 1, 2: Compression density measuring device 10: Upper plate

[0206] 20: Lower plate 30: Middle plate

[0207] 31: Pressing part 32: Flange

[0208] 40: (First) length sensor 50: Second length sensor

[0209] 60: Cylinder 70, 270: Pellet die

[0210] 71, 271: Measurement object 141, 142: First and second cathode materials

[0211] 151, 152, 153: First, second, and third aerogel powders

[0212] 161, 162, 163, 164: First, second, third, and fourth solid electrolytes

[0213] 171, 172, 173, 174, 175: 1st, 2nd, 3rd, 4th, 5th anode materials

[0214] AV: Average AV1: First average

[0215] AV2: Second average value P: Pressure

Claims

1. Upper plate; An intermediate plate provided at the lower portion of the upper plate and having a central pressing portion and a flange at the outer portion of the pressing portion; A lower plate that operates upward and downward from the lower side of the intermediate plate to pressurize a pellet die on which a pressure measurement target made of powder material is placed against the intermediate plate; A first length sensor installed on the upper plate and connected to the lower plate to measure length deformation according to pressure and apply the measurement to the control unit; and A second length sensor installed on the lower plate and connected to the middle plate to measure length deformation according to pressure and apply the measurement to the control unit. A device for measuring the compression density of a powder material of an all-solid-state secondary battery including .

2. In paragraph 1, It further includes a cylinder for pressurizing the upper plate and the lower plate, A device for measuring the compression density of a powder material of an all-solid-state secondary battery, wherein the cylinder is connected to the center of gravity of at least one side of the upper plate and the lower plate.

3. In paragraph 2, The above first length sensor Equipped in multiples, they are respectively arranged corresponding to the vertex positions of an equilateral triangle forming the first center of gravity of the upper plate and the lower plate, The above second length sensor A device for measuring the compression density of a powder material of an all-solid-state secondary battery, which is provided in multiples to form a flange of the middle plate and a second center of gravity of the lower plate, and is respectively arranged in correspondence with the inner side of the vertex position so that the second center of gravity coincides with the first center of gravity.

4. In paragraph 2, The pellet die is deformed by the pressure of the upper plate and the lower plate, The above control unit A device for measuring the compression density of a powder material of an all-solid-state secondary battery, which calculates an overall average value using the first average value of the first length sensor and the second average value of the second length sensor, and utilizes the overall average value as a pressure correction value of the pellet die.

5. In paragraph 1, The above powder material is A device for measuring the compression density of a powder material of an all-solid-state secondary battery, formed of one of an aerogel powder, a block, and a sheet.

6. Upper plate; A lower plate that operates upward and downward from the upper plate to pressurize a pellet die on which a pressure measurement target made of powder material is placed against the upper plate; A length sensor installed on the upper plate and connected to the lower plate to measure length deformation according to pressure and apply the measurement to the control unit. A device for measuring the compression density of a powder material of an all-solid-state secondary battery including .

7. In paragraph 6, Further comprising a cylinder for pressurizing the upper plate and the lower plate, A device for measuring the compression density of a powder material of an all-solid-state secondary battery, wherein the cylinder is connected to the center of gravity of at least one side of the upper plate and the lower plate.

8. In paragraph 7, The above length sensor A device for measuring the compression density of a powder material of an all-solid-state secondary battery, which is provided in multiples and is positioned corresponding to the vertex positions of an equilateral triangle forming the center of gravity of the upper plate and the lower plate.

9. In paragraph 7, The pressure measurement object is deformed by the pressure of the upper plate and the lower plate, The above control unit A device for measuring the compression density of a powder material of an all-solid-state secondary battery, which utilizes the average value of the above length sensor as a pressure correction value of the pressure measurement object.

10. A first step of pressing a pellet die having a pressure measurement target made of powder material placed on a lower plate that moves upward and downward from the lower side of the intermediate plate to the intermediate plate; A 21st step in which a first length sensor installed on the upper plate and connected to the lower plate measures the first length deformation according to pressure; and A 22nd step in which a second length sensor installed on the lower plate and connected to the middle plate measures the second length deformation according to pressure; and A third step in which the control unit, which has received the measurement value signals of the first length sensor and the second length sensor, utilizes the measurement value as a pressure correction value of the pellet die. A method for measuring the compressed density of a powder material of an all-solid-state secondary battery including .

11. In paragraph 10, The above first step is A method for measuring the compression density of a powder material of an all-solid-state secondary battery, wherein a pressure measurement target formed of one of aerogel powder, a block, and a sheet is pressurized using the above powder material.

12. In paragraph 10, The third step above is Calculate the first average value measured by the first length sensor, Calculate the second average value measured by the second length sensor, Calculate the overall average value using the first average value and the second average value, A method for measuring the compressed density of a powder material of an all-solid-state secondary battery, using the above-mentioned overall average value as the above-mentioned pressure correction value.

13. A first step of pressing a pellet die having a pressure measurement target made of powder material placed on a lower plate that moves upward and downward from the upper plate to the upper plate; A second step in which a length sensor installed on the upper plate and connected to the lower plate measures length deformation according to pressure; A third step in which the control unit, which has received the measurement value signal of the above length sensor, uses the measurement value as a pressure correction value of the pellet die. A method for measuring the compressed density of a powder material of an all-solid-state secondary battery including .

14. In paragraph 13, The third step above is Calculate the average value measured by the above length sensor, A method for measuring the compressed density of a powder material of an all-solid-state secondary battery, wherein the above average value is used as a pressure correction value of the pressure measurement object.

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