System and method for inspecting all-solid-state secondary battery

Abstract

An inspection system for an all-solid-state secondary battery according to an embodiment comprises: a cut surface forming device for forming a cut surface in a battery specimen including a positive electrode, a negative electrode, and a solid electrolyte layer; and a cut surface inspection device for inspecting the cut surface of the battery specimen, wherein the cut surface inspection device includes a first elastic member loading part for positioning a first elastic member on opposite surfaces of the battery specimen, a first pressing part for pressing opposite surfaces of the battery specimen, and an optical inspection part for optically inspecting the cut surface, and the first elastic member loading part aligns the first elastic member so that a side surface of the first elastic member protrudes further than the cut surface of the battery specimen.

Description

Inspection system and method for all-solid-state secondary batteries

[0001] The present disclosure relates to a system and method for inspecting an all-solid-state secondary battery.

[0002] Recent reports of explosion risks in batteries using liquid electrolytes have led to the development of all-solid-state secondary batteries. All-solid-state secondary batteries are composed entirely of solid materials and utilize solid electrolytes. These all-solid-state secondary batteries are safe, eliminating the risk of explosion due to electrolyte leakage. They also offer the advantages of being easy to manufacture in thin forms, offering high energy density and the ability to produce large capacities.

[0003] The above-described information disclosed in the background technology of this invention is only intended to enhance understanding of the background of the present invention, and therefore may include information that does not constitute prior art.

[0004] The embodiments are intended to provide an inspection system and method for an all-solid-state secondary battery that can perform accurate and reliable inspection of a battery specimen by minimizing damage to the cut surface of the battery specimen and protecting the cut surface.

[0005] However, the technical problems to be solved by the present invention are not limited to the problems described above, and other problems not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0006] According to one embodiment of the present invention for solving the above technical problem, an inspection system for an all-solid-state secondary battery includes a cut surface forming device for forming a cut surface in a battery specimen including a positive electrode, a negative electrode, and a solid electrolyte layer, and a cut surface inspection device for inspecting the cut surface of the battery specimen, wherein the cut surface inspection device includes a first elastic member loading unit for positioning a first elastic member on both sides of the battery specimen, a first pressing unit for pressing both sides of the battery specimen, and an optical inspection unit for optically inspecting the cut surface, wherein the first elastic member loading unit aligns the first elastic member such that a side surface of the first elastic member protrudes more than the cut surface of the battery specimen.

[0007] The first pressurizing portion includes a pressurizing plate that contacts both surfaces of the first elastic member, and a pressure providing portion that provides pressure to the pressurizing plate, and the first pressurizing portion can align the pressurizing plate so that a side surface of the pressurizing plate protrudes further than a side surface of the first elastic member.

[0008] The first elastic member loading portion may be configured to attach the alignment member to the battery specimen by allowing the edge portion of the alignment member to protrude further than the cut surface of the battery specimen, and the edge portion of the alignment member may be aligned on the same plane as the side surface of the first elastic member.

[0009] The above-described cut surface forming device may include a second elastic member loading portion that positions a second elastic member on both sides of the battery specimen, a second pressing portion that presses the second elastic member and the battery specimen, and a cutting portion that cuts the battery specimen and a portion of the second elastic member to form the cut surface in the battery specimen.

[0010] The above-mentioned cut surface forming device may further include a cut surface processing unit for surface-treating the cut surface.

[0011] The above-mentioned cut surface processing unit may include a polishing unit that forms a polishing groove by polishing a portion of the cut surface, and a protective member forming unit that forms a protective member on the cut surface.

[0012] The above cutting section may have a cross-sectional blade.

[0013] The above-described cross-section inspection device may further include a chamber in which the pressure plate is positioned, the chamber may include a chamber body that blocks the pressure plate from the outside, and an inspection window installed in the chamber body and positioned corresponding to the cross-section of the battery specimen.

[0014] The above-described cross-section inspection device may further include a charging / discharging unit that is electrically connected to the electrode tab of the battery specimen and charges and discharges the battery specimen.

[0015] In addition, a method for inspecting an all-solid-state secondary battery according to one embodiment includes the steps of forming a cut surface in a battery specimen including a positive electrode, a negative electrode, and a solid electrolyte layer; and inspecting the cut surface of the battery specimen, wherein the step of inspecting the cut surface includes the steps of positioning a first elastic member on both sides of the battery specimen, pressing the first elastic member and both sides of the battery specimen using a first pressing portion, and optically inspecting the cut surface, wherein a side surface of the first elastic member is aligned to protrude more than the cut surface of the battery specimen.

[0016] The first pressurizing portion includes a pressurizing plate that comes into contact with both sides of the first elastic member, and a pressure providing portion that provides pressure to the pressurizing plate, and in the step of pressing both sides of the battery sample, the side surface of the pressurizing plate can be aligned so that it protrudes more than the side surface of the elastic member.

[0017] The step of forming the cut surface in the battery specimen may include the step of positioning a second elastic member on both sides of the battery specimen, the step of pressing the second elastic member and the battery specimen, and the step of cutting a portion of the battery specimen and the second elastic member using a cutting portion to form the cut surface.

[0018] The above cutting section may have a cross-sectional blade.

[0019] The step of forming the cut surface on the above-mentioned battery specimen may further include a step of surface-treating the cut surface, and the step of surface-treating the cut surface may include a step of polishing a portion of the cut surface to form a polishing groove, and a step of forming a protective member on the cut surface.

[0020] The step of inspecting the cut surface further includes the step of positioning the pressure plate and the battery specimen inside the chamber body and blocking them from the outside, and the step of charging and discharging the battery specimen, and the cut surface can be optically inspected while charging and discharging the battery specimen through an inspection window installed in the chamber body.

[0021] According to embodiments, by applying pressure to a battery specimen while an elastic member is attached, the stack cells inside the battery specimen are uniformly adhered to all sides of the battery specimen, so that when the battery specimen is cut using a cutting section in a subsequent process, the cut surface is uniformly formed and damage to the cut surface can be minimized.

[0022] In addition, by aligning the side of the elastic member so that it protrudes further than the cut surface of the battery specimen and the side of the pressure plate so that it protrudes further than the side of the elastic member, the edge of the battery specimen adjacent to the cut surface of the battery specimen can be uniformly pressed. Accordingly, warping of the battery specimen, etc. can be prevented, and the cut surface of the battery specimen can be inspected more accurately.

[0023] In addition, by treating the surface of the cut surface of the battery specimen and forming a protective member on the cut surface, it is possible to minimize the cut surface from coming into contact with air or being physically damaged.

[0024] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0025] Figure 1 is a cross-sectional view of an all-solid-state battery.

[0026] Figure 2 is a cross-sectional view of an all-solid-state battery including a precipitated negative electrode.

[0027] FIG. 3 is a schematic diagram of an inspection system for an all-solid-state secondary battery according to one embodiment.

[0028] FIG. 4 is a drawing showing a state in which a battery specimen is pressed using the second elastic member loading portion and the second pressing portion of FIG. 3.

[0029] Fig. 5 is a drawing showing a state in which a part of a battery specimen is cut using the cutting section of Fig. 3.

[0030] Fig. 6 is a drawing showing a state in which a polishing groove is formed on a part of a battery specimen using the polishing section of Fig. 3.

[0031] Fig. 7 is a drawing showing a state in which a protective member is formed in a polishing groove of a battery specimen using the protective member forming part of Fig. 3.

[0032] FIG. 8 is a drawing illustrating a state in which a battery specimen is pressed using a first elastic member loading portion and a first pressurizing portion of a cross-section inspection device of an inspection system for an all-solid-state secondary battery according to one embodiment.

[0033] Figure 9 is a flowchart of a method for inspecting an all-solid-state secondary battery according to one embodiment.

[0034] 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.

[0035] 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.

[0036] 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 are other elements in between. Conversely, when an element is said to be "directly over" another element, it means that there are no other elements in between.

[0037] 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.

[0038] Cathode for all-solid-state secondary batteries

[0039] In one embodiment, a positive electrode for an all-solid-state secondary battery is provided, which includes a current collecting layer and a positive electrode active material layer positioned on the current collecting layer, wherein the positive electrode active material layer includes 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 include more or less components than the components described above.

[0040] In one embodiment, a positive electrode for an 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 material to a current collecting layer, followed by drying and rolling.

[0041] positive electrode active material

[0042] The cathode active material can be applied without limitation as long as it is one commonly used in all-solid-state secondary batteries. For example, the cathode active material may be a compound capable of reversible lithium intercalation and deintercalation, and may include a compound represented by any of the following chemical formulas.

[0043] Li a A 1-b X b D2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5);

[0044] 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);

[0045] 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);

[0046] Li a E 2-b X b O4-c D c (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05);

[0047] 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);

[0048] 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);

[0049] 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);

[0050] 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);

[0051] 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);

[0052] Li a Ni 1-b-c Mr b X c O 2-αT2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 <α < 2);

[0053] 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);

[0054] 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);

[0055] The a NiG b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0056] The a CoG b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0057] The a Mn 1-b G b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0058] The a Mn2G b O4(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0059] The a Mn 1-g G g PO4(0.90 ≤ a ≤ 1.8, 0 ≤ g ≤ 0.5);

[0060] QO2; QS2; LiQS2;

[0061] V2O5; LiV2O5;

[0062] LiZO2;

[0063] LiNiVO4;

[0064] Li (3-f) J2(PO4)3(0 ≤ f ≤ 2);

[0065] Li (3-f) Fe2(PO4)3(0 ≤ f ≤ 2);

[0066] Li a FePO4(0.90 ≤ a ≤ 1.8).

[0067] 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.

[0068] The cathode 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).

[0069] The 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.

[0070] [Chemical Formula 1]

[0071] Li a1 Ni x1 M 1 y1 M 2 1-x1-y1 O2

[0072] 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.

[0073] [Chemical Formula 2]

[0074] Li a2 Co x2 M 3 1-x2 O2

[0075] 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.

[0076] [Chemical Formula 3]

[0077] Li a3 Fe x3 M 4 (1-x3) PO4

[0078] In the above chemical formula 3, 0.9≤a3≤1.8, 0.6≤x3≤1, and M 4 is 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.

[0079] 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.

[0080] 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.

[0081] Sulfide-based solid electrolyte

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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 PS 6-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.

[0086] 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 the electrode layer and the 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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 the above content ranges are satisfied, the positive electrode for an all-solid-state secondary battery can maintain high adhesiveness while implementing high capacity and high ionic conductivity, and the viscosity of the positive electrode composition can be maintained at an appropriate level, thereby improving processability.

[0091] bookbinder

[0092] 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.

[0093] Challenge

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] All-solid-state secondary battery

[0099] In one embodiment, an all-solid-state secondary battery is provided, which includes the aforementioned positive electrode, 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.

[0100] Figure 1 is a cross-sectional view of an all-solid-state battery.

[0101] Referring to FIG. 1, the all-solid-state battery (1000) may have a structure in which an electrode assembly in which a negative electrode (40) including a negative electrode current collecting layer (41) and a negative electrode active material layer (43), a solid electrolyte layer (30), and a positive electrode (20) including a positive electrode active material layer (23) and a positive electrode current collecting layer (21) are laminated is housed in a case such as a pouch. The all-solid-state battery (1000) may further include an elastic layer (50) on the outer side of at least one of the positive electrode (20) and the negative electrode (40). Although FIG. 1 illustrates one electrode assembly including a negative electrode (40), a solid electrolyte layer (30), and a positive electrode (20), an all-solid-state battery may be manufactured by laminating two or more electrode assemblies.

[0102] cathode

[0103] An anode for an all-solid-state battery may include, for example, a current collecting layer and a negative electrode active material layer positioned on the current collecting layer. The negative electrode active material layer includes a negative electrode active material and may further include a binder, a conductive material, and / or a solid electrolyte.

[0104] The 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.

[0105] Materials capable of reversibly intercalating / deintercalating lithium ions include carbon-based negative electrode active materials, such as crystalline carbon, amorphous carbon, or a combination thereof. Examples of 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 amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, and calcined coke.

[0106] As an alloy of lithium metal, an alloy of lithium with 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.

[0107] As a material that can be doped and dedoped with lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material can be used, and as a Si-based negative electrode active material, silicon, silicon-carbon composite, SiO x(0<x<2), Si-Q 합금(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), Sn계 음극 활물질로는 Sn, SnO2, Sn-R 합금(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. 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.

[0108] 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.

[0109] The average particle diameter (D50) of the 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 in this case, 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 are 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.

[0110] The 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.

[0111] The content of the negative active material in the negative active material layer may be 95 wt% to 99 wt% with respect to the total weight of the negative active material layer.

[0112] 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.

[0113] The above binder serves to adhere the negative electrode active material particles well to each other and also to adhere the negative electrode active material well to the current collecting layer. The binder may include an insoluble binder, a water-soluble binder, or a combination thereof.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] The cathode current collecting layer 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.

[0119] 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.

[0120] Figure 2 is a cross-sectional view of an all-solid-state battery including a precipitated negative electrode.

[0121] Referring to FIG. 2, the precipitation-type negative electrode (40') may include a current collecting layer (41) and a negative electrode coating layer (45) positioned on the current collecting layer (41). An all-solid-state battery having such a precipitation-type negative electrode (40') starts initial charging in a state in which no negative electrode active material exists, and during charging, high-density lithium metal or the like is precipitated between the current collecting layer (41) and the negative electrode coating layer (45) to form a lithium metal layer (44), which may function as the negative electrode active material. Accordingly, in an all-solid-state battery that has been charged more than once, the precipitation-type negative electrode (40') may include a current collecting layer (41), a lithium metal layer (44) positioned on the current collecting layer (41), and a negative electrode coating layer (45) positioned on the metal layer. The lithium metal layer (44) refers to a layer in which lithium metal or the like 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.

[0122] The cathode coating layer (45) may include a metal, carbon material, or a combination thereof that acts as a catalyst.

[0123] 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 of these or an alloy of several types. When the metal is present in the form of particles, the average particle diameter (D50) may be about 4 μm or less, for example, 10 nm to 4 μm.

[0124] 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.

[0125] When the cathode coating layer (45) includes both metal and carbon material, the mixing ratio of the metal and 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 cathode coating layer (45) may include, for example, a carbon material supported with a catalytic metal, or may include a mixture of metal particles and carbon material particles.

[0126] The cathode coating layer (45) may include, for example, a metal and amorphous carbon, in which case the precipitation of lithium metal can be effectively promoted.

[0127] The cathode coating layer (45) may further include a binder, and the binder may be a conductive binder. In addition, the cathode coating layer (45) may further include general additives such as fillers, dispersants, and ionic conductive agents.

[0128] The thickness of the cathode coating layer (45) may be, for example, 100 nm to 20 ㎛, or 500 nm to 10 ㎛, or 1 ㎛ to 5 ㎛.

[0129] The precipitation-type negative electrode (40') may further include, for example, a thin film on the surface of the current collecting layer (41), that is, between the current collecting layer (41) and the negative electrode coating layer (45). 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 precipitation form of the lithium metal layer (44) 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.

[0130] solid electrolyte layer

[0131] The solid electrolyte layer (30) 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.

[0132] In one example, the solid electrolyte included in the positive electrode (20) and the solid electrolyte included in the solid electrolyte layer (30) may include the same compound or different compounds. For example, when both the positive electrode (20) and the solid electrolyte layer (30) 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 (20) and the solid electrolyte layer (30) 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.

[0133] Meanwhile, the average particle diameter (D50) of the solid electrolyte included in the positive electrode (20) may be smaller than the average particle diameter (D50) of the solid electrolyte included in the solid electrolyte layer (30). 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 (20) 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 (30) 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.

[0134] The solid electrolyte layer may further include a binder in addition to the solid electrolyte. The binder may include, but is not limited to, styrene butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, an acrylate polymer, or a combination thereof, and any binder used in the art may be used. The acrylate polymer may be, for example, butyl acrylate, polyacrylate, polymethacrylate, or a combination thereof.

[0135] A solid electrolyte layer can be formed by adding a solid electrolyte to a binder solution, coating the solution on a substrate film, and drying the solution. The solvent for the binder solution may be isobutyryl isobutyrate, xylene, toluene, benzene, hexane, or a combination thereof. The solid electrolyte layer formation process is widely known in the art, so a detailed description will be omitted.

[0136] The thickness of the solid electrolyte layer may be, for example, 10 μm to 150 μm.

[0137] The solid electrolyte layer may further include an alkali metal salt, and / or an ionic liquid, and / or a conductive polymer.

[0138] The alkali metal salt may be, for example, a lithium salt. The content of the lithium salt in the solid electrolyte layer may be greater than 1 M, for example, from 1 M to 4 M. In this case, the lithium salt may improve ionic conductivity by enhancing the mobility of lithium ions in the solid electrolyte layer.

[0139] 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.

[0140] Additionally, the lithium salt may be an imide type, for example, the imide type 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 the ionic liquid.

[0141] Ionic liquids are salts or molten salts that are composed only of ions and are liquid at room temperature, with a melting point below room temperature.

[0142] The ionic liquid may be a compound comprising a) one or more cations selected from ammonium, pyrrolidinium, pyridinium, pyrimidinium, imidazolium, piperidinium, pyrazolium, oxazolium, pyridazinium, phosphonium, sulfonium, triazolium, 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-.

[0143] The ionic liquid may be, for example, one or more selected from the group consisting of 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.

[0144] In the 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.

[0145] The all-solid-state battery may be a unit cell having a structure of anode / solid electrolyte layer / cathode, a bi-cell having a structure of cathode / solid electrolyte layer / cathode / solid electrolyte layer / cathode, or a laminated battery in which the structure of the unit cell is repeated.

[0146] The shape of the all-solid-state battery is not particularly limited, and may be, for example, coin-shaped, button-shaped, sheet-shaped, stacked, cylindrical, or flat. Furthermore, all-solid-state batteries can be applied to large-scale batteries used in electric vehicles, for example. For example, all-solid-state batteries can be used in hybrid vehicles such as plug-in hybrid electric vehicles (PHEVs). Furthermore, they can be used in fields requiring large amounts of power storage, such as electric bicycles or power tools.

[0147] Hereinafter, an inspection system for an all-solid-state secondary battery according to one embodiment will be described with reference to FIGS. 3 to 8.

[0148] FIG. 3 is a schematic diagram of an inspection system for an all-solid-state secondary battery according to one embodiment, FIG. 4 is a diagram illustrating a state in which a battery specimen is pressed using the second elastic member loading portion and the second pressurizing portion of FIG. 3, FIG. 5 is a diagram illustrating a state in which a portion of a battery specimen is cut using the cutting portion of FIG. 3, FIG. 6 is a diagram illustrating a state in which a polishing groove is formed in a portion of a battery specimen using the polishing portion of FIG. 3, and FIG. 7 is a diagram illustrating a state in which a protective member is formed in the polishing groove of a battery specimen using the protective member forming portion of FIG. 3.

[0149] As illustrated in FIG. 3, an inspection system for an all-solid-state secondary battery according to one embodiment includes a cut surface forming device (100) and a cut surface inspection device (200).

[0150] A cut surface forming device (100) can form a cut surface (CP) on a battery specimen (10). The battery specimen (10) can have a structure in which a stack cell structure in which a plurality of unit cells (UC) and a buffer member (CM) are stacked is formed inside a pouch. One unit cell (UC) can include a positive electrode (11), a negative electrode (13), and a solid electrolyte layer (12). Here, the positive electrode (11) can include a cathode, and the negative electrode (13) can include an anode. The positive electrode (11) can include a positive electrode current collecting layer (11a), and a positive electrode active material layer (11b) positioned on one surface of the positive electrode current collecting layer (11a). The negative electrode (13) can include a negative electrode current collecting layer (13a), and a negative electrode coating layer (13b) positioned on one surface of the negative electrode current collecting layer (13a). The solid electrolyte layer (12) may be positioned between the positive electrode active material layer (11b) and the negative electrode coating layer (13b). The cut surface (CP) of the battery specimen (10) may be formed on the opposite side of the side where the electrode tab (15, see FIG. 8) of the battery specimen (10) is positioned.

[0151] The cut surface forming device (100) may include a second elastic member loading portion (110), a second pressure portion (120), a cut portion (130), and a cut surface processing portion (140).

[0152] As illustrated in FIGS. 3 and 4, the second elastic member loading unit (110) can load the second elastic member (EM2) on both sides of the battery specimen (10). The second elastic member (EM2) may be a Teflon sheet (PTFE sheet), etc. In addition, the second pressurizing unit (120) can press the second elastic member (EM2) and the battery specimen (10). In this way, by pressing the battery specimen (10) while the second elastic member (EM2) is attached, the stack cells inside the battery specimen (10) can be uniformly adhered on all sides. In addition, since the battery specimen (10) is pressurized and the stack cells inside it are adhered, when the battery specimen (10) is cut using the cutting unit (130) in a subsequent process, the cut surface (CP) can be uniformly formed.

[0153] As illustrated in FIGS. 3 and 5, the cutting portion (130) can cut a portion of the battery specimen (10) and the second elastic member (EM2) to form a cutting plane (CP) on the battery specimen (10). At this time, since the cutting portion (130) has a cross-sectional blade (131), the cutting plane (CP) can form a vertical cross-section.

[0154] The cut surface treatment unit (140) can improve the surface roughness by surface treating the cut surface (CP) of the battery specimen (10) exposed by the cut section (130).

[0155] The cutting surface processing section (140) may include a polishing section (141) and a protective member forming section (142).

[0156] As illustrated in FIGS. 3 and 6, the polishing unit (141) can polish a portion of the cut surface (CP) to form a polishing groove (PH). The polishing unit (141) can improve the surface roughness of the bottom surface of the polishing groove (PH) by polishing the surface of the cut surface (CP). The polishing unit (141) may include an ion beam milling device that accelerates ions (IB) to etch an object. The height difference (h) between the bottom surface of the polishing groove (PH) and the cut surface (CP) may be within approximately 300 μm.

[0157] As illustrated in FIGS. 3 and 7, the protective member forming portion (142) can form a protective member (FI) on part or all of the cut surface (CP). The protective member (FI) can prevent damage and contamination of the cut surface (CP). The protective member (FI) may be a transparent filler filled in the polishing groove (PH). However, it is not necessarily limited thereto, and the protective member (FI) may be a sheet-shaped protective plate positioned on the cut surface (CP) and the polishing groove (PH), or a protective layer formed on the surface of the cut surface (CP) and the polishing groove (PH). The protective plate may be melted and adhered to the surface of the cut surface (CP) and the polishing groove (PH), and the protective layer may be applied and formed on the surface of the cut surface (CP) and the polishing groove (PH). The protective member (FI) may include at least one of polyurethane, ethylene vinyl acetate, polyvinyl butyral, silica gel, and polypropylene. By forming a rough shape on the surface of the protective member (FI), the adhesion between the protective member (FI) and the cut surface (CP) can be improved, and air entrapment in the protective member (FI) can be minimized.

[0158] Meanwhile, the cut surface inspection device (200) can inspect the cut surface (CP) of the battery specimen (10).

[0159] The cross-section inspection device (200) may include a first elastic member loading portion (210), a first pressurizing portion (220), an optical inspection portion (230), a chamber (240), and a charging / discharging portion (250).

[0160] FIG. 8 is a drawing illustrating a state in which a battery specimen is pressed using a first elastic member loading portion and a first pressurizing portion of a cross-section inspection device of an inspection system for an all-solid-state secondary battery according to one embodiment.

[0161] The first elastic member loading unit (240) can load the first elastic member (EM1) on both sides of the battery specimen (10). At this time, as illustrated in FIG. 8, the first elastic member loading unit (210) can align the first elastic member (EM1) so that the side surface (CM1a) of the first elastic member (EM1) protrudes further by a first length (L1) than the cut surface (CP) of the battery specimen (10).

[0162] In addition, the first elastic member loading part (210) attaches the alignment member (AM) to the battery specimen (10) so that the edge portion (AMa) of the alignment member (AM) protrudes further than the cut surface (CP) of the battery specimen (10) by a first length (L1). In addition, the first elastic member loading part (210) can align the edge portion (AMa) of the alignment member (AM) on the same plane (S1) as the side surface of the first elastic member (EM1). In this way, by using the alignment member (AM), the cut surface (CP) of the battery specimen (10) and the side surface of the second elastic member (EM2) can be easily aligned. This alignment member (AM) can be made of a thin film, etc.

[0163] The first pressurizing unit (220) can pressurize both sides of the battery sample (10).

[0164] The first pressurizing portion (220) may include a pressurizing plate (211) that contacts both surfaces of the first elastic member (EM1), and a pressure providing portion (212) that provides pressure to the pressurizing plate (211).

[0165] At this time, the first pressurizing portion (220) can align the pressurizing plate (211) so that the side surface (211a) of the pressurizing plate (211) protrudes further by a second length (L2) than the side surface (CM1a) of the first elastic member (EM1).

[0166] If the pressure applied to the battery specimen by the first pressurizing unit is uneven, the cut section may not represent the interior of the battery specimen, and the cut section of the battery specimen may be damaged. In this case, errors may occur in the inspection of the cut surface.

[0167] However, in the present embodiment, the side surface (CM1a) of the first elastic member (EM1) protrudes further than the cut surface (CP) of the battery specimen (10) by a first length (L1), so that the first elastic member (EM1) can cover the entire edge portion of the battery specimen (10). Therefore, when the battery specimen is pressed using the press plate (211), the edge portion of the battery specimen (10) adjacent to the cut surface of the battery specimen (10) can be uniformly pressed by the elastic force of the first elastic member (EM1).

[0168] In addition, since the side surface (211a) of the pressure plate (211) protrudes further by the second length (L2) than the side surface (CM1a) of the first elastic member (EM1), the pressure plate (211) can cover the entire edge portion of the first elastic member (EM1). Therefore, when the battery specimen (10) is pressed using the pressure plate (211), the edge portion of the battery specimen (10) adjacent to the cut surface (CP) of the battery specimen (10) and the edge portion of the first elastic member (EM1) can be uniformly pressed. Therefore, warping of the battery specimen (10), etc. can be prevented, and thus the cut surface (CP) of the battery specimen (10) can be inspected more accurately.

[0169] The optical inspection unit (230) can inspect the cross-section (CP) using an optical method.

[0170] The chamber (240) can have a pressure plate (211) and a battery sheet (10) positioned therein.

[0171] The chamber (240) may include a chamber body (241) and an inspection window (242).

[0172] The chamber body (241) can seal the pressure plate (211) and the battery specimen (10) and block them from the outside. The interior of the chamber body (241) is filled with a vacuum or dry gas, etc., so that the cut surface of the battery specimen can be prevented from coming into contact with moisture or air.

[0173] An inspection window (242) is installed in the chamber body (241) and can be positioned to correspond to the cut surface (CP) of the battery specimen (10). The inspection window (242) can be made of a transparent material. Therefore, the cut surface (CP) of the battery specimen can be easily observed and inspected using the inspection window (242).

[0174] The charge / discharge unit (250) is electrically connected to the electrode tab (15, see FIG. 8) of the battery specimen (10) and can charge and discharge the battery specimen (10). Therefore, the battery specimen (10) can be inspected more accurately by performing the charging and discharging process while simultaneously pressurizing the battery specimen (10).

[0175] Hereinafter, with reference to FIG. 9, an inspection method using an inspection system for an all-solid-state secondary battery according to one embodiment will be described in detail.

[0176] Figure 9 is a flowchart of a method for inspecting an all-solid-state secondary battery according to one embodiment.

[0177] As illustrated in FIG. 9, a method for inspecting an all-solid-state secondary battery according to one embodiment first forms a cut surface (CP) on a battery specimen (10) (S100).

[0178] Below, a method for forming a cut surface (CP) in a battery sample (10) is described in detail with reference to the drawings.

[0179] As illustrated in FIGS. 4 and 9, a second elastic member (EM2) is loaded on both sides of a battery specimen (10) using a second elastic member loading part (110) (S110). Then, the second elastic member (EM2) and the battery specimen (10) are pressed for a predetermined time, for example, about 10 minutes, using a second pressurizing part (120) (S120). In this way, by pressing the battery specimen (10) while the second elastic member (EM2) is attached, the stack cells inside the battery specimen (10) can be uniformly adhered on all sides. In addition, since the battery specimen (10) is pressed and the stack cells inside it are adhered, when the battery specimen (10) is cut using a cutting part (130) in a subsequent process, a cut surface (CP) can be uniformly formed.

[0180] And, as illustrated in FIGS. 5 and 9, a portion of the battery sample (10) and the second elastic member (EM2) is cut using a cutting portion (130) to form a cutting surface (CP) on the battery sample (10) (S130). At this time, since the cutting portion (130) has a cross-sectional blade (131), the cutting surface (CP) can form a vertical cross-section.

[0181] And, as shown in FIGS. 6, 7, and 9, the cut surface (CP) is surface-treated using the cut surface treatment unit (140) (S140). To this end, first, a part of the cut surface (CP) is polished using the polishing unit (141) to form a polishing groove (PH). Then, a protective member (FI) is formed on the cut surface (CP) using the protective member forming unit (142). At this time, the protective member (FI) may be a transparent filler that fills the polishing groove (PH). The protective member (FI) may be formed by immersing the cut surface (CP) of the battery specimen (10) in a liquid protective member solution, or by thinly applying a liquid protective member solution to the surface of the cut surface (CP) and then thermally curing or photo-curing.

[0182] These protective elements (FI) can protect the cut surface (CP) exposed to the polishing groove (PH).

[0183] Next, as shown in FIGS. 8 and 9, the cut surface (CP) of the battery specimen (10) is inspected (S200).

[0184] A method for inspecting the cross-section (CP) of a battery specimen (10) is described in detail with reference to the drawings.

[0185] First, the first elastic member (EM1) is positioned on both sides of the battery specimen (10) using the first elastic member loading part (240) (S210). At this time, the side surface of the first elastic member (EM1) can be aligned so as to protrude further by a first length (L1) than the cut surface (CP) of the battery specimen (10). In addition, the side surface (211a) of the pressure plate (211) can be aligned so as to protrude further by a second length (L2) than the side surface (CM1a) of the first elastic member (EM1).

[0186] Then, both sides of the battery sample (10) are pressed using the first pressurizing unit (220) (S220).

[0187] Then, the pressure plate (211) and the battery specimen (10) are positioned inside the chamber body (241) and blocked from the outside (S230).

[0188] And, while charging and discharging the battery sample (10) using the charging and discharging unit (250), the cut surface (CP) is optically inspected through the inspection window (242) installed in the chamber body (241) (S240).

[0189] Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention.

Claims

1. A cutting plane forming device for forming a cutting plane in a battery specimen including a positive electrode, a negative electrode, and a solid electrolyte layer, and A cut surface inspection device for inspecting the cut surface of the above battery specimen Including, The above cross-section inspection device A first elastic member loading section positioning a first elastic member on both sides of the above battery specimen, A first pressurizing portion for pressing both sides of the above-mentioned battery specimen, and Optical inspection unit for optically inspecting the above-mentioned cross-section Including, The above first elastic member loading part An inspection system for an all-solid-state secondary battery, wherein the first elastic member is aligned so that a side surface of the first elastic member protrudes further than the cut surface of the battery specimen.

2. In paragraph 1, The above first pressurizing part A pressure plate in contact with both surfaces of the first elastic member, and A pressure providing unit that provides pressure to the above-mentioned pressure plate Including, The above first pressurizing part An inspection system for an all-solid-state secondary battery, wherein the pressure plate is aligned so that a side surface of the pressure plate protrudes further than a side surface of the first elastic member.

3. In paragraph 2, The above first elastic member loading part Attach the alignment member to the battery specimen so that the edge of the alignment member protrudes further than the cut surface of the battery specimen, An inspection system for an all-solid-state secondary battery, wherein an edge portion of the alignment member is aligned on the same plane as a side surface of the first elastic member.

4. In paragraph 2, The above-mentioned cross-section forming device A second elastic member loading section positioning a second elastic member on both sides of the above battery specimen, A second pressurizing member for pressing the second elastic member and the battery specimen, and A cutting section for cutting a part of the above battery specimen and the second elastic member to form the cut surface on the above battery specimen An inspection system for an all-solid-state secondary battery, comprising:

5. In paragraph 4, An inspection system for an all-solid-state secondary battery, wherein the above-mentioned cross-section forming device further includes a cross-section processing unit for surface-processing the cross-section.

6. In paragraph 5, The above cross-section processing section A polishing section that forms a polishing groove by polishing a portion of the above-mentioned cross-section, and A protective member forming part that forms a protective member on the above-mentioned cut surface An inspection system for an all-solid-state secondary battery, comprising:

7. In paragraph 5, An inspection system for an all-solid-state secondary battery, wherein the cutting section has a cross-sectional blade.

8. In paragraph 2, The above cross-section inspection device further includes a chamber in which the pressure plate is positioned, The above chamber is A chamber body that blocks the above-mentioned pressure plate from the outside, and An inspection window installed in the chamber body and positioned corresponding to the cut surface of the battery specimen An inspection system for an all-solid-state secondary battery, comprising:

9. In paragraph 1, The above cross-section inspection device An inspection system for an all-solid-state secondary battery further comprising a charging / discharging unit electrically connected to the electrode tabs of the above-mentioned battery specimen and charging and discharging the above-mentioned battery specimen.

10. A step of forming a cut surface in a battery specimen including a positive electrode, a negative electrode, and a solid electrolyte layer; and A step of examining the cut surface of the above battery specimen Including, The step of inspecting the above cross-section is A step of positioning a first elastic member on both sides of the above battery specimen; A step of applying pressure to both sides of the first elastic member and the battery specimen using a first pressurizing portion, and Step of optically inspecting the above cross-section Including, A method for inspecting an all-solid-state secondary battery, wherein the side surface of the first elastic member is aligned to protrude further than the cut surface of the battery specimen.

11. In Article 10, The above first pressurizing part A pressure plate in contact with both surfaces of the first elastic member, and A pressure providing unit that provides pressure to the above-mentioned pressure plate Including, In the step of pressurizing both sides of the above battery specimen, A method for inspecting an all-solid-state secondary battery, wherein the side surface of the pressure plate is aligned so as to protrude further than the side surface of the elastic member.

12. In Article 11, The step of forming the cut surface on the above battery specimen is A step of positioning a second elastic member on both sides of the above battery specimen; A step of pressurizing the second elastic member and the battery specimen, and A step of forming the cut surface by cutting a part of the battery sample and the second elastic member using a cutting section. A method for inspecting an all-solid-state secondary battery, comprising:

13. In paragraph 12, A method for inspecting an all-solid-state secondary battery, wherein the above-mentioned cutting section has a cross-sectional blade.

14. In paragraph 13, The step of forming the cut surface on the above-mentioned battery specimen further includes the step of surface-treating the cut surface, The step of surface treatment of the above-mentioned cross-section is A step of polishing a portion of the above cut surface to form a polishing groove, and Step of forming a protective member on the above cut surface A method for inspecting an all-solid-state secondary battery, comprising:

15. In paragraph 12, The step of inspecting the above cross-section is A step of positioning the pressurized plate and the battery specimen inside the chamber body and blocking them from the outside, and Steps for charging and discharging the above battery specimen Including more, A method for inspecting an all-solid-state secondary battery, wherein the cross-section is optically inspected while charging and discharging the battery specimen through an inspection window installed in the chamber body.

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