Test apparatus and method for all-solid rechargeable battery

Abstract

An apparatus for testing an all-solid rechargeable battery, according to an embodiment, includes: a test body on which are loaded a plurality of all-solid-state cells having stacked therein unit cells each including a positive electrode, a negative electrode, and a solid electrolyte layer; a pressing unit which is installed in the test body and presses the plurality of all-solid-state cells; a pressure measurement unit which is installed in the pressing unit and measures a pressure applied to the all-solid-state cells; and a good / bad determination unit which determines whether the all-solid-state cells are good or bad by using a pressure deviation for each position of the pressure measured by the pressure measurement unit.

Description

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

[0001] The present disclosure relates to a device 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 device for an all-solid-state secondary battery capable of quickly determining whether an all-solid-state cell is good or bad, thereby improving the process speed.

[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, a device for testing an all-solid-state secondary battery includes: a testing body having a plurality of all-solid-state cells in which unit cells including a positive electrode, a negative electrode, and a solid electrolyte layer are stacked; a pressurizing unit installed in the testing body and pressurizing the plurality of all-solid-state cells; a pressure measuring unit installed in the pressurizing unit and measuring the pressure applied to the all-solid-state cells; and a pass / fail determination unit that determines whether the all-solid-state cells are pass / fail using a pressure deviation by position of the pressure measured by the pressure measuring unit.

[0007] The above pressurizing unit may include a pressurizing member that pressurizes the all-solid cell, and a pressure providing unit that provides pressure to the pressurizing member.

[0008] The above-mentioned pressure member may include a pair of main pressure members connected to the pressure providing portion and positioned at the outermost end, a plurality of sub-pressure members positioned between the pair of main pressure members and spaced apart from each other by a predetermined interval, and a pressure connecting member penetrating through the plurality of sub-pressure members to connect the plurality of sub-pressure members to each other.

[0009] The above pressure measuring unit may be installed on the sub-pressure member and may face both sides of the all-solid-state cell.

[0010] The above pressure measuring unit may have an area greater than the area of ​​the main surface of the above all-solid-state cell.

[0011] The battery may further include a charging / discharging unit electrically connected to the plurality of all-solid-state cells and charging and discharging the plurality of all-solid-state cells.

[0012] In addition, a method for inspecting an all-solid-state secondary battery according to one embodiment includes the steps of: mounting a plurality of all-solid-state cells including a unit cell including a positive electrode, a negative electrode, and a solid electrolyte layer on an inspection body; pressurizing the plurality of all-solid-state cells using a pressurizing unit installed on the inspection body; measuring a pressure deviation at each position of the all-solid-state cells using a pressure measuring unit installed on the pressurizing unit; and determining whether the all-solid-state cells are passable or fail using the pressure deviation at each position of the all-solid-state cells.

[0013] The pressurizing unit includes a pressurizing member that pressurizes the all-solid-state cell, and a pressure providing unit that provides pressure to the pressurizing member, and the pressurizing member may include a pair of main pressurizing members that are connected to the pressure providing unit and positioned at the outermost end, and a plurality of sub pressurizing members that are positioned between the pair of main pressurizing members and are positioned at a predetermined interval.

[0014] The pressure measuring unit is installed in the sub-pressurizing member, and in the step of pressurizing the plurality of all-solid-state cells, the pressure measuring unit can come into contact with both surfaces of the all-solid-state cells.

[0015] The above pressure measuring unit may have an area greater than the area of ​​the main surface of the above all-solid-state cell.

[0016] In addition, a method for inspecting an all-solid-state secondary battery according to another embodiment includes the steps of: mounting a plurality of all-solid-state cells, each of which is a stack of unit cells including a positive electrode, a negative electrode, and a solid electrolyte layer, on an inspection body; pressurizing the plurality of all-solid-state cells using a pressurizing unit installed on the inspection body; charging and discharging the pressurized plurality of all-solid-state cells using a charging and discharging unit; measuring a pressure deviation at each position of the all-solid-state cells using a pressure measuring unit installed on the pressurizing unit; and determining whether the all-solid-state cells are good or bad using the pressure deviation.

[0017] The pressurizing unit includes a pressurizing member that pressurizes the all-solid-state cell, and a pressure providing unit that provides pressure to the pressurizing member, and the pressurizing member may include a pair of main pressurizing members that are connected to the pressure providing unit and positioned at the outermost end, and a plurality of sub pressurizing members that are positioned between the pair of main pressurizing members and are positioned at a predetermined interval.

[0018] The pressure measuring unit is installed in the sub-pressurizing member, and in the step of pressurizing the plurality of all-solid-state cells, the pressure measuring unit can come into contact with both surfaces of the all-solid-state cells.

[0019] The above pressure measuring unit may have an area greater than the area of ​​the main surface of the above all-solid-state cell.

[0020] In the step of charging and discharging the plurality of all-solid-state cells, the charging and discharging unit can be electrically connected to the electrode tabs of the all-solid-state cells.

[0021] According to the embodiments, it is possible to quickly and accurately determine whether an all-solid-state cell is good or bad during pressurization or initial charging and discharging without using an optical method.

[0022] In other words, prior to initial charging and discharging, the pressure deviation at each location in the solid-state cell can be measured during the pressurization process without applying a separate voltage, thereby identifying solid-state cells with uneven pressure at each location and enabling a pass / fail judgment. Consequently, process speed can be improved.

[0023] Furthermore, during initial charging and discharging under pressure, the pressure deviation across the solid-state cell can be measured to identify all-solid-state cells with uneven pressure across locations, enabling a pass / fail judgment. Therefore, defective all-solid-state cells can be identified in advance due to continued uneven lithium deposition.

[0024] In addition, since it is possible to simultaneously determine whether multiple solid-state cells are good or bad, the process speed can be improved.

[0025] 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.

[0026] Figure 1 is a cross-sectional view of an all-solid-state battery.

[0027] Figure 2 is a cross-sectional view of an all-solid-state battery including a precipitated negative electrode.

[0028] Figure 3 is a schematic plan view of an inspection device for an all-solid-state secondary battery according to one embodiment.

[0029] Figure 4 is an enlarged view of a portion of Figure 3.

[0030] FIG. 5 is a flowchart sequentially illustrating a method for inspecting an all-solid-state secondary battery according to one embodiment.

[0031] Figure 6 is a plan view illustrating one step of Figure 5.

[0032] Figure 7 is a diagram showing the pressure deviation at each position of an all-solid-state cell and whether the all-solid-state cell is good or bad, measured by an inspection method for an all-solid-state secondary battery according to one embodiment for five experimental examples.

[0033] Figure 8 is a flowchart sequentially illustrating a method for inspecting an all-solid-state secondary battery according to one embodiment.

[0034] Figure 9 is a plan view illustrating one step of Figure 8.

[0035] Figure 10 is a diagram showing the pressure deviation at each position of an all-solid-state cell and whether the all-solid-state cell is good or bad, measured by a method for inspecting an all-solid-state secondary battery in another embodiment for five experimental examples.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] Cathode for all-solid-state secondary batteries

[0041] 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.

[0042] 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.

[0043] positive electrode active material

[0044] 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.

[0045] Li a A 1-b X b D2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5);

[0046] 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);

[0047] 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);

[0048] Li a E 2-b X b O 4-c D c (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05);

[0049] 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);

[0050] 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);

[0051] 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);

[0052] 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);

[0053] 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);

[0054] Li a Ni 1-b-c Mr b X c O 2-α T2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2);

[0055] Li a Ni b HAVE BEEN c G d O2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0.001 ≤ d ≤ 0.1);

[0056] Li a Ni b Co c Mr 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);

[0057] Li a NiG bO2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0058] Li a CoG b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0059] Li a Mn 1-b G b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0060] Li a Mn2G b O4(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0061] Li a Mn 1-g G g PO4(0.90 ≤ a ≤ 1.8, 0 ≤ g ≤ 0.5);

[0062] QO2; QS2; LiQS2;

[0063] V2O5; LiV2O5;

[0064] LiZO2;

[0065] LiNiVO4;

[0066] Li (3-f) J2(PO4)3(0 ≤ f ≤ 2);

[0067] Li (3-f) Fe2(PO4)3(0 ≤ f ≤ 2);

[0068] Li a FePO4(0.90 ≤ a ≤ 1.8).

[0069] 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.

[0070] 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).

[0071] 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.

[0072] [Chemical Formula 1]

[0073] Li a1 Ni x1 M 1 y1 M 2 1-x1-y1 O2

[0074] In the above chemical formula 1, 0.9≤a1≤1.8, 0.3≤x1≤1, 0≤y1≤0.7, and M 1 and M2 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.

[0075] [Chemical Formula 2]

[0076] Li a2 Co x2 M 3 1-x2 O2

[0077] 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.

[0078] [Chemical Formula 3]

[0079] Li a3 Fe x3 M 4 (1-x3) PO4

[0080] 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.

[0081] 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.

[0082] 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.

[0083] Sulfide-based solid electrolyte

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] Average particle diameter (D) of sulfide-based solid electrolyte particles according to an embodiment 50 ) 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 have an average particle diameter (D) of 0.1 ㎛ to 1.0 ㎛ depending on the location or purpose of use. 50 ) may be small particles, or may have an average particle diameter (D) of 1.5 ㎛ to 5.0 ㎛. 50 ) may be large particles. Sulfide-based solid electrolyte particles with this particle size range can effectively penetrate between solid particles in a battery, and have excellent contact with the 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, and for example, the particle size distribution is obtained by measuring the sizes of about 20 particles in a scanning electron microscope image, where D 50It may have been calculated.

[0091] 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.

[0092] 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.

[0093] bookbinder

[0094] 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.

[0095] Challenge

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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 Zr1-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.

[0100] All-solid-state secondary battery

[0101] 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.

[0102] Figure 1 is a cross-sectional view of an all-solid-state battery.

[0103] 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.

[0104] cathode

[0105] 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.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] Average particle diameter of silicon particles (D 50 ) 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 may be SiO x It can be a particle, in which case SiO x In the range x can be greater than 0 and less than 2. Here, the average particle diameter (D 50 ) is measured by a particle size analyzer using laser diffraction and means the diameter of particles with a cumulative volume of 50% in the particle size distribution.

[0112] 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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] Figure 2 is a cross-sectional view of an all-solid-state battery including a precipitated negative electrode.

[0123] 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.

[0124] The cathode coating layer (45) may include a metal, carbon material, or a combination thereof that acts as a catalyst.

[0125] 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.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] 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 ㎛.

[0131] 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.

[0132] solid electrolyte layer

[0133] 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.

[0134] 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.

[0135] Meanwhile, the average particle diameter (D) of the solid electrolyte included in the positive electrode (20) 50 ) is the average particle diameter (D) of the solid electrolyte included in the solid electrolyte layer (30). 50) may be smaller than the average particle size of the solid electrolyte (20). In this case, the overall performance can be improved by increasing the mobility of lithium ions while maximizing the energy density of the all-solid-state battery. For example, the average particle size (D) of the solid electrolyte included in the positive electrode (20) 50 ) may be 0.1 ㎛ to 1.0 ㎛, or 0.1 ㎛ to 0.8 ㎛, and the average particle diameter (D) of the solid electrolyte included in the solid electrolyte layer (30) 50 ) 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 the transfer of lithium ions is facilitated, thereby suppressing the resistance and improving the overall performance of the all-solid-state secondary battery. Here, the average particle diameter (D of the solid electrolyte 50 ) can be measured by a particle size analyzer using laser diffraction. Alternatively, the particle size is measured by selecting 20 random particles from a microscope image such as a scanning electron microscope and obtaining a particle size distribution, where D 50 You can also calculate the value.

[0136] 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.

[0137] 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.

[0138] The thickness of the solid electrolyte layer may be, for example, 10 μm to 150 μm.

[0139] The solid electrolyte layer may further include an alkali metal salt, and / or an ionic liquid, and / or a conductive polymer.

[0140] 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.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] The ionic liquid comprises a) one or more cations selected from ammonium, pyrrolidinium, pyridinium, pyrimidinium, imidazolium, piperidinium, pyrazolium, oxazolium, pyridazinium, phosphonium, sulfonium, triazolium, and mixtures thereof, and b) BF4. - , PF6 - , AsF6 - , SbF6 - , AlCl4 - , HSO4 - , ClO4 - , CH3SO3 - , CF3CO2 - , Cl - , Br - , I - , BF4 - , SO4 - , CF3SO3 - , (FSO2)2N - , (C2F5SO2)2N - , (C2F5SO2)(CF3SO2)N - , and (CF3SO2)2N - It may be a compound containing one or more anions selected from among.

[0145] 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.

[0146] 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.

[0147] 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 / anode / solid electrolyte layer / cathode, or a laminated battery in which the structure of the unit cell is repeated.

[0148] 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.

[0149] Hereinafter, an inspection device for an all-solid-state secondary battery according to one embodiment will be described with reference to FIGS. 3 and 4.

[0150] An inspection device for an all-solid-state secondary battery according to one embodiment of the present invention may be utilized in a manufacturing process of an all-solid-state secondary battery, utilized for evaluating a manufactured all-solid-state secondary battery, or utilized as a pressurizing means when using an all-solid-state secondary battery.

[0151] FIG. 3 is a schematic plan view of an inspection device for an all-solid-state secondary battery according to one embodiment, and FIG. 4 is an enlarged view of a portion of FIG. 3.

[0152] As illustrated in FIGS. 3 and 4, an inspection device for an all-solid-state secondary battery according to one embodiment includes an inspection body (100), a pressurizing unit (200), a charging / discharging unit (300), a pressure measuring unit (400), and a pass / fail judgment unit (500).

[0153] The inspection body (100) can be equipped with a plurality of all-solid-state cells (10). Here, the all-solid-state cells (10) can have a stacked cell structure in which a plurality of unit cells (UC) and an elastic member (EM) are stacked. 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 all-solid-state cell (10) may have an electrode tab (15) that may be electrically connected to the charge / discharge unit (300).

[0154] The pressurizing unit (200) can pressurize both sides of a plurality of all-solid-state cells (10).

[0155] The pressurizing unit (200) may include a pressurizing member (210) and a pressure providing unit (220).

[0156] The pressurizing member (210) can pressurize the all-solid-state cell (10). The pressurizing member (210) can include a pair of main pressurizing members (211) located at the outermost end and connected to the pressure providing unit (220), a plurality of sub pressurizing members (212) located between the pair of main pressurizing members (211) and spaced apart from each other by a predetermined interval, and a pressurizing connecting member (213) that penetrates through the plurality of sub pressurizing members (212) and is connected to the pair of main pressurizing members (211). The all-solid-state cell (10) can be located between adjacent sub pressurizing members (212).

[0157] The pressure providing unit (220) can apply pressure to both surfaces of the all-solid-state cell (10) by providing pressure to the pressurizing member (210). The pressure providing unit (220) can include a driving motor, etc. The pressure providing unit (220) can apply a pressure of 2 MPa to 3 MPa to both surfaces of the all-solid-state cell (10). As the gap between a pair of main pressurizing members (211) is reduced by the pressure provided by the pressure providing unit (220), the gap (D) between the adjacent sub-pressurizing members (212) is reduced, thereby pressurizing both surfaces of the all-solid-state cell (10). At this time, the plurality of sub-pressurizing members (212) can move along the pressurizing connecting member (213) and reduce the gap (D) between the adjacent sub-pressurizing members (212).

[0158] The charging and discharging unit (300) is electrically connected to a plurality of all-solid-state cells (10) and can charge and discharge a plurality of all-solid-state cells (10).

[0159] The pressure measuring unit (400) is installed in the pressing member (210) of the pressing member (200) and can measure the pressure applied to the all-solid-state cell (10) in real time. The pressure measuring unit (400) can be installed in the sub-pressuring member (212) of the pressing member (210) and can face both sides of the all-solid-state cell (10). Using the pressure measured by the pressure measuring unit (400), the pressure deviation by position of the pressure applied to the all-solid-state cell (10) can be measured in real time.

[0160] This pressure measuring unit (400) may have an area greater than the area of ​​the main surface, which has the largest area in the all-solid-state cell (10). Therefore, the pressure measuring unit (400) may measure the pressure deviation by position of the pressure applied to all areas of the main surface of the all-solid-state cell (10). This pressure measuring unit (400) may be formed of a plurality of pressure sensors, etc., formed on a flat plate.

[0161] The pass / fail judgment unit (500) can be connected to the pressure measurement unit (400). The pass / fail of the all-solid-state cell (10) can be determined using the pressure deviation by position of the pressure measured by the pressure measurement unit (400). That is, if the pressure deviation by position of the all-solid-state cell (10) is greater than a reference value, it can be determined to be defective.

[0162] Hereinafter, an inspection method using an inspection device for an all-solid-state secondary battery according to the above embodiment will be described in detail with reference to the drawings.

[0163] FIG. 5 is a flowchart sequentially illustrating a method for inspecting an all-solid-state secondary battery according to one embodiment, and FIG. 6 is a plan view illustrating one step of FIG. 5.

[0164] As illustrated in FIGS. 3 to 5, first, a plurality of all-solid-state cells (10) are mounted on the inspection body (100) (S100). At this time, the plurality of all-solid-state cells (10) may be mounted in alignment between a plurality of sub-pressure members (212) of the pressure member or between the main pressure member (211) and the sub-pressure member (212). Here, the all-solid-state cell (10) may be a final product having a stack cell structure in which a plurality of unit cells (UC) and elastic members (EM) are stacked.

[0165] Next, as illustrated in FIGS. 5 and 6, a plurality of all-solid-state cells (10) are pressurized using a pressurizing unit installed in the inspection body (S200). That is, as the gap between a pair of main pressurizing members (211) is reduced by the pressure provided by the pressure providing unit (220), the gap (D) between adjacent sub-pressurizing members (212) is reduced, thereby pressurizing both surfaces of the all-solid-state cells (10). At this time, the pressure measuring unit (400) can come into contact with both surfaces of the all-solid-state cells (10), and a pressure of 2 MPa to 3 MPa can be uniformly applied to both surfaces of the all-solid-state cells (10).

[0166] Next, after a predetermined period of time, for example, about 2 minutes, the pressure deviation at each position of the all-solid-state cell (10) is measured in real time using the pressure measuring unit (400) installed in the sub-pressure member (212) (S300). At this time, the charging / discharging unit (300) is not electrically connected to the electrode tab (15) of the all-solid-state cell (10).

[0167] Next, the pass / fail judgment unit (500) connected to the pressure measurement unit (400) determines whether the all-solid-state cell (10) is pass / fail using the pressure deviation by position of the all-solid-state cell (10) measured by the pressure measurement unit (400) (S400). At this time, if the pressure deviation by position of the all-solid-state cell (10) is greater than a reference value, it can be determined to be defective. Here, the all-solid-state cell (10) can be determined to be defective due to the pressure deviation by position of the all-solid-state cell (10) occurring due to uneven thickness or low alignment of the anode (11), cathode (13), solid electrolyte layer (12), and elastic member (EM) formed inside the all-solid-state cell (10).

[0168] Figure 7 is a diagram illustrating the pressure deviation by position in an all-solid-state cell and whether the all-solid-state cell is good or bad, measured by an inspection method for an all-solid-state secondary battery according to one embodiment for five experimental examples. Here, the reference value for the pressure deviation by position was set to 18.

[0169] As shown in Fig. 7, experimental examples 1 to 3 are judged as defective products because the pressure deviation by position exceeds the standard value of 18, and experimental examples 4 and 5 are judged as good products because the pressure deviation by position is less than the standard value of 18.

[0170] In this way, the inspection method of an all-solid-state secondary battery according to one embodiment can measure the pressure deviation at each position of the all-solid-state cell (10) in the pressurization process before conducting a charge and discharge test, thereby identifying an all-solid-state cell (10) with uneven pressure at each position, thereby enabling a pass / fail judgment. Therefore, the process speed can be improved.

[0171] In addition, since the solid-state cell (10) determined to be defective does not need to undergo separate charge and discharge tests, the process speed can be improved.

[0172] Meanwhile, in this embodiment, whether the solid-state cell is good or bad is determined before performing the charge and discharge test, but another embodiment in which whether the solid-state cell is good or bad is determined by performing the charge and discharge test under pressure is also possible.

[0173] Hereinafter, with reference to FIGS. 8 to 10, a method for inspecting an all-solid-state secondary battery according to another embodiment of the present invention will be described in detail.

[0174] FIG. 8 is a flowchart sequentially illustrating a method for inspecting an all-solid-state secondary battery according to one embodiment, and FIG. 9 is a plan view illustrating one step of FIG. 8.

[0175] The other embodiment illustrated in FIGS. 8 and 9 is substantially the same as the embodiment illustrated in FIGS. 5 and 6 except that it conducts charge and discharge tests under pressure and determines whether the solid-state cell is good or bad, and thus a repeated description thereof will be omitted.

[0176] As shown in Fig. 8, a method for inspecting an all-solid-state secondary battery according to another embodiment of the present invention first mounts a plurality of all-solid-state cells (10) on an inspection body (100) (S10).

[0177] Next, a plurality of all-solid-state cells (10) are pressurized using a pressurizing unit (200) installed in the inspection body (100) (S20).

[0178] Next, multiple all-solid-state cells (10) are charged and discharged under pressure (S30). At this time, the charging and discharging unit (300) can be electrically connected to the electrode tabs (15) of the all-solid-state cells (10).

[0179] Next, after a predetermined period of time, for example, about 2 minutes, the pressure measurement unit (400) installed in the sub-pressure member (212) is used to measure the pressure deviation at each position of the all-solid-state cell (10) in real time (S40). During charging and discharging of the all-solid-state cell (10), lithium is unevenly precipitated in the case of a defective all-solid-state cell (10), so residual lithium may occur in some areas, which may cause a pressure deviation at each position of the all-solid-state cell (10).

[0180] Next, the pass / fail judgment unit (500) connected to the pressure measurement unit (400) determines whether the solid-state cell (10) is pass / fail using the pressure deviation by position of the solid-state cell (10) measured by the pressure measurement unit (400) (S50). At this time, if the pressure deviation by position of the solid-state cell (10) is greater than a reference value, it can be determined to be defective.

[0181] Figure 10 is a diagram illustrating the pressure deviation by position in an all-solid-state cell and whether the all-solid-state cell is good or bad, measured by a different inspection method for an all-solid-state secondary battery in five experimental examples. Here, the reference value for the pressure deviation by position was set to 26.

[0182] As shown in Fig. 10, experimental examples 1 to 3 are judged as defective products because the pressure deviation by position exceeds the standard value of 26, and experimental examples 4 and 5 are judged as good products because the pressure deviation by position is less than the standard value of 26.

[0183] In this way, the inspection method of an all-solid-state secondary battery according to one embodiment can determine whether a solid-state cell (10) is good or bad by measuring the pressure deviation at each position of the solid-state cell (10) during initial charging and discharging during pressurization, thereby identifying an all-solid-state cell (10) with uneven pressure at each position. Accordingly, it is possible to determine in advance an all-solid-state cell (10) that was not initially determined to be defective, but will later become defective due to uneven lithium deposition that continuously occurs during charging and discharging.

[0184] 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 test body equipped with a plurality of all-solid-state cells in which unit cells including an anode, a cathode, and a solid electrolyte layer are stacked; A pressurizing unit installed in the above inspection body and pressurizing the plurality of all-solid-state cells; A pressure measuring unit installed in the above pressurized unit and measuring the pressure applied to the all-solid-state cell; and A pass / fail judgment unit that determines whether the all-solid-state cell is pass / fail by using the pressure difference at each location of the pressure measured by the pressure measurement unit. A device for testing an all-solid-state secondary battery including a .

2. In paragraph 1, The above pressurized part A pressure member that pressurizes the above-mentioned all-solid cell, and a pressure providing member that provides pressure to the above-mentioned pressure member An inspection device for an all-solid-state secondary battery, comprising:

3. In paragraph 2, The above pressurized member A pair of main pressurizing members connected to the above pressure providing member and located at the outermost part; A plurality of sub-pressure members positioned between the above pair of main pressurizing members and spaced apart by a predetermined interval, and A pressure connecting member that penetrates the plurality of sub-pressure members and connects the plurality of sub-pressure members to each other. An inspection device for an all-solid-state secondary battery, comprising:

4. In paragraph 3, An inspection device for an all-solid-state secondary battery, wherein the pressure measuring unit is installed on the sub-pressure member and faces both sides of the all-solid-state cell.

5. In paragraph 3, An inspection device for an all-solid-state secondary battery, wherein the pressure measuring unit has an area greater than the area of ​​the main surface of the all-solid-state cell.

6. In paragraph 1, An inspection device for an all-solid-state secondary battery, further comprising a charging / discharging unit electrically connected to the plurality of all-solid-state cells and charging and discharging the plurality of all-solid-state cells.

7. A step of mounting a plurality of all-solid-state cells including a unit cell including an anode, a cathode, and a solid electrolyte layer on the inspection body; A step of pressurizing the plurality of all-solid-state cells using a pressurizing unit installed in the inspection body; A step of measuring the pressure difference at each position of the all-solid-state cell using a pressure measuring unit installed in the pressurized unit; and A step for determining whether the solid-state cell is good or bad by using the pressure difference at each location of the solid-state cell. A method for inspecting an all-solid-state secondary battery including a .

8. In paragraph 7, The above pressurized part A pressure member that pressurizes the above-mentioned all-solid cell, and a pressure providing member that provides pressure to the above-mentioned pressure member Including, The above pressurized member A pair of main pressurizing members connected to the above pressure providing member and located at the outermost part, and A plurality of sub-pressure members positioned between the above pair of main pressurizing members and spaced apart by a predetermined interval A method for inspecting an all-solid-state secondary battery, comprising:

9. In paragraph 7, The above pressure measuring unit is installed in the sub-pressure member, A method for inspecting an all-solid-state secondary battery, wherein, in the step of pressurizing the plurality of all-solid-state cells, the pressure measuring unit is in contact with both surfaces of the all-solid-state cells.

10. In paragraph 8, A method for inspecting an all-solid-state secondary battery, wherein the pressure measuring unit has an area greater than the area of ​​the main surface of the all-solid-state cell.

11. A step of mounting a plurality of all-solid-state cells, each of which is a unit cell including an anode, a cathode, and a solid electrolyte layer, on the inspection body; A step of pressurizing the plurality of all-solid-state cells using a pressurizing unit installed in the inspection body; A step of charging and discharging the plurality of pressurized all-solid-state cells using a charging and discharging unit; A step of measuring the pressure difference at each position of the all-solid-state cell using a pressure measuring unit installed in the pressurized unit; and A step for determining whether the all-solid cell is good or bad by using the above pressure difference. A method for inspecting an all-solid-state secondary battery including a .

12. In Article 11, The above pressurizing part comprises a pressurizing member that pressurizes the all-solid cell, and a pressure providing member that provides pressure to the pressurizing member. Including, The above pressurized member A pair of main pressurizing members connected to the above pressure providing member and located at the outermost part, and A plurality of sub-pressure members positioned between the above pair of main pressurizing members and spaced apart by a predetermined interval A method for inspecting an all-solid-state secondary battery, comprising:

13. In paragraph 12, The above pressure measuring unit is installed in the sub-pressure member, A method for inspecting an all-solid-state secondary battery, wherein, in the step of pressurizing the plurality of all-solid-state cells, the pressure measuring unit is in contact with both surfaces of the all-solid-state cells.

14. In Article 12, A method for inspecting an all-solid-state secondary battery, wherein the pressure measuring unit has an area greater than the area of ​​the main surface of the all-solid-state cell.

15. In paragraph 12, In the step of charging and discharging the above plurality of all-solid-state cells, A method for inspecting an all-solid-state secondary battery, wherein the above charging and discharging unit is electrically connected to the electrode tab of the all-solid-state cell.

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