All-solid-state battery

Abstract

An all-solid-state battery including a first electrode, a second electrode, and a solid electrolyte layer positioned between the first electrode and the second electrode, according to one embodiment of the present invention, comprises a short-circuiting auxiliary layer and a short-circuiting metal layer which are laminated on the outermost first electrode positioned at the outermost side of the electrode battery, wherein the short-circuiting metal layer is electrically connected to the second electrode, and the short-circuiting auxiliary layer electrically connects between the short-circuiting metal layer and the outermost first electrode at a first temperature or higher.

Description

All-solid-state batteries

[0001] The present invention relates to an all-solid-state 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 batteries composed entirely of solid materials and utilize solid electrolytes.

[0003] These all-solid-state secondary batteries are safe because there is no risk of explosion due to electrolyte leakage, and they have the advantage of being easy to manufacture thin batteries.

[0004] The present invention provides an all-solid-state battery that quickly reduces the risk of fire or the like when a battery is penetrated.

[0005] In an all-solid-state battery having a plurality of stacked unit cells including a positive electrode including a first electrode, a negative electrode including a second electrode, and a solid electrolyte layer positioned between the positive electrode and the negative electrode according to one embodiment of the present invention, the all-solid-state battery includes a short-circuit auxiliary layer and a short-circuit metal layer stacked on the outermost first electrode positioned at the outermost side of the all-solid-state battery, the short-circuit metal layer being electrically connected to the first electrode or the second electrode, and the short-circuit auxiliary layer electrically connecting the short-circuit metal layer and the outermost first electrode at a first temperature or higher.

[0006] The above-mentioned auxiliary layer may have an increased electrical conductivity at a temperature higher than the first temperature.

[0007] The above first temperature is the melting point of the short-circuit auxiliary layer, and the electrical conductivity may increase as the short-circuit auxiliary layer melts.

[0008] The above-mentioned auxiliary layer may be a mixture in which a conductive filler having an electronic conductivity of 1 / 20 or higher than that of copper is mixed into a polymer resin.

[0009] The above conductive filler may include at least one of carbon black (CNT), exfoliated graphite, carbon nanofibers (CNF), and metal nanoparticles.

[0010] The above-mentioned short-circuit auxiliary layer has a metal-insulator transition characteristic, and may be an insulator below the first temperature and a conductor above the first temperature.

[0011] The above-described auxiliary layer may be a rare earth metal, such as EuNiO3 or SmNiO3.

[0012] The above-mentioned auxiliary layer can shrink above the first temperature.

[0013] As the above-mentioned short-circuit auxiliary layer shrinks, one surface of the above-mentioned short-circuit auxiliary layer and one surface of the outermost first electrode facing each other are exposed and can be electrically connected to each other.

[0014] The above-mentioned auxiliary layer can be reduced by 20 to 80% of its pre-shrinkage area.

[0015] The above-mentioned auxiliary layer may be made of a porous polymer resin.

[0016] The above-mentioned auxiliary layer may be any one of PVC, polyolefin, and fluoropolymer.

[0017] The thickness of the above-mentioned auxiliary layer may be 10 µm to 30 µm, and the first temperature may be 130°C to 150°C.

[0018] According to another embodiment, an all-solid-state battery comprises a first all-solid-state battery, a plurality of second all-solid-state batteries electrically connected to the first all-solid-state battery, and at least one of the second all-solid-state batteries may include an intermediate short-circuiting auxiliary layer overlapping an outermost first electrode of the second all-solid-state battery, and an intermediate short-circuiting metal layer overlapping the intermediate short-circuiting auxiliary layer and electrically connected to a second electrode having an opposite polarity to the outermost first electrode of the second all-solid-state battery.

[0019] The second solid-state battery is repeatedly stacked, and the first solid-state battery can be positioned on each side of the stacked second solid-state battery.

[0020] The above intermediate short-circuit auxiliary layer can electrically connect between the intermediate short-circuit metal layer and the first electrode at a temperature higher than the first temperature.

[0021] The above intermediate short-circuit auxiliary layer may be made of the same material as the above short-circuit auxiliary layer.

[0022] According to embodiments of the present invention, when a short circuit occurs due to penetration, a short circuit path can be quickly formed to disperse the short circuit current.

[0023] In addition, according to embodiments of the present invention, a safe all-solid-state battery can be manufactured by reducing the occurrence of fire due to heat by forming a short-circuit pass using surface contact.

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

[0025] Figures 2 and 3 are cross-sectional views of an all-solid-state battery according to another embodiment of the present invention.

[0026] FIG. 4 and FIG. 5 are drawings for explaining the penetration state of an all-solid-state battery according to one embodiment of the present invention.

[0027] Figures 6 to 8 are cross-sectional views of an all-solid-state battery according to another embodiment.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032]

[0033] All-solid-state batteries

[0034] In one embodiment, an all-solid-state 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 battery may also be referred to as an all-solid-state secondary battery or an all-solid-state lithium secondary battery.

[0035] Figure 1 is a cross-sectional view of an all-solid-state battery.

[0036] 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.

[0037]

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

[0039] In one embodiment, a positive electrode for an all-solid-state secondary battery is provided, comprising a current collector and a positive electrode active material layer positioned on the current collector, wherein the positive electrode active material layer comprises at least one of a positive electrode active material, a sulfide-based solid electrolyte, a binder, and a conductive material. However, without limitation thereto, the positive electrode for an all-solid-state secondary battery may comprise more or less components than the components described above.

[0040] In one embodiment, the positive electrode for the all-solid-state secondary battery is manufactured by applying a positive electrode composition including at least one of a positive electrode active material, a sulfide-based solid electrolyte, a binder, and a conductive agent to a current collector, followed by drying and rolling.

[0041]

[0042] positive electrode active material

[0043] The above-mentioned positive electrode active material can be applied without limitation as long as it is generally used in all-solid-state secondary batteries. For example, the above-mentioned positive electrode active material may be a compound capable of reversible intercalation and deintercalation of lithium, and may include a compound represented by any one of the following chemical formulas.

[0044] Li a A 1-b X b D2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5);

[0045] 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);

[0046] Li a HAVE BEEN 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 HAVE BEEN 2-b X b O 4-c D c (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05);

[0048] 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);

[0049] 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);

[0050] 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);

[0051] 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);

[0052] 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);

[0053] 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);

[0054] 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);

[0055] 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);

[0056] Li a NiG b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0057] Li a CoG b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0058] Li a Mn 1-b G b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0059] Li a Mn2G b O4(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0060] Li a Mn 1-g G g PO4(0.90 ≤ a ≤ 1.8, 0 ≤ g ≤ 0.5);

[0061] QO2; QS2; LiQS2;

[0062] V2O5; LiV2O5;

[0063] LiZO2;

[0064] LiNiVO4;

[0065] Li (3-f) J2(PO4)3(0 ≤ f ≤ 2);

[0066] Li (3-f) Fe2(PO4)3(0 ≤ f ≤ 2);

[0067] Li a FePO4(0.90 ≤ a ≤ 1.8).

[0068] 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.

[0069] The above-mentioned positive electrode active material may be, for example, lithium cobalt oxide (LCO), lithium nickel oxide (LNO), lithium nickel cobalt oxide (NC), lithium nickel cobalt aluminum oxide (NCA), lithium nickel cobalt manganese oxide (NCM), lithium nickel manganese oxide (NM), lithium manganese oxide (LMO), or lithium iron phosphate (LFP).

[0070] The above positive electrode active material may include a lithium nickel-based oxide represented by the following chemical formula 1, a lithium cobalt-based oxide represented by the following chemical formula 2, a lithium iron phosphate-based compound represented by the following chemical formula 3, or a combination thereof.

[0071] [Chemical Formula 1]

[0072] Li a1 Ni x1 M 1 y1 M 2 1-x1-y1 O2

[0073] 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.

[0074] [Chemical Formula 2]

[0075] Li a2 Co x2 M 3 1-x2 O2

[0076] 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.

[0077] [Chemical Formula 3]

[0078] Li a3 Fe x3 M 4 (1-x3) PO4

[0079] 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.

[0080] 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.

[0081] 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.

[0082]

[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, thereby finely agitating them and mixing 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 an electrode layer and a solid electrolyte layer. An all-solid-state battery including this can have improved battery performance, such as rate characteristics, Coulombic efficiency, and cycle life characteristics.

[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] 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.

[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 this content range is satisfied, the positive electrode for an all-solid-state secondary battery can implement high capacity and high ionic conductivity while maintaining high adhesiveness, and the viscosity of the positive electrode composition can be maintained at an appropriate level, thereby improving processability.

[0093]

[0094] bookbinder

[0095] 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.

[0096]

[0097] Challenge

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102]

[0103] All-solid-state secondary battery

[0104] In one embodiment, an all-solid-state secondary battery is provided, which includes the aforementioned positive electrode and negative electrode and a solid electrolyte layer positioned between the positive electrode and negative electrode. The all-solid-state secondary battery may also be referred to as an all-solid-state battery or an all-solid-state lithium secondary battery.

[0105]

[0106] cathode

[0107] An anode for an all-solid-state battery may include, for example, a current collector and a negative electrode active material layer positioned on the current collector. The negative electrode active material layer includes a negative electrode active material and may further include a binder, a conductive material, and / or a solid electrolyte.

[0108] The above negative active material may include a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0109] The material capable of reversibly intercalating / deintercalating the lithium ions may include a carbon-based negative electrode active material, for example, crystalline carbon, amorphous carbon, or a combination thereof. Examples of the crystalline carbon include graphite such as natural graphite or artificial graphite in an amorphous, plate-like, flake-like, spherical, or fibrous form, and examples of the amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, and the like.

[0110] As the above lithium metal alloy, an alloy of lithium and one or more metals selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn can be used.

[0111] As the material capable of doping and dedoping the lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material can be used, and the Si-based negative electrode active material may be silicon, a silicon-carbon composite, or SiO. x(0<x<2), Si-Q 합금(상기 Q는 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소, 15족 원소, 16족 원소, 전이금속, 희토류 원소 및 이들의 조합으로 이루어진 군에서 선택되는 원소이며, Si은 아님), 상기 Sn계 음극 활물질로는 Sn, SnO2, Sn-R 합금(상기 R은 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소, 15족 원소, 16족 원소, 전이금속, 희토류 원소 및 이들의 조합으로 이루어진 군에서 선택되는 원소이며, Sn은 아님) 등을 들 수 있고, 또한 이들 중 적어도 하나와 SiO2를 혼합하여 사용할 수도 있다. 상기 원소 Q 및 R로는 Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Tl, Ge, P, As, Sb, Bi, S, Se, Te, Po, 및 이들의 조합으로 이루어진 군에서 선택되는 것을 사용할 수 있다.

[0112] 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.

[0113] The average particle diameter (D50) of the above silicon particles may be 10 nm to 20 μm, for example, 10 nm to 500 nm. The silicon particles may exist in an oxidized form, and at this time, the atomic content ratio of Si:O in the silicon particles, which indicates the degree of oxidation, may be 99:1 to 33:67. The silicon particles may be SiO x It can be a particle, in which case SiO x In the range of x, it can be greater than 0 and less than 2. Here, the average particle diameter (D50) is measured by a particle size analyzer using laser diffraction and means the diameter of particles having a cumulative volume of 50% by volume in the particle size distribution.

[0114] The above Si-based negative electrode active material or Sn-based negative electrode active material can be used in combination with a carbon-based negative electrode active material. The mixing ratio of the Si-based negative electrode active material or Sn-based negative electrode active material and the carbon-based negative electrode active material can be 1:99 to 90:10 by weight.

[0115] The content of the negative active material in the above negative active material layer may be 95 wt% to 99 wt% with respect to the total weight of the negative active material layer.

[0116] 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.

[0117] The above binder serves to adhere the negative electrode active material particles well to each other and also to adhere the negative electrode active material well to the current collector. The binder may include an insoluble binder, a water-soluble binder, or a combination thereof.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] The negative electrode current collector may be selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and a combination thereof.

[0123] 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.

[0124] FIG. 2 is a schematic cross-sectional view of an all-solid-state secondary battery (1001) including a precipitated negative electrode according to one embodiment.

[0125] Referring to FIG. 2, the precipitation-type negative electrode (40') may include a current collector (41) and a negative electrode coating layer (45) positioned on the current collector. 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 is present, and during charging, high-density lithium metal or the like is precipitated between the current collector (41) and the negative electrode coating layer (45) to form a lithium metal layer (44), which may function as a negative electrode active material. Accordingly, in an all-solid-state battery that has been charged at least once, the precipitation-type negative electrode (40') may include a current collector (41), a lithium metal layer (44) positioned on the current collector, 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.

[0126] The above cathode coating layer (45) may include a metal, carbon material, or a combination thereof that acts as a catalyst.

[0127] The metal may include, for example, gold, platinum, palladium, silicon, silver, aluminum, bismuth, tin, zinc, or a combination thereof, and may be composed of one type of these or may be composed of an alloy of several types. When the metal is present in the form of particles, the average particle diameter (D50) thereof may be about 4 μm or less, for example, 10 nm to 4 μm.

[0128] 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.

[0129] When the above-described negative electrode coating layer (45) includes both the metal and the carbon material, the mixing ratio of the metal and the carbon material may be, for example, a weight ratio of 1:10 to 2:1. In this case, the precipitation of lithium metal can be effectively promoted and the characteristics of the all-solid-state battery can be improved. The above-described negative electrode coating layer (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.

[0130] The above cathode coating layer (45) may include, for example, the metal and amorphous carbon, in which case it can effectively promote the precipitation of lithium metal.

[0131] The above cathode coating layer (45) may further include a binder, and the binder may be a conductive binder. In addition, the above cathode coating layer (45) may further include general additives such as fillers, dispersants, and ionic conductive agents.

[0132] 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 ㎛.

[0133] The above-described precipitated negative electrode (40') may further include, for example, a thin film on the surface of the current collector, i.e., between the current collector and the negative electrode coating layer. The thin film may include an element capable of forming an alloy with lithium. The element capable of forming an alloy with lithium may be, for example, gold, silver, zinc, tin, indium, silicon, aluminum, bismuth, etc., and may be composed of one type thereof or may be composed of multiple types of alloys. The thin film may further flatten the precipitated form of the lithium metal layer (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.

[0134]

[0135] solid electrolyte layer

[0136] 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.

[0137] 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.

[0138] 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.

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

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

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

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

[0143] The above alkali metal salt may be, for example, a lithium salt. The content of the lithium salt in the solid electrolyte layer may be 1 M or more, for example, 1 M to 4 M. In this case, the lithium salt may improve ion conductivity by enhancing the lithium ion mobility of the solid electrolyte layer.

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

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

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

[0147] The above ionic liquid may be a compound including a) one or more cations selected from ammonium-based, pyrrolidinium-based, pyridinium-based, pyrimidinium-based, imidazolium-based, piperidinium-based, pyrazolium-based, oxazolium-based, pyridazinium-based, phosphonium-based, sulfonium-based, triazolium-based, and mixtures thereof, and b) one or more anions selected from BF4-, PF6-, AsF6-, SbF6-, AlCl4-, HSO4-, ClO4-, CH3SO3-, CF3CO2-, Cl-, Br-, I-, BF4-, SO4-, CF3SO3-, (FSO2)2N-, (C2F5SO2)2N-, (C2F5SO2)(CF3SO2)N-, and (CF3SO2)2N-.

[0148] The ionic liquid may be at least one selected from the group consisting of, for example, N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide, N-butyl-N-methylpyrrolidinium bis(3-trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide.

[0149] In the above solid electrolyte layer, the weight ratio of the solid electrolyte and the ionic liquid may be 0.1:99.9 to 90:10, for example, 10:90 to 90:10, 20:80 to 90:10, 30:70 to 90:10, 40:60 to 90:10, or 50:50 to 90:10. A solid electrolyte layer satisfying the above range can maintain or improve ionic conductivity by improving the electrochemical contact area with the electrode. Accordingly, the energy density, discharge capacity, rate characteristics, etc. of the all-solid-state battery can be improved.

[0150] The above-mentioned all-solid-state battery may be a unit battery having a structure of positive electrode / solid electrolyte layer / negative electrode, a bi-cell having a structure of positive electrode / solid electrolyte layer / negative electrode / solid electrolyte layer / positive electrode, or a laminated battery in which the structure of the unit battery is repeated.

[0151] The shape of the above-mentioned all-solid-state battery is not particularly limited, and may be, for example, coin-shaped, button-shaped, sheet-shaped, stacked, cylindrical, flat, etc. In addition, the above-mentioned all-solid-state battery can be applied to large-scale batteries used in electric vehicles, etc. For example, the above-mentioned all-solid-state battery can be used in hybrid vehicles such as plug-in hybrid electric vehicles (PHEVs). In addition, it can be used in fields requiring large amounts of power storage, and for example, it can be used in electric bicycles or power tools.

[0152] The above all-solid-state battery may further include a short circuit member, which is described below with reference to the drawings.

[0153] Figure 3 is a cross-sectional view of an all-solid-state battery according to one embodiment of the present invention.

[0154] Referring to FIG. 3, an all-solid-state battery (1002) according to one embodiment is composed of an all-solid-state battery in which a positive electrode (20) including a positive electrode collecting layer (21) and a positive electrode active material layer (23), a solid electrolyte layer (30), and a negative electrode (40) including a negative electrode collecting layer (41) and a negative electrode active material layer (43) are laminated.

[0155] The all-solid-state battery (1002) has a mono-cell structure in which a positive electrode (20) and a negative electrode (40) are alternately positioned with a solid electrolyte layer (30) in between, and the mono-cells can be repeatedly stacked (not shown).

[0156] Meanwhile, a short circuit member (500) may be laminated on the electrode located at the outermost side (hereinafter referred to as the outermost electrode). Since one anode and one cathode are illustrated in FIG. 3, either the anode or the cathode may be the outermost electrode, and FIG. 3 illustrates the cathode as an example.

[0157] The short circuit member (500) includes a short circuit metal layer (51), a short circuit auxiliary layer (53) positioned between the short circuit metal layer (51) and the cathode (40), which is the outermost electrode.

[0158] The metal layer (51) for short circuiting is a metal material that can easily be short circuited when a penetration occurs due to a penetrating nail or an external impact, and may be made of, for example, aluminum, copper, or nickel-plated copper.

[0159] In addition, the metal layer (51) for short circuiting may be formed of a positive electrode current collecting layer (21) or a negative electrode current collecting layer (21), and when formed of a separate metal, the strength can be increased by forming it thicker than the positive or negative electrode current collecting layer (21, 41). In addition, when the thickness of the metal layer (51) for short circuiting is formed thicker than the current collecting layer (21, 41) of the electrode, the resistance is reduced, so that a safer short circuit path can be formed when penetrating.

[0160] The short-circuit metal layer (51) can be electrically connected to the polarity opposite to that of the outermost electrode. In Fig. 3, the cathode is the outermost electrode, and the short-circuit member (500) is positioned on the cathode (40), so that the short-circuit metal layer (51) can be electrically connected to the anode (20).

[0161] Conversely, if the outermost electrode is an anode and a short-circuiting member is positioned over the anode, the short-circuiting metal layer can be electrically connected to the cathode.

[0162] The short-circuit auxiliary layer (53) is formed with a uniform thickness between one surface of the short-circuit metal layer (51) facing each other and one surface of the cathode current collecting layer (21), which is the outermost electrode.

[0163] The short-circuit metal layer (51) and the cathode, which is the outermost electrode, are maintained in an insulated state with the short-circuit auxiliary layer (53) interposed therebetween. Thereafter, at a first temperature or higher, the short-circuit auxiliary layer (52) electrically connects the short-circuit metal layer (51) and the cathode, which is the outermost electrode (40).

[0164] The short-circuit auxiliary layer (52) may be a material whose electrical conductivity increases at a first temperature or higher. Accordingly, when the electrical conductivity increases, the short-circuit metal layer (51) electrically connected to the positive electrode and the negative electrode current collecting layer (41), which is the outermost electrode, are electrically connected to form a short-circuit path. At this time, one surface of the negative electrode current collecting layer (41) and one surface of the negative electrode current collecting layer (51), which face each other, are electrically connected through the short-circuit auxiliary layer (53), so that heat generated by the short-circuit can be quickly dispersed and discharged by connecting them through surface contact.

[0165] The short-circuit auxiliary layer (53) may be a material having a first temperature as its melting point, and when the first temperature, which is the melting point, is higher than the first temperature, the short-circuit auxiliary layer (53) melts and its electrical conductivity increases. For example, the first temperature may be 130°C to 150°C, and a conductive filler may be included in a polymer resin such as PET.

[0166] Conductive fillers can have an electronic conductivity that is at least 1 / 20 that of copper. For example, conductive fillers can be carbon black (CNT), exfoliated graphite, carbon nanofibers (CNF), or metal nanoparticles.

[0167] If the first temperature is lower than 130℃, short circuits can be induced even at low temperatures, such as during the cell manufacturing process, which can irreversibly damage the cell being manufactured. Furthermore, if the cell is operated at high temperatures above 150℃, it is difficult to prevent a rapid temperature rise. To prevent a rapid temperature rise in the cell through surface short circuits, short circuits at excessively high temperatures are undesirable.

[0168] FIG. 4 and FIG. 5 are drawings for explaining the penetration state of an all-solid-state battery according to one embodiment.

[0169] As shown in Fig. 4, the penetration test is performed by a penetrating member (70), such as a penetrating nail, penetrating the all-solid-state battery (1002) to form a short circuit pass.

[0170] The penetrating member (70) quickly forms a short circuit pass by penetrating the short circuit member (500) and electrically connecting the short circuit metal layer (51) and the negative electrode current collecting layer (41) of the negative electrode, which is the outermost electrode.

[0171] Meanwhile, when the short-circuit metal layer (51) and the negative electrode current collecting layer (41) are short-circuited, a short-circuit pass is formed and heat is generated. The generated heat is transferred to the short-circuit auxiliary layer (53) through the penetrating nail (see arrow), and when the temperature of the short-circuit auxiliary layer (53) increases above the melting point, the short-circuit auxiliary layer (53) melts and the electrical conductivity increases.

[0172] As the short-circuit auxiliary layer (53) melts and the electrical conductivity increases, the short-circuit metal layer (51) and the negative electrode current collecting layer (41) are electrically connected, and one surface of the facing short-circuit metal layer (51) and one surface of the negative electrode current collecting layer (21) come into surface contact.

[0173] As heat spreads around the penetrating member (70), the area over which heat is transferred increases, and the area of ​​the short-circuit auxiliary layer (53) melted around the penetrating member (70) increases, so the surface contact area also increases. Therefore, the short-circuit current can be quickly dispersed.

[0174] Additionally, as the electrically connected area increases, the resistance between them decreases due to surface contact.

[0175] That is, when a short circuit pass is formed by connecting only with a penetrating member (70), the temperature may rise rapidly, but as the short circuit auxiliary layer (53) is melted by heat, the contact area between the short circuit metal layer (51) and the negative electrode current collecting layer (41) increases, reducing resistance and reducing the generated heat.

[0176] As described above, in one embodiment of the present invention, a short circuit member capable of surface contact is formed, thereby quickly forming a short circuit path and quickly dissipating the internal short circuit current.

[0177] In addition, by forming a short circuit auxiliary layer (53) and bringing the short circuit metal layer (51) and the negative electrode current collecting layer (41) into surface contact, the amount of heat generated due to the short circuit pass can be reduced.

[0178] Therefore, when a short circuit occurs due to penetration, it can quickly discharge the current and reduce heat generation, thereby preventing secondary accidents such as fire.

[0179] Again, referring to FIG. 3, the short-circuit auxiliary layer (53) may be a material whose insulating properties change depending on the temperature, and may be a material having insulating properties below a first temperature and having conductive properties with increased electrical conductivity above the first temperature, and may be made of EuNiO3 or SmNiO3, which are rare earth metals capable of causing a metal-insulator transition.

[0180] Additionally, the polymer resin may be formed of a polymer resin that shrinks at a first temperature of 130°C to 150°C or higher, and may be porous to increase the shrinkage rate. The shrinkage polymer may be a heat-shrinkable polymer, such as PVC, polyolefin, or a fluoropolymer.

[0181] Referring to FIG. 5, when the short-circuit auxiliary layer (53) increases above the first temperature, the short-circuit auxiliary layer (53) shrinks (see arrow), and due to the shrinkage, one surface of the short-circuit metal layer (51) under the short-circuit auxiliary layer (53) and one surface of the negative electrode current collecting layer (41), which is the outermost electrode, are exposed, and the exposed surfaces come into contact with each other to form a short-circuit pass.

[0182] The short-circuit auxiliary layer (53) may have a thickness of 10 μm to 30 μm. Even if the short-circuit auxiliary layer (53) shrinks, the all-solid-state battery is a battery assembled by applying pressure from the outside, and the negative electrode current collecting layer (41) and the short-circuit metal layer (51) are electrically connected regardless of the thickness of the short-circuit auxiliary layer (53). In addition, the contracted short-circuit auxiliary layer (53) electrically connects the short-circuit metal layer (51) and the negative electrode current collecting layer (41) in a state of shrinking and reducing in size.

[0183] The short-circuit auxiliary layer (53) can be reduced in area by 20% to 80% of the area before shrinkage.

[0184] FIG. 3 illustrates an all-solid-state battery including one positive electrode (100), one solid electrolyte layer (300), and one negative electrode (200), but is not limited thereto, and an all-solid-state battery can be manufactured by stacking multiple all-solid-state batteries using the all-solid-state battery of FIG. 3 as a unit battery.

[0185] Figures 6 to 8 are cross-sectional views of an all-solid-state battery according to another embodiment.

[0186] The all-solid-state batteries of FIGS. 6 to 8 are mostly the same as the all-solid-state batteries of FIGS. 2 and 3, so only the different parts will be specifically described.

[0187] The all-solid-state battery illustrated in FIG. 6 includes a precipitated negative electrode (40'), a solid electrolyte layer (30), and a positive electrode (20) as in FIG. 2.

[0188] Among the positive and negative electrodes, which are the outermost electrodes of the all-solid-state battery (1003), a short circuit member (500) may be formed on the positive electrode (20).

[0189] The short circuit member (500) includes a short circuit auxiliary layer (52) formed on the positive electrode current collecting layer (21) of the positive electrode, and a short circuit metal layer (51) formed on the short circuit auxiliary layer (52).

[0190] In addition, elastic layers (50) may be formed on both sides of the all-solid-state battery (1003). The elastic layers (50) may be buffer layers that reduce pressure due to volume changes during charging and discharging of the all-solid-state battery (1003).

[0191] Referring to FIG. 7, the all-solid-state battery (1004) according to one embodiment is mostly the same as the all-solid-state battery of FIG. 3, so only the different parts will be specifically described.

[0192] As illustrated in FIG. 7, an all-solid-state battery (1004) according to one embodiment may include a positive electrode (20) including a positive electrode current collecting layer (21) and a positive electrode active material layer (23), a solid electrolyte layer (30), and a negative electrode (40) including a negative electrode current collecting layer (41) and a negative electrode active material layer (43) laminated thereon.

[0193] The all-solid-state battery (1004) has a bi-cell structure in which a solid electrolyte layer (330) and a cathode (40) are positioned on both sides of the positive electrode (20), and the bi-cells can be repeatedly stacked.

[0194] The positive electrode (20) includes a positive electrode current collecting layer (21) and a positive electrode active material layer (23) formed on both sides of the positive electrode current collecting layer (21). In addition, a solid electrolyte layer (30) is positioned on each side of the positive electrode active material layer (23), a negative electrode active material layer (43) is positioned on each of the solid electrolyte layers (30), and a negative electrode current collecting layer (21) is positioned on the negative electrode active material layer (43).

[0195] Conversely, a solid electrolyte layer (30) and an anode (20) may be positioned on each side centered on the cathode (40).

[0196] Meanwhile, a short circuit member (500) may be laminated on the anode or cathode located at the outermost side. For example, in FIG. 7, the short circuit member (500) may be laminated on the cathode (40), which is the outermost electrode. Of course, in the opposite case, the short circuit member (500) may be laminated on the anode.

[0197] The short circuit member (500) includes a short circuit metal layer (51), a short circuit auxiliary layer (52) positioned between the short circuit metal layer (51) and the cathode (40), which is the outermost electrode.

[0198] In order to short-circuit with the cathode, which is the outermost electrode, the short-circuit metal layer (51) can be electrically connected to the anode.

[0199] Referring to FIG. 8, the all-solid-state battery (1005) according to one embodiment is mostly the same as the all-solid-state battery of FIG. 5, so only the different parts will be specifically described.

[0200] An all-solid-state battery (1005) according to one embodiment may have a structure in which the positive electrode (20), the solid electrolyte layer (30), and the negative electrode (40) of FIG. 5 are repeatedly laminated as a unit battery.

[0201] For convenience of explanation, the solid-state battery located at the outermost edge of the solid-state battery (1005) of FIG. 8 is referred to as the first solid-state battery (401), and the battery located between the first solid-state batteries is referred to as the second solid-state battery (402).

[0202] At this time, an elastic layer (50) may be positioned between neighboring unit cells. The elastic layer (50) may be a buffer layer that reduces pressure due to volume change during charging and discharging of an all-solid-state battery including an all-solid-state battery (1005).

[0203] The first all-solid-state battery may be the all-solid-state battery illustrated in FIG. 5.

[0204] Additionally, at least one of the plurality of second all-solid-state batteries (402) may include an intermediate short circuit member (510).

[0205] The intermediate short-circuit member (510) may have the same material and structure as the previously described short-circuit member (500). That is, the intermediate short-circuit auxiliary layer (54) is positioned on the current collector of the positive or negative electrode located at the outermost part of the second all-solid-state battery (402), and the intermediate short-circuit metal layer (56) is positioned on the intermediate short-circuit auxiliary layer (54).

[0206] The metal layer (56) for the intermediate short circuit is electrically connected to an electrode of a different polarity from the current collector of the electrode located at the outermost layer.

[0207] The intermediate short-circuit metal layer (56) and the outermost electrode, the cathode, are maintained in an insulated state with the intermediate short-circuit auxiliary layer (54) interposed therebetween. Thereafter, at a first temperature or higher, the intermediate short-circuit auxiliary layer (54) electrically connects the intermediate short-circuit metal layer (56) and the outermost electrode, the cathode (40).

[0208] The intermediate short-circuit auxiliary layer (54) may be a material whose electrical conductivity increases at a first temperature or higher. Therefore, when the electrical conductivity increases, the intermediate short-circuit metal layer (56) electrically connected to the positive electrode and the negative electrode current collecting layer (41), which is the outermost electrode, are electrically connected to form a short-circuit path. At this time, one surface of the negative electrode current collecting layer (41) and one surface of the intermediate short-circuit metal layer (56), which face each other, are electrically connected through the intermediate short-circuit auxiliary layer (54), so that heat generated by the short-circuit can be quickly dispersed and discharged by connecting them through surface contact.

[0209] The intermediate short-circuit auxiliary layer (54) may be a material having a first temperature as its melting point, and when the temperature is higher than the first temperature, which is the melting point, the intermediate short-circuit auxiliary layer (54) melts and its electrical conductivity increases.

[0210] The first temperature may be 130°C to 150°C, and the PET and polymer resin may include a conductive filler.

[0211] Conductive fillers can have an electronic conductivity that is at least 1 / 20 that of copper. For example, conductive fillers can be carbon black (CNT), exfoliated graphite, carbon nanofibers (CNF), or metal nanoparticles.

[0212] The intermediate short-circuit auxiliary layer (54) may be a material whose insulating properties change depending on the temperature, and may be a material having insulating properties below a first temperature and having conductive properties with increased electrical conductivity above the first temperature, and may be made of EuNiO3 or SmNiO3, which are rare earth metals capable of causing a metal-insulator transition.

[0213] Additionally, the intermediate short-circuit auxiliary layer (54) may be formed of a polymer resin that shrinks at a first temperature or higher, and may be porous to increase the shrinkage rate. The shrinkage polymer that shrinks at a first temperature or higher of 130°C to 150°C may be a heat-shrinkable polymer, such as any one of PVC, polyolefin, and fluoropolymer.

[0214] In FIG. 8, a short circuit member (510) is shown positioned between two or three second solid-state batteries, but this is not limited thereto, and an intermediate short circuit member may be positioned between one second solid-state battery or a greater number of second solid-state batteries as needed.

[0215] When multiple solid-state batteries are stacked, the capacity of the solid-state batteries increases, and the heat generated during penetration also increases. Therefore, as shown in Fig. 8, by forming intermediate short-circuit members not only in the outermost solid-state battery but also in the solid-state battery located in the middle, multiple short-circuit paths are formed, enabling rapid heat dissipation.

[0216] 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. In an all-solid-state battery, a plurality of unit cells are stacked, each unit cell including a positive electrode including a first electrode, a negative electrode including a second electrode, and a solid electrolyte layer positioned between the positive electrode and the negative electrode. A short-circuit auxiliary layer and a short-circuit metal layer laminated on the outermost first electrode located at the outermost surface of the above-mentioned all-solid-state battery Including, The above metal layer for short circuit is electrically connected to the first electrode or the second electrode, An all-solid-state battery in which the above-mentioned short-circuit auxiliary layer electrically connects between the above-mentioned short-circuit metal layer and the above-mentioned outermost first electrode at a first temperature or higher.

2. In paragraph 1, The above-mentioned short-circuit auxiliary layer is an all-solid-state battery in which the electrical conductivity increases at a temperature higher than the first temperature.

3. In paragraph 2, The above first temperature is the melting point of the short-circuit auxiliary layer, and the all-solid-state battery in which the electrical conductivity increases as the short-circuit auxiliary layer melts.

4. In paragraph 3, The above-mentioned auxiliary layer is an all-solid-state battery which is a mixture of a polymer resin and a conductive filler having an electronic conductivity of 1 / 20 or more that of copper.

5. In paragraph 4, An all-solid-state battery wherein the conductive filler comprises at least one of carbon black (CNT), exfoliated graphite, carbon nanofibers (CNF), and metal nanoparticles.

6. In paragraph 2, An all-solid-state battery in which the above-mentioned auxiliary layer has a metal-insulator transition characteristic, is an insulator below the first temperature, and is a conductor above the first temperature.

7. In paragraph 6, The above-mentioned auxiliary layer is an all-solid-state battery made of a rare earth metal, EuNiO3 or SmNiO3.

8. In paragraph 1, The above-mentioned short-circuit auxiliary layer is an all-solid-state battery that shrinks above the first temperature.

9. In paragraph 8, An all-solid-state battery in which one surface of the short-circuit auxiliary layer and one surface of the outermost first electrode facing each other are exposed and electrically connected to each other as the short-circuit auxiliary layer shrinks.

10. In paragraph 8, An all-solid-state battery in which the above-mentioned auxiliary layer is reduced by 20% to 80% of its pre-shrinkage area.

11. In paragraph 8, The above paragraph auxiliary layer is an all-solid-state battery made of a porous polymer resin.

12. In paragraph 8, The above paragraph auxiliary layer is an all-solid-state battery made of any one of PVC, polyolefin, and fluoropolymer.

13. In the first, An all-solid-state battery having a thickness of the above-mentioned auxiliary layer of 10㎛ to 30㎛.

14. In paragraph 1, An all-solid-state battery wherein the first temperature is 130°C to 150°C.

15. A first all-solid-state battery comprising an all-solid-state battery according to any one of claims 1 to 14; A plurality of second solid-state batteries electrically connected to the first solid-state battery Including, An all-solid-state battery, wherein at least one of the second all-solid-state batteries comprises an intermediate short-circuiting auxiliary layer overlapping the outermost first electrode of the second all-solid-state battery, and an intermediate short-circuiting metal layer overlapping the intermediate short-circuiting auxiliary layer and electrically connected to a second electrode having an opposite polarity to the outermost first electrode of the second all-solid-state battery.

16. In paragraph 15, The above second all-solid-state battery is repeatedly stacked, The above first all-solid-state battery is an all-solid-state battery positioned on each side of the stacked second all-solid-state battery.

17. In paragraph 15, An all-solid-state battery in which the intermediate short-circuit auxiliary layer electrically connects the intermediate short-circuit metal layer and the first electrode at a temperature higher than the first temperature.

18. In paragraph 15, An all-solid-state battery in which the intermediate short-circuit auxiliary layer is made of the same material as the short-circuit auxiliary layer.

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