All-solid-state rechargeable battery

Abstract

This all-solid-state rechargeable battery comprises: an all-solid-state electrode assembly including an anode, a cathode and a solid electrolyte layer positioned between the anode and the cathode; a pouch which accommodates the all-solid-state electrode assembly in the inner space and which includes a sealing portion that seals the inner space; an anode tab protruding from the anode of the all-solid-state electrode assembly through the sealing portion to the outside of the pouch; and a cathode tab which is spaced apart from the anode tab and which protrudes from the cathode of the all-solid-state electrode assembly through the sealing portion to the outside of the pouch.

Description

All-solid-state secondary battery

[0001] It is about all-solid-state secondary batteries.

[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] A conventional all-solid-state secondary battery includes an all-solid-state electrode assembly including a cathode, a cathode, and a solid electrolyte layer, and a pouch storing the same therein.

[0005] One embodiment is to provide an all-solid-state secondary battery in which a portion of the pouch is opened when heat is generated inside the pouch of the all-solid-state secondary battery, thereby suppressing thermal runaway of the all-solid-state secondary battery.

[0006] In addition, it is intended to provide an all-solid-state secondary battery that suppresses short-circuiting of electrodes of an all-solid-state electrode assembly when heat is generated inside a pouch of the all-solid-state secondary battery.

[0007] One aspect provides an all-solid-state secondary battery, comprising: an all-solid-state electrode assembly including a cathode, an anode, a solid electrolyte layer positioned between the cathode and the anode; a pouch that houses the all-solid-state electrode assembly in an internal space and includes a sealing portion that seals the internal space; a cathode tab that protrudes from the cathode of the all-solid-state electrode assembly through the sealing portion to the outside of the pouch; and a cathode tab that is spaced apart from the cathode tab and protrudes from the anode of the all-solid-state electrode assembly through the sealing portion to the outside of the pouch; the sealing portion includes a first organic layer that contacts the cathode tab and the anode tab and melts at a first temperature; and a second organic layer that contacts the cathode tab, the anode tab, and the first organic layer and melts at a second temperature lower than the first temperature.

[0008] The first organic layer may include a first lower organic layer positioned on the rear surface of the negative electrode tab and the rear surface of the positive electrode tab, and a first upper organic layer positioned on the front surface of the negative electrode tab and the front surface of the positive electrode tab.

[0009] The first lower organic layer may be in contact with the back surface of the negative tab.

[0010] The first lower organic layer may be spaced apart from the back surface of the positive electrode tab.

[0011] The second organic layer may include a second lower organic layer positioned between the first lower organic layer and the positive electrode tab.

[0012] The second lower organic layer can be in contact with the positive electrode tab.

[0013] The second lower organic layer can be inserted into the interior of the first lower organic layer.

[0014] The first upper organic layer can be in contact with the front surface of the positive electrode tab.

[0015] The first upper organic layer may be spaced apart from the front surface of the negative tab.

[0016] The second organic layer may be positioned between the first upper organic layer and the cathode tab.

[0017] The second upper organic layer can be in contact with the cathode tab.

[0018] The second upper organic layer can be inserted into the interior of the first upper organic layer.

[0019] The negative tab may be closer to the first lower organic layer than the positive tab, and the positive tab may be closer to the first upper organic layer than the negative tab.

[0020] The second organic layer may extend from between the front surface of the negative electrode tab and the first upper organic layer to between the back surface of the positive electrode tab and the first lower organic layer.

[0021] It may further include a pressurizing jig for pressurizing the front and back surfaces of the pouch.

[0022] The second temperature may include 130°C to 150°C.

[0023] The first temperature may include 170°C to 180°C.

[0024] The above pouch may further include a metal layer surrounding the all-solid-state electrode assembly, an inner organic layer positioned on the inner surface of the metal layer, and an outer organic layer positioned on the outer surface of the metal layer.

[0025] The above inner organic layer may be integral with the first organic layer.

[0026] Each of the above negative tab and the above positive tab may include a sealant coated on its surface.

[0027] According to one embodiment, an all-solid-state secondary battery is provided in which a portion of the pouch is opened when heat is generated inside the pouch of the all-solid-state secondary battery, thereby suppressing thermal runaway of the all-solid-state secondary battery.

[0028] In addition, an all-solid-state secondary battery is provided that suppresses short-circuiting of electrodes of an all-solid-state electrode assembly when heat is generated inside a pouch of the all-solid-state secondary battery.

[0029] Figure 1 is a cross-sectional view of an all-solid-state battery.

[0030] Figure 2 is a cross-sectional view of an all-solid-state battery including a precipitated negative electrode.

[0031] Figure 3 is a plan view showing an all-solid-state secondary battery according to one embodiment.

[0032] Figure 4 is a cross-sectional view taken along line IV-IV of Figure 3.

[0033] Figure 5 is a cross-sectional view taken along line V-V of Figure 3.

[0034] FIG. 6 is a cross-sectional view showing a portion of an all-solid-state secondary battery according to one embodiment to explain the effect of the all-solid-state secondary battery according to one embodiment.

[0035] Fig. 7 is a cross-sectional view showing a part of an all-solid-state secondary battery according to another embodiment.

[0036] FIG. 8 is a cross-sectional view showing a portion of an all-solid-state secondary battery according to another embodiment to explain the effect of the all-solid-state secondary battery according to another embodiment.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] Cathode for all-solid-state secondary batteries

[0042] 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.

[0043] 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.

[0044] positive electrode active material

[0045] 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.

[0046] Li a A 1-b X b D2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5);

[0047] 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);

[0048] 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);

[0049] 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);

[0050] 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);

[0051] 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);

[0052] 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);

[0053] 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);

[0054] 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);

[0055] 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);

[0056] 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);

[0057] Li a Ni b Co c Mr d G eO2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤0.5, 0.001 ≤ e ≤ 0.1);

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

[0059] Li a CoG b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0060] Li a Mn 1-b G b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0061] Li a Mn2G b O4(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0062] Li a Mn 1-g G g PO4(0.90 ≤ a ≤ 1.8, 0 ≤ g ≤ 0.5);

[0063] QO2; QS2; LiQS2;

[0064] V2O5; LiV2O5;

[0065] LiZO2;

[0066] LiNiVO4;

[0067] Li (3-f) J2(PO4)3(0 ≤ f ≤ 2);

[0068] Li (3-f) Fe2(PO4)3(0 ≤ f ≤ 2);

[0069] Li a FePO4(0.90 ≤ a ≤ 1.8).

[0070] 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.

[0071] 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).

[0072] 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.

[0073] [Chemical Formula 1]

[0074] Li a1 Ni x1 M 1 y1 M 2 1-x1-y1 O2

[0075] 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.

[0076] [Chemical Formula 2]

[0077] Li a2 Co x2 M 3 1-x2 O2

[0078] 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.

[0079] [Chemical Formula 3]

[0080] Li a3 Fe x3 M 4 (1-x3) PO4

[0081] 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.

[0082] 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.

[0083] 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.

[0084] Sulfide-based solid electrolyte

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[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] Challenge

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] All-solid-state secondary battery

[0102] 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.

[0103] Figure 1 is a cross-sectional view of an all-solid-state battery.

[0104] 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.

[0105] cathode

[0106] 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.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] The average particle diameter (D50) of the silicon particles may be 10 nm to 20 μm, for example, 10 nm to 500 nm. The silicon particles may exist in an oxidized form, and in this case, the atomic content ratio of Si:O in the silicon particles, which indicates the degree of oxidation, may be 99:1 to 33:67. The silicon particles are SiO x It can be a particle, in which case SiO x In the range of x, it can be greater than 0 and less than 2. Here, the average particle diameter (D50) is measured by a particle size analyzer using laser diffraction and means the diameter of particles having a cumulative volume of 50% by volume in the particle size distribution.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 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.

[0123] Figure 2 is a cross-sectional view of an all-solid-state battery including a precipitated negative electrode.

[0124] 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.

[0125] The cathode coating layer (45) may include a metal, carbon material, or a combination thereof that acts as a catalyst.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] 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 ㎛.

[0132] 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.

[0133] solid electrolyte layer

[0134] 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.

[0135] 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.

[0136] 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.

[0137] 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.

[0138] 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.

[0139] The thickness of the solid electrolyte layer may be, for example, 10 μm to 150 μm.

[0140] The solid electrolyte layer may further include an alkali metal salt, and / or an ionic liquid, and / or a conductive polymer.

[0141] The 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 ionic conductivity by enhancing the mobility of lithium ions in the solid electrolyte layer.

[0142] 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.

[0143] 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.

[0144] 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.

[0145] The ionic liquid may be a compound comprising a) one or more cations selected from ammonium, pyrrolidinium, pyridinium, pyrimidinium, imidazolium, piperidinium, pyrazolium, oxazolium, pyridazinium, phosphonium, sulfonium, triazolium, and mixtures thereof, and b) one or more anions selected from BF4-, PF6-, AsF6-, SbF6-, AlCl4-, HSO4-, ClO4-, CH3SO3-, CF3CO2-, Cl-, Br-, I-, BF4-, SO4-, CF3SO3-, (FSO2)2N-, (C2F5SO2)2N-, (C2F5SO2)(CF3SO2)N-, and (CF3SO2)2N-.

[0146] 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.

[0147] 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.

[0148] The all-solid-state battery may be a unit cell having a structure of anode / solid electrolyte layer / cathode, a bicell having a structure of cathode / solid electrolyte layer / cathode / solid electrolyte layer / cathode, or a laminated battery in which the structure of the unit cell is repeated.

[0149] 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.

[0150] Hereinafter, an all-solid-state secondary battery according to an embodiment will be described with reference to FIGS. 3 to 6. The all-solid-state secondary battery (1000) according to an embodiment is a secondary battery capable of being charged and discharged. Hereinafter, the positive electrode includes a cathode, and the negative electrode includes an anode.

[0151] Fig. 3 is a plan view showing an all-solid-state secondary battery according to one embodiment. Fig. 4 is a cross-sectional view taken along line IV-IV of Fig. 3.

[0152] Referring to FIGS. 3 and 4, an all-solid-state secondary battery (1000) according to one embodiment includes an all-solid-state electrode assembly (100), a pouch (200), a negative electrode tab (300), a positive electrode tab (400), a pressurizing jig (500), a first elastic layer (600), and a second elastic layer (700).

[0153] The all-solid-state electrode assembly (100) is housed inside a pouch (200). The all-solid-state electrode assembly (100) includes a cathode (110), an anode (120), and a solid electrolyte layer (130).

[0154] The negative electrode (110) may include, but is not limited to, the negative electrode included in the above-described all-solid-state secondary battery. The negative electrode (110) may have a plate or foil shape, but is not limited thereto.

[0155] The positive electrode (120) is positioned on the negative electrode (110) with a solid electrolyte layer (130) therebetween. The positive electrode (120) may include, but is not limited to, the positive electrode included in the aforementioned all-solid-state secondary battery. The positive electrode (120) may have a plate or foil shape, but is not limited thereto.

[0156] The solid electrolyte layer (130) is positioned between the negative electrode (110) and the positive electrode (120). The solid electrolyte layer (130) may include, but is not limited to, the solid electrolyte layer included in the above-described all-solid-state secondary battery. The solid electrolyte layer (130) may have a layer form between the negative electrode (110) and the positive electrode (120), but is not limited thereto.

[0157] The all-solid-state electrode assembly (100) may have various known laminated structures. For example, the all-solid-state electrode assembly (100) may have a unit cell having a structure of anode / solid electrolyte layer / cathode, a bi-cell having a structure of cathode / solid electrolyte layer / cathode / solid electrolyte layer / cathode, or a laminated cell structure in which the structure of the unit cells is repeated, but is not limited thereto.

[0158] The all-solid-state electrode assembly (100) may include a plurality of stacked all-solid-state electrode assemblies (100). For example, various known elastic layers may be positioned between the plurality of all-solid-state electrode assemblies (100) stacked in one direction.

[0159] The pouch (200) houses the all-solid-state electrode assembly (100) in its internal space. The pouch (200) has a square shape in plan, but is not limited thereto, and may have a polygonal shape such as a triangle, a pentagon, a hexagon, a heptagon, an octagon, a circle, an oval, or a loop shape in plan. The pouch (200) includes a sealing portion (210), a metal layer (220), an internal organic layer (230), and an external organic layer (240).

[0160] Figure 5 is a cross-sectional view taken along line V-V of Figure 3.

[0161] Referring to FIGS. 3 to 5, the sealing portion (210) surrounds the periphery of the all-solid-state electrode assembly (100) and seals the internal space of the pouch (200) in which the all-solid-state electrode assembly (100) is stored. The sealing portion (210) includes a first organic layer (OL1) and a second organic layer (OL2).

[0162] The first organic layer (OL1) is located on the inner surface of the metal layer (220) and contacts the negative electrode tab (300) and the positive electrode tab (400) that protrude from the all-solid-state electrode assembly (100) through the sealing portion (210) to the outside of the pouch (200). The first organic layer (OL1) can melt at a set first temperature. For example, the first organic layer (OL1) can melt at a first temperature including 170°C to 180°C or a first temperature including 140°C to 210°C, but is not limited thereto. The first organic layer (OL1) can include various known organic materials. For example, the first organic layer (OL1) can include a polymer including polypropylene, polyethylene terephthalate, polyimide, etc., but is not limited thereto.

[0163] The first organic layer (OL1) includes a first lower organic layer (BOL1) and a first upper organic layer (TOL1). For example, the first lower organic layer (BOL1) may be a layer positioned lower with respect to the negative electrode tab (300) and the positive electrode tab (400), but is not limited thereto, and the first lower organic layer (BOL1) may be a layer positioned upper with respect to the negative electrode tab (300) and the positive electrode tab (400). For another example, the first upper organic layer (TOL1) may be a layer positioned upper with respect to the negative electrode tab (300) and the positive electrode tab (400), but is not limited thereto, and the first upper organic layer (TOL1) may be a layer positioned lower with respect to the negative electrode tab (300) and the positive electrode tab (400).

[0164] The first lower organic layer (BOL1) is located on the rear surface of the negative electrode tab (300) and the rear surface of the positive electrode tab (400). The first lower organic layer (BOL1) is in contact with the rear surface of the negative electrode tab (300). The first lower organic layer (BOL1) is spaced apart from the rear surface of the positive electrode tab (400) with the second organic layer (OL2) interposed therebetween. The first lower organic layer (BOL1) may be in contact with the rear surface of the negative electrode tab (300) and may be bonded to the negative electrode tab (300), but is not limited thereto.

[0165] The first upper organic layer (TOL1) is located on the front surface of the negative electrode tab (300) and the front surface of the positive electrode tab (400). The first upper organic layer (TOL1) is in contact with the front surface of the positive electrode tab (400). The first upper organic layer (TOL1) is spaced apart from the front surface of the negative electrode tab (300) with the second organic layer (OL2) interposed therebetween. The first upper organic layer (TOL1) may be in contact with the front surface of the positive electrode tab (400) and may be bonded to the positive electrode tab (400), but is not limited thereto.

[0166] The first organic layer (OL1) may be positioned over the entire sealing portion (210), but is not limited thereto. For example, the first organic layer (OL1) may be positioned at a portion of the sealing portion (210) where the negative electrode tab (300) and the positive electrode tab (400) are positioned. As another example, the first organic layer (OL1) may be positioned over the entire interior of the pouch (200), but is not limited thereto.

[0167] The second organic layer (OL2) is positioned between the first organic layer (OL1) and the negative electrode tab (300) and between the first organic layer (OL1) and the positive electrode tab (400). The second organic layer (OL2) is in contact with the negative electrode tab (300), the positive electrode tab (400), and the first organic layer (OL1). The second organic layer (OL2) can melt at a second temperature set lower than the first temperature at which the first organic layer (OL1) melts. For example, the second organic layer (OL2) can melt at a second temperature including 130°C to 150°C or a second temperature including 100°C to 180°C, but is not limited thereto. The second organic layer (OL2) can include various known organic materials. For example, the second organic layer (OL2) may include a polymer including, but not limited to, polypropylene, polyethylene terephthalate, polyimide, etc.

[0168] The second organic layer (OL2) includes a second lower organic layer (BOL2) and a second upper organic layer (TOL2). For example, the second lower organic layer (BOL2) may be a layer positioned lower with respect to the negative electrode tab (300) and the positive electrode tab (400), but is not limited thereto, and the second lower organic layer (BOL2) may be a layer positioned upper with respect to the negative electrode tab (300) and the positive electrode tab (400). For another example, the second upper organic layer (TOL2) may be a layer positioned upper with respect to the negative electrode tab (300) and the positive electrode tab (400), but is not limited thereto, and the second upper organic layer (TOL2) may be a layer positioned lower with respect to the negative electrode tab (300) and the positive electrode tab (400).

[0169] The second lower organic layer (BOL2) is located between the first lower organic layer (BOL1) of the first organic layer (OL1) and the positive electrode tab (400). The second lower organic layer (BOL2) is in contact with the back surface of the positive electrode tab (400). The positive electrode tab (400) and the first lower organic layer (BOL1) of the first organic layer (OL1) are spaced apart from each other with the second lower organic layer (BOL2) therebetween. The second lower organic layer (BOL2) may be in contact with the positive electrode tab (400) and may be bonded to the positive electrode tab (400), but is not limited thereto. The second lower organic layer (BOL2) may be inserted into the interior of the first lower organic layer (BOL1), but is not limited thereto. For example, the second lower organic layer (BOL2) may be positioned on the first lower organic layer (BOL1) and between the positive electrode tab (400) and the first lower organic layer (BOL1).

[0170] The second upper organic layer (TOL2) is located between the first upper organic layer (TOL1) of the first organic layer (OL1) and the negative tab (300). The second upper organic layer (TOL2) is in contact with the front surface of the negative tab (300). The negative tab (300) and the first upper organic layer (TOL1) of the first organic layer (OL1) are spaced apart from each other with the second upper organic layer (TOL2) therebetween. The second upper organic layer (TOL2) may be in contact with the negative tab (300) and may be bonded to the negative tab (300), but is not limited thereto. The second upper organic layer (TOL2) may be inserted into the interior of the first upper organic layer (TOL1), but is not limited thereto. For example, the second upper organic layer (TOL2) may be positioned on the first upper organic layer (TOL1) and between the negative tab (300) and the first upper organic layer (TOL1).

[0171] The second organic layer (OL2) may be positioned on a portion of the sealing portion (210) where the negative electrode tab (300) and the positive electrode tab (400) are positioned, but is not limited thereto. For example, the second organic layer (OL2) may be positioned over the entire sealing portion (210). In another example, the second organic layer (OL2) may be positioned over the entire interior of the pouch (200), but is not limited thereto.

[0172] The metal layer (220) surrounds the all-solid-state electrode assembly (100). The metal layer (220) includes, but is not limited to, aluminum and may include various known metals.

[0173] The internal organic layer (230) is located on the inner surface of the metal layer (220) and is located between the all-solid-state electrode assembly (100) and the metal layer (220). The internal organic layer (230) may be coated on the inner surface of the metal layer (220), but is not limited thereto. The internal organic layer (230) may include a polymer including polypropylene, polyethylene terephthalate, polyimide, etc., but is not limited thereto. The internal organic layer (230) may be integral with the first organic layer (OL1) included in the sealing portion (210), but is not limited thereto. For example, the internal organic layer (230) may be the same layer as the first organic layer (OL1), but is not limited thereto, and the internal organic layer (230) may be a different layer from the first organic layer (OL1). The internal organic layer (230) may be a single layer or multiple layers.

[0174] The outer organic layer (240) is located on the outer surface of the metal layer (220). The outer organic layer (240) may be coated on the outer surface of the metal layer (220), but is not limited thereto. The outer organic layer (240) may include a polymer including, but is not limited to, nylon, polypropylene, polyethylene terephthalate, polyimide, etc. The outer organic layer (240) may be a single layer or a multi-layer.

[0175] The negative electrode tab (300) protrudes from the negative electrode (110) of the all-solid-state electrode assembly (100) through the sealing portion (210) to the outside of the pouch (200). The negative electrode tab (300) may be integral with the negative electrode (110) of the all-solid-state electrode assembly (100), but is not limited thereto and may include various known conductive tabs connected to the negative electrode (110) of the all-solid-state electrode assembly (100). The negative electrode tab (300) is positioned closer to the first lower organic layer (BOL1) of the first organic layer (OL1) of the sealing portion (210) than the positive electrode tab (400) and is bonded to the first lower organic layer (BOL1). The negative electrode tab (300) includes a first sealant (310) coated on the surface of the negative electrode tab (300).

[0176] The first sealant (310) is coated on the surface of the negative tab (300) and may include various known insulating materials.

[0177] The negative tab (300) is positioned adjacent to the positive tab (400), but is not limited thereto.

[0178] For example, the negative electrode tab (300) is positioned adjacent to the positive electrode tab (400) at one end of the all-solid-state electrode assembly (100), but is not limited thereto, and the negative electrode tab (300) may be positioned spaced apart from the positive electrode tab (400) at the other end of the all-solid-state electrode assembly (100) with the all-solid-state electrode assembly (100) interposed therebetween.

[0179] As another example, the negative tab (300) may protrude from the negative electrode (110) of the solid-state electrode assembly (100) through the sealing portion (201) and out of the pouch (200) at various known locations in the solid-state electrode assembly (100), regardless of the location of the positive tab (400).

[0180] The positive electrode tab (400) is spaced apart from the negative electrode tab (300) and protrudes from the positive electrode (120) of the all-solid-state electrode assembly (100) through the sealing portion (210) to the outside of the pouch (200). The positive electrode tab (400) may be integral with the positive electrode (120) of the all-solid-state electrode assembly (100), but is not limited thereto and may include various known conductive tabs connected to the positive electrode (120) of the all-solid-state electrode assembly (100). The positive electrode tab (400) is positioned closer to the first upper organic layer (TOL1) of the first organic layer (OL1) of the sealing portion (210) than the negative electrode tab (300) and is bonded to the first upper organic layer (TOL1).

[0181] The positive electrode tab (400) includes a second sealant (410) coated on the surface of the positive electrode tab (400).

[0182] The second sealant (410) is coated on the surface of the positive tab (400) and may include various known insulating materials.

[0183] The positive tab (400) is positioned adjacent to the negative tab (300), but is not limited thereto.

[0184] For example, the positive electrode tab (400) is positioned adjacent to the negative electrode tab (300) at one end of the all-solid-state electrode assembly (100), but is not limited thereto, and the positive electrode tab (400) may be positioned spaced apart from the negative electrode tab (300) at the other end of the all-solid-state electrode assembly (100) with the all-solid-state electrode assembly (100) interposed therebetween.

[0185] As another example, the positive electrode tab (400) may protrude from the positive electrode (120) of the solid-state electrode assembly (100) through the sealing portion (201) and out of the pouch (200) at various known locations in the solid-state electrode assembly (100), regardless of the location of the negative electrode tab (300).

[0186] The pressurizing jig (500) pressurizes the front surface and the rear surface of the pouch (200). The pressurizing jig (500) pressurizes the front surface and the rear surface of the pouch (200) to apply pressure to the all-solid-state electrode assembly (100) located inside the pouch (200). The battery efficiency of the all-solid-state electrode assembly (100) can be improved by the pressurizing jig (500). The pressurizing jig (500) can have various known jig shapes capable of pressing the pouch (200).

[0187] The first elastic layer (600) is positioned between the front surface of the pouch (200) and the pressurizing jig (500). The first elastic layer (600) can disperse the pressure of the pressurizing jig (500) applied to the pouch (200) and simultaneously prevent the pouch (200) from being damaged by the pressure of the pressurizing jig (500). The first elastic layer (600) includes various known elastic layers.

[0188] The second elastic layer (700) is positioned between the back surface of the pouch (200) and the pressurizing jig (500). The second elastic layer (700) can disperse the pressure of the pressurizing jig (500) applied to the pouch (200) and simultaneously prevent the pouch (200) from being damaged by the pressure of the pressurizing jig (500). The second elastic layer (700) includes various known elastic layers.

[0189] FIG. 6 is a cross-sectional view showing a portion of an all-solid-state secondary battery according to one embodiment to explain the effect of the all-solid-state secondary battery according to one embodiment.

[0190] Referring to FIG. 6, when the temperature of the all-solid-state electrode assembly located inside the pouch (200) rises, since the ignition limit temperature of the all-solid-state electrode assembly is higher than the limit temperature of the pouch (200), the second organic layer (OL2) and the first organic layer (OL1) included in the sealing portion (210) of the pouch (200) sequentially melt as the temperature of the negative electrode tab (300) and the positive electrode tab (400) connected to the all-solid-state electrode assembly rises, so that the heat inside the pouch (200) is released to the outside, thereby suppressing thermal runaway of the all-solid-state electrode assembly.

[0191] Specifically, referring to (A) and (B) of FIG. 6, when the temperature of the all-solid-state electrode assembly located inside the pouch (200) rises and the temperatures of the negative electrode tab (300) and the positive electrode tab (400) connected to the all-solid-state electrode assembly rise, the second upper organic layer (TOL2) of the second organic layer (OL2) in contact with the front surface of the negative electrode tab (300) and the second lower organic layer (BOL2) of the second organic layer (OL2) in contact with the back surface of the positive electrode tab (400) melt, thereby forming a first vent channel (VC1) first, and then the first upper organic layer (TOL1) and the first lower organic layer (BOL1) of the first organic layer (OL1) melt, thereby expanding the first vent channel (VC1), so that heat inside the pouch (200) is released to the outside through the first vent channel (VC1), thereby suppressing thermal runaway of the all-solid-state electrode assembly.

[0192] In addition, since a portion of the sealing portion (210) of the pouch (200) where the negative tab (300) in contact with the first lower organic layer (BOL1) of the first organic layer (OL1) and the positive tab (400) in contact with the first upper organic layer (TOL1) of the first organic layer (OL1) are located by the first band channel (VC1) formed by melting the second organic layer (OL2) are opened in different directions, a short circuit between the negative tab (300) and the positive tab (400) and a short circuit between the negative tab (300) and the positive tab (400) and the metal layer (220) of the pouch (200) are suppressed.

[0193] Referring to (C) of FIG. 6, even if the first organic layer (OL1) included in the sealing portion (210) of the pouch (200), the first sealant (310) of the negative electrode tab (300), and the second sealant (410) of the positive electrode tab (400) melt as the temperature of the negative electrode tab (300) and the positive electrode tab (400) rises, a short circuit between the negative electrode tab (300) and the positive electrode tab (400) is suppressed because the negative electrode tab (300) and the positive electrode tab (400) come into contact with the metal layer (220) of the pouch (200) located in different directions.

[0194] For example, an all-solid-state secondary battery is provided in which a portion of the pouch (200) is opened when heat is generated inside the pouch (200) of the all-solid-state secondary battery (1000) to suppress thermal runaway of the all-solid-state secondary battery (1000).

[0195] In addition, an all-solid-state secondary battery (1000) is provided that suppresses short-circuiting of electrodes of an all-solid-state electrode assembly (100) when heat is generated inside a pouch (200) of the all-solid-state secondary battery (1000).

[0196] Hereinafter, with reference to FIGS. 7 and 8, an all-solid-state secondary battery according to another embodiment will be described. Below, differences from the all-solid-state secondary battery according to the above-described embodiment will be described.

[0197] Fig. 7 is a cross-sectional view showing a part of an all-solid-state secondary battery according to another embodiment.

[0198] Referring to FIG. 7, the sealing portion (210) of an all-solid-state secondary battery (1000) according to another embodiment includes a first organic layer (OL1) and a second organic layer (OL2).

[0199] The first organic layer (OL1) is located on the inner surface of the metal layer (220) and contacts the negative electrode tab (300) and the positive electrode tab (400) that protrude from the all-solid-state electrode assembly (100) through the sealing portion (210) to the outside of the pouch (200). The first organic layer (OL1) can melt at a set first temperature. For example, the first organic layer (OL1) can melt at a first temperature including 170°C to 180°C or a first temperature including 140°C to 210°C, but is not limited thereto. The first organic layer (OL1) can include various known organic materials. For example, the first organic layer (OL1) can include a polymer including polypropylene, polyethylene terephthalate, polyimide, etc., but is not limited thereto.

[0200] The first organic layer (OL1) includes a first lower organic layer (BOL1) and a first upper organic layer (TOL1). For example, the first lower organic layer (BOL1) may be a layer positioned lower with respect to the negative electrode tab (300) and the positive electrode tab (400), but is not limited thereto, and the first lower organic layer (BOL1) may be a layer positioned upper with respect to the negative electrode tab (300) and the positive electrode tab (400). For another example, the first upper organic layer (TOL1) may be a layer positioned upper with respect to the negative electrode tab (300) and the positive electrode tab (400), but is not limited thereto, and the first upper organic layer (TOL1) may be a layer positioned lower with respect to the negative electrode tab (300) and the positive electrode tab (400).

[0201] The first lower organic layer (BOL1) is located on the rear surface of the negative electrode tab (300) and the rear surface of the positive electrode tab (400). The first lower organic layer (BOL1) is in contact with the rear surface of the negative electrode tab (300). The first lower organic layer (BOL1) is spaced apart from the rear surface of the positive electrode tab (400) with the second organic layer (OL2) interposed therebetween. The first lower organic layer (BOL1) may be in contact with the rear surface of the negative electrode tab (300) and may be bonded to the negative electrode tab (300), but is not limited thereto.

[0202] The first upper organic layer (TOL1) is located on the front surface of the negative electrode tab (300) and the front surface of the positive electrode tab (400). The first upper organic layer (TOL1) is in contact with the front surface of the positive electrode tab (400). The first upper organic layer (TOL1) is spaced apart from the front surface of the negative electrode tab (300) with the second organic layer (OL2) interposed therebetween. The first upper organic layer (TOL1) may be in contact with the front surface of the positive electrode tab (400) and may be bonded to the positive electrode tab (400), but is not limited thereto.

[0203] The first organic layer (OL1) may be positioned over the entire sealing portion (210), but is not limited thereto. For example, the first organic layer (OL1) may be positioned at a portion of the sealing portion (210) where the negative electrode tab (300) and the positive electrode tab (400) are positioned. As another example, the first organic layer (OL1) may be positioned over the entire interior of the pouch (200), but is not limited thereto.

[0204] The second organic layer (OL2) is positioned between the first organic layer (OL1) and the negative electrode tab (300) and between the first organic layer (OL1) and the positive electrode tab (400). The second organic layer (OL2) is in contact with the negative electrode tab (300), the positive electrode tab (400), and the first organic layer (OL1). The second organic layer (OL2) can melt at a second temperature set lower than the first temperature at which the first organic layer (OL1) melts. For example, the second organic layer (OL2) can melt at a second temperature including 130°C to 150°C or a second temperature including 100°C to 180°C, but is not limited thereto. The second organic layer (OL2) can include various known organic materials. For example, the second organic layer (OL2) may include a polymer including, but not limited to, polypropylene, polyethylene terephthalate, polyimide, etc.

[0205] The second organic layer (OL2) extends from between the front surface of the negative electrode tab (300) and the first upper organic layer (TOL1) to between the back surface of the positive electrode tab (400) and the first lower organic layer (BOL1). The second organic layer (OL2) is located between the first lower organic layer (BOL1) of the first organic layer (OL1) and the positive electrode tab (400). The second organic layer (OL2) is in contact with the back surface of the positive electrode tab (400). The positive electrode tab (400) and the first lower organic layer (BOL1) of the first organic layer (OL1) are spaced apart from each other with the second organic layer (OL2) therebetween. The second organic layer (OL2) may be in contact with the positive electrode tab (400) and bonded to the positive electrode tab (400), but is not limited thereto.

[0206] The second organic layer (OL2) is located between the first upper organic layer (TOL1) of the first organic layer (OL1) and the negative tab (300). The second organic layer (OL2) is in contact with the front surface of the negative tab (300). The negative tab (300) and the first upper organic layer (TOL1) of the first organic layer (OL1) are spaced apart from each other with the second organic layer (OL2) therebetween. The second organic layer (OL2) may be in contact with the negative tab (300) and bonded to the negative tab (300), but is not limited thereto.

[0207] The second organic layer (OL2) may be positioned on a portion of the sealing portion (210) where the negative electrode tab (300) and the positive electrode tab (400) are positioned, but is not limited thereto. For example, the second organic layer (OL2) may be positioned over the entire sealing portion (210). In another example, the second organic layer (OL2) may be positioned over the entire interior of the pouch (200), but is not limited thereto.

[0208] FIG. 8 is a cross-sectional view showing a portion of an all-solid-state secondary battery according to another embodiment to explain the effect of the all-solid-state secondary battery according to another embodiment.

[0209] Referring to FIG. 8, when the temperature of the all-solid-state electrode assembly located inside the pouch (200) rises, since the ignition limit temperature of the all-solid-state electrode assembly is higher than the limit temperature of the pouch (200), the second organic layer (OL2) and the first organic layer (OL1) included in the sealing portion (210) of the pouch (200) sequentially melt as the temperature of the negative electrode tab (300) and the positive electrode tab (400) connected to the all-solid-state electrode assembly rises, so that the heat inside the pouch (200) is released to the outside, thereby suppressing thermal runaway of the all-solid-state electrode assembly.

[0210] Specifically, referring to (A) and (B) of FIG. 8, when the temperature of the all-solid-state electrode assembly located inside the pouch (200) rises and the temperatures of the negative electrode tab (300) and the positive electrode tab (400) connected to the all-solid-state electrode assembly rise, the second organic layer (OL2) in contact with the front surface of the negative electrode tab (300) and the back surface of the positive electrode tab (400) melts to first form a second vent channel (VC2), and then the first upper organic layer (TOL1) and the first lower organic layer (BOL1) of the first organic layer (OL1) melt to expand the second vent channel (VC2), thereby discharging heat inside the pouch (200) to the outside through the second vent channel (VC2), thereby suppressing thermal runaway of the all-solid-state electrode assembly.

[0211] In addition, since a portion of the sealing portion (210) of the pouch (200) where the negative tab (300) in contact with the first lower organic layer (BOL1) of the first organic layer (OL1) and the positive tab (400) in contact with the first upper organic layer (TOL1) of the first organic layer (OL1) are located by the second band channel (VC2) formed by melting the second organic layer (OL2) are opened in different directions, a short circuit between the negative tab (300) and the positive tab (400) and a short circuit between the negative tab (300) and the positive tab (400) and the metal layer (220) of the pouch (200) are suppressed.

[0212] Referring to (C) of FIG. 8, even if the first organic layer (OL1) included in the sealing portion (210) of the pouch (200), the first sealant (310) of the negative tab (300), and the second sealant (410) of the positive tab (400) melt as the temperature of the negative tab (300) and the positive tab (400) rises, a short circuit between the negative tab (300) and the positive tab (400) is suppressed because the negative tab (300) and the positive tab (400) come into contact with the metal layer (220) of the pouch (200) located in different directions.

[0213] For example, an all-solid-state secondary battery is provided in which a portion of the pouch (200) is opened when heat is generated inside the pouch (200) of the all-solid-state secondary battery (1000) to suppress thermal runaway of the all-solid-state secondary battery (1000).

[0214] In addition, an all-solid-state secondary battery (1000) is provided that suppresses the electrodes of the all-solid-state electrode assembly (100) from being short-circuited when heat is generated inside the pouch (200) of the all-solid-state secondary battery (1000).

[0215] 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.

[0216] [Explanation of symbols]

[0217] All-solid-state electrode assembly (100), negative electrode (110), positive electrode (120), solid electrolyte layer (130), pouch (200), sealing portion (210), first organic layer (OL1), second organic layer (OL2), negative electrode tab (300), positive electrode tab (400)

Claims

1. An all-solid-state electrode assembly comprising a cathode, an anode, and a solid electrolyte layer positioned between the cathode and the anode; A pouch that houses the above-mentioned all-solid-state electrode assembly in an internal space and includes a sealing portion that seals the internal space; A cathode tab protruding from the cathode of the above solid-state electrode assembly through the sealing portion and out of the pouch; and A cathode tab separated from the cathode tab and protruding from the anode of the all-solid-state electrode assembly through the sealing portion to the outside of the pouch. Including, The above sealing part, a first organic layer in contact with the cathode tab and the anode tab, the first organic layer melting at a first temperature; and A second organic layer in contact with the cathode tab, the anode tab, and the first organic layer, and melting at a second temperature lower than the first temperature. An all-solid-state secondary battery comprising:

2. In paragraph 1, The above first organic layer is, A first lower organic layer positioned on the rear surface of the negative tab and the rear surface of the positive tab; and A first upper organic layer positioned on the front surface of the negative tab and the front surface of the positive tab An all-solid-state secondary battery comprising:

3. In paragraph 2, An all-solid-state secondary battery wherein the first lower organic layer is in contact with the back surface of the negative tab.

4. In paragraph 3, An all-solid-state secondary battery wherein the first lower organic layer is spaced apart from the back surface of the positive electrode tab.

5. In paragraph 4, An all-solid-state secondary battery, wherein the second organic layer comprises a second lower organic layer positioned between the first lower organic layer and the positive electrode tab.

6. In paragraph 5, An all-solid-state secondary battery wherein the second lower organic layer is in contact with the positive electrode tab.

7. In paragraph 5, An all-solid-state secondary battery, wherein the second lower organic layer is inserted into the interior of the first lower organic layer.

8. In paragraph 2, An all-solid-state secondary battery wherein the first upper organic layer is in contact with the front surface of the positive electrode tab.

9. In paragraph 8, An all-solid-state secondary battery wherein the first upper organic layer is spaced apart from the front surface of the negative tab.

10. In Article 9, An all-solid-state secondary battery, wherein the second organic layer comprises a second upper organic layer positioned between the first upper organic layer and the negative electrode tab.

11. In Article 10, An all-solid-state secondary battery wherein the second upper organic layer is in contact with the negative tab.

12. In Article 10, An all-solid-state secondary battery wherein the second upper organic layer is inserted into the interior of the first upper organic layer.

13. In paragraph 2, The above negative tab is closer to the first lower organic layer than the above positive tab, An all-solid-state secondary battery, wherein the positive electrode tab is closer to the first upper organic layer than the negative electrode tab.

14. In paragraph 2, An all-solid-state secondary battery in which the second organic layer extends from between the front surface of the negative electrode tab and the first upper organic layer to between the back surface of the positive electrode tab and the first lower organic layer.

15. In paragraph 1, An all-solid-state secondary battery further comprising a pressurizing jig for pressurizing the front and back surfaces of the pouch.

16. In paragraph 1, An all-solid-state secondary battery wherein the second temperature comprises 130°C to 150°C.

17. In paragraph 1, An all-solid-state secondary battery, wherein the first temperature comprises 170°C to 180°C.

18. In paragraph 1, The above pouch, A metal layer surrounding the above all-solid-state electrode assembly; An internal organic layer located on the inner surface of the above metal layer; An external organic layer located on the outer surface of the above metal layer An all-solid-state secondary battery further comprising:

19. In Article 18, An all-solid-state secondary battery wherein the inner organic layer is integral with the first organic layer.

20. In paragraph 1, An all-solid-state secondary battery, wherein each of the negative tab and the positive tab includes a sealant coated on its surface.

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