All-solid rechargeable battery

Abstract

An all-solid rechargeable battery comprising: all-solid cell stack; a first can covering the lower portion of the all-solid cell stack; and a second can covering the upper portion of the all-solid cell stack and welded to the first can so as to press the all-solid cell stack toward the first can, wherein the first can comprises a first weld surface comprising an uneven structure that is welded to the second can.

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] Since all-solid-state secondary batteries are composed entirely of solid materials, the interfacial resistance between the layers that make up the all-solid-state secondary battery (for example, the interfacial resistance between the electrode and the solid electrolyte layer) must be minimized.

[0005] One embodiment seeks to provide an all-solid-state secondary battery having minimized interfacial resistance even when the all-solid-state cell stack is enclosed by a can.

[0006] One side provides an all-solid-state secondary battery including an all-solid-state cell stack, a first can covering a lower portion of the all-solid-state cell stack, a second can covering an upper portion of the all-solid-state cell stack and welded to the first can to press the all-solid-state cell stack in the direction of the first can, and a first cap covering one side of the all-solid-state cell stack and having the first can and the second can inserted therein, wherein the first can includes a first welding surface welded to the second can, and a first non-welding surface extending from the first welding surface in the direction of the first cap in a non-welded state with the second can and inserted into the first cap.

[0007] The first non-welding surface may be inclined and extended away from the first welding surface and the second can.

[0008] At least a portion of the first non-contacting surface may be non-contacting with the second can.

[0009] The distance between the first non-welding surface and the second can has a first length when the all-solid-state cell stack is pressurized, and when the first non-welding surface is inserted into the first cap, it can have a second length that is longer than the first length due to the restoring force of the first can.

[0010] The first welding surface may include a protruding structure extending in the direction of the first non-welding surface.

[0011] The above-mentioned structure of the above-mentioned first welding surface may include a convex surface.

[0012] The above-mentioned structure of the above-mentioned first welding surface may include a triangular surface.

[0013] The above first welding surface may include a stepped structure sunken from the second can direction.

[0014] The step structure of the first welding surface may include a first barrier wall positioned between the second can and the all-solid-state cell stack.

[0015] The other side of the above solid-state cell stack may further include a second cap having the first can and the second can inserted therein.

[0016] The first non-welding surface can extend from the first welding surface in the direction of the second cap and be inserted into the inside of the second cap.

[0017] The first can may further include a first plate portion covering the lower portion of the all-solid-state cell stack, and a first side wall portion extending by bending from the first plate portion to surround the all-solid-state cell stack, where the first welding surface and the first non-welding surface are located.

[0018] The second can may include a second welding surface welded to the first welding surface of the first can, and a second non-welded surface extending from the second welding surface in the direction of the first cap and inserted into the inside of the first cap while being non-welded to the first non-welded surface of the first can.

[0019] The second non-welding surface may be extended at an angle away from the second welding surface and away from the first non-welding surface of the first can.

[0020] At least a portion of the second non-contacting surface may be non-contacting with the first non-contacting surface of the first can.

[0021] The distance between the second non-welding surface and the first non-welding surface has a first length when the all-solid-state cell stack is pressurized, and when the second non-welding surface and the first non-welding surface are inserted into the first cap, the distance can have a second length that is longer than the first length due to the restoring force of the second can and the first can.

[0022] The interface between the second welding surface and the first welding surface may include a protruding structure extending in the first cap direction.

[0023] The second welding surface may include a stepped structure sunken from the first can direction.

[0024] The step structure of the second welding surface may include a second barrier wall positioned between the first can and the all-solid-state cell stack.

[0025] The second can may further include a second plate portion covering the upper portion of the all-solid-state cell stack, and a second side wall portion extending by bending from the second plate portion to surround the all-solid-state cell stack, where the second welding surface and the second non-welding surface are located.

[0026] According to one embodiment, an all-solid-state secondary battery is provided with minimized interfacial resistance even when the all-solid-state cell stack is surrounded by a can.

[0027] Figure 1 is a cross-sectional view of an all-solid-state battery.

[0028] Figure 2 is a cross-sectional view of an all-solid-state battery including a precipitated negative electrode.

[0029] Figure 3 is a perspective view showing an all-solid-state secondary battery according to one embodiment.

[0030] Figure 4 is a cross-sectional view taken along line IV-IV of Figure 3.

[0031] Figure 5 is a cross-sectional view taken along line V-V of Figure 3.

[0032] FIG. 6 is a perspective view showing an example of bonding a first cap to one side of a first can and a second can in an all-solid-state secondary battery according to one embodiment.

[0033] Figure 7 is a perspective view showing an all-solid-state secondary battery according to another embodiment.

[0034] Figure 8 is a perspective view showing an all-solid-state secondary battery according to another embodiment.

[0035] Figure 9 is a perspective view showing an all-solid-state secondary battery according to another embodiment.

[0036] Fig. 10 is a cross-sectional view taken along Ⅹ-Ⅹ of Fig. 9.

[0037] FIG. 11 is a partial cross-sectional view showing welding using a laser beam between a first welding surface and a second welding surface of an all-solid-state secondary battery according to another embodiment illustrated in FIG. 10.

[0038] Fig. 12 is a cross-sectional view showing an all-solid-state secondary battery according to another embodiment.

[0039] Fig. 13 is a perspective view showing an all-solid-state secondary battery according to another embodiment.

[0040] Fig. 14 is a perspective view showing an all-solid-state secondary battery according to another embodiment.

[0041] Fig. 15 is a cross-sectional view taken along ⅩⅤ-ⅩⅤ of Fig. 14.

[0042] 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.

[0043] 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.

[0044] To clearly illustrate various layers and regions in the drawings, their thicknesses are enlarged, and similar parts are designated by the same drawing reference numerals throughout the specification. When an element such as a layer, film, region, or plate is said to be "over" or "on" another element, this includes not only the case where it is "directly over" the other element, but also the case where there is another element in between. Conversely, when an element is said to be "directly over" another element, it means that there is no other element in between.

[0045] 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, and for example, "A or B" is interpreted to include A, B, A+B, etc.

[0046] Cathode for all-solid-state secondary batteries

[0047] 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.

[0048] 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.

[0049] positive electrode active material

[0050] 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.

[0051] Li a A 1-b X b D2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5);

[0052] 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);

[0053] 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);

[0054] Li a E 2-b Xb O 4-c D c (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05);

[0055] 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);

[0056] 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);

[0057] 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);

[0058] 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);

[0059] 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);

[0060] Li a Ni 1-b-c Mr b X c O 2-αT2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 <α < 2);

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

[0062] The a Nor b Co c Mn d G e O2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤0.5, 0.001 ≤ e ≤ 0.1);

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

[0064] The a CoG b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0065] The a Mn 1-b G b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0066] The a Mn2G b O4(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0067] The a Mn 1-g G g PO4(0.90 ≤ a ≤ 1.8, 0 ≤ g ≤ 0.5);

[0068] QO2; QS2; LiQS2;

[0069] V2O5; LiV2O5;

[0070] LiZO2;

[0071] LiNiVO4;

[0072] Li (3-f) J2(PO4)3(0 ≤ f ≤ 2);

[0073] Li (3-f) Fe2(PO4)3(0 ≤ f ≤ 2);

[0074] Li a FePO4(0.90 ≤ a ≤ 1.8).

[0075] 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.

[0076] 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).

[0077] 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.

[0078] [Chemical Formula 1]

[0079] Li a1 Ni x1 M 1 y1 M 2 1-x1-y1 O2

[0080] In the above chemical formula 1, 0.9≤a1≤1.8, 0.3≤x1≤1, 0≤y1≤0.7, and M 1 and M 2 is one or more elements independently selected from the group consisting of Al, B, Ba, Ca, Ce, Co, Cr, Cu, F, Fe, Mg, Mn, Mo, Nb, P, S, Si, Sr, Ti, V, W, and Zr.

[0081] [Chemical Formula 2]

[0082] Li a2 Co x2 M 3 1-x2 O2

[0083] 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.

[0084] [Chemical Formula 3]

[0085] Li a3 Fe x3 M 4 (1-x3) PO4

[0086] 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.

[0087] 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.

[0088] 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.

[0089] Sulfide-based solid electrolyte

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] Sulfide-based solid electrolyte particles containing these argyrodite-type sulfides have an ionic conductivity of 10, which is the ionic conductivity of a typical liquid electrolyte at room temperature. -4 10 inland -2 It has a high ionic conductivity approaching the S / cm range, can form a close bond between a positive electrode active material and a solid electrolyte without causing a decrease in ionic conductivity, and can further form a close interface between the electrode layer and the solid electrolyte layer. An all-solid-state battery including this can have improved battery performance, such as rate characteristics, Coulombic efficiency, and cycle life characteristics.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] bookbinder

[0100] 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.

[0101] Challenge

[0102] 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.

[0103] 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.

[0104] 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.

[0105] Meanwhile, the positive electrode for the lithium secondary battery may further include an oxide-based inorganic solid electrolyte in addition to the above-described solid electrolyte. The oxide-based inorganic solid electrolyte may be, for example, Li 1+x Ti 2-x Al(PO4)3(LTAP)(0≤x≤4), Li 1+x+y Al x Ti 2-x Si y P 3-y O 12 (0 <x<2, 0≤y<3), BaTiO3, Pb(Zr,Ti)O3(PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT)(0≤x<1, 0≤y<1), PB(Mg3Nb 2 / 3 )O3-PbTiO3(PMN-PT), HfO2, SrTiO3, SnO2, CeO2, Na2O, MgO, NiO, CaO, BaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiO2, lithium phosphate (Li3PO4), lithium titanium phosphate (Li x Ti y(PO4)3, 0 <x<2, 0<y<3), Li 1+x+y (Al, Ga) x (Ti, Ge) 2-x Si y P 3-y O 12 (0≤x≤1, 0≤y≤1), lithium lanthanum titanate (Li x La y TiO3, 0 <x<2, 0<y<3), Li2O, LiAlO2, Li2O-Al2O3-SiO2-P2O5-TiO2-GeO2계 세라믹스, 가넷(Garnet)계 세라믹스 Li 3+x La3M2O 12 (M= Te, Nb, or Zr; x is an integer from 1 to 10), or a combination thereof.

[0106] All-solid-state secondary battery

[0107] 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.

[0108] Fig. 1 is a cross-sectional view of an all-solid-state secondary battery according to one embodiment. Referring to Fig. 1, the all-solid-state secondary battery (1000) may have a structure in which an electrode assembly in which a negative electrode (40) including a negative electrode current collector (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 collector (21) are laminated is housed in a case such as a pouch. The all-solid-state secondary 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.

[0109] cathode

[0110] An anode for an all-solid-state battery may include, for example, a current collector and a layer of anode active material positioned on the current collector. The layer of anode active material includes a cathode active material and may further include a binder, a conductive material, and / or a solid electrolyte.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] In one embodiment, the negative electrode active material layer further comprises a binder and may optionally further comprise 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 comprises a conductive material, the negative electrode active material layer may comprise 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.

[0120] The above binder serves to adhere the negative active material particles well to each other and also to adhere the negative active material well to the current collector. The binder may include an insoluble binder, a water-soluble binder, or a combination thereof.

[0121] 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.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] FIG. 2 is a schematic cross-sectional view of an all-solid-state secondary battery including a precipitation-type negative electrode according to one embodiment. Referring to FIG. 2, the precipitation-type negative electrode (40') may include a current collector (41) and a negative electrode coating layer (45) positioned on the current collector. An all-solid-state battery including such a precipitation-type negative electrode (40') starts initial charging in a state in which no negative electrode active material is present, and upon charging, a 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 above lithium metal layer (44) refers to a layer in which lithium metal, etc. is precipitated during the charging process of the battery, and may be referred to as a metal layer or a negative electrode active material layer.

[0128] The above cathode coating layer (45) may include a metal, carbon material, or a combination thereof that acts as a catalyst.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] 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 ㎛.

[0135] 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.

[0136] solid electrolyte layer

[0137] 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.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] 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.

[0142] The thickness of the solid electrolyte layer may be, for example, 10 ㎛ to 150 ㎛.

[0143] The above solid electrolyte layer may further include an alkali metal salt, and / or an ionic liquid, and / or a conductive polymer.

[0144] 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.

[0145] 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.

[0146] 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.

[0147] 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.

[0148] 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-.

[0149] 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.

[0150] 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.

[0151] 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.

[0152] 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.

[0153] Hereinafter, an all-solid-state secondary battery according to one embodiment will be described with reference to FIGS. 3 to 6.

[0154] Fig. 3 is a perspective 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. Fig. 5 is a cross-sectional view taken along line V-V of Fig. 3. Fig. 5 is a cross-sectional view showing a first non-welding surface of a first can and a second non-welding surface of a second can located inside a first cap.

[0155] Referring to FIGS. 3 to 5, an all-solid-state secondary battery (1001) according to one embodiment minimizes the interface resistance of an all-solid-state cell stack (100), and includes an all-solid-state cell stack (100), a first can (200), a second can (300), a first cap (400), and a second cap (500).

[0156] The all-solid-state cell stack (100) is a stack in which at least one all-solid-state cell, which is the above-described all-solid-state battery, is stacked in the thickness direction. The stacked structure of the all-solid-state cell stack (100) may include various known stacked structures.

[0157] The first can (200) covers the lower part of the all-solid-state cell stack (100). The first can (200) is combined with the second can (300), the first cap (400), and the second cap (500) to surround the all-solid-state cell stack (100) and simultaneously pressurize the all-solid-state cell stack (100) in the thickness direction. The first can (200) is welded to the second can (300) to pressurize the all-solid-state cell stack (100) toward the second can (300). The first can (200) may include various known metals such as stainless steel and aluminum.

[0158] The first can (200) includes a first plate portion (210), a first side wall portion (220), a first welding surface (230), and a first non-welding surface (240).

[0159] The first plate (210) covers the lower part of the all-solid-state cell stack (100). The first plate (210) completely covers the lower part of the all-solid-state cell stack (100), and each of the ends on both sides of the first direction (X) of the first plate (210) is inserted into the interior of each of the first cap (400) and the second cap (500).

[0160] The first side wall portion (220) is bent and extended from the first plate portion (210) to surround the all-solid-state cell stack (100). A first welding surface (230) and a first non-welding surface (240) are located on the first side wall portion (220). The first side wall portion (220) is bent and extended from both ends of the first plate portion (210) in the second direction (Y) intersecting the first direction (X) in the third direction (Z) to surround both sides of the all-solid-state cell stack (100) in the second direction (Y). Here, the third direction (Z) intersects the first direction (X) and the second direction (Y). The first side wall portion (220) is welded to the second side wall portion (320) of the second can (300) by the first welding surface (230).

[0161] The first welding surface (230) extends along the first direction (X) from the central region of the first side wall portion (220). The first welding surface (230) is welded with the second welding surface (330) of the second can (300). The first welding surface (230) is welded with the second welding surface (330) of the second can (300) while the first can (200) and the second can (300) are pressurizing the all-solid-state cell stack (100). The first welding surface (230) may be welded with the second welding surface (330) using a welding means such as a laser beam, but is not limited thereto and may be welded with the second welding surface (330) using various known welding means. The first welding surface (230) of the first can (200) and the second can (300) are welded to the second welding surface (330) of the second can (300) while the first can (200) and the second can (300) are pressurizing the all-solid-state cell stack (100) while being welded to each other.

[0162] The first non-welding surface (240) is adjacent to the first welding surface (230) and extends along the first direction (X) in the outer region of the first side wall portion (220). The first non-welding surface (240) is inserted into the interior of the first cap (400) by extending from the first welding surface (230) in the first direction (X) toward the first cap (400) while being non-welded with the second can (300). At least a portion of the first non-welding surface (240) is inserted into the interior of the first cap (400), but is not limited thereto, and the entire first non-welding surface (240) may be inserted into the interior of the first cap (400). The first non-welding surface (240) is inserted into the interior of the second cap (500) by extending from the first welding surface (230) in the first direction (X) toward the second cap (500) while being non-welded with the second can (300). At least a portion of the first non-welding surface (240) is inserted into the interior of the second cap (500), but is not limited thereto, and the entire first non-welding surface (240) may be inserted into the interior of the second cap (500). The first non-welding surface (240) extends in a first direction (X) inclined away from the first welding surface (230) and away from the second can (300). At least a portion of the first non-welding surface (240) does not contact the second non-welding surface (340) of the second can (300). For example, referring to FIG. 5, the first non-welding surface (240) extends in an inclined manner along the first direction (X) away from the first welding surface (230) and the second non-welding surface (340) of the second can (300) in the third direction (Z), so that the first non-welding surfaces (240) located at both ends of the first side wall portion (220) in the first direction (X) do not contact the second non-welding surface (340) of the second can (300).

[0163] The second can (300) covers the upper part of the all-solid-state cell stack (100). The second can (300) is combined with the first can (200), the first cap (400), and the second cap (500) to surround the all-solid-state cell stack (100) and simultaneously pressurize the all-solid-state cell stack (100) in the third direction (Z), which is the thickness direction. The second can (300) is welded to the first can (200) to pressurize the all-solid-state cell stack (100) in the third direction (Z), which is the direction of the first can (200). The second can (300) may include various known metals, such as stainless steel and aluminum.

[0164] The second can (300) includes a second plate portion (310), a second side wall portion (320), a second welding surface (330), and a second non-welding surface (340).

[0165] The second plate (310) covers the upper portion of the all-solid-state cell stack (100). The second plate (310) completely covers the upper portion of the all-solid-state cell stack (100), and each of the ends of the second plate (310) in the first direction (X) is inserted into the interior of each of the first cap (400) and the second cap (500). The second plate (310) presses the all-solid-state cell stack (100) together with the first plate (210) of the first can (200) in the third direction (Z).

[0166] The second side wall portion (320) is bent and extended from the second plate portion (310) to surround the all-solid-state cell stack (100). A second welding surface (330) and a second non-welding surface (340) are located on the second side wall portion (320). The second side wall portion (320) is bent and extended from both ends of the second plate portion (310) in the second direction (Y) in the third direction (Z) to surround both sides of the all-solid-state cell stack (100) in the second direction (Y). The second side wall portion (320) is welded to the first side wall portion (220) of the first can (200) by the second welding surface (330).

[0167] The second welding surface (330) extends along the first direction (X) from the central region of the second side wall portion (320). The second welding surface (330) is welded with the first welding surface (230) of the first can (200). The second welding surface (330) is welded with the first welding surface (230) of the first can (200) while the second can (300) and the first can (200) press the all-solid-state cell stack (100) in the third direction (Z). The second welding surface (330) may be welded with the first welding surface (230) using a welding means such as a laser beam, but is not limited thereto and may be welded with the first welding surface (230) using various known welding means. The second welding surface (330) of the second can (300) is welded to the first welding surface (230) of the first can (200) while the second can (300) and the first can (200) pressurize the all-solid-state cell stack (100) in the third direction (Z), which is the thickness direction. As a result, the second can (300) and the first can (200) are welded to each other and pressurize the all-solid-state cell stack (100) in the third direction (Z).

[0168] The second non-welding surface (340) is adjacent to the second welding surface (330) and extends along the first direction (X) from the outer region of the second side wall portion (320). The second non-welding surface (340) is inserted into the interior of the first cap (400) by extending from the second welding surface (330) in the first direction (X) toward the first cap (400) while being non-welded with the first can (200). At least a portion of the second non-welding surface (340) is inserted into the interior of the first cap (400), but is not limited thereto, and the entire second non-welding surface (340) may be inserted into the interior of the first cap (400). The second non-welding surface (340) is inserted into the interior of the second cap (500) by extending from the second welding surface (330) in the first direction (X) toward the second cap (500) while being non-welded with the first can (200). At least a portion of the second non-welding surface (340) is inserted into the interior of the second cap (500), but is not limited thereto, and the entire second non-welding surface (340) may be inserted into the interior of the second cap (500). The second non-welding surface (340) extends in a first direction (X) inclined away from the second welding surface (330) and away from the first can (200). At least a portion of the second non-welding surface (340) does not contact the first non-welding surface (240) of the first can (200). For example, referring to FIG. 5, the second non-welding surface (340) extends in an inclined manner along the first direction (X) away from the second welding surface (330) and the first non-welding surface (240) of the first can (200) in the third direction (Z), so that the second non-welding surfaces (340) located at both ends of the second side wall portion (320) in the first direction (X) do not contact the first non-welding surface (240) of the first can (200).

[0169] The first cap (400) covers one side of the all-solid-state cell stack (100), and the first can (200) and the second can (300) are inserted into the interior of the first cap (400). The first cap (400) covers one side of the all-solid-state cell stack (100) in the first direction (X), and the first non-welding surface (240) of the first can (200) and the second non-welding surface (340) of the second can (300) are inserted. By inserting the inclined first non-welding surface (240) of the first can (200) and the inclined second non-welding surface (340) of the second can (300) into the first cap (400), the first non-welding surface (240) of the first can (200) moves together with the first plate portion (210) toward the second can (300), and the second non-welding surface (340) of the second can (300) moves together with the second plate portion (310) toward the first can (200), so that the first can (200) and the second can (300), which pressurize the all-solid-state cell stack (100) in the third direction (Z) which is the thickness direction by welding with each other, further pressurize the all-solid-state cell stack (100) in the third direction (Z) which is the thickness direction. The first cap (400) may be welded to the first can (200) and the second can (300), but is not limited thereto. The first cap (400) may include various known metals, such as stainless steel and aluminum.

[0170] Fig. 6 is a perspective view illustrating an example of coupling a first cap to one side of a first can and a second can in an all-solid-state secondary battery according to one embodiment. In order to clearly illustrate the coupling structure, Fig. 6 does not illustrate the all-solid-state cell stack positioned inside the first can and the second can. However, when the first cap is coupled to one side of the first can and the second can, the all-solid-state cell stack is positioned inside the first can and the second can and is pressurized by the first can and the second can.

[0171] For example, referring to FIG. 6, when the first cap (400) is coupled to one side of the first can (200) and the second can (300) in the first direction (X), the first non-welding surface (240) of the first can (200) and the second non-welding surface (340) of the second can (300) are pressed (PR) in the third direction (Z) and inserted (IN) into the first cap (400). At this time, the distance between the first non-welding surface (240) of the first can (200) and the second non-welding surface (340) of the second can (300) has a first length (L1) when pressurized (PR) in the third direction (Z) of the all-solid-state cell stack, and when the first non-welding surface (240) and the second non-welding surface (340) are inserted (IN) into the first cap (400), the distance has a second length (L2) that is longer than the first length (L1) due to the restoring force of each of the first can (200) and the second can (300). Here, the first length (L1) and the second length (L2) of the distance between the first non-welding surface (240) of the first can (200) and the second non-welding surface (340) of the second can (300) are smaller than the initial distance between the first non-welding surface (240) of the first can (200) and the second non-welding surface (340) of the second can (300). Therefore, the first can (200) and the second can (300), which pressurize the all-solid-state cell stack in the third direction (Z) in the thickness direction by welding each other, further pressurize the all-solid-state cell stack in the third direction (Z) in the thickness direction.

[0172] Meanwhile, in another embodiment, the first non-welding surfaces (240) located on both sides of the first can (200) and the second can (300) in the first direction (X) are inserted into the first cap (400) and the second cap (500), and the first can (200) and the second can (300) are pressed in the third direction (Z) to weld between the first welding surface (230) of the first can (200) and the second welding surface (330) of the second can (300).

[0173] Referring to FIG. 3, the second cap (500) covers the other side of the all-solid-state cell stack (100), and the first can (200) and the second can (300) are inserted into the interior of the second cap (500). The second cap (500) covers the other side of the all-solid-state cell stack (100) in the first direction (X), and the first non-welding surface (240) of the first can (200) and the second non-welding surface (340) of the second can (300) are inserted. By inserting the inclined first non-welding surface (240) of the first can (200) and the inclined second non-welding surface (340) of the second can (300) into the second cap (500), the first non-welding surface (240) of the first can (200) moves together with the first plate portion (210) toward the second can (300), and the second non-welding surface (340) of the second can (300) moves together with the second plate portion (310) toward the first can (200), so that the first can (200) and the second can (300), which pressurize the all-solid-state cell stack (100) in the third direction (Z) in the thickness direction by welding each other, further pressurize the all-solid-state cell stack (100) in the third direction (Z) in the thickness direction. The second cap (500) may be welded to the first can (200) and the second can (300), but is not limited thereto. The second cap (500) may include various known metals, such as stainless steel and aluminum.

[0174] In this way, in the all-solid-state secondary battery (1001) according to one embodiment, the first welding surface (230) of the first can (200) is welded to the second welding surface (330) of the second can (300) while the first can (200) and the second can (300) press the all-solid-state cell stack (100) in the third direction (Z), which is the thickness direction, so that even if the all-solid-state cell stack (100) is wrapped by the first can (200) and the second can (300) which have elastic restoring force due to their own strength, the interface resistance of the all-solid-state cell stack (100) is minimized.

[0175] In addition, in an all-solid-state secondary battery (1001) according to one embodiment, the first non-welding surface (240) and the second non-welding surface (340) of each of the first can (200) and the second can (300), which pressurize the all-solid-state cell stack (100) in the third direction (Z) in the thickness direction by welding each other, are inserted into the inside of each of the first cap (400) and the second cap (500), so that the first can (200) and the second can (300) further pressurize the all-solid-state cell stack (100) in the third direction (Z) in the thickness direction, thereby minimizing the interface resistance of the all-solid-state cell stack (100) even when the all-solid-state cell stack (100) is wrapped by the first can (200) and the second can (300) having elastic restoring force due to their own strength.

[0176] That is, even if the all-solid-state cell stack is wrapped by a can, an all-solid-state secondary battery (1001) with minimized interfacial resistance is provided.

[0177] Hereinafter, an all-solid-state secondary battery according to another embodiment will be described with reference to FIG. 7. Below, differences from the all-solid-state secondary battery according to the above-described embodiment will be described.

[0178] Figure 7 is a perspective view showing an all-solid-state secondary battery according to another embodiment.

[0179] Referring to FIG. 7, an all-solid-state secondary battery (1002) according to another embodiment minimizes the interfacial resistance of an all-solid-state cell stack, and includes an all-solid-state cell stack, a first can (200), a second can (300), a first cap (400), and a second cap (500).

[0180] The first can (200) includes a first plate portion (210), a first side wall portion (220), a first welding surface (230), and a first non-welding surface (240).

[0181] The first welding surface (230) extends along the first direction (X) from the central region of the first side wall portion (220). The first welding surface (230) is welded with the second welding surface (330) of the second can (300). The first welding surface (230) is welded with the second welding surface (330) of the second can (300) while the first can (200) and the second can (300) are pressurized to form an all-solid-state cell laminate. The first welding surface (230) may be welded with the second welding surface (330) using a welding means such as a laser beam, but is not limited thereto and may be welded with the second welding surface (330) using various known welding means. The first welding surface (230) of the first can (200) is welded to the second welding surface (330) of the second can (300) while the first can (200) and the second can (300) are pressurized to form an all-solid-state cell laminate, thereby pressing the all-solid-state cell laminate in the third direction (Z), which is the thickness direction, while the first can (200) and the second can (300) are welded to each other.

[0182] The first welding surface (230) includes an irregular structure (IRS) extending in a first direction (X) toward the first non-welding surface (240). An interface between the first welding surface (230) and the second welding surface (330) includes an irregular structure (IRS) extending in the first direction (X) toward the first cap (400) and the second cap (500). The irregular structure (IRS) of the first welding surface (230) includes a convex surface.

[0183] The second can (300) includes a second plate portion (310), a second side wall portion (320), a second welding surface (330), and a second non-welding surface (340).

[0184] The second welding surface (330) extends along the first direction (X) from the central region of the second side wall portion (320). The second welding surface (330) is welded with the first welding surface (230) of the first can (200). The second welding surface (330) is welded with the first welding surface (230) of the first can (200) while the second can (300) and the first can (200) are pressurizing the all-solid-state cell laminate in the third direction (Z). The second welding surface (330) may be welded with the first welding surface (230) using a welding means such as a laser beam, but is not limited thereto and may be welded with the first welding surface (230) using various known welding means. The second welding surface (330) of the second can (300) is welded to the first welding surface (230) of the first can (200) while the second can (300) and the first can (200) are pressurized in the third direction (Z) in the thickness direction of the all-solid-state cell stack, thereby pressing the all-solid-state cell stack in the third direction (Z) while the second can (300) and the first can (200) are welded to each other.

[0185] The second welding surface (330) includes an irregular structure (IRS) extending in a first direction (X) toward the second non-welding surface (340). The interface between the second welding surface (330) and the first welding surface (230) includes an irregular structure (IRS) extending in the first direction (X) toward the first cap (400) and the second cap (500). The irregular structure (IRS) of the second welding surface (330) includes a convex surface.

[0186] In this way, the all-solid-state secondary battery (1002) according to another embodiment includes an interfacial roughening structure (IRS) between the first welding surface (230) and the second welding surface (330), so that the surface area of ​​the interface between the first welding surface (230) and the second welding surface (330) increases, so that the all-solid-state cell stack is firmly pressed in the third direction (Z) while the first can (200) and the second can (300) are welded to each other, and thus the interface resistance of the all-solid-state cell stack is minimized even when the all-solid-state cell stack is wrapped by the first can (200) and the second can (300) having elastic restoring force due to their own strength.

[0187] In addition, in an all-solid-state secondary battery (1002) according to another embodiment, the first non-welding surface (240) and the second non-welding surface (340) of each of the first can (200) and the second can (300), which firmly press the all-solid-state cell stack in the third direction (Z) in the thickness direction by welding each other, are inserted into the inside of each of the first cap (400) and the second cap (500), so that the first can (200) and the second can (300) further press the all-solid-state cell stack in the third direction (Z) in the thickness direction, thereby minimizing the interface resistance of the all-solid-state cell stack even when the all-solid-state cell stack is wrapped by the first can (200) and the second can (300) having elastic restoring force due to their own strength.

[0188] That is, even if the all-solid-state cell stack is wrapped by a can, an all-solid-state secondary battery (1002) with minimized interfacial resistance is provided.

[0189] Hereinafter, an all-solid-state secondary battery according to another embodiment will be described with reference to FIG. 8. Below, differences from the all-solid-state secondary battery according to the above-described embodiment will be described.

[0190] Figure 8 is a perspective view showing an all-solid-state secondary battery according to another embodiment.

[0191] Referring to FIG. 8, an all-solid-state secondary battery (1003) according to another embodiment minimizes the interfacial resistance of an all-solid-state cell stack, and includes an all-solid-state cell stack, a first can (200), a second can (300), a first cap (400), and a second cap (500).

[0192] The first can (200) includes a first plate portion (210), a first side wall portion (220), a first welding surface (230), and a first non-welding surface (240).

[0193] The first welding surface (230) extends along the first direction (X) from the central region of the first side wall portion (220). The first welding surface (230) is welded with the second welding surface (330) of the second can (300). The first welding surface (230) is welded with the second welding surface (330) of the second can (300) while the first can (200) and the second can (300) are pressurized to form an all-solid-state cell laminate. The first welding surface (230) may be welded with the second welding surface (330) using a welding means such as a laser beam, but is not limited thereto and may be welded with the second welding surface (330) using various known welding means. The first welding surface (230) of the first can (200) is welded to the second welding surface (330) of the second can (300) while the first can (200) and the second can (300) are pressurized to form an all-solid-state cell laminate, thereby pressing the all-solid-state cell laminate in the third direction (Z), which is the thickness direction, while the first can (200) and the second can (300) are welded to each other.

[0194] The first welding surface (230) includes an irregular structure (IRS) extending in a first direction (X) toward the first non-welding surface (240). An interface between the first welding surface (230) and the second welding surface (330) includes an irregular structure (IRS) extending in the first direction (X) toward the first cap (400) and the second cap (500). The irregular structure (IRS) of the first welding surface (230) includes a triangular surface.

[0195] The second can (300) includes a second plate portion (310), a second side wall portion (320), a second welding surface (330), and a second non-welding surface (340).

[0196] The second welding surface (330) extends along the first direction (X) from the central region of the second side wall portion (320). The second welding surface (330) is welded with the first welding surface (230) of the first can (200). The second welding surface (330) is welded with the first welding surface (230) of the first can (200) while the second can (300) and the first can (200) are pressurizing the all-solid-state cell laminate in the third direction (Z). The second welding surface (330) may be welded with the first welding surface (230) using a welding means such as a laser beam, but is not limited thereto and may be welded with the first welding surface (230) using various known welding means. The second welding surface (330) of the second can (300) is welded to the first welding surface (230) of the first can (200) while the second can (300) and the first can (200) are pressurized in the third direction (Z) in the thickness direction of the all-solid-state cell stack, thereby pressing the all-solid-state cell stack in the third direction (Z) while the second can (300) and the first can (200) are welded to each other.

[0197] The second welding surface (330) includes an irregular structure (IRS) extending in a first direction (X) toward the second non-welding surface (340). The interface between the second welding surface (330) and the first welding surface (230) includes an irregular structure (IRS) extending in the first direction (X) toward the first cap (400) and the second cap (500). The irregular structure (IRS) of the second welding surface (330) includes a triangular surface.

[0198] Meanwhile, in another embodiment, the irregularity structure (IRS) of the first welding surface (230) and the second welding surface (330) may include various known irregularity structures such as circular, elliptical, square, pentagonal, polygonal, and irregular.

[0199] In this way, the all-solid-state secondary battery (1003) according to another embodiment includes an interfacial roughening structure (IRS) between the first welding surface (230) and the second welding surface (330), so that the surface area of ​​the interface between the first welding surface (230) and the second welding surface (330) increases, and thus the all-solid-state cell stack is firmly pressed in the third direction (Z) while the first can (200) and the second can (300) are welded to each other. Therefore, even if the all-solid-state cell stack is wrapped by the first can (200) and the second can (300) having elastic restoring force due to their own strength, the interface resistance of the all-solid-state cell stack is minimized.

[0200] In addition, according to another embodiment, the all-solid-state secondary battery (1003) has a first non-welding surface (240) and a second non-welding surface (340) of each of the first can (200) and the second can (300), which firmly press the all-solid-state cell stack in the third direction (Z) in the thickness direction by welding each other, and are inserted into the inside of each of the first cap (400) and the second cap (500), so that the first can (200) and the second can (300) further press the all-solid-state cell stack in the third direction (Z) in the thickness direction, thereby minimizing the interface resistance of the all-solid-state cell stack even when the all-solid-state cell stack is wrapped by the first can (200) and the second can (300) having elastic restoring force due to their own strength.

[0201] That is, even if the all-solid-state cell stack is wrapped by a can, an all-solid-state secondary battery (1003) with minimized interfacial resistance is provided.

[0202] Hereinafter, an all-solid-state secondary battery according to another embodiment will be described with reference to FIGS. 9 to 11. Below, differences from the all-solid-state secondary battery according to the above-described embodiment will be described.

[0203] Fig. 9 is a perspective view showing an all-solid-state secondary battery according to another embodiment. Fig. 10 is a cross-sectional view taken along line Ⅹ-Ⅹ of Fig. 9.

[0204] Referring to FIGS. 9 and 10, an all-solid-state secondary battery (1004) according to another embodiment minimizes the interface resistance of an all-solid-state cell stack (100), and includes an all-solid-state cell stack (100), a first can (200), a second can (300), a first cap (400), and a second cap (500).

[0205] The first can (200) includes a first plate portion (210), a first side wall portion (220), a first welding surface (230), and a first non-welding surface (240).

[0206] The first welding surface (230) extends along the first direction (X) from the central region of the first side wall portion (220). The first welding surface (230) is welded with the second welding surface (330) of the second can (300). The first welding surface (230) is welded with the second welding surface (330) of the second can (300) while the first can (200) and the second can (300) are pressurizing the all-solid-state cell stack (100). The first welding surface (230) may be welded with the second welding surface (330) using a welding means such as a laser beam, but is not limited thereto and may be welded with the second welding surface (330) using various known welding means. The first welding surface (230) of the first can (200) is welded to the second welding surface (330) of the second can (300) while the first can (200) and the second can (300) are pressurizing the all-solid-state cell stack (100) in the third direction (Z), which is the thickness direction, while the first can (200) and the second can (300) are welded to each other.

[0207] The first welding surface (230) includes a step structure (STS) that is sunken in the third direction (Z) from the direction of the second can (300). The step structure (STS) of the first welding surface (230) includes a first barrier wall (231) that protrudes in the third direction (Z) and is positioned between the second can (300) and the all-solid-state cell stack (100).

[0208] The second can (300) includes a second plate portion (310), a second side wall portion (320), a second welding surface (330), and a second non-welding surface (340).

[0209] The second welding surface (330) extends along the first direction (X) from the central region of the second side wall portion (320). The second welding surface (330) is welded with the first welding surface (230) of the first can (200). The second welding surface (330) is welded with the first welding surface (230) of the first can (200) while the second can (300) and the first can (200) press the all-solid-state cell stack (100) in the third direction (Z). The second welding surface (330) may be welded with the first welding surface (230) using a welding means such as a laser beam, but is not limited thereto and may be welded with the first welding surface (230) using various known welding means. The second welding surface (330) of the second can (300) is welded to the first welding surface (230) of the first can (200) while the second can (300) and the first can (200) pressurize the all-solid-state cell stack (100) in the third direction (Z), which is the thickness direction. As a result, the second can (300) and the first can (200) are welded to each other and pressurize the all-solid-state cell stack (100) in the third direction (Z).

[0210] The second welding surface (330) includes a step structure corresponding to the first welding surface (230) including a step structure (STS).

[0211] FIG. 11 is a partial cross-sectional view showing welding using a laser beam between a first welding surface and a second welding surface of an all-solid-state secondary battery according to another embodiment illustrated in FIG. 10.

[0212] Referring to FIG. 11, when welding between the first welding surface (230) of the first can (200) and the second welding surface (330) of the second can (300) using a laser beam (LB), the first blocking wall (231) included in the step structure (STS) of the first welding surface (230) protrudes in the third direction (Z) and is positioned between the second can (300) and the all-solid-state cell stack (100), so that the laser beam (LB) is blocked from passing through the all-solid-state cell stack (100) by the first blocking wall (231), thereby suppressing the all-solid-state cell stack (100) from being damaged by welding between the first can (200) and the second can (300).

[0213] In this way, the all-solid-state secondary battery (1004) according to another embodiment includes a step structure (STS) in which the first welding surface (230) includes a first blocking wall (231), so that the laser beam (LB) welding between the first welding surface (230) and the second welding surface (330) is blocked from passing through the all-solid-state cell stack (100) by the first blocking wall (231), thereby suppressing the all-solid-state cell stack (100) from being damaged by welding between the first can (200) and the second can (300).

[0214] In addition, in an all-solid-state secondary battery (1004) according to another embodiment, the first welding surface (230) of the first can (200) is welded to the second welding surface (330) of the second can (300) while the first can (200) and the second can (300) press the all-solid-state cell stack (100) in the third direction (Z) in the thickness direction, so that even if the all-solid-state cell stack (100) is wrapped by the first can (200) and the second can (300) which have elastic restoring force due to their own strength, the interface resistance of the all-solid-state cell stack (100) is minimized.

[0215] In addition, according to another embodiment, the all-solid-state secondary battery (1004) is configured such that the first non-welding surface (240) and the second non-welding surface (340) of each of the first can (200) and the second can (300), which pressurize the all-solid-state cell stack (100) in the third direction (Z) in the thickness direction by welding each other, are inserted into the inside of each of the first cap (400) and the second cap (500), so that the first can (200) and the second can (300) further pressurize the all-solid-state cell stack (100) in the third direction (Z) in the thickness direction, thereby minimizing the interface resistance of the all-solid-state cell stack (100) even when the all-solid-state cell stack (100) is wrapped by the first can (200) and the second can (300) having elastic restoring force due to their own strength.

[0216] That is, even if the all-solid-state cell stack is wrapped by a can, an all-solid-state secondary battery (1004) is provided in which breakage of the all-solid-state cell stack due to can welding is suppressed and interface resistance is minimized.

[0217] Hereinafter, an all-solid-state secondary battery according to another embodiment will be described with reference to FIG. 12. Below, differences from the all-solid-state secondary battery according to the above-described embodiment will be described.

[0218] Fig. 12 is a cross-sectional view showing an all-solid-state secondary battery according to another embodiment.

[0219] Referring to FIG. 12, an all-solid-state secondary battery (1005) according to another embodiment minimizes the interface resistance of an all-solid-state cell stack (100), and includes an all-solid-state cell stack (100), a first can (200), a second can (300), a first cap, and a second cap.

[0220] The first can (200) includes a first plate portion (210), a first side wall portion (220), a first welding surface (230), and a first non-welding surface.

[0221] The first welding surface (230) includes a step structure corresponding to the second welding surface (330) including a step structure (STS).

[0222] The second can (300) includes a second plate portion (310), a second side wall portion (320), a second welding surface (330), and a second non-welding surface (340).

[0223] The second welding surface (330) includes a step structure (STS) that is sunken in the third direction (Z) from the direction of the first can (200). The step structure (STS) of the second welding surface (330) includes a second blocking wall (331) that protrudes in the third direction (Z) and is positioned between the first can (200) and the all-solid-state cell stack (100).

[0224] When welding between the first welding surface (230) of the first can (200) and the second welding surface (330) of the second can (300) using a laser beam, the second blocking wall (331) included in the step structure (STS) of the second welding surface (330) protrudes in the third direction (Z) and is positioned between the first can (200) and the all-solid-state cell stack (100), so that the laser beam is blocked from passing through the all-solid-state cell stack (100) by the second blocking wall (331), thereby suppressing the all-solid-state cell stack (100) from being damaged by welding between the first can (200) and the second can (300).

[0225] In this way, the all-solid-state secondary battery (1005) according to another embodiment includes a step structure (STS) in which the second welding surface (330) includes a second blocking wall (331), so that the laser beam welding between the first welding surface (230) and the second welding surface (330) is blocked from passing through the all-solid-state cell stack (100) by the second blocking wall (331), thereby suppressing the all-solid-state cell stack (100) from being damaged by welding between the first can (200) and the second can (300).

[0226] That is, even if the all-solid-state cell stack is wrapped by a can, an all-solid-state secondary battery (1005) is provided in which breakage of the all-solid-state cell stack due to can welding is suppressed and interface resistance is minimized.

[0227] Hereinafter, an all-solid-state secondary battery according to another embodiment will be described with reference to FIG. 13. Hereinafter, differences from the all-solid-state secondary battery according to the above-described embodiment will be described.

[0228] Fig. 13 is a perspective view showing an all-solid-state secondary battery according to another embodiment.

[0229] Referring to FIG. 13, an all-solid-state secondary battery (1006) according to another embodiment minimizes the interfacial resistance of an all-solid-state cell stack, and includes an all-solid-state cell stack, a first can (200), a second can (300), and a first cap (400).

[0230] The first can (200) covers the lower portion of the all-solid-state cell stack. The first can (200) is combined with the second can (300) and the first cap (400) to enclose the all-solid-state cell stack and simultaneously pressurize the all-solid-state cell stack in the thickness direction. The first can (200) is welded to the second can (300) to pressurize the all-solid-state cell stack toward the second can (300). The first can (200) may include various known metals such as stainless steel and aluminum.

[0231] The first can (200) includes a first plate portion (210), a first side wall portion (220), a first welding surface (230), and a first non-welding surface (240).

[0232] The first plate (210) covers the lower part of the all-solid-state cell stack. The first plate (210) completely covers the lower part of the all-solid-state cell stack, and one end of the first plate (210) in the first direction (X) is inserted into the interior of the first cap (400).

[0233] The first side wall portion (220) is bent and extended from the first plate portion (210) to surround the all-solid-state cell stack. A first welding surface (230) and a first non-welding surface (240) are located on the first side wall portion (220). The first side wall portion (220) is bent and extended from both ends of the first plate portion (210) in the second direction (Y) intersecting the first direction (X) in the third direction (Z) to surround both sides of the all-solid-state cell stack in the second direction (Y). Here, the third direction (Z) intersects the first direction (X) and the second direction (Y). The first side wall portion (220) is welded to the second side wall portion (320) of the second can (300) by the first welding surface (230).

[0234] The first welding surface (230) extends along the first direction (X) from the central region of the first side wall portion (220). The first welding surface (230) is welded with the second welding surface (330) of the second can (300). The first welding surface (230) is welded with the second welding surface (330) of the second can (300) while the first can (200) and the second can (300) are pressurized to form an all-solid-state cell laminate. The first welding surface (230) may be welded with the second welding surface (330) using a welding means such as a laser beam, but is not limited thereto and may be welded with the second welding surface (330) using various known welding means. The first welding surface (230) of the first can (200) is welded to the second welding surface (330) of the second can (300) while the first can (200) and the second can (300) are pressurized to form an all-solid-state cell stack, thereby pressing the all-solid-state cell stack while the first can (200) and the second can (300) are welded to each other.

[0235] The first non-welding surface (240) is adjacent to the first welding surface (230) and extends along the first direction (X) from the outer region of the first side wall portion (220). The first non-welding surface (240) is inserted into the interior of the first cap (400) by extending from the first welding surface (230) in the first direction (X) toward the first cap (400) while being non-welded with the second can (300). At least a portion of the first non-welding surface (240) is inserted into the interior of the first cap (400), but is not limited thereto, and the entire first non-welding surface (240) may be inserted into the interior of the first cap (400). The first non-welding surface (240) is extended along the first direction (X) at an angle from the first welding surface (230) away from the second can (300). At least a portion of the first non-contact surface (240) is not in contact with the second non-contact surface (340) of the second can (300).

[0236] The second can (300) covers the upper part of the all-solid-state cell stack. The second can (300) is combined with the first can (200) and the first cap (400) to enclose the all-solid-state cell stack and simultaneously pressurize the all-solid-state cell stack in the third direction (Z), which is the thickness direction. The second can (300) is welded to the first can (200) to pressurize the all-solid-state cell stack in the third direction (Z), which is the direction of the first can (200). The second can (300) may include various known metals, such as stainless steel and aluminum.

[0237] The second can (300) includes a second plate portion (310), a second side wall portion (320), a second welding surface (330), and a second non-welding surface (340).

[0238] The second plate (310) covers the upper part of the all-solid-state cell stack. The second plate (310) completely covers the upper part of the all-solid-state cell stack, and one end of the second plate (310) in the first direction (X) is inserted into the interior of the first cap (400). The second plate (310) presses the all-solid-state cell stack together with the first plate (210) of the first can (200) in the third direction (Z).

[0239] The second side wall portion (320) is bent and extended from the second plate portion (310) to surround the all-solid-state cell stack. A second welding surface (330) and a second non-welding surface (340) are located on the second side wall portion (320). The second side wall portion (320) is bent and extended from both ends of the second plate portion (310) in the second direction (Y) in the third direction (Z) to surround both sides of the all-solid-state cell stack in the second direction (Y). The second side wall portion (320) is welded to the first side wall portion (220) of the first can (200) by the second welding surface (330).

[0240] The second welding surface (330) extends along the first direction (X) from the central region of the second side wall portion (320). The second welding surface (330) is welded with the first welding surface (230) of the first can (200). The second welding surface (330) is welded with the first welding surface (230) of the first can (200) while the second can (300) and the first can (200) are pressurizing the all-solid-state cell laminate in the third direction (Z). The second welding surface (330) may be welded with the first welding surface (230) using a welding means such as a laser beam, but is not limited thereto and may be welded with the first welding surface (230) using various known welding means. The second welding surface (330) of the second can (300) is welded to the first welding surface (230) of the first can (200) while the second can (300) and the first can (200) are pressurized in the third direction (Z) in the thickness direction of the all-solid-state cell stack, thereby pressing the all-solid-state cell stack in the third direction (Z) while the second can (300) and the first can (200) are welded to each other.

[0241] The second non-welding surface (340) is adjacent to the second welding surface (330) and extends along the first direction (X) from the outer region of the second side wall portion (320). The second non-welding surface (340) is inserted into the interior of the first cap (400) by extending from the second welding surface (330) in the first direction (X) toward the first cap (400) while being non-welded with the first can (200). At least a portion of the second non-welding surface (340) is inserted into the interior of the first cap (400), but is not limited thereto, and the entire second non-welding surface (340) may be inserted into the interior of the first cap (400). The second non-welding surface (340) is extended along the first direction (X) at an angle away from the second welding surface (330) and the first can (200). At least a portion of the second non-contact surface (340) is not in contact with the first non-contact surface (240) of the first can (200).

[0242] The first cap (400) covers one side of the all-solid-state cell stack, and the first can (200) and the second can (300) are inserted into the interior of the first cap (400). The first cap (400) covers one side of the all-solid-state cell stack in the first direction (X), and the first non-welding surface (240) of the first can (200) and the second non-welding surface (340) of the second can (300) are inserted. By inserting the inclined first non-welding surface (240) of the first can (200) and the inclined second non-welding surface (340) of the second can (300) into the first cap (400), the first non-welding surface (240) of the first can (200) moves together with the first plate portion (210) toward the second can (300), and the second non-welding surface (340) of the second can (300) moves together with the second plate portion (310) toward the first can (200), so that the first can (200) and the second can (300), which pressurize the all-solid-state cell stack in the third direction (Z) in the thickness direction by welding each other, further pressurize the all-solid-state cell stack in the third direction (Z) in the thickness direction. The first cap (400) may be welded to the first can (200) and the second can (300), but is not limited thereto. The first cap (400) may include various known metals such as stainless steel and aluminum.

[0243] In this way, in the all-solid-state secondary battery (1006) according to another embodiment, the first welding surface (230) of the first can (200) is welded to the second welding surface (330) of the second can (300) while the first can (200) and the second can (300) press the all-solid-state cell stack in the third direction (Z), which is the thickness direction, so that even if the all-solid-state cell stack is wrapped by the first can (200) and the second can (300) which have elastic restoring force due to their own strength, the interface resistance of the all-solid-state cell stack is minimized.

[0244] In addition, according to another embodiment, an all-solid-state secondary battery (1006) is formed in such a manner that each of the first non-welding surface (240) and the second non-welding surface (340) of the first can (200) and the second can (300), which pressurize the all-solid-state cell stack in the third direction (Z) in the thickness direction by welding each other, is inserted into the first cap (400), so that the first can (200) and the second can (300) further pressurize the all-solid-state cell stack in the third direction (Z) in the thickness direction, thereby minimizing the interface resistance of the all-solid-state cell stack even when the all-solid-state cell stack is wrapped by the first can (200) and the second can (300) having elastic restoring force due to their own strength.

[0245] That is, even if the all-solid-state cell stack is wrapped by a can, an all-solid-state secondary battery (1006) with minimized interfacial resistance is provided.

[0246] Hereinafter, an all-solid-state secondary battery according to another embodiment will be described with reference to FIGS. 14 and 15. Below, differences from the all-solid-state secondary battery according to the above-described embodiment will be described.

[0247] Fig. 14 is a perspective view showing an all-solid-state secondary battery according to another embodiment. Fig. 15 is a cross-sectional view taken along ⅩⅤ-ⅩⅤ of Fig. 14.

[0248] Referring to FIGS. 14 and 15, an all-solid-state secondary battery (1007) according to another embodiment minimizes the interfacial resistance of the all-solid-state cell stack (100), and includes an all-solid-state cell stack (100), a first can (200), and a second can (300).

[0249] The first can (200) covers the lower part of the all-solid-state cell stack (100). The first can (200) is combined with the second can (300) to enclose the all-solid-state cell stack (100) and simultaneously pressurize the all-solid-state cell stack (100) in the third direction (Z), which is the thickness direction. The first can (200) is welded to the second can (300) to pressurize the all-solid-state cell stack (100) toward the second can (300). The first can (200) may include various known metals, such as stainless steel and aluminum.

[0250] The first can (200) includes a first plate portion (210), a first side wall portion (220), and a first welding surface (230).

[0251] The first plate (210) covers the lower part of the all-solid-state cell stack (100). The first plate (210) completely covers the lower part of the all-solid-state cell stack (100).

[0252] The first side wall portion (220) is bent and extended from the first plate portion (210) to surround the all-solid-state cell stack (100). A first welding surface (230) is located on the first side wall portion (220). The first side wall portion (220) is bent and extended in the third direction (Z) from the edge of the first plate portion (210) to surround the side of the all-solid-state cell stack (100). The first side wall portion (220) is welded to the second side wall portion (320) of the second can (300) by the first welding surface (230).

[0253] The first welding surface (230) extends along the first side wall portion (220). The first welding surface (230) is welded to the second welding surface (330) of the second can (300). The first welding surface (230) is welded to the second welding surface (330) of the second can (300) while the first can (200) and the second can (300) are pressurizing the all-solid-state cell stack (100). The first welding surface (230) may be welded to the second welding surface (330) using a welding means such as a laser beam, but is not limited thereto, and may be welded to the second welding surface (330) using various known welding means. The first welding surface (230) of the first can (200) and the second can (300) are welded to the second welding surface (330) of the second can (300) while the first can (200) and the second can (300) are pressurizing the all-solid-state cell stack (100) while being welded to each other.

[0254] The first welding surface (230) includes an irregular surface structure (IRS). The interface between the first welding surface (230) and the second welding surface (330) includes an irregular surface structure (IRS). The irregular surface structure (IRS) of the first welding surface (230) includes a convex surface, but is not limited thereto, and may include various irregular structures known in the art.

[0255] The second can (300) covers the upper part of the all-solid-state cell stack (100). The second can (300) is combined with the first can (200) to enclose the all-solid-state cell stack (100) and simultaneously pressurizes the all-solid-state cell stack (100) in the third direction (Z), which is the thickness direction. The second can (300) is welded to the first can (200) to pressurize the all-solid-state cell stack (100) toward the first can (200). The second can (300) may include various known metals, such as stainless steel and aluminum.

[0256] The second can (300) includes a second plate portion (310), a second side wall portion (320), and a second welding surface (330).

[0257] The second plate (310) covers the lower part of the all-solid cell stack (100). The second plate (310) completely covers the lower part of the all-solid cell stack (100).

[0258] The second side wall portion (320) is bent and extended from the second plate portion (310) to surround the all-solid-state cell stack (100). A second welding surface (330) is located on the second side wall portion (320). The second side wall portion (320) is bent and extended in the third direction (Z) from the edge of the second plate portion (310) to surround the side of the all-solid-state cell stack (100). The second side wall portion (320) is welded to the first side wall portion (220) of the first can (200) by the second welding surface (330).

[0259] The second welding surface (330) extends along the second side wall portion (320). The second welding surface (330) is welded with the first welding surface (230) of the first can (200). The second welding surface (330) is welded with the first welding surface (230) of the first can (200) while the second can (300) and the first can (200) are pressurizing the all-solid-state cell stack (100). The second welding surface (330) may be welded with the first welding surface (230) using a welding means such as a laser beam, but is not limited thereto, and may be welded with the first welding surface (230) using various known welding means. The second welding surface (330) of the second can (300) is welded to the first welding surface (230) of the first can (200) while the second can (300) and the first can (200) are pressurizing the all-solid-state cell stack (100) while being welded to each other.

[0260] The second welding surface (330) includes an irregular surface structure (IRS). The interface between the second welding surface (330) and the first welding surface (230) includes an irregular surface structure (IRS). The irregular surface structure (IRS) of the second welding surface (330) includes a convex surface, but is not limited thereto, and may include various irregular structures known in the art.

[0261] In this way, the all-solid-state secondary battery (1007) according to another embodiment has an interface between the first welding surface (230) and the second welding surface (330) including an irregularity structure (IRS), thereby increasing the surface area of ​​the interface between the first welding surface (230) and the second welding surface (330), so that the all-solid-state cell stack (100) is firmly pressed in the third direction (Z) while the first can (200) and the second can (300) are welded to each other, and thus the interface resistance of the all-solid-state cell stack (100) is minimized even when the all-solid-state cell stack (100) is wrapped by the first can (200) and the second can (300) having elastic restoring force due to their own strength.

[0262] That is, even if the all-solid-state cell stack is wrapped by a can, an all-solid-state secondary battery (1007) with minimized interfacial resistance is provided.

[0263] 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.

[0264] [Explanation of symbols]

[0265] All-solid-state cell stack (100), first can (200), first plate portion (210), first welding surface (230), first non-welding surface (240), second can (300), second plate portion (310), second welding surface (330), second non-welding surface (340), first cap (400), second cap (500)

Claims

1. All-solid cell laminate; A first can covering the lower part of the above all-solid cell laminate; and A second can covering the upper part of the above solid-state cell laminate and welded to the first can to press the above solid-state cell laminate in the direction of the first can. Including, An all-solid-state secondary battery, wherein the first can includes a first welding surface including a protruding structure welded to the second can.

2. In paragraph 1, An all-solid-state secondary battery wherein the above-mentioned structure of the above-mentioned first welding surface includes a convex surface.

3. In paragraph 1, An all-solid-state secondary battery wherein the above-mentioned structure of the above-mentioned first welding surface includes a triangular surface.

4. In paragraph 1, An all-solid-state secondary battery in which the uneven structure of the first welding surface includes a stepped structure sunken from the second can direction.

5. In paragraph 4, An all-solid-state secondary battery, wherein the step structure of the first welding surface includes a first barrier wall positioned between the second can and the all-solid-state cell stack.

6. In paragraph 1, Covering one side of the above solid-state cell laminate, further comprising a first cap having the first can and the second can inserted therein, A secondary battery wherein the first can further includes a first non-welded surface extending from the first welding surface in the direction of the first cap and inserted into the first cap while being non-welded with the second can.

7. In paragraph 6, An all-solid-state secondary battery in which the first non-welding surface extends at an angle away from the first welding surface and away from the second can.

8. In paragraph 6, An all-solid-state secondary battery, wherein at least a portion of the first non-contacting surface is not in contact with the second can.

9. In paragraph 6, An all-solid-state secondary battery, wherein the distance between the first non-welding surface and the second can has a first length when the all-solid-state cell stack is pressurized, and has a second distance that is longer than the first length due to the restoring force of the first can when the first non-welding surface is inserted into the first cap.

10. In paragraph 6, An all-solid-state secondary battery in which the above-mentioned uneven structure of the above-mentioned first welding surface extends in the direction of the above-mentioned first non-welding surface.

11. In paragraph 6, The above first can, A first plate portion covering the lower portion of the above-mentioned all-solid cell laminate; and A first side wall portion that is bent and extended from the first plate portion to surround the all-solid cell laminate, and where the first welding surface and the first non-welding surface are located. An all-solid-state secondary battery further comprising:

12. In paragraph 6, Covering the other side of the above solid-state cell laminate, further comprising a second cap having the first can and the second can inserted therein, An all-solid-state secondary battery in which the first non-welded surface extends from the first welding surface in the direction of the second cap and is inserted into the interior of the second cap.

13. In paragraph 6, The second can above, A second welding surface welded to the first welding surface of the first can; and A second non-welded surface that is inserted into the first cap and extends from the second welding surface in the direction of the first cap while being non-welded with the first non-welded surface of the first can. An all-solid-state secondary battery comprising:

14. In paragraph 13, An all-solid-state secondary battery in which the second non-welding surface extends at an angle away from the second welding surface and the first non-welding surface of the first can.

15. In paragraph 13, An all-solid-state secondary battery, wherein at least a portion of the second non-contacting surface is in non-contact with the first non-contacting surface of the first can.

16. In paragraph 13, An all-solid-state secondary battery, wherein the distance between the second non-welding surface and the first non-welding surface has a first length when the all-solid-state cell stack is pressurized, and has a second distance that is longer than the first length due to the restoring force of the second can and the first can when the second non-welding surface and the first non-welding surface are inserted into the first cap.

17. In paragraph 13, An all-solid-state secondary battery wherein the interface between the second welding surface and the first welding surface includes a protruding structure extending in the first cap direction.

18. In paragraph 13, An all-solid-state secondary battery, wherein the second welding surface includes a step structure sunken from the first can direction.

19. In Article 18, An all-solid-state secondary battery, wherein the step structure of the second welding surface includes a second barrier wall positioned between the first can and the all-solid-state cell stack.

20. In paragraph 13, The second can above, A second plate portion covering the upper portion of the above all-solid cell laminate; and A second side wall portion that is bent and extended from the second plate portion to surround the all-solid cell laminate, and where the second welding surface and the second non-welding surface are located. An all-solid-state secondary battery further comprising:

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