All-solid rechargeable battery

Abstract

This all-solid rechargeable battery comprises: an all-solid cell laminate comprising a plurality of all-solid unit cells laminated in a first direction; a case for housing the all-solid cell laminate therein; a first end plate positioned between the case and a first end part of the all-solid cell laminate in the first direction; and a plurality of first metal wave springs positioned between the first end plate and case.

Description

All-solid-state secondary battery

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

[0002] Recent reports of explosion risks in batteries using liquid electrolytes have led to the development of all-solid-state secondary batteries. All-solid-state secondary batteries are batteries composed entirely of solid materials and utilize solid electrolytes.

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

[0004] A conventional all-solid-state secondary battery includes an all-solid-state cell stack including a plurality of all-solid-state unit cells stacked in one direction, a case that houses the all-solid-state cell stack therein, and a pressurizing means that pressurizes the case to pressurize the all-solid-state cell stack.

[0005] One embodiment is directed to providing an all-solid-state secondary battery in which an all-solid-state cell stack whose thickness can change during charging and discharging is uniformly pressed over a wide temperature range, thereby improving impact resistance, reducing the overall thickness, and improving energy density per thickness.

[0006] One aspect provides an all-solid-state secondary battery including an all-solid-state cell stack including a plurality of all-solid-state unit cells stacked in a first direction, a case accommodating the all-solid-state cell stack therein, a first end plate positioned between a first end of the all-solid-state cell stack in the first direction and the case, and a plurality of first metal wave springs positioned between the first end plate and the case.

[0007] The plurality of first metal wave springs can be in contact with the first end plate.

[0008] The first end plate includes a plurality of first recessed portions spaced apart from each other in a second direction intersecting the first direction, and each of the plurality of first metal wave springs can be inserted into each of the plurality of first recessed portions.

[0009] It may further include a second end plate positioned between the plurality of first metal wave springs and the case and in contact with the plurality of first metal wave springs.

[0010] The second end plate includes a plurality of second recessed portions spaced apart from each other in the second direction corresponding to the plurality of first recessed portions of the first end plate, and each of the plurality of first metal wave springs can be inserted into each of the plurality of second recessed portions.

[0011] The second end plate can be in contact with the case.

[0012] The plurality of first metal wave springs can be in contact with the case.

[0013] Each of the plurality of first metal wave springs may include a ring type wave spring.

[0014] The above ring type wave spring may include a wave spring in which waves of symmetrical shapes are laminated and extended in a direction in which elastic restoring force is generated.

[0015] The above ring type wave spring may include a wave spring in which a single layer of waves extends in a ring shape.

[0016] The above ring type wave spring may include a wave spring in which waves of the same shape are laminated and extended in a direction in which elastic restoring force is generated.

[0017] The solid-state cell stack may further include a third end plate positioned between the second end in the first direction and the case, and a plurality of second metal wave springs positioned between the third end plate and the case.

[0018] The plurality of second metal wave springs can be in contact with the third end plate.

[0019] The third end plate includes a plurality of third recessed portions spaced apart from each other in a second direction intersecting the first direction, and each of the plurality of second metal wave springs can be inserted into each of the plurality of third recessed portions.

[0020] It may further include a fourth end plate positioned between the plurality of second metal wave springs and the case and in contact with the plurality of second metal wave springs.

[0021] The fourth end plate includes a plurality of fourth recessed portions spaced apart from each other in the second direction corresponding to the plurality of third recessed portions of the third end plate, and each of the plurality of second metal wave springs can be inserted into each of the plurality of fourth recessed portions.

[0022] The fourth end plate can be in contact with the case.

[0023] The plurality of second metal wave springs can be in contact with the case.

[0024] The above all-solid-state cell stack may further include a plurality of cushioning pads positioned between the plurality of all-solid-state unit cells.

[0025] Each of the above all-solid-state unit cells may include a cathode, an anode positioned on the cathode, and a solid electrolyte layer positioned between the cathode and the anode.

[0026] According to one embodiment, an all-solid-state secondary battery is provided in which an all-solid-state cell stack whose thickness can change during charging and discharging is uniformly pressed over a wide temperature range, thereby improving impact resistance, reducing the overall thickness, and improving energy density per thickness.

[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 cross-sectional view showing an all-solid-state secondary battery according to one embodiment.

[0030] Figure 4 is an enlarged cross-sectional view of part A of Figure 3.

[0031] FIG. 5 is a drawing showing an example of a first metal wave spring of an all-solid-state secondary battery according to one embodiment.

[0032] FIG. 6 is a drawing showing another example of a first metal wave spring of an all-solid-state secondary battery according to one embodiment.

[0033] FIG. 7 is a drawing showing another example of a first metal wave spring of an all-solid-state secondary battery according to one embodiment.

[0034] Figure 8 is an enlarged cross-sectional view of part B of Figure 3.

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

[0036] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. The present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0037] Additionally, throughout the specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0038] To clearly illustrate various layers and regions in the drawings, their thicknesses are enlarged, and similar parts are designated by the same drawing reference numerals throughout the specification. When an element such as a layer, film, region, or plate is said to be "over" or "on" another element, this includes not only the case where it is "directly over" the other element, but also the case where there are other elements in between. Conversely, when an element is said to be "directly over" another element, it means that there are no other elements in between.

[0039] Furthermore, the term "layer" here includes not only shapes formed on the entire surface when observed in a plan view, but also shapes formed on a portion of the surface. Here, "or" is not interpreted in an exclusive sense; for example, "A or B" is interpreted to include A, B, A+B, etc.

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

[0041] In one embodiment, a positive electrode for an all-solid-state secondary battery is provided, which includes a current collecting layer and a positive electrode active material layer positioned on the current collecting layer, wherein the positive electrode active material layer includes at least one of a positive electrode active material, a sulfide-based solid electrolyte, a binder, and a conductive material. However, without limitation thereto, the positive electrode for an all-solid-state secondary battery may include more or less components than the components described above.

[0042] In one embodiment, a positive electrode for an all-solid-state secondary battery is manufactured by applying a positive electrode composition including at least one of a positive electrode active material, a sulfide-based solid electrolyte, a binder, and a conductive material to a current collecting layer, followed by drying and rolling.

[0043] positive electrode active material

[0044] The cathode active material can be applied without limitation as long as it is one commonly used in all-solid-state secondary batteries. For example, the cathode active material may be a compound capable of reversible lithium intercalation and deintercalation, and may include a compound represented by any of the following chemical formulas.

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

[0046] Li a A 1-b X b O 2-c D c (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05);

[0047] Li a E 1-b X b O 2-c D c (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05);

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

[0049] Li a Ni 1-b-c Co b X c D α (0.90 ≤ a ≤1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.5, 0 <α ≤ 2);

[0050] Li a Ni 1-b-c Co b X c O 2-α T α(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2);

[0051] Li a Ni 1-b-c Co b X c O 2-α T2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2);

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

[0053] Li a Ni 1-b-c Mr b X c O 2-α T α (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2);

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

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

[0056] Li a Ni b Co c Mr d G eO2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤0.5, 0.001 ≤ e ≤ 0.1);

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

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

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

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

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

[0062] QO2; QS2; LiQS2;

[0063] V2O5; LiV2O5;

[0064] LiZO2;

[0065] LiNiVO4;

[0066] Li (3-f) J2(PO4)3(0 ≤ f ≤ 2);

[0067] Li (3-f) Fe2(PO4)3(0 ≤ f ≤ 2);

[0068] Li a FePO4(0.90 ≤ a ≤ 1.8).

[0069] In the above chemical formulas, A is selected from the group consisting of Ni, Co, Mn, and combinations thereof; X is selected from the group consisting of Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements, and combinations thereof; D is selected from the group consisting of O, F, S, P, and combinations thereof; E is selected from the group consisting of Co, Mn, and combinations thereof; T is selected from the group consisting of F, S, P, and combinations thereof; G is selected from the group consisting of Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, and combinations thereof; Q is selected from the group consisting of Ti, Mo, Mn, and combinations thereof; Z is selected from the group consisting of Cr, V, Fe, Sc, Y, and combinations thereof; J is selected from the group consisting of V, Cr, Mn, Co, Ni, Cu, and combinations thereof.

[0070] The cathode active material may be, for example, lithium cobalt oxide (LCO), lithium nickel oxide (LNO), lithium nickel cobalt oxide (NC), lithium nickel cobalt aluminum oxide (NCA), lithium nickel cobalt manganese oxide (NCM), lithium nickel manganese oxide (NM), lithium manganese oxide (LMO), or lithium iron phosphate (LFP).

[0071] The positive electrode active material may include a lithium nickel-based oxide represented by the following chemical formula 1, a lithium cobalt-based oxide represented by the following chemical formula 2, a lithium iron phosphate-based compound represented by the following chemical formula 3, or a combination thereof.

[0072] [Chemical Formula 1]

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

[0074] In the above chemical formula 1, 0.9≤a1≤1.8, 0.3≤x1≤1, 0≤y1≤0.7, and M 1 and M2 is one or more elements independently selected from the group consisting of Al, B, Ba, Ca, Ce, Co, Cr, Cu, F, Fe, Mg, Mn, Mo, Nb, P, S, Si, Sr, Ti, V, W, and Zr.

[0075] [Chemical Formula 2]

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

[0077] In the above chemical formula 2, 0.9≤a2≤1.8, 0.6≤x2≤1, and M 3 is one or more elements selected from the group consisting of Al, B, Ba, Ca, Ce, Cr, Cu, F, Fe, Mg, Mn, Mo, Nb, P, S, Si, Sr, Ti, V, W, and Zr.

[0078] [Chemical Formula 3]

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

[0080] In the above chemical formula 3, 0.9≤a3≤1.8, 0.6≤x3≤1, and M 4 is one or more elements selected from the group consisting of Al, B, Ba, Ca, Ce, Co, Cr, Cu, F, Fe, Mg, Mn, Mo, Nb, P, S, Si, Sr, Ti, V, W, and Zr.

[0081] The average particle diameter (D50) of the positive electrode active material may be 1 μm to 25 μm, for example, 3 μm to 25 μm, 5 μm to 25 μm, 5 μm to 20 μm, 8 μm to 20 μm, or 10 μm to 18 μm. A positive electrode active material having such a particle diameter range can be harmoniously mixed with other components within the positive electrode active material layer and can realize high capacity and high energy density.

[0082] The above-mentioned positive electrode active material may be in the form of a secondary particle formed by agglomeration of a plurality of primary particles, or may be in the form of a single particle. In addition, the above-mentioned positive electrode active material may be spherical or nearly spherical in shape, or may be polyhedral or irregular in shape.

[0083] Sulfide-based solid electrolyte

[0084] Sulfide-based solid electrolytes include, for example, Li2S-P2S5, Li2S-P2S5--LiX (where X is a halogen element, for example, I or Cl), Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z. m S n (m, n are integers, Z is Ge, Zn or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p, q are integers, and M is P, Si, Ge, B, Al, Ga or In), or a combination thereof.

[0085] Such sulfide-based solid electrolytes can be obtained, for example, by mixing Li2S and P2S5 in a molar ratio of 50:50 to 90:10, or 50:50 to 80:20, and optionally heat-treating them. Within the above mixing ratio range, a sulfide-based solid electrolyte having excellent ionic conductivity can be produced. Here, the ionic conductivity can be further improved by further including other components such as SiS2, GeS2, and B2S3.

[0086] Methods for mixing sulfur-containing raw materials for producing sulfide-based solid electrolytes include mechanical milling or the solution method. Mechanical milling involves placing the starting raw materials in a reactor and vigorously stirring them with a ball mill or similar device to finely atomize and mix them. Using the solution method, the starting raw materials are mixed in a solvent to obtain a solid electrolyte as a precipitate. Furthermore, heat treatment after mixing can solidify the crystals of the solid electrolyte and improve ionic conductivity. For example, a sulfide-based solid electrolyte can be produced by mixing sulfur-containing raw materials and heat-treating them twice or more, resulting in a sulfide-based solid electrolyte with high ionic conductivity and robustness.

[0087] For example, the sulfide-based solid electrolyte particles may include argyrodite-type sulfides. The argyrodite-type sulfides may include, for example, Li a M b P c S d A e (wherein a, b, c, d and e are all 0 or more and 12 or less, M is a metal other than Li or a combination of multiple metals other than Li, and A is F, Cl, Br, or I) and a specific example is Li 7-x PS 6-x A x (x is 0.2 or more and 1.8 or less, and A is F, Cl, Br, or I) can be expressed by the chemical formula. The above argyrodite-type sulfide is specifically Li3PS4, Li7P3S 11 , Li7PS6, Li6PS5Cl, Li6PS5Br, Li 5.8 PS 4.8 Cl 1.2 , Li 6.2 PS 5.2 Br 0.8 It could be the back.

[0088] Sulfide-based solid electrolyte particles containing these argyrodite-type sulfides have an ionic conductivity of 10, which is the ionic conductivity of a typical liquid electrolyte at room temperature. -4 10 inland -2 It has a high ionic conductivity approaching the S / cm range, can form a close bond between a positive electrode active material and a solid electrolyte without causing a decrease in ionic conductivity, and can further form a close interface between the electrode layer and the solid electrolyte layer. An all-solid-state battery including this can have improved battery performance, such as rate characteristics, Coulombic efficiency, and cycle life characteristics.

[0089] An argyrodite-type sulfide-based solid electrolyte can be prepared, for example, by mixing lithium sulfide, phosphorus sulfide, and optionally, a lithium halide. After mixing, a heat treatment may be performed. The heat treatment may include, for example, two or more heat treatment steps.

[0090] According to one embodiment, the average particle diameter (D50) of the sulfide-based solid electrolyte particles may be 5.0 ㎛ or less, for example, 0.1 ㎛ to 5.0 ㎛, 0.1 ㎛ to 4.0 ㎛, 0.1 ㎛ to 3.0 ㎛, 0.5 ㎛ to 2.0 ㎛, or 0.1 ㎛ to 1.5 ㎛. Alternatively, the sulfide-based solid electrolyte particles may be small particles having an average particle diameter (D50) of 0.1 ㎛ to 1.0 ㎛, or may be large particles having an average particle diameter (D50) of 1.5 ㎛ to 5.0 ㎛, depending on the location or purpose of use. The sulfide-based solid electrolyte particles having such a particle diameter range can effectively penetrate between solid particles in a battery, and have excellent contact with an electrode active material and connectivity between solid electrolyte particles. The average particle size of the sulfide-based solid electrolyte particles may be measured from a microscope image, for example, by measuring the sizes of about 20 particles in a scanning electron microscope image to obtain a particle size distribution and calculating D50 from this.

[0091] The content of the solid electrolyte in the positive electrode for the all-solid-state battery may be 0.5 wt% to 35 wt%, for example, 1 wt% to 35 wt%, 5 wt% to 30 wt%, 8 wt% to 25 wt%, or 10 wt% to 20 wt%. This is the content relative to the total weight of components in the positive electrode, and specifically, it can be said to be the content relative to the total weight of the positive electrode active material layer.

[0092] In one embodiment, the positive electrode active material layer may include 50 wt% to 99.35 wt% of the positive electrode active material, 0.5 wt% to 35 wt% of the sulfide-based solid electrolyte, 0.1 wt% to 10 wt% of the fluorine-based resin binder, and 0.05 wt% to 5 wt% of the vanadium oxide, based on 100 wt% of the positive electrode active material layer. When the above content ranges are satisfied, the positive electrode for an all-solid-state secondary battery can maintain high adhesiveness while implementing high capacity and high ionic conductivity, and the viscosity of the positive electrode composition can be maintained at an appropriate level, thereby improving processability.

[0093] bookbinder

[0094] The binder serves to adhere the positive electrode active material particles well to each other and also to adhere the positive electrode active material well to the current collector, and representative examples thereof include, but are not limited to, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon, etc.

[0095] Challenge

[0096] The above-described positive electrode active material layer may further include a conductive material. The conductive material is used to impart conductivity to the electrode, and may include, for example, carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, and carbon nanotubes; metal-based materials containing copper, nickel, aluminum, silver, and the like in the form of metal powder or metal fibers; conductive polymers such as polyphenylene derivatives; or combinations thereof.

[0097] The conductive material may be included in an amount of 0.1 wt% to 5 wt%, or 0.1 wt% to 3 wt%, based on the total weight of each component of the positive electrode for the all-solid-state battery, or based on the total weight of the positive electrode active material layer. Within the above content range, the conductive material can improve electrical conductivity without degrading battery performance.

[0098] When the positive electrode active material layer further includes a conductive material, the positive electrode active material layer may include 45 wt% to 99.25 wt% of the positive electrode active material, 0.5 wt% to 35 wt% of the sulfide-based solid electrolyte, 0.1 wt% to 10 wt% of the fluorine-based resin binder, 0.05 wt% to 5 wt% of the vanadium oxide, and 0.1 wt% to 5 wt% of the conductive material, based on 100 wt% of the positive electrode active material layer.

[0099] Meanwhile, the positive electrode for the lithium secondary battery may further include an oxide-based inorganic solid electrolyte in addition to the above-described solid electrolyte. The oxide-based inorganic solid electrolyte may be, for example, Li 1+x Ti 2-x Al(PO4)3(LTAP)(0≤x≤4), Li 1+x+y Al x Ti 2-x Si y P 3-y O 12 (0 <x<2, 0≤y<3), BaTiO3, Pb(Zr,Ti)O3(PZT), Pb 1-x La x Zr1-y Ti y O3(PLZT)(0≤x<1, 0≤y<1), PB(Mg3Nb 2 / 3 )O3-PbTiO3(PMN-PT), HfO2, SrTiO3, SnO2, CeO2, Na2O, MgO, NiO, CaO, BaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiO2, lithium phosphate (Li3PO4), lithium titanium phosphate (Li x Ti y (PO4)3, 0 <x<2, 0<y<3), Li 1+x+y (Al, Ga) x (Ti, Ge) 2-x Si y P 3-y O 12 (0≤x≤1, 0≤y≤1), lithium lanthanum titanate (Li x La y TiO3, 0 <x<2, 0<y<3), Li2O, LiAlO2, Li2O-Al2O3-SiO2-P2O5-TiO2-GeO2계 세라믹스, 가넷(Garnet)계 세라믹스 Li 3+x La3M2O 12 (M= Te, Nb, or Zr; x is an integer from 1 to 10), or a combination thereof.

[0100] All-solid-state secondary battery

[0101] In one embodiment, an all-solid-state secondary battery is provided, which includes the aforementioned positive electrode, negative electrode, and a solid electrolyte layer positioned between the positive electrode and negative electrode. The all-solid-state secondary battery may also be referred to as an all-solid-state battery or an all-solid-state lithium secondary battery.

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

[0103] Referring to FIG. 1, the all-solid-state battery (1000) may have a structure in which an electrode assembly in which a negative electrode (40) including a negative electrode current collecting layer (41) and a negative electrode active material layer (43), a solid electrolyte layer (30), and a positive electrode (20) including a positive electrode active material layer (23) and a positive electrode current collecting layer (21) are laminated is housed in a case such as a pouch or a can. The all-solid-state battery (1000) may further include an elastic layer (50) on the outer side of at least one of the positive electrode (20) and the negative electrode (40). Although FIG. 1 illustrates one electrode assembly including a negative electrode (40), a solid electrolyte layer (30), and a positive electrode (20), an all-solid-state battery may be manufactured by laminating two or more electrode assemblies.

[0104] cathode

[0105] An anode for an all-solid-state battery may include, for example, a current collecting layer and a negative electrode active material layer positioned on the current collecting layer. The negative electrode active material layer includes a negative electrode active material and may further include a binder, a conductive material, and / or a solid electrolyte.

[0106] The negative active material may include a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0107] Materials capable of reversibly intercalating / deintercalating lithium ions include carbon-based negative electrode active materials, such as crystalline carbon, amorphous carbon, or a combination thereof. Examples of crystalline carbon include graphite, such as natural graphite or artificial graphite in an amorphous, plate-like, flake-like, spherical, or fibrous form, and examples of amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, and calcined coke.

[0108] As an alloy of lithium metal, an alloy of lithium with one or more metals selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn can be used.

[0109] As a material that can be doped and dedoped with lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material can be used, and as a Si-based negative electrode active material, silicon, silicon-carbon composite, SiO x (0 <x<2), Si-Q 합금(Q는 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소, 15족 원소, 16족 원소, 전이금속, 희토류 원소 및 이들의 조합으로 이루어진 군에서 선택되는 원소이며, Si은 아님), Sn계 음극 활물질로는 Sn, SnO2, Sn-R 합금(R은 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소, 15족 원소, 16족 원소, 전이금속, 희토류 원소 및 이들의 조합으로 이루어진 군에서 선택되는 원소이며, Sn은 아님) 등을 들 수 있고, 또한 이들 중 적어도 하나와 SiO2를 혼합하여 사용할 수도 있다. 원소 Q 및 R로는 Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Tl, Ge, P, As, Sb, Bi, S, Se, Te, Po, 및 이들의 조합으로 이루어진 군에서 선택되는 것을 사용할 수 있다.

[0110] The silicon-carbon composite may be, for example, a silicon-carbon composite including a core comprising crystalline carbon and silicon particles and an amorphous carbon coating layer positioned on the surface of the core. The crystalline carbon may be artificial graphite, natural graphite, or a combination thereof. As the amorphous carbon precursor, coal pitch, mesophase pitch, petroleum pitch, coal oil, petroleum heavy oil, or a polymer resin such as a phenol resin, a furan resin, or a polyimide resin may be used. At this time, the content of silicon may be 10 wt% to 50 wt% with respect to the total weight of the silicon-carbon composite. In addition, the content of the crystalline carbon may be 10 wt% to 70 wt% with respect to the total weight of the silicon-carbon composite, and the content of the amorphous carbon may be 20 wt% to 40 wt% with respect to the total weight of the silicon-carbon composite. In addition, the thickness of the amorphous carbon coating layer may be 5 nm to 100 nm.

[0111] The average particle diameter (D50) of the silicon particles may be 10 nm to 20 μm, for example, 10 nm to 500 nm. The silicon particles may exist in an oxidized form, and in this case, the atomic content ratio of Si:O in the silicon particles, which indicates the degree of oxidation, may be 99:1 to 33:67. The silicon particles are SiO x It can be a particle, in which case SiO x In the range of x, it can be greater than 0 and less than 2. Here, the average particle diameter (D50) is measured by a particle size analyzer using laser diffraction and means the diameter of particles having a cumulative volume of 50% by volume in the particle size distribution.

[0112] The Si-based negative electrode active material or Sn-based negative electrode active material can be used in combination with a carbon-based negative electrode active material. The mixing ratio of the Si-based negative electrode active material or Sn-based negative electrode active material and the carbon-based negative electrode active material can be 1:99 to 90:10 by weight.

[0113] The content of the negative active material in the negative active material layer may be 95 wt% to 99 wt% with respect to the total weight of the negative active material layer.

[0114] In one embodiment, the negative electrode active material layer further includes a binder and may optionally further include a conductive material. The content of the binder in the negative electrode active material layer may be 1 wt% to 5 wt% based on the total weight of the negative electrode active material layer. In addition, when the negative electrode active material layer further includes a conductive material, the negative electrode active material layer may include 90 wt% to 98 wt% of the negative electrode active material, 1 wt% to 5 wt% of the binder, and 1 wt% to 5 wt% of the conductive material.

[0115] The above binder serves to adhere the negative electrode active material particles well to each other and also to adhere the negative electrode active material well to the current collecting layer. The binder may include an insoluble binder, a water-soluble binder, or a combination thereof.

[0116] The above-described non-aqueous binder may include, for example, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, a polymer comprising ethylene oxide, an ethylene propylene copolymer, polystyrene, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, or a combination thereof.

[0117] The water-soluble binder may be a rubber-based binder or a polymer resin binder. The rubber-based binder may be selected from styrene-butadiene rubber, acrylated styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylic rubber, butyl rubber, fluororubber, and combinations thereof. The polymer resin binder may be selected from polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, polyacrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0118] When a water-soluble binder is used as the negative electrode binder, a thickener capable of imparting viscosity may be used together, and the thickener may include, for example, a cellulose-based compound. The cellulose-based compound may include carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, an alkali metal salt thereof, or a combination thereof. Na, K, or Li may be used as the alkali metal. The amount of the thickener used may be 0.1 to 3 parts by weight based on 100 parts by weight of the negative electrode active material.

[0119] The conductive material is used to provide conductivity to the electrode, and may include, for example, carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, and carbon nanotubes; metal-based materials in the form of metal powder or metal fibers, including copper, nickel, aluminum, and silver; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0120] The cathode current collecting layer may be selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and a combination thereof.

[0121] As another example, the negative electrode for the all-solid-state battery may be a precipitation-type negative electrode. The precipitation-type negative electrode refers to a negative electrode that does not include a negative electrode active material when the battery is assembled, but in which lithium metal or the like is precipitated when the battery is charged, and this acts as a negative electrode active material.

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

[0123] Referring to FIG. 2, the precipitation-type negative electrode (40') may include a current collecting layer (41) and a negative electrode coating layer (45) positioned on the current collecting layer (41). An all-solid-state battery having such a precipitation-type negative electrode (40') starts initial charging in a state in which no negative electrode active material exists, and during charging, high-density lithium metal or the like is precipitated between the current collecting layer (41) and the negative electrode coating layer (45) to form a lithium metal layer (44), which may function as the negative electrode active material. Accordingly, in an all-solid-state battery that has been charged more than once, the precipitation-type negative electrode (40') may include a current collecting layer (41), a lithium metal layer (44) positioned on the current collecting layer (41), and a negative electrode coating layer (45) positioned on the metal layer. The lithium metal layer (44) refers to a layer in which lithium metal or the like is precipitated during the charging process of the battery, and may be referred to as a metal layer or a negative electrode active material layer.

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

[0125] The metal may include, for example, gold, platinum, palladium, silicon, silver, aluminum, bismuth, tin, zinc, or a combination thereof, and may be composed of one of these or an alloy of several types. When the metal is present in the form of particles, the average particle diameter (D50) may be about 4 μm or less, for example, 10 nm to 4 μm.

[0126] The carbon material may be, for example, crystalline carbon, amorphous carbon, or a combination thereof. The crystalline carbon may be, for example, natural graphite, artificial graphite, mesophase carbon microbeads, or a combination thereof. The amorphous carbon may be, for example, carbon black, activated carbon, acetylene black, Denka black, Ketjen black, or a combination thereof.

[0127] When the cathode coating layer (45) includes both metal and carbon material, the mixing ratio of the metal and carbon material may be, for example, a weight ratio of 1:10 to 2:1. In this case, the precipitation of lithium metal can be effectively promoted and the characteristics of the all-solid-state battery can be improved. The cathode coating layer (45) may include, for example, a carbon material supported with a catalytic metal, or may include a mixture of metal particles and carbon material particles.

[0128] The cathode coating layer (45) may include, for example, a metal and amorphous carbon, in which case the precipitation of lithium metal can be effectively promoted.

[0129] The cathode coating layer (45) may further include a binder, and the binder may be a conductive binder. In addition, the cathode coating layer (45) may further include general additives such as fillers, dispersants, and ionic conductive agents.

[0130] The thickness of the cathode coating layer (45) may be, for example, 100 nm to 20 ㎛, or 500 nm to 10 ㎛, or 1 ㎛ to 5 ㎛.

[0131] The precipitation-type negative electrode (40') may further include, for example, a thin film on the surface of the current collecting layer (41), that is, between the current collecting layer (41) and the negative electrode coating layer (45). The thin film may include an element capable of forming an alloy with lithium. The element capable of forming an alloy with lithium may be, for example, gold, silver, zinc, tin, indium, silicon, aluminum, bismuth, etc., and may be composed of one type thereof or may be composed of multiple types of alloys. The thin film may further flatten the precipitation form of the lithium metal layer (44) and further improve the characteristics of the all-solid-state battery. The thin film may be formed by, for example, a vacuum deposition method, a sputtering method, a plating method, etc. The thickness of the thin film may be, for example, 1 nm to 500 nm.

[0132] solid electrolyte layer

[0133] The solid electrolyte layer (30) may include a sulfide-based solid electrolyte, an oxide-based solid electrolyte, etc. The specific details of the sulfide-based solid electrolyte and the oxide-based solid electrolyte are as described above.

[0134] In one example, the solid electrolyte included in the positive electrode (20) and the solid electrolyte included in the solid electrolyte layer (30) may include the same compound or different compounds. For example, when both the positive electrode (20) and the solid electrolyte layer (30) include an argyrodite-type sulfide-based solid electrolyte, the overall performance of the all-solid-state secondary battery may be improved. In addition, for example, when both the positive electrode (20) and the solid electrolyte layer (30) include the above-described coated solid electrolyte, the all-solid-state secondary battery may implement high capacity and high energy density while implementing excellent initial efficiency and lifespan characteristics.

[0135] Meanwhile, the average particle diameter (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.

[0136] The solid electrolyte layer may further include a binder in addition to the solid electrolyte. The binder may include, but is not limited to, styrene butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, an acrylate polymer, or a combination thereof, and any binder used in the art may be used. The acrylate polymer may be, for example, butyl acrylate, polyacrylate, polymethacrylate, or a combination thereof.

[0137] A solid electrolyte layer can be formed by adding a solid electrolyte to a binder solution, coating the solution on a substrate film, and drying the solution. The solvent for the binder solution may be isobutyryl isobutyrate, xylene, toluene, benzene, hexane, or a combination thereof. The solid electrolyte layer formation process is widely known in the art, so a detailed description will be omitted.

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

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

[0140] The alkali metal salt may be, for example, a lithium salt. The content of the lithium salt in the solid electrolyte layer may be greater than 1 M, for example, from 1 M to 4 M. In this case, the lithium salt may improve ionic conductivity by enhancing the mobility of lithium ions in the solid electrolyte layer.

[0141] Lithium salts include, for example, LiSCN, LiN(CN)2, Li(CF3SO2)3C, LiC4F9SO3, LiN(SO2CF2CF3)2, LiCl, LiF, LiBr, LiI, LiB(C2O4)2, LiBF4, LiBF3(C2F5), lithium bis(oxalato)borate (LiBOB), lithium oxalyldifluoroborate (LIODFB), lithium difluoro(oxalato)borate (LiDFOB), lithium bis(trifluoro methanesulfonyl)imide (LiTFSI, LiN(SO2CF3)2), lithium bis(fluorosulfonyl)imide (LiFSI, It may include LiN(SO2F)2), LiCF3SO3, LiAsF6, LiSbF6, LiClO4 or mixtures thereof.

[0142] Additionally, the lithium salt may be an imide type, for example, the imide type lithium salt may include lithium bis(trifluoro methanesulfonyl)imide (LiTFSI, LiN(SO2CF3)2), lithium bis(fluorosulfonyl)imide (LiFSI, LiN(SO2F)2). The lithium salt may maintain or improve ionic conductivity by appropriately maintaining chemical reactivity with the ionic liquid.

[0143] Ionic liquids are salts or molten salts that are composed only of ions and are liquid at room temperature, with a melting point below room temperature.

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

[0145] The ionic liquid may be, for example, one or more selected from the group consisting of N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide, N-butyl-N-methylpyrrolidinium bis(3-trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide.

[0146] In the solid electrolyte layer, the weight ratio of the solid electrolyte and the ionic liquid may be 0.1:99.9 to 90:10, for example, 10:90 to 90:10, 20:80 to 90:10, 30:70 to 90:10, 40:60 to 90:10, or 50:50 to 90:10. A solid electrolyte layer satisfying the above range can maintain or improve ionic conductivity by improving the electrochemical contact area with the electrode. Accordingly, the energy density, discharge capacity, rate characteristics, etc. of the all-solid-state battery can be improved.

[0147] The all-solid-state battery may be a unit cell having a structure of anode / solid electrolyte layer / cathode, a bi-cell having a structure of cathode / solid electrolyte layer / cathode / solid electrolyte layer / cathode, or a laminated battery in which the structure of the unit cell is repeated.

[0148] The shape of the all-solid-state battery is not particularly limited, and may be, for example, coin-shaped, button-shaped, sheet-shaped, stacked, cylindrical, or flat. Furthermore, all-solid-state batteries can be applied to large-scale batteries used in electric vehicles, for example. For example, all-solid-state batteries can be used in hybrid vehicles such as plug-in hybrid electric vehicles (PHEVs). Furthermore, they can be used in fields requiring large amounts of power storage, such as electric bicycles or power tools.

[0149] Hereinafter, an all-solid-state secondary battery according to an embodiment will be described with reference to FIGS. 3 to 7. The all-solid-state secondary battery according to an embodiment is a secondary battery capable of being charged and discharged. Hereinafter, the positive electrode includes a cathode, and the negative electrode includes an anode.

[0150] For example, an all-solid-state secondary battery according to one embodiment includes an all-solid-state cell stack including a plurality of all-solid-state unit cells stacked in one direction. Each of the plurality of all-solid-state unit cells of the all-solid-state cell stack includes an all-solid-state battery including a precipitation-type negative electrode as described above with reference to FIG. 2, so that the thickness thereof can change due to a lithium metal layer formed during charging, but is not limited thereto.

[0151] As another example, each of the plurality of all-solid-state unit cells of the all-solid-state cell stack of the all-solid-state secondary battery according to one embodiment may include an all-solid-state battery including the negative electrode described above with reference to FIG. 1.

[0152] Figure 3 is a cross-sectional view showing an all-solid-state secondary battery according to one embodiment.

[0153] Referring to FIG. 3, an all-solid-state secondary battery (1000) according to one embodiment includes an all-solid-state cell stack (100), a case (200), a first end plate (300), a plurality of first metal wave springs (400), a second end plate (500), a third end plate (600), a plurality of second metal wave springs (700), and a fourth end plate (800).

[0154] The all-solid-state cell stack (100) is located inside the case (200). The all-solid-state cell stack (100) includes a plurality of all-solid-state unit cells (110) and a plurality of cushioning pads (120).

[0155] A plurality of all-solid-state unit cells (110) are stacked in a first direction (X). Each of the plurality of all-solid-state unit cells (110) includes a cathode, an anode, and a solid electrolyte layer. Here, the first direction (X) may include a vertical direction in FIG. 3, but is not limited thereto.

[0156] The negative electrode may include at least one of the negative electrode and the deposition-type negative electrode included in the above-described all-solid-state secondary battery, but is not limited thereto. The negative electrode may have a plate or foil shape, but is not limited thereto.

[0157] The positive electrode is positioned on the negative electrode with a solid electrolyte layer between them. The positive electrode may include, but is not limited to, the positive electrode included in the aforementioned all-solid-state secondary battery. The positive electrode may have a plate or foil shape, but is not limited thereto.

[0158] The solid electrolyte layer is positioned between the negative electrode and the positive electrode. The solid electrolyte layer may include, but is not limited to, the solid electrolyte layer included in the aforementioned all-solid-state secondary battery. The solid electrolyte layer may have a layer form between the negative electrode and the positive electrode, but is not limited thereto.

[0159] Each of the plurality of all-solid-state unit cells (110) may have a variety of known laminated structures. For example, the all-solid-state unit cell (110) may have a unit cell having a structure of anode / solid electrolyte layer / cathode, a bicell having a structure of anode / solid electrolyte layer / cathode / solid electrolyte layer / anode, or a laminated battery structure in which the structure of the unit cells is repeated, but is not limited thereto.

[0160] A plurality of cushioning pads (120) are positioned between a plurality of all-solid unit cells (110) stacked in a first direction (X). Each of the plurality of cushioning pads (120) is positioned between an adjacent all-solid unit cell (110) among the plurality of all-solid unit cells (110). A cushioning pad (120) positioned at an uppermost layer in the first direction (X) among the plurality of cushioning pads (120) is positioned between a first end plate (300) and an all-solid unit cell (110) positioned at an uppermost layer among the plurality of all-solid unit cells (110). A cushioning pad (120) positioned at a lowermost layer in the first direction (X) among the plurality of cushioning pads (120) is positioned between a third end plate (600) and an all-solid unit cell (110) positioned at a lowermost layer among the plurality of all-solid unit cells (110). The plurality of cushioning pads (120) may include various known elastic layers used in various known all-solid-state secondary batteries (1000).

[0161] The case (200) houses the all-solid-state cell stack (100) in its internal space. The case (200) has a metal can shape, but is not limited thereto, and may have a pouch shape. The case (200) may have a square column shape, but is not limited thereto, and may have a polygonal column shape such as a triangular column shape, a pentagonal column shape, a hexagonal column shape, a heptagonal column shape, an octagonal column shape, a circular column shape, an elliptical column shape, or a loop column shape. Various known coating layers may be coated on the inner and outer surfaces of the case (200).

[0162] Figure 4 is an enlarged cross-sectional view of part A of Figure 3.

[0163] Referring to FIGS. 3 and 4, a first end plate (300) is positioned between a first end (101) of the all-solid-state cell stack (100) in the first direction (X) and the case (200). The first end plate (300) is positioned between a cushioning pad (120) positioned at the uppermost layer of the all-solid-state cell stack (100) in the first direction (X) and a plurality of first metal wave springs (400). The first end plate (300) is in contact with the cushioning pad (120) and the plurality of first metal wave springs (400). The first end plate (300) presses the all-solid-state cell stack (100) in the first direction (X) by the elastic restoring force of the plurality of first metal wave springs (400). The first end plate (300) includes a plurality of first depressed portions (310).

[0164] A plurality of first recessed portions (310) are arranged to be spaced apart from each other in a second direction (Y) intersecting the first direction (X). Here, the second direction (Y) may include, but is not limited to, a horizontal direction in FIG. 3. The plurality of first recessed portions (310) have a recessed shape from the surface of the first end plate (300). A plurality of first metal wave springs (400) are inserted into each of the plurality of first recessed portions (310). By inserting and supporting the plurality of first metal wave springs (400) into the plurality of first recessed portions (310), the plurality of first metal wave springs (400) are prevented from being separated from the plurality of first recessed portions (310).

[0165] The first end plate (300) has a plate shape including a metal including at least one of aluminum and stainless steel, but is not limited thereto. For example, the first end plate (300) may include various known materials such as polymers, amorphous materials, and ceramics.

[0166] A plurality of first metal wave springs (400) are positioned between a first end plate (300) and a case (200). The plurality of first metal wave springs (400) are positioned between the first end plate (300) and the second end plate (500). The plurality of first metal wave springs (400) are in contact with the first end plate (300) and the second end plate (500). The plurality of first metal wave springs (400) are spaced apart from each other in a second direction (Y) between the first end plate (300) and the second end plate (500). Each of the plurality of first metal wave springs (400) is inserted into each of the plurality of first recessed portions (310) of the first end plate (300) and each of the plurality of second recessed portions (510) of the second end plate (500) and is supported by the first recessed portions (310) and the second recessed portions (510). A plurality of first metal wave springs (400) are inserted and supported in a plurality of first recessed portions (310) and a plurality of second recessed portions (510) between a first end plate (300) and a second end plate (500), thereby preventing the plurality of first metal wave springs (400) from being separated from the plurality of first recessed portions (310) of the first end plate (300) and the plurality of second recessed portions (510) of the second end plate (500).

[0167] Each of the plurality of first metal wave springs (400) includes a metal wave spring. Since each of the plurality of first metal wave springs (400) includes a metal wave spring, even if it has a thinner thickness in the first direction (X) compared to a known coil spring, it has greater elastic recovery force, so that the thickness of the all-solid-state secondary battery (1000) in the first direction (X) is thinned.

[0168] In addition, since each of the plurality of first metal wave springs (400) includes a metal wave spring, even if the thickness of the all-solid-state cell stack (100) in the first direction (X) changes during charging and discharging, the first end plate (300) uniformly presses the all-solid-state cell stack (100) in the first direction (X) by the elastic recovery force of the plurality of first metal wave springs (400).

[0169] In addition, since each of the plurality of first metal wave springs (400) includes a metal wave spring, there is no change in the physical properties of the metal in a wide temperature range (for example, -20°C to 80°C) compared to a polymer elastic layer, which is a known pressurizing means, so that the first end plate (300) uniformly presses the all-solid-state cell stack (100) in the first direction (X) by the elastic recovery force of the plurality of first metal wave springs (400) in a wide temperature range.

[0170] In addition, since each of the plurality of first metal wave springs (400) includes a metal wave spring, the all-solid-state cell stack (100) has elasticity in the first direction (X) and is supported by the plurality of first metal wave springs (400) and the first end plate (300), so that the impact resistance of the all-solid-state secondary battery (1000) is improved.

[0171] In addition, since each of the plurality of first metal wave springs (400) includes a metal wave spring, the inherent thermal conductivity of the metal is improved compared to a polymer elastic layer, which is a known pressurizing means, and thus the heat from the all-solid-state cell stack (100) is conducted and radiated through the first end plate (300) and the plurality of first metal wave springs (400), and thus the heat dissipation effect for the all-solid-state cell stack (100) is improved.

[0172] For example, by including a plurality of first metal wave springs (400) and a first end plate (300), an all-solid-state secondary battery (1000) is provided that uniformly pressurizes an all-solid-state cell stack (100) over a wide temperature range, improves impact resistance, improves heat dissipation effect for the all-solid-state cell stack (100), reduces overall thickness, and improves energy density per thickness, corresponding to an all-solid-state cell stack (100) whose thickness can change during charging and discharging.

[0173] For example, each of the plurality of first metal wave springs (400) includes a ring type wave spring. Since each of the plurality of first metal wave springs (400) includes a ring type wave spring, the lifespan can be improved compared to a known flat type wave spring, and at the same time, the generation of powder due to friction caused by spring elastic recovery can be suppressed. Here, the flat type wave spring may include a plate type wave spring whose longitudinal cross section has a wave shape, but is not limited thereto.

[0174] FIG. 5 is a drawing showing an example of a first metal wave spring of an all-solid-state secondary battery according to one embodiment.

[0175] Referring to FIG. 5, as an example of the first metal wave spring (400), the first metal wave spring (400) may include a wave spring in which waves of symmetrical shapes are laminated and extended in a direction in which elastic restoring force is generated. The first metal wave spring (400) may include a crest-to-crest wave spring, but is not limited thereto.

[0176] Since the first metal wave spring (400) includes a wave spring in which waves of a symmetrical shape are laminated and extended in the direction in which elastic restoring force is generated, the lifespan is improved compared to a flat type wave spring, and at the same time, the generation of powder due to friction caused by spring elastic recovery can be suppressed.

[0177] FIG. 6 is a drawing showing another example of a first metal wave spring of an all-solid-state secondary battery according to one embodiment.

[0178] Referring to Fig. 6, as another example of the first metal wave spring (400), the first metal wave spring (400) may include a wave spring in which a single-layer wave extends in a ring shape. The first metal wave spring (400) may include a single-turn wave spring, but is not limited thereto. Since the first metal wave spring (400) includes a wave spring in which a single-layer wave extends in a ring shape, the lifespan can be improved and the thickness can be reduced compared to a flat type wave spring.

[0179] FIG. 7 is a drawing showing another example of a first metal wave spring of an all-solid-state secondary battery according to one embodiment.

[0180] Referring to FIG. 7, as another example of the first metal wave spring (400), the first metal wave spring (400) may include a wave spring in which waves of the same shape are laminated and extended in a direction in which an elastic restoring force is generated. The first metal wave spring (400) may include a nested wave spring, but is not limited thereto. Since the first metal wave spring (400) includes a wave spring in which waves of the same shape are laminated and extended in a direction in which an elastic restoring force is generated, the lifespan may be improved, the thickness may be reduced, and the elastic restoring force may be improved compared to a flat type wave spring.

[0181] Referring to FIGS. 3 and 4, a second end plate (500) is positioned between a plurality of first metal wave springs (400) and a case (200). The second end plate (500) contacts the case (200) and the plurality of first metal wave springs (400). The second end plate (500) includes a plurality of second recessed portions (510).

[0182] A plurality of second recessed portions (510) are arranged to be spaced apart from each other in the second direction (Y) in correspondence with the plurality of first recessed portions (310) of the first end plate (300). The plurality of second recessed portions (510) face the plurality of first recessed portions (310) with the plurality of first metal wave springs (400) interposed therebetween. The plurality of second recessed portions (510) have a recessed shape from the surface of the second end plate (500). A plurality of first metal wave springs (400) are inserted into each of the plurality of second recessed portions (510). By inserting and supporting the plurality of second metal wave springs (700) into the plurality of second recessed portions (510), the plurality of second metal wave springs (700) are prevented from being separated from the plurality of second recessed portions (510).

[0183] The second end plate (500) has a plate shape including a metal including at least one of aluminum and stainless steel, but is not limited thereto. For example, the second end plate (500) may include various known materials such as polymers, amorphous materials, and ceramics.

[0184] Figure 8 is an enlarged cross-sectional view of part B of Figure 3.

[0185] Referring to FIGS. 3 and 8, a third end plate (600) is positioned between a second end (102) in the first direction (X) of the all-solid-state cell stack (100) and the case (200). The third end plate (600) is positioned between a cushioning pad (120) located at the lowest layer in the first direction (X) of the all-solid-state cell stack (100) and a plurality of second metal wave springs (700). The third end plate (600) is in contact with the cushioning pad (120) and the plurality of second metal wave springs (700). The third end plate (600) presses the all-solid-state cell stack (100) in the first direction (X) by the elastic restoring force of the plurality of second metal wave springs (700). The third end plate (600) includes a plurality of third recessed portions (610).

[0186] A plurality of third recessed portions (610) are arranged spaced apart from each other in the second direction (Y). The plurality of third recessed portions (610) have a recessed shape from the surface of the third end plate (600). A plurality of second metal wave springs (700) are inserted into each of the plurality of third recessed portions (610). By inserting and supporting the plurality of second metal wave springs (700) into the plurality of third recessed portions (610), the plurality of second metal wave springs (700) are prevented from being separated from the plurality of third recessed portions (610).

[0187] The third end plate (600) has a plate shape including a metal including at least one of aluminum and stainless steel, but is not limited thereto. For example, the third end plate (600) may include various known materials such as polymers, amorphous materials, and ceramics.

[0188] A plurality of second metal wave springs (700) are positioned between the third end plate (600) and the case (200). The plurality of second metal wave springs (700) are positioned between the third end plate (600) and the fourth end plate (800). The plurality of second metal wave springs (700) are in contact with the third end plate (600) and the fourth end plate (800). The plurality of second metal wave springs (700) are spaced apart from each other in the second direction (Y) between the third end plate (600) and the fourth end plate (800). Each of the plurality of second metal wave springs (700) is inserted into each of the third recessed portions (610) of the third end plate (600) and each of the fourth recessed portions (810) of the fourth end plate (800) and is supported by the third recessed portions (610) and the fourth recessed portions (810). A plurality of second metal wave springs (700) are inserted and supported in a plurality of third recessed portions (610) and a plurality of fourth recessed portions (810) between a third end plate (600) and a fourth end plate (800), thereby preventing the plurality of second metal wave springs (700) from being separated from the plurality of third recessed portions (610) of the third end plate (600) and the plurality of fourth recessed portions (810) of the fourth end plate (800).

[0189] Each of the plurality of second metal wave springs (700) includes a metal wave spring. Since each of the plurality of second metal wave springs (700) includes a metal wave spring, even if it has a thinner thickness in the first direction (X) compared to a known coil spring, it has a greater elastic recovery force, so that the thickness of the all-solid-state secondary battery (1000) in the first direction (X) is thinned.

[0190] In addition, since each of the plurality of second metal wave springs (700) includes a metal wave spring, even if the thickness of the all-solid-state cell stack (100) in the first direction (X) changes during charging and discharging, the third end plate (600) uniformly presses the all-solid-state cell stack (100) in the first direction (X) by the elastic recovery force of the plurality of second metal wave springs (700).

[0191] In addition, since each of the plurality of second metal wave springs (700) includes a metal wave spring, there is no change in the physical properties of the metal in a wide temperature range (for example, -20°C to 80°C) compared to a polymer elastic layer, which is a known pressurizing means, so that the third end plate (600) uniformly presses the all-solid-state cell stack (100) in the first direction (X) by the elastic recovery force of the plurality of second metal wave springs (700) in a wide temperature range.

[0192] In addition, since each of the plurality of second metal wave springs (700) includes a metal wave spring, the all-solid-state cell stack (100) is supported by the plurality of second metal wave springs (700) and the third end plate (600) while having elasticity in the first direction (X), thereby improving the impact resistance of the all-solid-state secondary battery (1000).

[0193] In addition, since each of the plurality of second metal wave springs (700) includes a metal wave spring, the inherent thermal conductivity of the metal is improved compared to a polymer elastic layer, which is a known pressurizing means, and thus the heat from the all-solid-state cell stack (100) is conducted and radiated through the third end plate (600) and the plurality of second metal wave springs (700), so that the heat dissipation effect for the all-solid-state cell stack (100) is improved.

[0194] For example, by including a plurality of second metal wave springs (700) and a third end plate (600), an all-solid-state secondary battery (1000) is provided that uniformly pressurizes an all-solid-state cell stack (100) over a wide temperature range, improves impact resistance, improves heat dissipation effect for the all-solid-state cell stack (100), reduces overall thickness, and improves energy density per thickness, corresponding to an all-solid-state cell stack (100) whose thickness can change during charging and discharging.

[0195] For example, each of the plurality of second metal wave springs (700) includes a ring type wave spring. Since each of the plurality of second metal wave springs (700) includes a ring type wave spring, the lifespan can be improved compared to a known flat type wave spring, and at the same time, the generation of powder due to friction caused by spring elastic recovery can be suppressed. Here, the flat type wave spring may include a plate type wave spring whose longitudinal cross section has a wave shape, but is not limited thereto.

[0196] As an example of the second metal wave spring (700), the second metal wave spring (700) may include a wave spring in which waves of a symmetrical shape are laminated and extended in the direction in which elastic restoring force is generated, but is not limited thereto.

[0197] Since the second metal wave spring (700) includes a wave spring in which waves of a symmetrical shape are laminated and extended in the direction in which elastic restoring force is generated, the lifespan is improved compared to a flat type wave spring, and at the same time, the generation of powder due to friction caused by spring elastic recovery can be suppressed.

[0198] As another example of the second metal wave spring (700), the second metal wave spring (700) may include, but is not limited to, a wave spring in which a single layer of waves extends in a ring shape.

[0199] Since the second metal wave spring (700) includes a wave spring in which the single-layer wave is extended in a ring shape, the lifespan can be improved and the thickness can be reduced compared to a flat type wave spring.

[0200] As another example of the second metal wave spring (700), the second metal wave spring (700) may include, but is not limited to, a wave spring in which waves of the same shape are laminated and extended in the direction in which elastic restoring force is generated.

[0201] Since the second metal wave spring (700) includes a wave spring in which waves of the same shape are laminated and extended in the direction in which elastic restoring force is generated, the lifespan can be improved compared to a flat type wave spring, and the thickness can be reduced while the elastic restoring force can be improved.

[0202] The fourth end plate (800) is positioned between the plurality of second metal wave springs (700) and the case (200). The fourth end plate (800) contacts the case (200) and the plurality of second metal wave springs (700). The fourth end plate (800) includes a plurality of fourth recessed portions (810).

[0203] A plurality of fourth recessed portions (810) are arranged to be spaced apart from each other in the second direction (Y) in correspondence with the plurality of third recessed portions (610) of the third end plate (600). The plurality of fourth recessed portions (810) face the plurality of third recessed portions (610) with the plurality of second metal wave springs (700) interposed therebetween. The plurality of fourth recessed portions (810) have a recessed shape from the surface of the fourth end plate (800). A plurality of second metal wave springs (700) are inserted into each of the plurality of fourth recessed portions (810). By inserting and supporting the plurality of second metal wave springs (700) into the plurality of fourth recessed portions (810), the plurality of second metal wave springs (700) are prevented from being separated from the plurality of fourth recessed portions (810).

[0204] The fourth end plate (800) has a plate shape including a metal including at least one of aluminum and stainless steel, but is not limited thereto. For example, the fourth end plate (800) may include various known materials such as polymers, amorphous materials, and ceramics.

[0205] For example, since each of the plurality of first metal wave springs (400) and each of the plurality of second metal wave springs (700) includes a metal wave spring, even though it has a thinner thickness in the first direction (X) compared to a known coil spring, it has a greater elastic recovery force, so the thickness of the all-solid-state secondary battery (1000) in the first direction (X) is thinned.

[0206] In addition, since each of the plurality of first metal wave springs (400) and each of the plurality of second metal wave springs (700) includes a metal wave spring, even if the thickness of the all-solid-state cell stack (100) in the first direction (X) changes during charging and discharging, the first end plate (300) and the third end plate (600) uniformly press the all-solid-state cell stack (100) in the first direction (X) by the elastic recovery force of the plurality of first metal wave springs (400) and the plurality of second metal wave springs (700).

[0207] In addition, since each of the plurality of first metal wave springs (400) and each of the plurality of second metal wave springs (700) includes a metal wave spring, there is no change in the physical properties of the metal in a wide temperature range (for example, -20°C to 80°C) compared to a polymer elastic layer, which is a known pressurizing means, so that the first end plate (300) and the third end plate (600) uniformly pressurize the all-solid-state cell stack (100) in the first direction (X) by the elastic recovery force of the plurality of first metal wave springs (400) and the plurality of second metal wave springs (700) in a wide temperature range.

[0208] In addition, since each of the plurality of first metal wave springs (400) and each of the plurality of second metal wave springs (700) includes a metal wave spring, the all-solid-state cell stack (100) has elasticity in the first direction (X) and is supported by the plurality of first metal wave springs (400) and the first end plate (300) and the plurality of second metal wave springs (700) and the third end plate (600), so that the impact resistance of the all-solid-state secondary battery (1000) is improved.

[0209] In addition, since each of the plurality of first metal wave springs (400) and each of the plurality of second metal wave springs (700) includes a metal wave spring, the inherent thermal conductivity of the metal is improved compared to a polymer elastic layer, which is a known pressurizing means, so that heat from the all-solid-state cell stack (100) is conducted and radiated through the first end plate (300) and the plurality of first metal wave springs (400), the third end plate (600) and the plurality of second metal wave springs (700), and the case (200), the heat dissipation effect for the all-solid-state cell stack (100) is improved.

[0210] For example, by including a plurality of first metal wave springs (400) and a first end plate (300) and a plurality of second metal wave springs (700) and a third end plate (600), an all-solid-state secondary battery (1000) is provided, which uniformly pressurizes an all-solid-state cell stack (100) over a wide temperature range, improves impact resistance, improves heat dissipation effect for the all-solid-state cell stack (100), and reduces the overall thickness while improving energy density per thickness, in response to an all-solid-state cell stack (100) whose thickness can change during charging and discharging.

[0211] Hereinafter, an all-solid-state secondary battery according to another embodiment will be described with reference to FIG. 9.

[0212] Below, the parts that are different from the all-solid-state secondary battery according to the above-described embodiment are described.

[0213] Fig. 9 is a cross-sectional view showing an all-solid-state secondary battery according to another embodiment.

[0214] Referring to FIG. 9, an all-solid-state secondary battery (1000) according to another embodiment includes an all-solid-state cell stack (100), a case (200), a first end plate (300), a plurality of first metal wave springs (400), a third end plate (600), and a plurality of second metal wave springs (700).

[0215] A plurality of first metal wave springs (400) are positioned between a first end plate (300) and a case (200). The plurality of first metal wave springs (400) are in contact with the first end plate (300) and the case (200). The plurality of first metal wave springs (400) are spaced apart from each other in a second direction (Y) between the first end plate (300) and the case (200). Each of the plurality of first metal wave springs (400) is inserted into each of the plurality of first recessed portions of the first end plate (300) and supported by the first recessed portions. By inserting and supporting the plurality of first metal wave springs (400) between the first end plate (300) and the case (200), the plurality of first metal wave springs (400) are prevented from being separated from between the first end plate (300) and the case (200).

[0216] For example, the case (200) may include, but is not limited to, a plurality of different recessed portions into which a plurality of first metal wave springs (400) are inserted and supported.

[0217] A plurality of second metal wave springs (700) are positioned between a third end plate (600) and a case (200). The plurality of second metal wave springs (700) are in contact with the third end plate (600) and the case (200). The plurality of second metal wave springs (700) are spaced apart from each other in a second direction (Y) between the third end plate (600) and the case (200). Each of the plurality of second metal wave springs (700) is inserted into each of the plurality of third recessed portions of the third end plate (600) and supported by the third recessed portions. By inserting and supporting the plurality of second metal wave springs (700) in the plurality of third recessed portions between the third end plate (600) and the case (200), the plurality of second metal wave springs (700) are prevented from being separated from between the third end plate (600) and the case (200).

[0218] For example, the case (200) may include, but is not limited to, a plurality of other recessed portions into which a plurality of second metal wave springs (700) are inserted and supported.

[0219] For example, since each of the plurality of first metal wave springs (400) and each of the plurality of second metal wave springs (700) includes a metal wave spring, even though it has a thinner thickness in the first direction (X) compared to a known coil spring, it has a greater elastic recovery force, so the thickness of the all-solid-state secondary battery (1000) in the first direction (X) is thinned.

[0220] In addition, since each of the plurality of first metal wave springs (400) and each of the plurality of second metal wave springs (700) includes a metal wave spring, even if the thickness of the all-solid-state cell stack (100) in the first direction (X) changes during charging and discharging, the first end plate (300) and the third end plate (600) uniformly press the all-solid-state cell stack (100) in the first direction (X) by the elastic recovery force of the plurality of first metal wave springs (400) and the plurality of second metal wave springs (700).

[0221] In addition, since each of the plurality of first metal wave springs (400) and each of the plurality of second metal wave springs (700) includes a metal wave spring, there is no change in the physical properties of the metal in a wide temperature range (for example, -20°C to 80°C) compared to a polymer elastic layer, which is a known pressurizing means, so that the first end plate (300) and the third end plate (600) uniformly pressurize the all-solid-state cell stack (100) in the first direction (X) by the elastic recovery force of the plurality of first metal wave springs (400) and the plurality of second metal wave springs (700) in a wide temperature range.

[0222] In addition, since each of the plurality of first metal wave springs (400) and each of the plurality of second metal wave springs (700) includes a metal wave spring, the all-solid-state cell stack (100) has elasticity in the first direction (X) and is supported by the plurality of first metal wave springs (400) and the first end plate (300) and the plurality of second metal wave springs (700) and the third end plate (600), so that the impact resistance of the all-solid-state secondary battery (1000) is improved.

[0223] In addition, since each of the plurality of first metal wave springs (400) and each of the plurality of second metal wave springs (700) includes a metal wave spring, the inherent thermal conductivity of the metal is improved compared to a polymer elastic layer, which is a known pressurizing means, so that heat from the all-solid-state cell stack (100) is conducted and radiated through the first end plate (300) and the plurality of first metal wave springs (400), the third end plate (600) and the plurality of second metal wave springs (700), and the case (200), the heat dissipation effect for the all-solid-state cell stack (100) is improved.

[0224] For example, by including a plurality of first metal wave springs (400) and a first end plate (300) and a plurality of second metal wave springs (700) and a third end plate (600), an all-solid-state secondary battery (1000) is provided, which uniformly pressurizes an all-solid-state cell stack (100) over a wide temperature range, improves impact resistance, improves heat dissipation effect for the all-solid-state cell stack (100), and reduces the overall thickness while improving energy density per thickness, in response to an all-solid-state cell stack (100) whose thickness can change during charging and discharging.

[0225] 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.

[0226] [Explanation of symbols]

[0227] All-solid unit cell (110), all-solid cell stack (100), case (200), first end plate (300), first metal wave spring (400)

Claims

1. An all-solid cell stack comprising a plurality of all-solid unit cells stacked in a first direction; A case storing the above all-solid-state cell stack inside; A first end plate positioned between the first end of the first direction of the above solid-state cell stack and the case; and A plurality of first metal wave springs positioned between the first end plate and the case An all-solid-state secondary battery comprising:

2. In paragraph 1, An all-solid-state secondary battery in which the plurality of first metal wave springs are in contact with the first end plate.

3. In paragraph 2, The first end plate includes a plurality of first recessed portions spaced apart from each other in a second direction intersecting the first direction, An all-solid-state secondary battery, wherein each of the plurality of first metal wave springs is inserted into each of the plurality of first recessed portions.

4. In paragraph 3, An all-solid-state secondary battery further comprising a second end plate positioned between the plurality of first metal wave springs and the case, the second end plate being in contact with the plurality of first metal wave springs.

5. In paragraph 4, The second end plate includes a plurality of second recessed portions spaced apart from each other in the second direction corresponding to the plurality of first recessed portions of the first end plate, An all-solid-state secondary battery, wherein each of the plurality of first metal wave springs is inserted into each of the plurality of second recessed portions.

6. In paragraph 4, The above second end plate is an all-solid-state secondary battery in contact with the case.

7. In paragraph 2, The above plurality of first metal wave springs are an all-solid-state secondary battery in contact with the case.

8. In paragraph 1, An all-solid-state secondary battery, wherein each of the plurality of first metal wave springs comprises a ring type wave spring.

9. In paragraph 8, The above ring type wave spring is an all-solid-state secondary battery including a wave spring in which waves of symmetrical shapes are laminated and extended in the direction in which elastic restoring force is generated.

10. In paragraph 8, The above ring type wave spring is an all-solid-state secondary battery including a wave spring in which a single layer of waves is extended in a ring shape.

11. In Article 8, The above ring type wave spring is an all-solid-state secondary battery including a wave spring in which waves of the same shape are laminated and extended in the direction in which elastic restoring force is generated.

12. In paragraph 1, A third end plate positioned between the second end of the first direction of the above solid-state cell stack and the case; and A plurality of second metal wave springs positioned between the third end plate and the case. An all-solid-state secondary battery further comprising:

13. In Article 12, An all-solid-state secondary battery in which the plurality of second metal wave springs are in contact with the third end plate.

14. In paragraph 13, The third end plate includes a plurality of third recessed portions spaced apart from each other in a second direction intersecting the first direction, An all-solid-state secondary battery, wherein each of the plurality of second metal wave springs is inserted into each of the plurality of third recessed portions.

15. In paragraph 14, An all-solid-state secondary battery further comprising a fourth end plate positioned between the plurality of second metal wave springs and the case, the fourth end plate being in contact with the plurality of second metal wave springs.

16. In Article 15, The fourth end plate includes a plurality of fourth recessed portions spaced apart from each other in the second direction corresponding to the plurality of third recessed portions of the third end plate, An all-solid-state secondary battery, wherein each of the plurality of second metal wave springs is inserted into each of the plurality of fourth recessed portions.

17. In Article 15, The above fourth end plate is an all-solid-state secondary battery in contact with the case.

18. In paragraph 12, The above-mentioned plurality of second metal wave springs are an all-solid-state secondary battery in contact with the case.

19. In paragraph 1, An all-solid-state secondary battery, wherein the above all-solid-state cell stack further includes a plurality of cushioning pads positioned between the plurality of all-solid-state unit cells.

20. In paragraph 1, Each of the above all-solid unit cells, cathode; an anode positioned on the cathode; and A solid electrolyte layer positioned between the cathode and the anode An all-solid-state secondary battery comprising:

Images