All-solid-state secondary battery

Abstract

An all-solid-state secondary battery is provided. The all-solid-state secondary battery includes: a stack in which a positive electrode and a negative electrode are respectively stacked on both surfaces of a solid electrolyte layer to form a unit cell, a plurality of unit cells is stacked, and electrode tabs respectively connected to the positive electrode and the negative electrode are drawn out to opposite sides in a first direction; a case in which a first portion case and a second portion case are welded to face each other to accommodate the stack, so that welding lines are formed on the opposite sides in the first direction and opposite sides in a second direction crossing the first direction, and outlets are formed on the opposite sides in the first direction; an insulator provided in the outlets to electrically insulate the outlets to form insulation outlets, and allowing the electrode tabs to be drawn out in the first direction through the insulation outlets; and a cap assembly having a terminal electrically connected to the electrode tabs in an electrical insulation state and welded to the case in the first direction.

Description

All-solid-state secondary battery

[0001] The present disclosure relates to an all-solid rechargeable battery.

[0002] Recently, driven by industrial demands, the development of batteries with high energy density and safety is actively underway. For example, lithium-ion batteries are being commercialized not only in the fields of information and communication devices but also in the automotive sector. In the automotive sector, safety is considered particularly important because it is directly related to human life.

[0003] Currently commercially available lithium-ion batteries use electrolytes containing flammable organic solvents, so there is a possibility of overheating and fire in the event of a short circuit. In response to this, all-solid-state secondary batteries using solid electrolytes instead of liquid electrolytes are being proposed.

[0004] All-solid-state secondary batteries can significantly reduce the likelihood of fire or explosion in the event of a short circuit by not using flammable organic solvents. Therefore, these all-solid-state batteries can offer significantly higher safety compared to lithium-ion batteries that use liquid electrolytes.

[0005] The information described above, disclosed in the background technology of this invention, is intended only to enhance understanding of the background of this disclosure and may therefore include information that does not constitute prior art.

[0006] One embodiment aims to provide an all-solid-state secondary battery that secures the rigidity of a case containing a stack.

[0007] One embodiment aims to provide an all-solid-state secondary battery that simplifies the assembly process of a cap assembly while improving welding quality and rigidity.

[0008] A solid-state secondary battery according to one embodiment comprises: a stack formed by stacking a positive electrode and a negative electrode on each side of a solid electrolyte layer to form a unit cell, and stacking a plurality of the unit cells to form electrode tabs connected to each of the positive electrode and the negative electrode, each being drawn out to both sides of a first direction; a case formed by welding a first part case and a second part case together to accommodate the stack, forming welding lines on both sides of the first direction and on both sides of a second direction intersecting the first direction, and forming outlets on both sides of the first direction; an insulator provided at the outlet to electrically insulate the outlet to form an insulated outlet, and to draw out the electrode tabs to the first direction through the insulated outlet; and a cap assembly that is provided with a terminal electrically connected to the electrode tabs in an electrically insulated state and welded to the case in the first direction.

[0009] The above outlet may be formed by a first groove of the first part case and a second groove of the second part case facing each other.

[0010] The electrode tab may include a first tab connected to the positive electrode and drawn out in a first positive (+) direction, and a second tab connected to the negative electrode and drawn out in a first negative (-) direction.

[0011] The above electrode tab can be formed as a double tab by separating from the first positive (+) direction to the second direction, and can be formed as a double tab by separating from the first negative (-) direction to the second direction.

[0012] The above case may include a pair of outlets corresponding to a double tap on both sides of the first direction, a first side wall formed in a portion excluding the pair of outlets, and a second side wall formed on both sides of the second direction.

[0013] The welding line may include a first weld formed on the first side wall by welding the first part case and the second part case, and a second weld formed on the second side wall by welding the first part case and the second part case.

[0014] The first side wall is provided at both ends of the second direction to be connected to the second side wall, and may be further provided between a pair of outlets.

[0015] The first weld may include end welds provided at both ends of the second direction, and a central weld provided between a pair of outlets.

[0016] The above insulator may include a first insulating part coupled to one of the pair of outlets to form a first insulating outlet, and a second insulating part connected to the first insulating part and coupled to the other of the pair of outlets to form a second insulating outlet.

[0017] The above insulator may include a connecting portion that contacts the cross-section of the case forming the outlet, a projection that protrudes from one side of the connecting portion and supports one side of the case, and a hook that protrudes from the other side of the connecting portion and is coupled to the other side of the case.

[0018] The above cap assembly may include a subplate connected to the electrode tab having a through hole corresponding to the first insulating outlet and the second insulating outlet, respectively, a subtab connecting the subplate to the terminal, and a cap plate that accommodates the subplate and the subtab in an insulating structure.

[0019] The electrode tab of the double-tap structure can be drawn out through the first insulating outlet and the through hole, and the second insulating outlet and the through hole other than, and placed between the subplate and the sub-tap and welded.

[0020] One electrode tab of the double-tap structure is bent in a positive (+) stacking direction from the outer side of the drawn-out sub-plate to contact the outer surface of the sub-plate, and the other electrode tab of the double-tap structure is bent in a negative (-) stacking direction from the outer side of the drawn-out sub-plate to contact the outer surface of the sub-plate.

[0021] The above cap plate can be welded to the above case.

[0022] The above terminal can be drawn out to the outside of the cap plate by interposing a terminal insulator in the terminal hole of the cap plate.

[0023] A solid-state secondary battery of one embodiment may further include a buffer member between the stack and the case.

[0024] The above insulator may include a first insulator coupled to one of a pair of outlets corresponding to a double tap on both sides of the first direction to form a first insulating outlet, and a second insulator formed separately from the first insulator and coupled to the other of the pair of outlets to form a second insulating outlet.

[0025] The above insulator may include a first part insulator coupled to the first groove, and a second part insulator coupled to the second groove and in contact with the first part insulator to form the insulating outlet.

[0026] The above insulator may include a first injection portion that is insert-molded into the first groove of the first part case, and a second injection portion that is insert-molded into the second groove of the second part case and contacts the first injection portion to form the insulating outlet.

[0027] The insulator may include a first O-ring insulator that is coupled to one of a pair of outlets corresponding to a double tap on both sides of the first direction to form a first insulating outlet, and a second O-ring insulator that is formed separately from the first O-ring insulator and is coupled to the other of the pair of outlets to form a second insulating outlet.

[0028] The above insulator may include a first part insulator coupled to the first groove, and a second part insulator coupled to the second groove and in contact with the first part insulator to form the insulating outlet.

[0029] The above insulator may include a connecting portion that contacts the cross-section of the case forming the outlet, and two protrusions that protrude from both sides of the connecting portion and support both sides of the case.

[0030] The above cap assembly may include a subplate connected to the electrode tab having a through hole corresponding to the insulating outlet, a subtab connecting the subplate to the terminal, and a cap plate that accommodates the subplate and the subtab in an insulating structure.

[0031] The electrode tab of the double-tap structure can be drawn out through the insulating outlet and the through hole and placed between the subplate and the sub-tap to be welded.

[0032] One electrode tab of the double-tap structure is bent in a positive (+) stacking direction from the outer side of the drawn-out sub-plate to contact the outer surface of the sub-plate, and the other electrode tab of the double-tap structure is bent in a negative (-) stacking direction from the outer side of the drawn-out sub-plate to contact the outer surface of the sub-plate.

[0033] The above cap plate can be welded to the above case.

[0034] The above terminal can be drawn out to the outside of the cap plate by interposing a terminal insulator in the terminal hole of the cap plate.

[0035] In one embodiment, the first part case and the second part case are welded facing each other to form welding lines on both sides of the first direction and both sides of the second direction, thereby ensuring the rigidity of the case containing the stack.

[0036] In one embodiment, outlets are formed on both sides of the first direction, and an insulator is provided in the outlets so that the electrode tab is drawn out through the insulated outlets, thereby simplifying the assembly process of the cap assembly.

[0037] In addition, one embodiment forms outlets on both sides of the first direction, and by combining an insulator with the outlets to draw out the electrode tabs through the insulated outlets, the assembly process of the cap assembly can be simplified.

[0038] FIG. 1 is a cross-sectional view showing an all-solid-state secondary battery according to one embodiment.

[0039] FIG. 2 is a cross-sectional view showing the formation of a lithium metal layer of an all-solid-state secondary battery according to one embodiment.

[0040] FIG. 3 is a plan view of an all-solid-state secondary battery according to a first embodiment of the present invention.

[0041] Figure 4 is an exploded perspective view of the all-solid-state secondary battery of Figure 3 (before welding the case).

[0042] Fig. 5 is an exploded perspective view of the all-solid-state secondary battery of Fig. 3 (after welding the case).

[0043] FIG. 6 is an exploded perspective view of the all-solid-state secondary battery of FIG. 5 equipped with an insulator.

[0044] Fig. 7 is an inner side view of the insulator of Fig. 6.

[0045] Figure 8 is a plan view of the insulator of Figure 7.

[0046] Figure 9 is a cross-sectional view taken along the line IX-IX of Figure 6.

[0047] FIG. 10 is a perspective view of the state before welding the subplate to the electrode tab of FIG. 6.

[0048] FIG. 11 is a perspective view of the state in which the electrode tab of FIG. 10 and the sub-tab are welded to the sub-plate.

[0049] Figure 12 is a diagram showing the state of assembling and welding a cap assembly to the case of Figure 11.

[0050] FIG. 13 is a cross-sectional view taken along the line XIII-XIII of FIG. 12.

[0051] FIG. 14 is an inner side view of an insulator applied to an all-solid-state secondary battery according to a second embodiment of the present invention.

[0052] Fig. 15 is a plan view of the insulator of Fig. 14.

[0053] FIG. 16 is an inner side view of an insulator applied to an all-solid-state secondary battery according to a third embodiment of the present invention.

[0054] FIG. 17 is a combined inner side view of a case and an insulator applied to an all-solid-state secondary battery according to the fourth embodiment of the present invention.

[0055] FIG. 18 is an inner side view of an insulator applied to an all-solid-state secondary battery according to the fifth embodiment of the present invention.

[0056] FIG. 19 is a combined inner side view of the case and insulator of FIG. 18.

[0057] FIG. 20 is an exploded perspective view of an all-solid-state secondary battery (after the insulator is coupled to the case) according to the 6th embodiment of the present invention.

[0058] Fig. 21 is an inner side view of the insulator of Fig. 20.

[0059] Fig. 22 is a plan view of the insulator of Fig. 21.

[0060] Figure 23 is a diagram showing the state of welding the case of Figure 20.

[0061] FIG. 24 is a cross-sectional view taken along the line IX-IX of FIG. 23.

[0062] FIG. 25 is a perspective view of the state before welding the subplate to the electrode tab of FIG. 23.

[0063] FIG. 26 is a perspective view of the state in which the electrode tab of FIG. 25 and the sub-tab are welded to the sub-plate.

[0064] Figure 27 is a diagram showing the state of assembling and welding a cap assembly to the case of Figure 26.

[0065] FIG. 28 is a cross-sectional view taken along the line XIII-XIII of FIG. 27.

[0066] Hereinafter, embodiments of the present invention are 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 embodied in various different forms and is not limited to the embodiments described herein.

[0067] Furthermore, throughout the specification, when a part is described as "including" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0068] In the drawings, thicknesses have been enlarged to clearly represent various layers and regions, and the same reference numerals have been used for similar parts throughout the specification. When a part such as a layer, film, region, or plate is described as being "on" or "on" another part, this includes not only cases where it is "immediately on" another part, but also cases where there is another part in between. Conversely, when a part is described as being "immediately on" another part, it means that there is no other part in between.

[0069] In addition, the term "layer" here includes not only shapes formed on the entire surface when viewed in a plan view, but also shapes formed on some surfaces. Here, "or" is not interpreted in an exclusive sense, and for example, "A or B" is interpreted to include A, B, A+B, etc.

[0070] cathode for all-solid-state secondary batteries

[0071] In one embodiment, a positive electrode for an all-solid-state secondary battery is provided, comprising a current collector and a positive active material layer located on the current collector, wherein the positive active material layer comprises at least one of a positive active material, a sulfide-based solid electrolyte, a binder, and a conductive material. However, the positive electrode for an all-solid-state secondary battery is not limited thereto, and may include more or fewer components than the components described above.

[0072] In one embodiment, the positive electrode for the all-solid-state secondary battery is manufactured by applying a positive electrode composition comprising at least one of a positive electrode active material, a sulfide-based solid electrolyte, a binder, and a conductive material to a current collector, and then drying and rolling.

[0073] positive electrode active material

[0074] The above-mentioned positive active material may be applied without limitation as long as it is commonly used in all-solid-state secondary batteries. For example, the above-mentioned positive 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.

[0075] Li a A 1-b X b D2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5);

[0076] 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);

[0077] Li a HAVE BEEN 1-b X b O 2-c D c (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05);

[0078] Li a HAVE BEEN 2-b X b O 4-c D c (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05);

[0079] 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);

[0080] 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);

[0081] 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);

[0082] 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);

[0083] Li a Ni1-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);

[0084] 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);

[0085] 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);

[0086] Li a Ni b Co c Mr d G e O2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤0.5, 0.001 ≤ e ≤ 0.1);

[0087] Li a NiG b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0088] Li a CoG b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0089] Li a Mr 1-b G b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0090] Li a Mn2G b O4(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1);

[0091] Li a Mn 1-g G g PO4(0.90 ≤ a ≤ 1.8, 0 ≤ g ≤ 0.5);

[0092] QO2; QS2; LiQS2;

[0093] V2O5; LiV2O5;

[0094] LiZO2;

[0095] LiNiVO4;

[0096] Li (3-f) J2(PO4)3(0 ≤ f ≤ 2);

[0097] Li (3-f) Fe2(PO4)3(0 ≤ f ≤ 2);

[0098] Li a FePO4(0.90 ≤ a ≤ 1.8).

[0099] 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; and J is selected from the group consisting of V, Cr, Mn, Co, Ni, Cu, and combinations thereof.

[0100] 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 oxide (LFP).

[0101] The above positive 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.

[0102] [Chemical Formula 1]

[0103] Li a1 Ni x1 M 1 y1 M 2 1-x1-y1 O2

[0104] 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 Each is independently 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.

[0105] [Chemical Formula 2]

[0106] Li a2 Co x2 M 3 1-x2 O2

[0107] In the above chemical formula 2, 0.9≤a2≤1.8, 0.6≤x2≤1, and M 3 It 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.

[0108] [Chemical Formula 3]

[0109] Li a3 Fe x3 M 4 (1-x3) PO4

[0110] 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.

[0111] Average particle size (D of the above positive active material) 50 The particle size can 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 size range can be harmoniously mixed with other components within the positive electrode active material layer and can achieve high capacity and high energy density.

[0112] The above positive active material may be in the form of secondary particles formed by the aggregation of a plurality of primary particles, or in the form of a single particle. In addition, the above positive active material may be spherical or have a shape close to spherical, or may be polyhedral or amorphous.

[0113] Sulfide-based solid electrolytes

[0114] Sulfide-based solid electrolytes include, for example, Li2S-P2S5, Li2S-P2S5-LiX (where X is a halogen element, e.g., 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, and Li2S-P2S5-Z mS n (m and n are integers, and 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 may include a combination thereof.

[0115] 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. Within the above mixing ratio range, a sulfide-based solid electrolyte having excellent ionic conductivity can be manufactured. Additionally, ionic conductivity may be further improved by including other components such as SiS2, GeS2, B2S3, etc.

[0116] Mechanical milling or the solution method can be applied as mixing methods for sulfur-containing raw materials to manufacture sulfide-based solid electrolytes. Mechanical milling is a method in which starting materials are placed in a reactor and vigorously stirred with a ball mill or similar device to finely pulverize and mix the starting materials. When using the solution method, starting materials are mixed in a solvent to obtain a solid electrolyte as a precipitate. Furthermore, if heat treatment is performed after mixing, the crystals of the solid electrolyte can become more robust and the ionic conductivity can be improved. For example, a sulfide-based solid electrolyte can be manufactured by mixing sulfur-containing raw materials and heat-treating them two or more times; in this case, a robust sulfide-based solid electrolyte with high ionic conductivity can be produced.

[0117] For example, the sulfide-based solid electrolyte particles may include an argyrodite-type sulfide. The argyrodite-type sulfide is, for example, Li a M b P c S d A eIt can be expressed by the chemical formula (where a, b, c, d, and e are all between 0 and 12, M is a metal excluding Li or a combination of multiple metals excluding Li, and A is F, Cl, Br, or I), and as a specific example, Li 7-x PS 6-x A x It can be expressed by the chemical formula (where x is 0.2 or greater and 1.8 or less, and A is F, Cl, Br, or I). Specifically, the azirodite-type sulfide is 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.

[0118] Sulfide-based solid electrolyte particles containing such azirodite-type sulfides have an ionic conductivity of 10 at room temperature, which is the ionic conductivity of a typical liquid electrolyte. -4 to 10 -2 It has high ionic conductivity close to the S / cm range and can form a tight bond between the positive active material and the solid electrolyte without causing a decrease in ionic conductivity, and furthermore, can form a tight interface between the electrode layer and the solid electrolyte layer. An all-solid-state battery including this can improve battery performance such as rate characteristics, Coulomb efficiency, and lifespan characteristics.

[0119] An azirodite-type sulfide-based solid electrolyte can be prepared by mixing, for example, lithium sulfide and phosphorus sulfide, and optionally lithium halide. After mixing these, heat treatment may be performed. The heat treatment may include, for example, two or more heat treatment steps.

[0120] According to one embodiment, the average particle size (D50) of the sulfide-based solid electrolyte particles may be 5.0 μm or less, for example, 0.1 μm to 5.0 μm, 0.1 μm to 4.0 μm, 0.1 μm to 3.0 μm, 0.5 μm to 2.0 μm, or 0.1 μm to 1.5 μm. Alternatively, depending on the location or purpose of use, the sulfide-based solid electrolyte particles may be small particles having an average particle size (D50) of 0.1 μm to 1.0 μm, or large particles having an average particle size (D50) of 1.5 μm to 5.0 μm. Sulfide-based solid electrolyte particles within this particle size range can effectively penetrate between solid particles within the battery, and have excellent contact with the electrode active material and connectivity between solid electrolyte particles. The average particle size of the sulfide-based solid electrolyte particles may be measured using a microscopic image, for example, by measuring the size of about 20 particles in a scanning electron microscope image to obtain the particle size distribution and calculating D50 from it.

[0121] The content of the solid electrolyte in the anode 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 the components in the anode, and specifically, it can be said to be the content relative to the total weight of the anode active material layer.

[0122] In one embodiment, the positive active material layer may comprise, with respect to 100 weight% of the positive active material layer, 50 weight% to 99.35 weight% of a positive active material, 0.5 weight% to 35 weight% of a sulfide-based solid electrolyte, 0.1 weight% to 10 weight% of a fluorine-based resin binder, and 0.05 weight% to 5 weight% of vanadium oxide. When such content ranges are satisfied, the positive electrode for an all-solid-state secondary battery can achieve high capacity and high ionic conductivity while maintaining high adhesion, and the viscosity of the positive electrode composition can be maintained at an appropriate level, thereby improving processability.

[0123] bookbinder

[0124] The binder serves to adhere the positive active material particles well to each other and also to adhere the positive active material well to the current collector. Representative examples include polyvinyl alcohol, carboxymethylcellulose, hydroxypropylcellulose, diacetylcellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon, etc., but are not limited thereto.

[0125] Challenge

[0126] The above positive 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, carbon nanotubes; metal-based materials containing copper, nickel, aluminum, silver, etc., in the form of metal powder or metal fibers; conductive polymers such as polyphenylene derivatives; or a combination thereof.

[0127] The conductive material may be included in an amount of 0.1% to 5% by weight, or 0.1% to 3% by weight, relative to the total weight of each component of the anode for the all-solid-state battery, or relative to the total weight of the anode active material layer. Within the above content range, the conductive material can improve electrical conductivity without degrading battery performance.

[0128] When the above positive active material layer further comprises a conductive material, the above positive active material layer may comprise, with respect to 100 weight% of the above positive active material layer, 45 weight% to 99.25 weight% of a positive active material, 0.5 weight% to 35 weight% of a sulfide-based solid electrolyte, 0.1 weight% to 10 weight% of a fluorine-based resin binder, 0.05 weight% to 5 weight% of vanadium oxide, and 0.1 weight% to 5 weight% of a conductive material.

[0129] Meanwhile, the cathode for the lithium secondary battery described above may further include an oxide-based inorganic solid electrolyte in addition to the solid electrolyte described above. The oxide-based inorganic solid electrolyte is, 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 may include a combination thereof.

[0130] All-solid-state secondary battery

[0131] In one embodiment, an all-solid-state secondary battery is provided, comprising the aforementioned positive and negative electrodes and a solid electrolyte layer located between the positive and negative electrodes. 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.

[0132] 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 (100) may have a structure in which an electrode assembly is stacked, comprising a negative electrode (400) including a negative electrode current collector (401) and a negative electrode active material layer (403), a solid electrolyte layer (300), and a positive electrode (200) including a positive electrode active material layer (203) and a positive electrode current collector (201), and the assembly is housed in a case such as a pouch. The all-solid-state secondary battery (100) may further include an elastic layer (500) on the outer side of at least one of the positive electrode (200) and the negative electrode (400). FIG. 1 shows a single electrode assembly including a negative electrode (400), a solid electrolyte layer (300), and a positive electrode (200), but an all-solid-state battery may be manufactured by stacking two or more electrode assemblies.

[0133] cathode

[0134] A negative electrode for an all-solid-state battery may, for example, include a current collector and a negative electrode active material layer located on the current collector. The negative electrode active material layer may include a negative electrode active material and may further include a binder, a conductive material, and / or a solid electrolyte.

[0135] The above negative electrode 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.

[0136] A 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 amorphous, plate-like, flake-like, spherical, or fibrous natural graphite or artificial graphite, and examples of the amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, etc.

[0137] As the above lithium metal alloy, 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 may be used.

[0138] As a material capable of doping and undoping the above lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material may be used, and the above Si-based negative electrode active material may include silicon, silicon-carbon composites, and SiO₂. 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.

[0139] The silicon-carbon composite may be, for example, a silicon-carbon composite comprising a core containing crystalline carbon and silicon particles and an amorphous carbon coating layer located 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-based pitch, mesophase pitch, petroleum-based pitch, coal-based oil, petroleum-based heavy oil, or polymer resins such as phenolic resin, furan resin, or polyimide resin may be used. In this case, the silicon content may be 10% to 50% by weight of the total weight of the silicon-carbon composite. Additionally, the content of the crystalline carbon may be 10% to 70% by weight of the total weight of the silicon-carbon composite, and the content of the amorphous carbon may be 20% to 40% by weight of the total weight of the silicon-carbon composite. Furthermore, the thickness of the amorphous carbon coating layer may be 5nm to 100nm.

[0140] The average particle size (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, wherein the atomic content ratio of Si:O within the silicon particles indicating the degree of oxidation may be 99:1 to 33:67. The silicon particles are SiO x It can be a particle, and in this case, SiO x In this case, the range of x may be greater than 0 and less than 2. Here, the average particle size (D50) is measured by a particle size analyzer using laser diffraction and refers to the diameter of a particle with a cumulative volume of 50% in the particle size distribution.

[0141] The above Si-based negative electrode active material or Sn-based negative electrode active material may 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 may be 1:99 to 90:10 by weight.

[0142] The content of the negative electrode active material in the above negative electrode active material layer may be 95% to 99% by weight with respect to the total weight of the negative electrode active material layer.

[0143] In one embodiment, the negative electrode active material layer further comprises a binder and optionally further comprises a conductive material. The content of the binder in the negative electrode active material layer may be 1% to 5% by weight based on the total weight of the negative electrode active material layer. Additionally, when further comprising a conductive material, the negative electrode active material layer may comprise 90% to 98% by weight of the negative electrode active material, 1% to 5% by weight of the binder, and 1% to 5% by weight of the conductive material.

[0144] The above binder serves to effectively bond the negative electrode active material particles to each other and also to effectively bond the negative electrode active material to the current collector. The above binder may include a water-insoluble binder, a water-soluble binder, or a combination thereof.

[0145] The above-mentioned water-insoluble 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.

[0146] Examples of the above water-soluble binders include rubber-based binders or polymer resin binders. 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, ethylenepropylenediene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0147] When a water-soluble binder is used as the above-mentioned cathode 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, alkali metal salts thereof, or combinations thereof. Na, K, or Li may be used as the alkali metal. The content of such a thickener may be 0.1 to 3 parts by weight per 100 parts by weight of the cathode active material.

[0148] The above conductive material is used to impart conductivity to an electrode and may include, for example, carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, carbon nanotubes; metal-based materials in the form of metal powder or metal fibers including copper, nickel, aluminum, silver, etc.; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0149] As the above-mentioned cathode current collector, a material selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and combinations thereof may be used.

[0150] 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 contain a negative electrode active material when assembling the battery, but where lithium metal, etc., is precipitated during charging of the battery and acts as the negative electrode active material.

[0151] 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 (400') may include a current collector (401) and a negative electrode coating layer (405) located on the current collector. An all-solid-state battery having such a precipitation type negative electrode (400') is initially charged in a state where no negative electrode active material is present, and during charging, a high-density lithium metal, etc. is precipitated between the current collector (401) and the negative electrode coating layer (405) to form a lithium metal layer (404), which can act as a negative electrode active material. Accordingly, in an all-solid-state battery that has undergone one or more charges, the precipitation type negative electrode (400') may include a current collector (401), a lithium metal layer (404) located on the current collector, and a negative electrode coating layer (405) located on the metal layer. The above lithium metal layer (404) refers to a layer in which lithium metal, etc. is precipitated during the charging process of the battery, and can be referred to as a metal layer or a negative electrode active material layer.

[0152] The above cathode coating layer (405) may include a metal, a carbon material, or a combination thereof that acts as a catalyst.

[0153] The above 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 may be composed of several types of alloys. When the above metal exists in the form of particles, the average particle size (D50) may be about 4 μm or less, and for example, 10 nm to 4 μm.

[0154] 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 micro beads, 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.

[0155] When the above-mentioned cathode coating layer (405) 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-mentioned cathode coating layer (405) may include, for example, a carbon material supported with a catalyst metal, or may include a mixture of metal particles and carbon material particles.

[0156] The above cathode coating layer (405) may, for example, include the metal and amorphous carbon, and in this case, can effectively promote the precipitation of lithium metal.

[0157] The above cathode coating layer (405) may further include a binder, and the binder may be a conductive binder. Additionally, the above cathode coating layer (405) may further include general additives such as fillers, dispersants, ion conductive materials, etc.

[0158] The thickness of the above cathode coating layer (405) may be, for example, 100 nm to 20 μm, or 500 nm to 10 μm, or 1 μm to 5 μm.

[0159] The above-mentioned precipitation type cathode (400') may, for example, further include a thin film on the surface of the current collector, that is, between the current collector and the cathode 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 of these or composed of several types of alloys. The thin film can further flatten the precipitation shape of the lithium metal layer (404) and further improve the characteristics of the all-solid-state battery. The thin film may be formed by, for example, vacuum deposition, sputtering, plating, etc. The thickness of the thin film may be, for example, 1 nm to 500 nm.

[0160] solid electrolyte layer

[0161] The solid electrolyte layer (300) 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.

[0162] In one example, the solid electrolyte included in the anode (200) and the solid electrolyte included in the solid electrolyte layer (300) may include the same compound or different compounds. For example, if both the anode (200) and the solid electrolyte layer (300) include an azirodite-type sulfide-based solid electrolyte, the overall performance of the all-solid-state secondary battery may be improved. In addition, for example, if both the anode (200) and the solid electrolyte layer (300) include the aforementioned coated solid electrolyte, the all-solid-state secondary battery may achieve high capacity and high energy density while achieving excellent initial efficiency and lifespan characteristics.

[0163] Meanwhile, the average particle size (D) of the solid electrolyte included in the anode (200) 50 ) is the average particle size (D) of the solid electrolyte included in the solid electrolyte layer (300). 50It may be smaller than ). In this case, overall performance can be improved by increasing the mobility of lithium ions while maximizing the energy density of the all-solid-state battery. For example, the average particle size (D) of the solid electrolyte included in the cathode (200) 50 ) may be 0.1 μm to 1.0 μm, or 0.1 μm to 0.8 μm, and the average particle size (D) of the solid electrolyte included in the solid electrolyte layer (300) 50 The particle size ) can be 1.5 μm to 5.0 μm, or 2.0 μm to 4.0 μm, or 2.5 μm to 3.5 μm. When such a particle size range is satisfied, the energy density of the all-solid-state secondary battery is maximized, while lithium ion transport is facilitated to suppress resistance, thereby improving the overall performance of the all-solid-state secondary battery. Here, the average particle size (D) of the solid electrolyte 50 ) may be measured using a particle size analyzer utilizing laser diffraction. Alternatively, approximately 20 random particles may be selected from microscopic images such as those of a scanning electron microscope, their particle sizes measured, and their particle size distribution obtained, where D 50 You can also calculate the value.

[0164] The above solid electrolyte layer may further include a binder in addition to the solid electrolyte. In this case, styrene butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, acrylate-based polymers, or combinations thereof may be used as the binder, but are not limited thereto, and any material used as a binder in the relevant technical field may be used. The above acrylate-based polymer may be, for example, butyl acrylate, polyacrylate, polymethacrylate, or a combination thereof.

[0165] The above solid electrolyte layer can be formed by adding a solid electrolyte to a binder solution, coating it onto a substrate film, and drying it. The solvent of the binder solution may be isobutyryl isobutylate, xylene, toluene, benzene, hexane, or a combination thereof. Since the process for forming the above solid electrolyte layer is widely known in the field, a detailed description will be omitted.

[0166] The thickness of the solid electrolyte layer may be, for example, 10 μm to 150 μm.

[0167] The above solid electrolyte layer may further include an alkali metal salt, and / or an ionic liquid, and / or a conductive polymer.

[0168] The above alkali metal salt may be, for example, a lithium salt. The content of the lithium salt in the above solid electrolyte layer may be 1 M or more, for example, 1 M to 4 M. In this case, the lithium salt can improve ion conductivity by improving the lithium ion mobility of the solid electrolyte layer.

[0169] The above lithium salts are, 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(trifluoromethanesulfonyl)imide (LiTFSI, LiN(SO2CF3)2), lithium bis(fluorosulfonyl)imide (LiFSI), It may include LiN(SO2F)2), LiCF3SO3, LiAsF6, LiSbF6, LiClO4, or a mixture thereof.

[0170] In addition, the lithium salt may be imide-based, for example, the imide-based lithium salt may include lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, LiN(SO2CF3)2) and lithium bis(fluorosulfonyl)imide (LiFSI, LiN(SO2F)2). The lithium salt can maintain or improve ionic conductivity by appropriately maintaining chemical reactivity with the ionic liquid.

[0171] The above ionic liquid refers to a salt or room temperature molten salt that has a melting point below room temperature, is in a liquid state at room temperature, and consists only of ions.

[0172] The above ionic liquid comprises 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) BF4 - , PF6 - , AsF6 - , SbF6 - , AlCl4 - , HSO4 - , ClO4 - , CH3SO3 - , CF3CO2 - , Cl - , Br - , I - , BF4 - , SO4 - , CF3SO3 - , (FSO2)2N - , (C2F5SO2)2N - , (C2F5SO2)(CF3SO2)N - , and (CF3SO2)2N - It may be a compound containing one or more anions selected from among.

[0173] The above ionic liquid may be one or more 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-methylimidazoliium bis(trifluoromethylsulfonyl)amide, and 1-ethyl-3-methylimidazoliium bis(trifluoromethylsulfonyl)amide.

[0174] The weight ratio of the solid electrolyte to the ionic liquid in the above solid electrolyte layer may be 0.1:99.9 to 90:10, and 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 increasing 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.

[0175] The above all-solid-state battery may be a unit cell having a structure of a positive electrode / solid electrolyte layer / negative electrode, a bicell having a structure of a negative electrode / solid electrolyte layer / positive electrode / solid electrolyte layer / negative electrode, or a stacked battery in which the structure of the unit cell is repeated.

[0176] The shape of the above-described solid-state battery is not particularly limited and may be, for example, coin-type, button-type, sheet-type, stacked-type, cylindrical-type, flat-type, etc. In addition, the above-described solid-state battery can be applied to large batteries used in electric vehicles, etc. For example, the above-described 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 a large amount of power storage, and for example, it can be used in electric bicycles or power tools.

[0177] FIG. 3 is a plan view of an all-solid-state secondary battery according to a first embodiment of the present invention, FIG. 4 is an exploded perspective view of the all-solid-state secondary battery of FIG. 3 (before welding the case), and FIG. 5 is an exploded perspective view of the all-solid-state secondary battery of FIG. 3 (after welding the case). Referring to FIG. 3 to FIG. 5, the all-solid-state secondary battery of the first embodiment includes a unit cell (UC), a stack (ST), a case (30), an insulator (40), and a cap assembly (50).

[0178] A unit cell (UC) is formed by stacking a positive electrode (11) and a negative electrode (12) on each side of a solid electrolyte layer (13). A stack (ST) is formed by stacking unit cells (UC). A buffer member (60) may be provided between the stack (ST) and the case (30) (see FIG. 9).

[0179] The positive electrode (11) and the negative electrode (12) are each provided with an electrode tab (101) connected to them, and the electrode tab (101) is drawn out in both directions in a first direction (x-axis direction). The electrode tab (101) includes a first tab (111) connected to the positive electrode (11) and drawn out in a first positive (+) direction (x-axis direction), and a second tab (121) connected to the negative electrode (12) and drawn out in a first negative (-) direction (x-axis direction).

[0180] The electrode tab (101) is separated from the first positive (+) direction into the second direction (y-axis direction) to form a double tab, and separated from the first negative (-) direction into the second direction (y-axis direction) to form a double tab. The second direction (y-axis direction) intersects the first direction (x-axis direction).

[0181] In the stack (ST), the first taps (111) form a double-tap structure that is drawn out in the first positive (+) direction (x-axis direction) from both ends of the second direction (y-axis direction). Also in the stack (ST), the second taps (121) form a double-tap structure that is drawn out in the first negative (-) direction (x-axis direction) from both ends of the second direction (y-axis direction).

[0182] The case (30) includes a first part case (31) and a second part case (32) to accommodate a stack (ST), and is formed by welding (W) the first and second part cases (31, 32) facing each other. The case (30) may be formed from a weldable metal material.

[0183] After inserting a stack (ST) into the first part case (31) and the second part case (32), pressurize to reach the target compression ratio, and while maintaining external pressure, avoid the first and second tabs (111, 121) and weld (W) the first side (311, 321) and the second side (312, 322) in the first and second directions (x, y axis directions) of the case (30).

[0184] For example, the first part case (31) and the second part case (32) form welding lines (WL) on both sides of the first direction (x-axis direction) and on both sides of the second direction (y-axis direction) intersecting the first direction, and form outlets (303) on both sides of the first direction (x-axis direction). The first part case (31) and the second part case (32) are welded (W) in a state of pressure stacking in the third direction (z-axis direction).

[0185] The outlet (303) is formed by the first groove (313) of the first part case (31) and the second groove (323) of the second part case (32) facing each other. Since a welding line (WL) is formed in the first and second directions (x, y axis directions) of the first and second part cases (31, 32), the outlet (303) is formed by the first and second grooves (313, 323). That is, the outlet (303) is formed because the first and second grooves (313, 323) are connected in the stacking direction (z axis direction).

[0186] Specifically, the case (30), that is, the first and second parts of the case (31, 32), includes a first side wall (311, 321) formed by bending on both sides in the first direction (x-axis direction) and a second side wall (312, 322) formed by bending on both sides in the second direction (y-axis direction). The first side wall (311, 321) is provided with a pair of outlets (303) corresponding to a double tap on both sides in the first direction (x-axis direction) and is formed in the part excluding the pair of outlets (303). The second side wall (312, 322) is formed on both sides in the second direction (y-axis direction).

[0187] Since the first side wall (311, 321) is formed with the same structure on both sides of the first direction (x-axis direction), the positive (+) direction on one side is described, and the negative (-) direction on the other side is omitted. Since the second side wall (312, 322) is formed with the same structure on both sides of the second direction (y-axis direction), the positive (+) direction on one side is described, and the negative (-) direction on the other side is omitted.

[0188] The welding line (WL) includes a first weld (WL1) and a second weld (WL2). The first weld (WL1) is formed on the first side wall (311, 321) by welding (W) the first part case (31) and the second part case (32). The second weld (WL2) is formed on the second side wall (312, 322) by welding (W) the first part case (31) and the second part case (32).

[0189] Since the first side wall (311, 321) is formed with the same structure on both sides of the first direction (x-axis direction), the first side wall (311) of both (+) first directions (x-axis direction) is described as an example. The first side wall (311, 321) is provided at both ends of the second direction (y-axis direction) so as to be connected to the second side wall (312, 322), and is further provided between a pair of outlets (303, 303).

[0190] Accordingly, the first weld (WL1) includes a double-ended weld (WL11) provided at both ends in the second direction (y-axis direction) and a central weld (WL12) provided between a pair of outlets (303, 303). The double-ended weld (WL11) provides and improves the weld strength of the case (30) at both ends in the second direction (y-axis direction). The central weld (WL12) provides and improves the weld strength of the case (30), i.e., the weld strength of the first and second parts of the case (31, 32), at the center in the second direction (y-axis direction).

[0191] Additionally, the central weld (WL12) suppresses expansion in the central part of the case (30). Furthermore, the central weld (WL12) enables the design of a case (30) with high resistance to internal pressure. Since the case (30) absorbs most of the expansion force, the internal pressure applied to the cap assembly (50) is reduced. Therefore, the assembly quality and welding quality of the case (30) and the cap assembly (50) can be improved.

[0192] FIG. 6 is an exploded perspective view of the all-solid-state secondary battery of FIG. 5 equipped with an insulator, FIG. 7 is an inner side view of the insulator of FIG. 6, FIG. 8 is a plan view of the insulator of FIG. 7, and FIG. 9 is a cross-sectional view taken along the line IX-IX of FIG. 6.

[0193] Referring to FIGS. 4 to 9, an insulator (40) is formed of an electrical insulating material and provided in the outlet (303, 303) to electrically insulate the outlet (303, 303) to form an insulating outlet (413, 414). The electrode tab (101) is drawn out in a first direction (x-axis direction) through the insulating outlet (413, 414).

[0194] The insulator (40) includes a first insulating part (411) and a second insulating part (412) formed integrally. The first insulating part (411) is coupled to one of a pair of outlets (303, 303) formed by the first and second grooves (313, 323) of the first and second part cases (31, 32) to form a first insulating outlet (413). The second insulating part (412) is coupled to the other of a pair of outlets (303, 303) formed by the first and second grooves (313, 323) of the first and second part cases (31, 32) to form a second insulating outlet (414).

[0195] For example, the insulator (40) includes a connecting part (41) that contacts the cross-section of the case (30) forming the outlet (303), a projection (42) that protrudes from one side of the connecting part (41) and supports one side of the case (30), and a hook (43) that protrudes from the other side of the connecting part (41) and is coupled to the other side of the case (30).

[0196] The protrusion (42) and the hook (43) strengthen the fastening force between the insulator (40) and the case (30), and the hook (43) facilitates the process of fastening the insulator (40) to the case (30). That is, the hook (43) enables the insulator (40) to be connected in the first direction to the case (30) formed by welding (W) of the first and second parts of the case (31, 32).

[0197] Referring again to FIGS. 4 to 6, the cap assembly (50) includes a subplate (51) connected to an electrode tab (101) having through holes (513, 513) corresponding to first and second insulating outlets (413, 414), a subtab (52) connecting the subplate (51) to a terminal (53), and a cap plate (54) that accommodates the subplate (51) and the subtab (52) in an insulating structure.

[0198] FIG. 10 is a perspective view of the state before welding a subplate to the electrode tab of FIG. 6, and FIG. 11 is a perspective view of the state in which a subtab is welded to the electrode tab and subplate of FIG. 10. Referring to FIG. 10 and FIG. 11, the electrode tab (101) of the double-tab structure is continuously drawn out through the first and second insulating outlets (413, 414) and the through-holes (513, 513) (see FIG. 10) and is placed between the subplate (51) and the subtab (52) and welded (W) (see FIG. 11).

[0199] That is, one electrode tab (101) of the double-tap structure is bent in a positive (+) stacking direction from the outside of the drawn-out sub-plate (51) and contacts the outer surface of the sub-plate (51), and the other electrode tab (101) of the double-tap structure is bent in a negative (-) stacking direction from the outside of the drawn-out sub-plate (51) and contacts the outer surface of the sub-plate (51).

[0200] Since the electrode tab (101) of the double-tap structure is bent in the positive (+) and negative (-) stacking directions (z-axis direction), the connection structure between the electrode tab (101) and the sub-plate (51) and the connection structure between the electrode tab (101) and the sub-tap (52) can be stably secured.

[0201] In addition, since the electrode tab (101) at the positive electrode (11) and the negative electrode (12) has a symmetrical structure in the first direction (x-axis direction), the welding strength of the connection structure between the electrode tab (101) and the sub-plate (51) and the connection structure between the electrode tab (101) and the sub-tab (52) can be balanced at the first tab (111) of the positive electrode (11) and the second tab (121) of the negative electrode (12).

[0202] FIG. 12 is a diagram showing the state of assembling and welding a cap assembly to the case of FIG. 11, and FIG. 13 is a cross-sectional view taken along the line XIII-XIII of FIG. 12. Referring to FIG. 12 and FIG. 13, after the welding of the case (30) is finished and the assembly of the cap assembly (50) is completed, the outer edge of the cap plate (54) is welded to the case (30).

[0203] The cap plate (54) is welded (W) to the case (30), and a third weld (WL3) is formed at the joint boundary between the cap plate (54) and the case (30). The terminal (53) is drawn out to the outside of the cap plate (54) by interposing a terminal insulator (55) in the terminal hole (504) of the cap plate (54). The terminal (53) is welded (W) to the sub-tap (52).

[0204] Various embodiments of the present invention are described below. Compared to the first embodiment and the previously described embodiment, the description of identical configurations is omitted, and the description of different configurations is provided.

[0205] FIG. 14 is an inner side view of an insulator coupled to a case of an all-solid-state secondary battery according to a second embodiment of the present invention, and FIG. 15 is a plan view of the insulator of FIG. 14. Referring to FIG. 14 and FIG. 15, in the all-solid-state secondary battery of the second embodiment, the insulator (240) includes a first insulator (241) and a second insulator (242) that are formed separately. The first insulator (241) is coupled to one of a pair of outlets (303, 303) corresponding to a double tap on both sides of a first direction (x-axis direction) to form a first insulating outlet (243). The second insulator (242) is coupled to the other of a pair of outlets (303, 303) corresponding to a double tap on both sides of the first direction to form a second insulating outlet (244).

[0206] As in the first embodiment, the connecting part (41), which is formed with the same structure on the first and second insulators (241, 242), contacts the cross-section of the case (30) that forms the outlet (303), the projection (42) protrudes from one side of the connecting part (41) to support one side of the case (30), and the hook (43) is formed protruding from the other side of the connecting part (41) to be coupled to the other side of the case (30). Since the first and second insulators (241, 242) can be formed separately and coupled to the outlet of the welded case (30), the assembly process of the insulator (240) is facilitated.

[0207] FIG. 16 is an inner side view of an insulator applied to an all-solid-state secondary battery according to a third embodiment of the present invention. Referring to FIG. 16, in the all-solid-state secondary battery of the third embodiment, the insulator (340) includes a first part insulator (341) coupled to a first groove (313) of a first part case (31), and a second part insulator (342) coupled to a second groove (323) of a second part case (32) and in contact with the first part insulator (341) to form an insulating outlet (343).

[0208] The connecting portion (41), protrusion (42), and hook (43) of the insulator (340) are formed on the first and second part insulators (341, 342) and are connected to each other when the first and second part insulators (341, 342) are coupled to the groove (303) of the case (30). Since the first and second part insulators (341, 342) can be coupled to the outlet (303) of the welded case (30), the assembly process of the insulator (340) is facilitated.

[0209] FIG. 17 is a combined inner side view of a case and an insulator applied to an all-solid-state secondary battery according to a fourth embodiment of the present invention. Referring to FIG. 17, in the all-solid-state secondary battery of the fourth embodiment, the insulator (440) includes a first injection portion (441) and a second injection portion (442) that are formed separately.

[0210] The first injection portion (441) is formed by insert injection into the first groove (313) of the first part case (31). The second injection portion (442) is inserted injection into the second groove (323) of the second part case (32) and forms an insulating outlet (443) in contact with the first injection portion (441). The first and second injection portions (441, 442) eliminate the process of separately assembling an insulator (440) to the first and second part cases (31, 32) during the all-solid-state secondary battery assembly process.

[0211] FIG. 18 is an inner side view of an insulator applied to an all-solid-state secondary battery according to the fifth embodiment of the present invention, and FIG. 19 is an inner side view of the combined case and insulator of FIG. 18. Referring to FIG. 18 and FIG. 19, in the all-solid-state secondary battery of the fifth embodiment, the insulator (540) includes a first O-ring insulator (541) and a second O-ring insulator (542) that are formed separately.

[0212] The first O-ring insulator (541) is coupled to one of a pair of outlets (303, 303) corresponding to a double tap on both sides of the first direction to form a first insulating outlet (543). The second O-ring insulator (542) is coupled to the other of a pair of outlets (303, 303) corresponding to a double tap on both sides of the first direction to form a second insulating outlet (544).

[0213] The first and second O-ring insulators (541, 542) can be formed separately and coupled to the outlets (303, 303) of the welded case (30), thereby facilitating the assembly process of the insulator (540).

[0214] FIG. 20 is an exploded perspective view of an all-solid-state secondary battery (after the insulator is coupled to the case) according to the 6th embodiment of the present invention. Referring to FIG. 20, the all-solid-state secondary battery of the 6th embodiment includes a unit cell (UC), a stack (ST), a case (30), an insulator (140), and a cap assembly (50).

[0215] FIG. 21 is an inner side view of the insulator of FIG. 20, FIG. 22 is a top view of the insulator of FIG. 21, FIG. 23 is a state view of welding the case of FIG. 20, and FIG. 24 is a cross-sectional view taken along the line IX-IX of FIG. 23.

[0216] Referring to FIGS. 20 to 24, an insulator (140) is formed of an electrical insulating material and coupled to an outlet (303) to electrically insulate the outlet (303) to form an insulating outlet (1413). The electrode tab (101) is drawn out in a first direction (x-axis direction) through the insulating outlet (1413).

[0217] The insulator (140) includes a first part insulator (1411) and a second part insulator (1412). The first part insulator (1411) is coupled to a first groove (313) of a first part case (31), and the second part insulator (1412) is coupled to a second groove (323) of a second part case (32) and comes into contact with the first part insulator (1411). Thus, the first and second grooves (313, 323) are connected to each other to form an insulating outlet (1413).

[0218] For example, the insulator (140) includes a connecting portion (141) that contacts the cross-section of the case (30) forming the outlet (303), and two protrusions (142) that protrude from both sides of the connecting portion (141) and support both sides of the case (30). The two protrusions (142) strengthen the fastening force between the insulator (140) and the case (30).

[0219] Referring to FIGS. 20 and 23, the welding line (WL) includes a first weld (WL1) and a second weld (WL2). The first weld (WL1) is formed on the first side wall (311, 321) by welding (W) the first part case (31) and the second part case (32). The second weld (WL2) is formed on the second side wall (312, 322) by welding (W) the first part case (31) and the second part case (32).

[0220] Since the first side wall (311, 321) is formed with the same structure on both sides of the first direction (x-axis direction), the first side wall (311) of both (+) first directions (x-axis direction) is described as an example. The first side wall (311, 321) is provided at both ends of the second direction (y-axis direction) so as to be connected to the second side wall (312, 322), and is further provided between a pair of outlets (303, 303).

[0221] Accordingly, the first weld (WL1) includes a double-ended weld (WL11) provided at both ends in the second direction (y-axis direction) and a central weld (WL12) provided between a pair of outlets (303, 303). The double-ended weld (WL11) provides and improves the weld strength of the case (30) at both ends in the second direction (y-axis direction). The central weld (WL12) provides and improves the weld strength of the case (30), i.e., the weld strength of the first and second parts of the case (31, 32), at the center in the second direction (y-axis direction).

[0222] Additionally, the central weld (WL12) suppresses expansion in the central part of the case (30). Furthermore, the central weld (WL12) enables the design of a case (30) with high resistance to internal pressure. Since the case (30) absorbs most of the expansion force, the internal pressure applied to the cap assembly (50) is reduced. Therefore, the assembly quality and welding quality of the case (30) and the cap assembly (50) can be improved.

[0223] Referring again to FIG. 20 and FIG. 23, the cap assembly (50) includes a subplate (51) connected to an electrode tab (101) having a through hole (513) corresponding to an insulating outlet (1413), a subtab (52) connecting the subplate (51) to a terminal (53), and a cap plate (54) that accommodates the subplate (51) and the subtab (52) in an insulating structure.

[0224] FIG. 25 is a perspective view of the state before welding the subplate to the electrode tab of FIG. 23, and FIG. 26 is a perspective view of the state in which the subtab is welded to the electrode tab and subplate of FIG. 25. Referring to FIG. 25 and FIG. 26, the electrode tab (101) of the double-tab structure is continuously drawn out through the insulating outlet (1413) and the through hole (513) (see FIG. 25) and is placed and welded (W) between the subplate (51) and the subtab (52) (see FIG. 26).

[0225] That is, one electrode tab (101) of the double-tap structure is bent in a positive (+) stacking direction from the outside of the drawn-out sub-plate (51) and contacts the outer surface of the sub-plate (51), and the other electrode tab (101) of the double-tap structure is bent in a negative (-) stacking direction from the outside of the drawn-out sub-plate (51) and contacts the outer surface of the sub-plate (51).

[0226] Since the electrode tab (101) of the double-tap structure is bent in the positive (+) and negative (-) stacking directions (z-axis direction), the connection structure between the electrode tab (101) and the sub-plate (51) and the connection structure between the electrode tab (101) and the sub-tap (52) can be stably secured.

[0227] In addition, since the electrode tab (101) at the positive electrode (11) and the negative electrode (12) has a symmetrical structure in the first direction (x-axis direction), the welding strength of the connection structure between the electrode tab (101) and the sub-plate (51) and the connection structure between the electrode tab (101) and the sub-tab (52) can be balanced at the first tab (111) of the positive electrode (11) and the second tab (121) of the negative electrode (12).

[0228] FIG. 27 is a diagram showing the state of assembling and welding a cap assembly to the case of FIG. 26, and FIG. 28 is a cross-sectional view taken along the line XIII-XIII of FIG. 27. Referring to FIG. 27 and FIG. 28, after the welding of the case (30) is finished and the assembly of the cap assembly (50) is completed, the outer edge of the cap plate (54) is welded to the case (30).

[0229] The cap plate (54) is welded (W) to the case (30), and a third weld (WL3) is formed at the joint boundary between the cap plate (54) and the case (30). The terminal (53) is drawn out to the outside of the cap plate (54) by interposing a terminal insulator (55) in the terminal hole (504) of the cap plate (54). The terminal (53) is welded (W) to the sub-tap (52).

[0230] The above description is merely one embodiment for implementing an all-solid-state secondary battery according to the present disclosure, and the present disclosure is not limited to the above-described embodiment. The technical spirit of the present disclosure extends to the scope in which various modifications can be made by anyone with ordinary knowledge in the field to which the invention belongs, without departing from the gist of the present disclosure as claimed in the following patent claims.

[0231] - Explanation of the symbols -

[0232] 11: Positive electrode 12: Negative electrode

[0233] 13: Solid electrolyte layer 30: Case

[0234] 31: Part 1 Case 32: Part 2 Case

[0235] 40: Insulator 41: Connection part

[0236] 42: Protrusion 43: Hook

[0237] 50: Cap assembly 51: Subplate

[0238] 52: Sub-tab 53: Terminal

[0239] 54: Cap plate 60: Cushioning member

[0240] 101: Electrode tab 111: First tab

[0241] 121: 2nd Tap 240: Insulator

[0242] 241: 1st Insulator 242: 2nd Insulator

[0243] 243: First insulated outlet 244: Second insulated outlet

[0244] 303: Exit 323: Second Home

[0245] 311, 321: First side wall 312, 322: Second side wall

[0246] 313, 323: 1st and 2nd grooves 340: Insulator

[0247] 341: Part 1 Insulator 342: Part 2 Insulator

[0248] 343: Insulated outlet 411: First insulating section

[0249] 412: Second insulating section 413: First insulating outlet

[0250] 414: Second insulation outlet 440: Insulator

[0251] 441: Part 1 injection section 442: Part 2 injection section

[0252] 443: Insulated outlet 513: Penetration

[0253] 540: Insulator 541: First O-ring Insulator

[0254] 542: Second O-ring insulator 543: First insulating outlet

[0255] 544: Second insulation outlet ST: Stack

[0256] UC: Unit cell W: Welding

[0257] WL: Welding line WL1: First weld

[0258] WL2: 2nd weld WL3: 3rd weld

[0259] 140: Insulator 141: Connection part

[0260] 142: Bilateral projection 411: First part insulator

[0261] 412: Part 2 Insulator 1413: Insulating Outlet

Claims

A stack formed by stacking a positive electrode and a negative electrode on each side of a solid electrolyte layer to form a unit cell, and stacking multiple unit cells to form a stack, wherein electrode tabs connected to each of the positive electrode and the negative electrode are drawn out to each side of a first direction; A case formed by welding a first part case and a second part case facing each other to accommodate the stack, forming welding lines on both sides of the first direction and on both sides of the second direction intersecting the first direction, and forming outlets on both sides of the first direction; An insulator provided in the above outlet to electrically insulate the outlet to form an insulated outlet, and to allow the electrode tab to be drawn out in the first direction through the insulated outlet; and A cap assembly welded to the case in the first direction, having a terminal electrically connected to the electrode tab in an electrically insulated state. All-solid-state secondary battery including In paragraph 1, The above outlet is A solid-state secondary battery formed by a first groove of the first part case and a second groove of the second part case facing each other. In paragraph 1, The above electrode tab is A first tap connected to the above positive electrode and drawn out in a first positive (+) direction, and A second tap connected to the above negative electrode and drawn out in the first negative (-) direction. All-solid-state secondary battery including In paragraph 1, The above electrode tab is It is separated from the first positive (+) direction into the second direction and formed as a double tap, and A solid-state secondary battery formed as a double tap by separating from the first negative (-) direction to the second direction. In paragraph 4, The above case is A pair of outlets are provided to correspond to a double tap on both sides of the first direction, and a first side wall is formed in the portion excluding the pair of outlets, and Second side walls formed on both sides of the second direction above All-solid-state secondary battery including In paragraph 5, The above welding line is A first welded portion formed on the first side wall by welding the first part case and the second part case, and A second welded portion formed on the second side wall by welding the first part case and the second part case. All-solid-state secondary battery including In paragraph 6, The above-mentioned first side wall is Provided at both ends of the second direction to be connected to the second side wall, A solid-state secondary battery further provided between the pair of outlets mentioned above. In Paragraph 7, The above first weld is The two-end welded portions provided at both ends of the second direction above, and A central weld provided between the pair of the above outlets All-solid-state secondary battery including In paragraph 5, The above insulator is A first insulating part coupled to one of the pair of outlets to form a first insulating outlet, and A second insulating part connected to the first insulating part and coupled to the other of the pair of outlets to form a second insulating outlet. All-solid-state secondary battery including In Paragraph 9, The above insulator is A connecting part in contact with the cross-section of the case forming the above outlet, A projection protruding from one side of the above-mentioned connection portion to support one surface of the above-mentioned case, and A solid-state secondary battery comprising a hook formed protruding from the other side of the above-mentioned connection portion and coupled to the other side of the above-mentioned case. In Paragraph 9, The above cap assembly is A subplate connected to the electrode tab, each having a through hole corresponding to the first insulating outlet and the second insulating outlet, A sub-tab connecting the above sub-plate to the above terminal, and All-solid-state secondary battery comprising a cap plate that accommodates the above-mentioned subplate and the above-mentioned subtab in an insulating structure. In Paragraph 11, The above electrode tab with a double-tap structure is A solid-state secondary battery that is drawn out through the first insulating outlet and the through hole, and the second insulating outlet and the through hole other than the first insulating outlet, and is placed and welded between the subplate and the subtab. In Paragraph 12, One side electrode tab of the double-tap structure is The outer side of the withdrawn subplate is folded in a positive (+) stacking direction and contacts the outer surface of the subplate, and The other electrode tab of the double-tap structure is A solid-state secondary battery that is bent in a negative (-) stacking direction on the outer side of the withdrawn subplate and contacts the outer surface of the subplate. In Paragraph 12, The above cap plate is All-solid-state secondary battery welded to the above case. In Paragraph 14, The above terminal is A solid-state secondary battery that is drawn out to the outside of the cap plate by interposing a terminal insulator in the terminal hole of the cap plate. In paragraph 1, A solid-state secondary battery comprising a buffer member between the stack and the case. In paragraph 5, The above insulator is A first insulator coupled to one of a pair of outlets corresponding to a double tap on both sides of the first direction to form a first insulating outlet, and A second insulator formed separately from the first insulator and coupled to the other of the pair of outlets to form a second insulating outlet. All-solid-state secondary battery including In paragraph 2, The above insulator is A first part insulator coupled to the first groove, and A second part insulator coupled to the second groove and in contact with the first part insulator to form the insulating outlet All-solid-state secondary battery including In paragraph 2, The above insulator is A first injection part that is insert-molded into the first groove of the first part case, and A second injection part that is insert-molded into the second groove of the second part case and contacts the first injection part to form the insulating outlet. All-solid-state secondary battery including In paragraph 5, The above insulator is A first O-ring insulator coupled to one of the pair of outlets corresponding to the double tap on both sides of the first direction to form a first insulating outlet, and A second O-ring insulator formed separately from the first O-ring insulator and coupled to the other of the pair of outlets to form a second insulating outlet. All-solid-state secondary battery including In paragraph 2, The above insulator is A first part insulator coupled to the first groove, and A second part insulator coupled to the second groove and in contact with the first part insulator to form the insulating outlet All-solid-state secondary battery including In paragraph 21, The above insulator is A connecting part in contact with the cross-section of the case forming the above outlet, and Two protrusions protruding from both sides of the above-mentioned connection part to support both sides of the above-mentioned case All-solid-state secondary battery including In paragraph 21, The above cap assembly is A subplate connected to the electrode tab having a through hole corresponding to the insulating outlet, A sub-tab connecting the above sub-plate to the above terminal, and All-solid-state secondary battery comprising a cap plate that accommodates the above-mentioned subplate and the above-mentioned subtab in an insulating structure. In Paragraph 23, The above electrode tab with a double-tap structure is A solid-state secondary battery that is drawn out through the insulating outlet and the through hole and is placed and welded between the subplate and the subtab. In paragraph 24, One side electrode tab of the double-tap structure is The outer side of the withdrawn subplate is folded in a positive (+) stacking direction and contacts the outer surface of the subplate, and The other electrode tab of the double-tap structure is A solid-state secondary battery that is bent in a negative (-) stacking direction on the outer side of the withdrawn subplate and contacts the outer surface of the subplate. In paragraph 24, The above cap plate is All-solid-state secondary battery welded to the above case. In Paragraph 26, The above terminal is A solid-state secondary battery that is drawn out to the outside of the cap plate by interposing a terminal insulator in the terminal hole of the cap plate.

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