All-solid-state secondary battery and method for manufacturing all-solid-state secondary battery

Abstract

The present invention relates to an all-solid-state secondary battery and a method for manufacturing an all-solid-state secondary battery. The all-solid-state secondary battery comprises two or more types of unit cells, each unit cell including a positive electrode, a negative electrode, and a solid electrolyte. The positive electrode and the negative electrode included in one unit cell include one type of positive electrode active material and one type of negative electrode active material, respectively, and the two or more types of unit cells differ from one another in at least one of the positive electrode, the negative electrode, and the solid electrolyte.

Description

All-solid-state secondary battery and method for manufacturing the all-solid-state secondary battery

[0001] This invention claims the benefit of priority from Korean Patent Application No. 10-2024-0121137, filed September 5, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to an all-solid-state secondary battery and a method for manufacturing an all-solid-state secondary battery including a combination of electrodes each having different performance.

[0003] As technological development and demand for electric vehicles and energy storage systems (ESS) increase, the demand for batteries as an energy source is rapidly increasing, and research is being conducted on batteries that can meet various needs.

[0004] In particular, to achieve longer battery life on a single charge, batteries need to be increased in capacity, and this requires large-area electrode technology. However, the process of increasing the electrode area can degrade electrode performance, and there are concerns about thermal runaway and heat propagation to other electrodes in the event of a fire.

[0005] Accordingly, interest in all-solid-state secondary batteries with excellent safety has been increasing recently. The all-solid-state secondary batteries are secondary batteries that use non-flammable inorganic solid electrolytes instead of liquid electrolytes. Compared to lithium secondary batteries that use liquid electrolytes, they have higher thermal stability, have a very low risk of explosion due to leakage during overcharging, and are attracting attention because they do not require additional equipment to prevent such explosion risks.

[0006] In general, the above-mentioned all-solid-state secondary battery has a sequentially laminated structure of a cathode, a solid electrolyte layer, and a cathode, and up to now, when trying to apply two or more types of cathode and anode materials to the cathode and anode, they are mixed to configure a battery with one type of cathode and one type of anode, and in this case, the characteristics of the electrode differ depending on the mixing ratio of each of the two or more types of cathode and anode materials. Therefore, when manufacturing an electrode with two or more types of cathode materials with different characteristics, or two or more types of cathode materials, a long development period is required to optimize this by taking into account electrode adhesion, electrode swelling, etc., and additional research is also required to optimize the all-solid-state electrolyte.

[0007] Therefore, there is a need to develop a method for more easily and quickly finding electrodes for all-solid-state secondary batteries and their combinations.

[0008] The problem to be solved by the present invention is to provide an all-solid-state secondary battery manufactured by mixing two or more types of unit cells using positive and negative electrodes that have been previously researched and developed.

[0009] Another problem to be solved by the present invention is to provide a method for manufacturing an all-solid-state secondary battery by stacking two or more types of unit cells combining a positive electrode and a negative electrode.

[0010] The present invention provides an all-solid-state secondary battery to solve the above problem.

[0011] [1] The present invention provides an all-solid-state secondary battery comprising two or more types of unit cells including a positive electrode, a negative electrode, and a solid electrolyte, wherein the positive electrode and the negative electrode included in one unit cell each include one type of positive electrode active material and one type of negative electrode active material, and wherein at least one of the positive electrode, the negative electrode, and the solid electrolyte of the two or more types of unit cells is different from each other.

[0012] [2] The present invention provides an all-solid-state secondary battery in the above [1], wherein two or more unit cells are stacked or are rolled in one direction after being stacked.

[0013] [3] The present invention provides an all-solid-state secondary battery, wherein in at least one of the above [1] and [2], the all-solid-state secondary battery includes two or more types of unit cells in which at least one of the positive electrode active material and the negative electrode active material is different from each other.

[0014] [4] The present invention provides an all-solid-state secondary battery, wherein in any one or more of the above [1] to [3], the all-solid-state secondary battery includes two types of unit cells, and at least one of the positive electrode active material, the negative electrode active material, and the solid electrolyte is different from each other.

[0015] [5] The present invention provides an all-solid-state secondary battery, wherein in any one or more of the above [1] to [4], the all-solid-state secondary battery includes two types of unit cells, and the two types of unit cells have two or more different positive electrode active materials, negative electrode active materials, and solid electrolytes.

[0016] [6] The present invention provides an all-solid-state secondary battery, wherein in any one or more of the above [1] to [5], the all-solid-state secondary battery includes a first unit cell including a first positive electrode, a first negative electrode, and a first solid electrolyte, and a second unit cell including a second positive electrode, a second negative electrode, and a second solid electrolyte.

[0017] [7] The present invention provides an all-solid-state secondary battery, wherein in any one or more of the above [1] to [6], the all-solid-state secondary battery further includes a third unit cell including a third positive electrode, a third negative electrode, and a third solid electrolyte.

[0018] In addition, the present invention provides a method for manufacturing an all-solid-state secondary battery.

[0019] [8] The present invention provides a method for manufacturing an all-solid-state secondary battery, comprising: (S1) a step of manufacturing a unit cell including a positive electrode including one type of positive electrode active material, a negative electrode including one type of negative electrode active material, and a solid electrolyte; (S2) a step of manufacturing a unit cell in which at least one of the positive electrode, the negative electrode, and the solid electrolyte is different from the unit cell manufactured in (S1); and (S3) a step of laminating the unit cell manufactured in (S1) and the unit cell manufactured in (S2), or winding the unit cell in one direction after laminating it.

[0020] [9] The present invention provides a method for manufacturing an all-solid-state secondary battery, wherein, in the above [8], the unit cell manufactured in the step S2 is different from the unit cell manufactured in the step S1 in at least one of a positive electrode active material, a negative electrode active material, and a solid electrolyte.

[0021]

[0010] The present invention provides a method for manufacturing an all-solid-state secondary battery, wherein in at least one of the above [8] and [9], the unit cell manufactured in step S2 is different from the unit cell manufactured in step S1 in two or more of the positive electrode active material, the negative electrode active material, and the solid electrolyte.

[0022]

[0011] The present invention provides a method for manufacturing an all-solid-state secondary battery, wherein in any one or more of the above [8] to

[0010] , two types of unit cells are manufactured in which at least one of a positive electrode, a negative electrode, and a solid electrolyte is different in the step S2.

[0023] The all-solid-state secondary battery of the present invention is manufactured by mixing two or more types of unit cells having a combination of positive and negative electrodes that have been previously researched and developed, and is an all-solid-state secondary battery that can shorten the research period of mixed materials by utilizing each optimized electrode combination.

[0024] When manufacturing an all-solid-state secondary battery by the method for manufacturing an all-solid-state secondary battery of the present invention, compared to manufacturing an all-solid-state secondary battery by newly mixing two or more types of positive electrode materials or a negative electrode by mixing two or more types of negative electrode materials, and then determining its characteristics, an optimized electrode combination can be found in a simpler and faster manner.

[0025] Figure 1 is a cross-sectional view schematically showing one embodiment of a conventional all-solid-state secondary battery.

[0026] Figure 2 is a cross-sectional view schematically showing an all-solid-state secondary battery according to one embodiment of the present invention.

[0027] The advantages and features of the present invention, and the methods for achieving them, will become clearer with reference to the embodiments described in detail below together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and may be implemented in various different forms. These embodiments are provided only to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Like reference numerals designate like elements throughout the specification.

[0028] Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used in their common sense to those of ordinary skill in the art to which the present invention pertains. Furthermore, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0029] The terminology used herein is for the purpose of describing embodiments and is not intended to limit the present invention. In this specification, singular forms also include plural forms, unless specifically stated otherwise. As used herein, the terms "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components in addition to the components mentioned.

[0030] In this specification, when it is said that a part includes a certain component, this does not mean that other components are excluded, but rather that other components may be included, unless specifically stated otherwise.

[0031] In this specification, the description of “A and / or B” means A, or B, or A and B.

[0032] In this specification, “%” means weight percent unless explicitly indicated otherwise.

[0033]

[0034] All-solid-state secondary batteries

[0035]

[0036] An all-solid-state secondary battery according to the present invention comprises two or more types of unit cells including a positive electrode, a negative electrode, and a solid electrolyte, wherein the positive electrode and the negative electrode included in one unit cell each include one type of positive electrode active material and one type of negative electrode active material, and at least one of the positive electrode, the negative electrode, and the solid electrolyte of the two or more types of unit cells is different from each other.

[0037] In the all-solid-state secondary battery according to the present invention, one unit cell includes a positive electrode including one type of positive electrode active material, a negative electrode including one type of negative electrode active material, and a solid electrolyte disposed between the positive electrode and the negative electrode, and at least two unit cells in which at least one of the positive electrode active material, the negative electrode active material, and the solid electrolyte is different from each other are included in the all-solid-state secondary battery.

[0038] The above unit cells may be stacked in two or more layers, or may be rolled in one direction after being stacked, and may specifically form a stack-type or jellyroll-type all-solid-state secondary battery.

[0039] At least one of the positive electrode active material, the negative electrode active material, and the solid electrolyte included in the unit cell may be different from at least one of the positive electrode active material, the negative electrode active material, and the solid electrolyte included in another unit cell, and specifically, the all-solid-state secondary battery may include two or more types of unit cells in which at least one of the positive electrode active material and the negative electrode active material is different.

[0040] In one embodiment of the present invention, the all-solid-state secondary battery may include at least two types of either a positive electrode or a negative electrode. The all-solid-state secondary battery according to one embodiment of the present invention may include at least two types of either a positive electrode or a negative electrode, and may include two or more combinations of positive and negative electrodes, and may form one cell by stacking unit cells having these combinations.

[0041] Different types of positive electrodes may mean that the type and / or content of any one of the positive electrode active material, positive electrode current collector, binder, and conductive agent is different, and specifically may mean that the type and / or content of the positive electrode active material is different from each other.

[0042] Different types of negative electrodes may mean that the type and / or content of any one of the negative electrode active material, negative electrode current collector, binder, and conductive material is different, and specifically, may mean that the type and / or content of the negative electrode active material is different from each other.

[0043] Different types of solid electrolytes may have different types and / or contents of electrolyte compounds and binders, and specifically may mean different types and / or contents of electrolyte compounds.

[0044] The all-solid-state secondary battery of the present invention, when including two or more kinds of at least one of a positive electrode active material, a negative electrode active material, and a solid electrolyte, instead of mixing them and including them as a single positive electrode material, a negative electrode material, and a solid electrolyte, divides them into separate unit cells each containing only one kind, and mixes the unit cells to implement a mixing ratio in an overall single cell. Therefore, if the characteristics of the positive electrode / negative electrode / solid electrolyte constituting each unit cell are already known, the effect upon mixing can be predicted in advance based on this, and it is easy to implement the combination of active materials and the mixing ratio. In addition, since there is no concern about mixing between the solid electrolytes included in each unit cell due to the characteristics of the all-solid-state secondary battery, it is also possible to confirm the results of applying various solid electrolytes to a single electrode combination.

[0045] In one embodiment of the present invention, the all-solid-state secondary battery may include two types of unit cells, and the two types of unit cells may have at least one different positive electrode active material, negative electrode active material, and solid electrolyte, and specifically, two or more may be different from each other.

[0046] In one embodiment of the present invention, specifically, the all-solid-state secondary battery may include a first unit cell including a first positive electrode, a first negative electrode, and a first solid electrolyte, and a second unit cell including a second positive electrode, a second negative electrode, and a second solid electrolyte.

[0047] The first positive electrode and the second positive electrode may be the same or different from each other, the first negative electrode and the second negative electrode may be the same or different from each other, and the first solid electrolyte and the second solid electrolyte may be the same or different from each other. In this case, at least one of the first positive electrode, the first negative electrode, and the first solid electrolyte is different from the second positive electrode, the second negative electrode, and the second solid electrolyte.

[0048] When the above-mentioned all-solid-state secondary battery includes two or more of the two types of unit cells, there is no particular limitation on the stacking order of the unit cells. For example, the two types of unit cells may be stacked crosswise, or different types of unit cells stacked by dividing the space may be combined and stacked.

[0049] The first unit cell and the second unit cell can be cross-stacked, and after a plurality of first unit cells are stacked and a plurality of second unit cells are stacked, the stacked first unit cells and the stacked second unit cells can be stacked facing each other.

[0050] The above-mentioned all-solid-state secondary battery may additionally include a third unit cell including a third positive electrode, a third negative electrode, and a third solid electrolyte.

[0051] When the above-mentioned all-solid-state secondary battery further includes a third unit cell, the third unit cell is different from the first unit cell and the second unit cell in that any one of the third positive electrode, the third negative electrode, and the third solid electrolyte is different from the first positive electrode, the first negative electrode, and the first solid electrolyte, the second positive electrode, the second negative electrode, and the second solid electrolyte.

[0052] The first unit cell, the second unit cell, and the third unit cell may be cross-stacked, and a plurality of first unit cells, a plurality of second unit cells, and a plurality of third unit cells may be stacked, respectively, and then may be stacked while facing each other, such as stacked first unit cell-stacked second unit cell-stacked third unit cell, stacked second unit cell-stacked first unit cell-stacked third unit cell, or stacked first unit cell-stacked third unit cell-stacked second unit cell.

[0053] In one embodiment of the present invention, when the unit cells are stacked, each unit cell can be stacked with the solid electrolyte interposed therebetween.

[0054] The above unit cell may be a mono-cell such as anode-solid electrolyte-cathode, anode-solid electrolyte-cathode-solid electrolyte, or cathode-solid electrolyte-anode-solid electrolyte, or a bi-cell such as anode-solid electrolyte-cathode-solid electrolyte-anode or cathode-solid electrolyte-anode-solid electrolyte-cathode.

[0055] The positive electrode may be opposite to the negative electrode, and the positive electrode may include a positive electrode current collector; and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector, and the negative electrode may include a negative electrode current collector; and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector.

[0056] The above positive electrode current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the positive electrode or the battery, and may include, for example, at least one selected from the group consisting of stainless steel, copper, aluminum, nickel, titanium, and calcined carbon, and specifically may include aluminum.

[0057] The above positive electrode active material layer may include a positive electrode active material and a solid electrolyte.

[0058] The above positive electrode active material is a layered compound such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), or a compound substituted with one or more transition metals; chemical formula Li 1+x Mn 2-x Lithium manganese oxides such as O4 (where x is 0 to 0.33), LiMnO3, LiMn2O3, LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, LiV3O4, V2O5, Cu2V2O7; chemical formula LiNi 1-x M x Ni-site type lithium nickel oxide represented by O2 (where M = Co, Mn, Al, Cu, Fe, Mg, B, or Ga, and x = 0.01 to 0.3); chemical formula LiMn 1-x Mx Lithium manganese complex oxides expressed as O2 (wherein, M = Co, Ni, Fe, Cr, Zn or Ta, and x = 0.01 to 0.1) or Li2Mn3MO8 (wherein, M = Fe, Co, Ni, Cu or Zn); LiNi x Mn 2-x It may include lithium manganese composite oxides with a spinel structure represented by O4; LiMn2O4 in which some of the Li in the chemical formula is replaced by an alkaline earth metal ion; disulfide compounds; Fe2(MoO4)3, etc., but is not limited to these.

[0059] The positive electrode active material may be included in the positive electrode active material layer in an amount of 50 wt% to 85 wt%, specifically 65 wt% to 80 wt%.

[0060] The above solid electrolyte may specifically include at least one selected from the group consisting of a polymer solid electrolyte, an oxide-based solid electrolyte, and a sulfide-based solid electrolyte.

[0061] The polymer solid electrolyte may be a composite of a lithium salt and a polymer resin. Specifically, the polymer solid electrolyte may be formed by adding a polymer resin to a solvated lithium salt. Specifically, the ionic conductivity of the polymer solid electrolyte may be about 1×10 -7　 S / cm or more, preferably about 1×10 -3　 It can be more than S / cm.

[0062] The polymer resin may include, but is not limited to, polyether polymers, polycarbonate polymers, acrylate polymers, polysiloxane polymers, phosphazene polymers, polyethylene derivatives, alkylene oxide derivatives such as polyethylene oxide, phosphate ester polymers, polyagitation lysine, polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, polymers containing ionic dissociation groups, and the like, and may include one or more of these. In addition, the polymer solid electrolyte may include, as examples, a branched copolymer, a comb-like polymer, and a cross-linked polymer resin, wherein an amorphous polymer such as PMMA, polycarbonate, polysiloxane (PDMS), and / or phosphazene is copolymerized with a polyethylene oxide (PEO) main chain as a comonomer, and one or more of these may be included.

[0063] The above lithium salt is ionizable, Li + X - It can be expressed as . The anion of these lithium salts is not particularly limited, but F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , PF6 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - ,　 CF3CF2(CF3)2CO - , (CF3SO2)2CH -, (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - , (CF3CF2SO2)2N - Examples may include:

[0064] The above oxide-based solid electrolyte may contain oxygen (O) and have the ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table. Non-limiting examples thereof include LLTO-based compounds, Li6La2CaTa2O 12 , Li6La2ANb2O 12 (A is Ca or Sr), Li2Nd3TeSbO 12 , Li3BO 2.5 N 0.5 , Li9SiAlO8, LAGP compounds, LATP compounds, Li 1+x Ti 2-x Al x Si y (PO4) 3-y (where, 0≤x≤1, 0≤y≤1), LiAl x Zr 2-x (PO4)3(where, 0≤x≤1, 0≤y≤1), LiTi x Zr 2-x (PO4)3 (wherein, 0≤x≤1, 0≤y≤1), may include at least one selected from among LISICON compounds, LIPON compounds, perovskite compounds, NASICON compounds, and LLZO compounds. However, it is not particularly limited thereto.

[0065] The above sulfide-based solid electrolyte contains sulfur (S) and has the ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and may include Li-PS-based glass or Li-PS-based glass ceramic. Non-limiting examples of such sulfide-based solid electrolytes include Li6PS5Cl, Li2S-P2S5, Li2S-LiI-P2S5, Li2S-LiI-Li2O-P2S5, Li2S-LiBr-P2S5, Li2S-Li2O-P2S5, Li2S-Li3PO4-P2S5, Li2S-P2S5-P2O5, Li2S-P2S5-SiS2, Li2S-P2S5-SnS, Li2S-P2S5-Al2S3, Li2S-GeS2, Li2S-GeS2-ZnS, etc., and may include one or more of these. However, it is not particularly limited to this.

[0066] The above solid electrolyte may be included in the positive electrode active material layer in an amount of 10 wt% to 30 wt%, specifically 15 wt% to 25 wt%.

[0067] The above positive electrode active material layer may further include a conductive material.

[0068] The conductive material is not particularly limited as long as it has conductivity without causing a chemical change in the positive electrode or the battery, and may include, for example, one or a mixture of two or more selected from conductive materials such as graphite such as natural graphite or artificial graphite; carbon black such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, and summer black; conductive fibers such as carbon fiber or metal fiber; fluorinated carbon; metal powder such as aluminum or nickel powder; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; and polyphenylene derivatives.

[0069] The above-mentioned conductive material may be included in the positive electrode active material layer at 1 wt% to 30 wt%.

[0070] The above positive electrode active material layer may further include a binder.

[0071] The above binder is not particularly limited as long as it is a component that assists in bonding of a positive electrode active material, a conductive material, etc., and bonding to a current collector, and specifically may include at least one selected from the group consisting of polyvinylidene fluoride (PVdF), polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene monomer (EPDM), styrene-butadiene rubber (SBR), and fluororubber.

[0072] The above binder may be included in the positive electrode active material layer at 1 wt% to 30 wt%.

[0073] The above-mentioned positive electrode active material layer may include one or more additives, such as an oxidation stabilizing additive, a reduction stabilizing additive, a flame retardant, a heat stabilizer, an antifogging agent, etc., as needed.

[0074]

[0075] The negative electrode current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery, and for example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel surface-treated with carbon, nickel, titanium, silver, etc., aluminum-cadmium alloy, etc. can be used. In addition, like the positive electrode current collector, the bonding strength of the negative electrode active material can be strengthened by forming fine unevenness on the surface, and can be used in various forms such as a film, sheet, foil, net, porous body, foam, non-woven fabric, etc.

[0076] The above negative electrode active material layer may include a negative electrode active material and a solid electrolyte.

[0077] In addition, the negative electrode active material may include at least one selected from the group consisting of lithium metal, a carbon material capable of reversibly intercalating / deintercalating lithium ions, a metal or an alloy of these metals and lithium, a metal composite oxide, a material capable of doping and dedoping lithium, and a transition metal oxide.

[0078] As the carbon material capable of reversibly intercalating / deintercalating the lithium ions, any carbon-based negative electrode active material commonly used in lithium-ion secondary batteries can be used without particular limitation, and representative examples thereof include crystalline carbon, amorphous carbon, or a combination thereof. Examples of the crystalline carbon include graphite such as natural graphite or artificial graphite in an amorphous, plate-like, flake-like, spherical, or fibrous form, and examples of the amorphous carbon include soft carbon (low-temperature calcined carbon), hard carbon, mesophase pitch carbide, calcined coke, etc.

[0079] The above metal composite oxides include PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, Bi2O5, Li x Fe2O3(0≤x≤1), Li x WO2(0≤x≤1), and Sn x Me 1-x Me' y O z (Me: Mn, Fe, Pb, Ge; Me': Al, B, P, Si, elements of group 1, 2, and 3 of the periodic table, halogens; 0 <x≤1; 1≤y≤3; 1≤z≤8) 로 이루어진 군에서 선택되는 것이 사용될 수 있다.

[0080] Materials capable of doping and dedoping the above lithium include Si, SiO x(0 <x≤2), Si-Y 합금(상기 Y는 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소, 전이금속, 희토류 원소 및 이들의 조합으로 이루어진 군에서 선택되는 원소이며, Si은 아님), Sn, SnO2, Sn-Y(상기 Y는 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 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 Y로는 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, Ti, Ge, P, As, Sb, Bi, S, Se, Te, Po, 및 이들의 조합으로 이루어진 군에서 선택될 수 있다.

[0081] Examples of the above transition metal oxides include lithium-containing titanium composite oxide (LTO), vanadium oxide, and lithium vanadium oxide.

[0082] The above negative electrode active material may be included in an amount of 80 wt% to 99 wt% based on the total weight of the solid content in the negative electrode slurry.

[0083] The above solid electrolyte may specifically include at least one selected from the group consisting of a polymer solid electrolyte, an oxide-based solid electrolyte, and a sulfide-based solid electrolyte.

[0084] The description of the above solid electrolyte refers to the description of the solid electrolyte included in the aforementioned positive electrode active material layer.

[0085] The above solid electrolyte may be included in the negative electrode active material layer in an amount of 10 wt% to 30 wt%, specifically 15 wt% to 25 wt%.

[0086] The above negative active material layer may further include a conductive material.

[0087] The conductive agent is a component for further improving the conductivity of the negative electrode active material, and can be added in an amount of 1 to 20 wt% based on the total weight of the solid content in the negative electrode slurry. The conductive agent may be the same as or different from the conductive agent used in the manufacture of the positive electrode, and examples thereof include carbon powders such as carbon black, acetylene black (or Denka black), Ketjen black, channel black, furnace black, lamp black, or thermal black; graphite powders such as natural graphite, artificial graphite, or graphite with a highly developed crystal structure; conductive fibers such as carbon fibers or metal fibers; metal powders such as fluorocarbon, aluminum, and nickel powders; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives.

[0088] The above-mentioned conductive material may be included in the negative electrode active material layer at 1 wt% to 30 wt%.

[0089] The above negative active material layer may further include a binder.

[0090] The above binder is a component that assists in bonding between the conductive material, the active material, and the current collector, and is typically added in an amount of 1 to 30 wt% based on the total weight of the solid content in the negative electrode slurry. Examples of such binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene-butadiene rubber, fluororubber, and various copolymers thereof.

[0091] The solvent may include water or an organic solvent such as NMP or alcohol, and may be used in an amount that provides a desirable viscosity when including the negative electrode active material and optionally a binder and a conductive material. For example, the solvent may be included so that the solid concentration in the slurry including the negative electrode active material and optionally a binder and a conductive material is 50 wt% to 95 wt%, preferably 70 wt% to 90 wt%.

[0092]

[0093] The above solid electrolyte layer may be interposed between the negative electrode and the positive electrode in an all-solid-state secondary battery, and may function as an insulating and ion-conducting channel. Specifically, the ion conductivity of the solid electrolyte layer is about 1×10 -7　 S / cm or more, preferably about 1×10 -3　 It can be more than S / cm.

[0094] The above solid electrolyte may specifically include at least one selected from the group consisting of a polymer solid electrolyte, an oxide-based solid electrolyte, and a sulfide-based solid electrolyte.

[0095] The polymer solid electrolyte may be a composite of a lithium salt and a polymer resin. Specifically, the polymer solid electrolyte may be formed by adding a polymer resin to a solvated lithium salt. Specifically, the ionic conductivity of the polymer solid electrolyte may be about 1×10 -7　 S / cm or more, preferably about 1×10 -3　 It can be more than S / cm.

[0096] The polymer resin may include, but is not limited to, polyether polymers, polycarbonate polymers, acrylate polymers, polysiloxane polymers, phosphazene polymers, polyethylene derivatives, alkylene oxide derivatives such as polyethylene oxide, phosphate ester polymers, polyagitation lysine, polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, polymers containing ionic dissociation groups, and the like, and may include one or more of these. In addition, the polymer solid electrolyte may include, as a polymer resin, a branched copolymer obtained by copolymerizing an amorphous polymer such as PMMA, polycarbonate, polysiloxane (PDMS) and / or phosphazene with a polyethylene oxide (PEO) main chain as a comonomer, a comb-like polymer, and a cross-linked polymer resin, and one or more of these may be included.

[0097] The above lithium salt is ionizable, Li + X - It can be expressed as . The anion of these lithium salts is not particularly limited, but F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , PF6 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - ,　 CF3CF2(CF3)2CO - , (CF3SO2)2CH -, (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - , (CF3CF2SO2)2N - Examples may include:

[0098] The above oxide-based solid electrolyte may contain oxygen (O) and have the ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table. Non-limiting examples thereof include LLTO-based compounds, Li6La2CaTa2O 12 , Li6La2ANb2O 12 (A is Ca or Sr), Li2Nd3TeSbO 12 , Li3BO 2.5 N 0.5 , Li9SiAlO8, LAGP compounds, LATP compounds, Li 1+x Ti 2-x Al x Si y (PO4) 3-y (where, 0≤x≤1, 0≤y≤1), LiAl x Zr 2-x (PO4)3(where, 0≤x≤1, 0≤y≤1), LiTi x Zr 2-x (PO4)3 (wherein, 0≤x≤1, 0≤y≤1), may include at least one selected from among LISICON compounds, LIPON compounds, perovskite compounds, NASICON compounds, and LLZO compounds. However, it is not particularly limited thereto.

[0099] The above sulfide-based solid electrolyte contains sulfur (S) and has the ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and may include Li-PS-based glass or Li-PS-based glass ceramics. Non-limiting examples of such sulfide-based solid electrolytes include Li6PS5Cl, Li2S-P2S5, Li2S-LiI-P2S5, Li2S-LiI-Li2O-P2S5, Li2S-LiBr-P2S5, Li2S-Li2O-P2S5, Li2S-Li3PO4-P2S5, Li2S-P2S5-P2O5, Li2S-P2S5-SiS2, Li2S-P2S5-SnS, Li2S-P2S 5- Examples include Al2S3, Li2S-GeS2, Li2S-GeS2-ZnS, etc., and may include one or more of these, but are not particularly limited thereto.

[0100] The above solid electrolyte layer may further include a binder. The binder resin may be introduced for bonding between the solid electrolyte and the solid electrolyte layer and battery elements (e.g., a positive electrode, a negative electrode, etc.) laminated on both sides thereof. The binder material is not particularly limited and may be appropriately selected within the range of components used as binders in all-solid-state secondary batteries.

[0101] Specifically, the binder may include at least one selected from the group consisting of polyvinylidene fluoride (PVdF), polyvinyl alcohol (PVA), carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene monomer (EPDM), styrene-butadiene rubber (SBR), and fluoroelastomer.

[0102] The thickness of the solid electrolyte layer may be 15 ㎛ to 90 ㎛, specifically 20 ㎛ to 80 ㎛, taking into consideration ionic conductivity, physical strength, energy density of the battery to be applied, etc. In addition, the tensile strength of the solid electrolyte layer may be 500 kgf / cm.2 Up to 2,000 kgf / cm 2 It may be. In addition, the porosity of the solid electrolyte layer may be 15% or less or about 10% or less.

[0103]

[0104] The present invention provides a method for manufacturing the above-mentioned all-solid-state secondary battery.

[0105] An all-solid-state secondary battery according to one embodiment of the present invention can be manufactured according to a method for manufacturing an all-solid-state secondary battery, comprising: (S1) a step of manufacturing a unit cell including a positive electrode including one type of positive electrode active material, a negative electrode including one type of negative electrode active material, and a solid electrolyte; (S2) a step of manufacturing a unit cell in which at least one of the positive electrode, the negative electrode, and the solid electrolyte is different from the unit cell manufactured in (S1); and (S3) a step of stacking the unit cell manufactured in (S1) and the unit cell manufactured in (S2), or winding the unit cell in one direction after stacking.

[0106] In one embodiment of the present invention, the unit cell manufactured in step S2 may have at least one different positive electrode active material, negative electrode active material, and solid electrolyte from the unit cell manufactured in step S1.

[0107] In one embodiment of the present invention, the unit cell manufactured in step S2 may have two or more different positive electrode active materials, negative electrode active materials, and solid electrolytes from the unit cell manufactured in step S1.

[0108] In one embodiment of the present invention, two types of unit cells can be manufactured in which at least one of the positive electrode, negative electrode, and solid electrolyte is different in step S2.

[0109]

[0110] In addition, the present invention provides a battery module including the all-solid-state secondary battery as a unit battery, a battery pack including the battery module, and a device including the battery pack as a power source. At this time, specific examples of the device include, but are not limited to, a power tool that is powered by an electric motor; an electric vehicle including an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), etc.; an electric two-wheeled vehicle including an electric bicycle (E-bike) and an electric scooter (E-scooter); an electric golf cart; and a power storage system.

[0111]

[0112] Hereinafter, the present invention will be further described with reference to the drawings, but the drawings are provided to illustrate the present invention and the scope of the present invention is not limited to these drawings.

[0113] Fig. 1 schematically illustrates an embodiment of a conventional all-solid-state secondary battery. The all-solid-state secondary battery of Fig. 1 has a negative electrode (20), a solid electrolyte (30), and a positive electrode (10) sequentially laminated, and the positive electrode (10) has a positive electrode active material layer (11) disposed on one surface and the other surface of a positive electrode current collector (12), and the negative electrode (20) has a negative electrode active material layer (21) disposed on one surface and the other surface of a negative electrode current collector (22). Conventionally, when two or more types of positive electrode active materials and negative electrode active materials are to be applied to one all-solid-state secondary battery, two or more types of positive electrode active materials and negative electrode active materials are mixed and included in the positive electrode active material layer (11) and the negative electrode active material layer (21), respectively. As shown in Fig. 1, a mixture of two or more types of positive electrode active materials and a mixture of two or more types of negative electrode active materials constitute one positive electrode active material layer (11) and one negative electrode active material layer (21), respectively, and only one type of positive electrode active material layer (11) and negative electrode active material layer (21) are included in the all-solid-state secondary battery.

[0114] FIG. 2 schematically illustrates an all-solid-state secondary battery according to one embodiment of the present invention.

[0115] The all-solid-state secondary battery of FIG. 2 sequentially stacks a negative electrode (200), a solid electrolyte (301), a positive electrode (100), a solid electrolyte (301), a negative electrode (200), a solid electrolyte (302), a positive electrode (110), a solid electrolyte (303), and a negative electrode (210), and includes two types of positive electrodes (100, 110), two types of negative electrodes (200, 210), and three types of solid electrolytes (301, 302, 303).

[0116] An all-solid-state secondary battery according to one embodiment of the present invention includes two types of unit cells, a bi-cell (400) and a mono-cell (500), and a cathode active material layer (101, 111) and an anode active material layer (201, 211) included in each of the unit cells each include only one type of cathode active material or anode active material as the cathode active material or the anode active material. At this time, the types of cathode active materials may be different between different cathode active material layers (101, 111), and the types of anode active materials may be different between different cathode active material layers (201, 211). In addition, since there is no concern that the solid electrolytes (301, 302, 303) will be mixed with each other, the types of solid electrolytes may all be different between different solid electrolytes (301, 302, 303).

[0117] In this way, since the all-solid-state secondary battery according to one embodiment of the present invention includes a unit cell (400) composed of one positive electrode (201), one negative electrode (201), and one solid electrolyte (301) and a unit cell (500) composed of one positive electrode (111), one negative electrode (211), and one solid electrolyte (303), if the characteristics of the positive electrode active material and the negative electrode active material constituting each unit cell (400, 500) are already known, the optimal ratio can be developed more quickly and easily through a combination of cells using them.

[0118] In FIG. 2, the positive electrodes (101, 111), the negative electrodes (201, 211), and the solid electrolytes (301, 302, 303) are each shown as being different from each other, but if necessary, the type of the positive electrode active material, the type of the negative electrode active material, and the type of the solid electrolyte may be the same despite the different indications, and if at least one of the positive electrode, the negative electrode, and the solid electrolyte is of two or more types, it corresponds to one embodiment of the present invention.

[0119] [Explanation of symbols]

[0120] 10: Bipolar

[0121] 11: Positive active material layer

[0122] 12: Positive current collector

[0123] 20: Cathode

[0124] 21: Negative active material layer

[0125] 22: Negative current collector

[0126] 30: Solid electrolyte

[0127] 100, 110: positive

[0128] 101, 111: Positive active material layer

[0129] 102: Positive current collector

[0130] 200, 210: cathode

[0131] 201, 211: Negative active material layer

[0132] 202: Negative current collector

[0133] 301, 302, 303: Solid electrolyte

[0134] 400, 500: unit cell

Claims

1. Contains two or more unit cells including a positive electrode, a negative electrode, and a solid electrolyte, The positive and negative electrodes contained in one unit cell each contain one type of positive active material and negative active material, An all-solid-state secondary battery, wherein the two or more unit cells above have at least one different positive electrode, negative electrode, and solid electrolyte.

2. In paragraph 1, An all-solid-state secondary battery in which two or more of the above unit cells are stacked or are rolled in one direction after being stacked.

3. In paragraph 1, The above all-solid-state secondary battery is an all-solid-state secondary battery comprising two or more unit cells in which at least one of the positive electrode active material and the negative electrode active material is different from each other.

4. In paragraph 1, The above all-solid-state secondary battery includes two types of unit cells, An all-solid-state secondary battery, wherein at least one of the positive electrode active material, the negative electrode active material, and the solid electrolyte is different from each other.

5. In paragraph 1, The above all-solid-state secondary battery includes two types of unit cells, The above two types of unit cells are all-solid-state secondary batteries, wherein at least two of the positive electrode active material, the negative electrode active material, and the solid electrolyte are different from each other.

6. In paragraph 1, An all-solid-state secondary battery comprising a first unit cell including a first positive electrode, a first negative electrode, and a first solid electrolyte, and a second unit cell including a second positive electrode, a second negative electrode, and a second solid electrolyte.

7. In paragraph 1, An all-solid-state secondary battery, wherein the above all-solid-state secondary battery further includes a third unit cell including a third positive electrode, a third negative electrode, and a third solid electrolyte. 8.(S1) A step of manufacturing a unit cell including a positive electrode including one type of positive electrode active material, a negative electrode including one type of negative electrode active material, and a solid electrolyte; (S2) a step of manufacturing a unit cell in which at least one of the positive electrode, negative electrode, and solid electrolyte is different from the unit cell manufactured in (S1); and (S3) A method for manufacturing an all-solid-state secondary battery, comprising a step of stacking the unit cell manufactured in (S1) and the unit cell manufactured in (S2), or winding the unit cell in one direction after stacking.

9. In paragraph 8, A method for manufacturing an all-solid-state secondary battery, wherein the unit cell manufactured in the above step S2 is different from the unit cell manufactured in the above step S1 in at least one of a positive electrode active material, a negative electrode active material, and a solid electrolyte.

10. In paragraph 8, A method for manufacturing an all-solid-state secondary battery, wherein the unit cell manufactured in the above step S2 is different from the unit cell manufactured in the above step S1 in two or more of the positive electrode active material, the negative electrode active material, and the solid electrolyte.

11. In paragraph 8, A method for manufacturing an all-solid-state secondary battery, wherein two types of unit cells are manufactured in which at least one of a positive electrode, a negative electrode, and a solid electrolyte is different in the above step S2.

Images