KR-20260066533-A - ALL-SOLID-STATE BATTERY AND METHOD FOR MANUFACTURING THE SAME WHICH INCLUDES DOUBLE LAYER SOLID ELECTROLYTE

KR20260066533AKR 20260066533 AKR20260066533 AKR 20260066533AKR-20260066533-A

Abstract

The present invention relates to an all-solid-state battery comprising a solid electrolyte double layer that suppresses thermal runaway phenomena, improves robustness, and exhibits excellent electrochemical characteristics compared to conventional batteries, and a method for manufacturing the same. Specifically, the invention provides an all-solid-state battery comprising: a negative electrode; a first solid electrolyte layer located on the negative electrode; a second solid electrolyte layer located on the first solid electrolyte layer; and a positive electrode located on the second solid electrolyte layer; wherein the first solid electrolyte layer comprises an inorganic flame retardant and the second solid electrolyte layer comprises an endothermic flame retardant.

Inventors

김민선
윤여민
최용석
남영진

Assignees

현대자동차주식회사
기아 주식회사

Dates

Publication Date: 20260512
Application Date: 20241104

Claims (15)

cathode; A first solid electrolyte layer located on the above cathode; A second solid electrolyte layer located on the first solid electrolyte layer; and A positive electrode located on the second solid electrolyte layer; comprising The first solid electrolyte layer above contains an inorganic flame retardant, and The above-mentioned second solid electrolyte layer comprises an endothermic flame retardant, in a solid-state battery.
In claim 1, The all-solid-state battery comprising one or more inorganic flame retardants selected from the group consisting of LLZO, LATP, SiO2, ZnO, SnO2, Mn3O4, Sn2P2O7 , aluminum oxide , magnesium oxide , zeolite, zirconium compounds, calcium salts, and boron compounds.
In claim 1, An all-solid-state battery in which the above-mentioned inorganic flame retardant is included in an amount of 20% or more and 50% or less based on the solid electrolyte in the first solid electrolyte layer.
In claim 1, The above-mentioned heat-absorbing flame retardant comprises one or more selected from the group consisting of Mg(OH ) ₂ , Al(OH) ₃ , Sb₂O₃ , H₃BO₃ , Fe(OH) ₃ , CaCO₃ , Ca(OH) ₂ , Zn(OH) ₂ , NaOH, calcium-magnesium hydroxides, hydrotalcite, boehmite, talc, dosonite, calcium sulfate hydrate, and magnesium sulfate hydrate, in an all-solid-state battery.
In claim 1, An all-solid-state battery in which the above-mentioned heat-absorbing flame retardant is included in an amount of 5% or more and 20% or less based on the solid electrolyte in the second solid electrolyte layer.
In claim 1, An all-solid-state battery in which the ratio between the thickness of the first solid electrolyte layer and the thickness of the second solid electrolyte layer is 1:9 to 9:1.
In claim 1, An all-solid-state battery characterized in that the sum of the thicknesses of the first solid electrolyte layer and the second solid electrolyte layer is 10㎛ or more and 120㎛ or less.
In claim 1, A solid-state battery characterized by additionally including a binder in the first solid electrolyte layer and the second solid electrolyte layer.
In claim 8, The above binder is included in an amount of 0.5 weight% or more and 5 weight% or less, respectively, relative to the weight of the solid electrolyte in the first solid electrolyte layer and the solid electrolyte in the second solid electrolyte layer.
In claim 8, The all-solid-state battery, wherein the binder comprises one or more selected from the group consisting of polybutadiene rubber (BR), styrene-butadiene rubber (SBR), nitrile butadiene rubber (NBR), polyimide (PI), polyvinylidene fluoride (PVDF), and ethylene propylene diene rubber (EPDM).
The method comprises the step (S0) of manufacturing an all-solid-state battery stacked in the order of a negative electrode, a first solid electrolyte layer, a second solid electrolyte layer, and a positive electrode. The first solid electrolyte layer above includes an inorganic flame retardant, and A method for manufacturing an all-solid-state battery, wherein the second solid electrolyte layer comprises an endothermic flame retardant.
In claim 11, The above S0 step is, A step (S1) of manufacturing a cathode assembly by stacking a cathode, a first solid electrolyte layer, and a second solid electrolyte layer in that order; and A method for manufacturing an all-solid-state battery, comprising the step (S2) of stacking the cathode assembly and the anode such that the second solid electrolyte layer faces the anode.
In claim 11, The above S0 step is, A step of manufacturing an anode assembly by stacking an anode, a second solid electrolyte layer, and a first solid electrolyte layer in that order (S1'); and A method for manufacturing an all-solid-state battery, comprising the step (S2') of stacking the positive electrode assembly and the negative electrode such that the first solid electrolyte layer faces the negative electrode.
In claim 11, The above S0 step is, A step of manufacturing a cathode assembly including a cathode and a first solid electrolyte layer (S1); Step of manufacturing an anode assembly including an anode and a second solid electrolyte layer (S2); and A method for manufacturing an all-solid-state battery, comprising the step (S3) of stacking the cathode assembly and the anode assembly so that the first solid electrolyte layer and the second solid electrolyte layer face each other.
In any one of claims 12 to 14, A method for manufacturing an all-solid-state battery, wherein the above-mentioned negative electrode assembly or positive electrode assembly is manufactured by a wet-on-wet or wet-on-dry method, respectively.

Description

All-solid-state battery including a double layer of solid electrolyte and method for manufacturing the same The present invention relates to an all-solid-state battery comprising a solid electrolyte double layer capable of suppressing thermal runaway and improving the robustness of the electrolyte layer, and a method for manufacturing the same. Lithium-ion batteries have been widely used in various fields, such as electric vehicles and portable electronic devices, but they present several safety issues during operation. In particular, when aiming for high energy density, cathode materials with a high nickel (Ni) content are primarily used; however, this has the disadvantage of lowering the thermal decomposition initiation temperature, which increases heat generation and thus increases the risk of thermal runaway. Additionally, when aiming for high theoretical capacity, silicon (Si) anodes are used; however, silicon anodes undergo severe volume expansion during charging and discharging, and during long-term charging and discharging, the precipitation of lithium metal causes short circuits within the battery, which have resulted in thermal runaway. Consequently, all-solid-state batteries are receiving significant attention as next-generation energy storage devices because, unlike conventional lithium-ion batteries, they utilize solid electrolytes to reduce the risk of electrolyte leakage or fire; however, all-solid-state batteries are not entirely free from stability issues such as thermal runaway. In particular, due to the multilayer structure of all-solid-state batteries, it is difficult to simultaneously maintain thermal and mechanical stability between the anode and cathode. Therefore, there is a need to develop all-solid-state batteries capable of securing both thermal and mechanical stability while maintaining energy density and performance. Figure 1 is a graph showing the results of Differential Scanning Calorimetry (DSC) analysis of an all-solid-state battery according to an embodiment and a comparative example of the present invention. Figure 2 is a graph showing the robustness characteristics of an all-solid-state battery according to an embodiment and a comparative example of the present invention, measured using Saicas equipment. FIG. 3a is a graph showing the charge/discharge characteristics of an all-solid-state battery according to an embodiment and a comparative example of the present invention. FIG. 3b is a graph showing the capacity retention rate (%) according to the cycle repetition of an all-solid-state battery according to an embodiment and a comparative example of the present invention. Figures 4a and 4b are CT analysis figures showing cross-sections of an all-solid-state battery after impact according to an embodiment and a comparative example of the present invention, respectively. FIG. 5 is a diagram showing a cross-section of an all-solid-state battery according to an embodiment of the present invention. The present invention will be described in more detail below. Terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention. All-solid-state battery The present invention provides an all-solid-state battery comprising: a cathode; a first solid electrolyte layer located on the cathode; a second solid electrolyte layer located on the first solid electrolyte layer; and an anode located on the second solid electrolyte layer, wherein the first solid electrolyte layer comprises an inorganic flame retardant and the second solid electrolyte layer comprises an endothermic flame retardant. The components of the all-solid-state battery of the present invention will be described in detail below. cathode The cathode of the present invention may be in the form in which a cathode active material layer is coated on a cathode current collector. The above-mentioned negative electrode current collector performs the role of collecting current so that electrons can move to the external circuit of the battery, and provides high electrical conductivity to enable electrons to move quickly. The type of the above-mentioned negative electrode current collector is not significantly limited as long as it is a material that is conductive without causing chemical changes in the battery, but preferably, it may include one or more selected from the group consisting of copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel surface treated with carbon, nickel, titanium, silver, etc., and aluminum-cadmium alloy. The above-mentioned cathode active material layer may include a cathode active material, a binder for fixing cathode active material particles, a conductive material for