KR-20260066942-A - All-solid secondary battery and manufacturing method thereof

KR20260066942AKR 20260066942 AKR20260066942 AKR 20260066942AKR-20260066942-A

Abstract

The present invention provides an all-solid-state secondary battery comprising at least one structure including a unit cell and a frame surrounding the outer surface of the unit cell, wherein the unit cell comprises at least one positive current collector layer, a positive composite layer, a solid electrolyte layer, a negative composite layer, and a negative current collector layer, and wherein the positive composite layer, the solid electrolyte layer, and the negative composite layer are stacked in the height direction, have equal areas, and satisfy the following condition 1. [Condition 1] (Unit cell thickness (excluding current collector layer thickness)/2)×70% ≤ Thickness in the direction perpendicular to the height direction of the frame ≤ (Unit cell thickness (excluding current collector layer thickness)/2)×130%. According to the present invention, cracks in the solid electrolyte layer and short circuits in the battery are controlled, thereby providing an all-solid-state secondary battery having excellent capacity and lifespan characteristics and a method for manufacturing the same.

Inventors

안상혁
김정길
최락영

Assignees

주식회사 엘지에너지솔루션

Dates

Publication Date: 20260512
Application Date: 20241105

Claims (17)

An all-solid-state secondary battery having at least one structure comprising a unit cell and a frame surrounding the outer surface of the unit cell, The above unit cell comprises at least one each of an anode current collector layer, an anode composite layer, a solid electrolyte layer, a cathode composite layer, and a cathode current collector layer, and The above anode composite layer, solid electrolyte layer, and cathode composite layer are stacked in the height direction and have the same area as each other, and All-solid-state secondary battery characterized by satisfying the following condition 1: [Condition 1] (Unit cell thickness (excluding current collector layer thickness)/2)×70% ≤ Thickness in the direction perpendicular to the height direction of the frame ≤ (Unit cell thickness (excluding current collector layer thickness)/2)×130%.
In Article 1, The above unit cell, along the height direction, A solid-state secondary battery characterized by sequentially including a positive current collector layer, a positive composite layer, a solid electrolyte layer, a negative composite layer, and a negative current collector layer.
In Article 1, The above unit cell, along the height direction, positive current collector layer, A pair of positive composite layers arranged with the above positive current collector layer in between, A pair of solid electrolyte layers positioned between the above pair of anode composite layers, A pair of cathode composite layers disposed between the above pair of solid electrolyte layers, and A solid-state secondary battery characterized by including a pair of negative current collector layers arranged between the above pair of negative composite layers.
In Article 1, The above unit cell, along the height direction, cathode current collector layer, A pair of cathode composite layers arranged with the above-mentioned cathode current collector layer in between, A pair of solid electrolyte layers positioned between the above pair of cathode composite layers, A pair of anode composite layers disposed between the above pair of solid electrolyte layers, and A solid-state secondary battery characterized by including a pair of positive current collector layers arranged between the pair of positive composite layers mentioned above.
In Article 1, A solid-state secondary battery characterized by including a buffer pad on at least one surface of the above-mentioned structure.
In Article 5, The above-described buffer pad is characterized by having an elastic modulus of 0.1 to 5 GPa, in an all-solid-state secondary battery.
In Article 5, An all-solid-state secondary battery characterized in that the thickness of the above-mentioned buffer pad is 80% to 150% of the thickness in the direction perpendicular to the height direction of the frame.
In Article 5, All-solid-state secondary battery characterized by the thickness of the buffer pad being 10 to 500 μm.
In Article 1, It includes a plurality of structures stacked in the height direction, and A solid-state secondary battery characterized by including buffer pads between each of adjacent structures.
In Article 9, A solid-state secondary battery characterized by further including a buffer pad on each of the outermost surfaces of a plurality of structures.
In Article 5, A solid-state secondary battery characterized in that the area of the above-mentioned buffer pad is the same as the area of the structure.
In Article 1, The above frame is a flame-retardant inert member comprising a matrix and a filler; or high All-solid-state secondary battery characterized by having an insulating layer comprising a molecule, or a composite of a polymer and an inorganic material.
In Article 5, The above-described buffer pad is characterized by including an elastic material, in a solid-state secondary battery.
In Article 13, The above elastic material is characterized by comprising polyurethane, polyacrylate, fluorinated polymer, natural rubber, spandex, butyl rubber, fluoroelastomer, elastomer, ethylene-propylene rubber (EPR), styrene-butadiene rubber (SBR), isoprene rubber, polybutadiene, nitrile rubber, thermoplastic elastomer, silicone rubber, ethylene-propylene-diene rubber (EPDM), ethylene vinyl acetate (EVA), neoprene, acrylic, copolymers thereof, or combinations thereof, in an all-solid-state secondary battery.
In Article 1, A solid-state secondary battery characterized in that the above-mentioned solid electrolyte layer comprises a sulfide-based solid electrolyte, an oxide-based solid electrolyte, or a polymer-based solid electrolyte.
A method for manufacturing an all-solid-state secondary battery comprising at least one structure including a unit cell and a frame surrounding the outer surface of the unit cell, A step of manufacturing a structure having a unit cell comprising at least one each of an anode current collector layer, an anode composite layer, a solid electrolyte layer, a cathode composite layer, and a cathode current collector layer, and a frame surrounding the outer surface of the unit cell (step S1); and The method includes the step of applying isotropic pressure to the above structure (step S2), and The above anode composite layer, solid electrolyte layer, and cathode composite layer are stacked in the height direction and have the same area as each other, and A method for manufacturing an all-solid-state secondary battery characterized by satisfying the following condition 1: [Condition 1] (Unit cell thickness (excluding current collector layer thickness)/2)×70% ≤ Thickness in the direction perpendicular to the height direction of the frame ≤ (Unit cell thickness (excluding current collector layer thickness)/2)×130%.
In Article 16, A method for manufacturing an all-solid-state secondary battery, characterized by further including the step (step S3) of introducing a buffer pad on at least one surface of the above-mentioned structure.

Description

All-solid secondary battery and manufacturing method thereof All-solid secondary battery and manufacturing method thereof The present invention relates to an all-solid-state secondary battery and a method for manufacturing the same. All-solid-state secondary batteries require high heat and pressure to lower resistance and improve contact between solid particles. However, applying high heat and pressure causes the solid electrolyte layer to become brittle; this leads to cracking in the electrolyte layer and a tendency for battery short circuits due to volume changes (expansion or contraction) during charging and discharging. In particular, the surface area of the positive electrode composite layer is generally designed to be smaller than that of the solid electrolyte layer and the negative electrode composite layer; applying high heat and pressure to such a structure exacerbates the problems of cracking and battery short circuits. FIGS. 1 to 6 are images of a cross-section of an all-solid-state secondary battery (case not shown) according to one embodiment of the present invention, viewed from the side. FIG. 7 is an image showing a cross-section of an all-solid-state secondary battery (case not shown) according to one embodiment of the present invention, viewed from the top or bottom. FIG. 8 illustrates a flowchart of a method for manufacturing an all-solid-state secondary battery according to one embodiment of the present invention. FIG. 9 is a graph showing the results of evaluating capacity and Coulomb efficiency according to cycles for an all-solid-state secondary battery according to one embodiment of the present invention. 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 may appropriately define the concept of the terms to best describe his invention. Accordingly, the configurations of the embodiments described in this specification are merely one preferred embodiment of the invention and do not represent all aspects of the technical spirit of the invention; therefore, it should be understood that various equivalents and modifications capable of replacing them may exist at the time of filing this application. In this specification, singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, when a part is described as “comprising” a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. Thus, for example, a composition comprising compound A may include compounds other than A. However, the term “comprising” also encompasses, in a more restrictive sense as a specific embodiment thereof, “essentially/essentially composed of” and “composed of,” so, for example, a “composition comprising compound A” may also be (essentially/essentially) composed of compound A. In connection with this, terms such as “comprising” or “having,” as described in this specification, are intended to specify the existence of the implemented features, numbers, steps, components, or combinations thereof, and should not be understood as precluding the existence or addition of one or more other features, numbers, steps, components, or combinations thereof. In the present specification, when any member, layer, film, etc. is described as being located “on” another arbitrary member, layer, film, etc., this includes not only cases where such member, layer, film, etc. is in contact with another member, layer, film, etc., but also cases where another member, layer, film, etc. exists between two members, layers, films, etc. In this specification, “identical” area, length, width, thickness, and/or shape includes all cases having “substantially identical” area, length, width, thickness, and/or shape, except where the area, length, width, thickness, and/or shape are intentionally made different from one another. “Identical” area, length, width, and/or thickness includes a range in which the unintended difference in the area, length, width, and/or thickness of the objects being compared is, for example, less than 1%, less than 0.5%, or less than 0.1%. The drawings attached to this specification illustrate an embodiment of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the content of the invention; therefore, the present invention should not be interpreted as being limited only to the matters described in the drawings. In the drawings, thicknesses have been enlarged or reduced to clearly represent various layers and regions. Throughout the specification, similar parts are given the same reference numerals. In this specification and drawings, components having substantially the same f