Solid Battery Electrolyte Crystallization for Layer Bonding
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Solution Overview
Problem
Lithium ion secondary batteries with solid electrolytes face challenges in achieving high ion conductivity and strong interlayer bonds due to the low ion conducting properties of amorphous oxides and glass binders, which can lead to separation of electrode and electrolyte layers during sintering.
Innovation Solution
A method involving the use of amorphous oxide glass powder with precipitated lithium ion conducting crystallines in the electrolyte and electrode green sheets, sintered together to form a laminate with optimized oxide glass content, ensuring high ion conductivity and strong adhesion between layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If amorphous oxide glass powder is used as binder in solid electrolyte green sheet, then adhesion between layers is improved, but lithium ion conductivity deteriorates
Solution Approach 1:
The patent changes the physical state parameter of the glass powder from amorphous to crystalline by controlling the sintering process. This parameter change transforms the glass powder into lithium ion conducting crystalline particles that maintain both adhesion functionality and high ion conductivity, resolving the contradiction between bonding strength and ion conductivity.
Solution Approach 2:
The patent creates a composite structure where lithium ion conducting crystalline particles are dispersed within the glass binder matrix. This composite material combines the adhesive properties of glass with the high ion conductivity of crystalline phases, achieving both strong interlayer bonding and excellent lithium ion transport.
2Strength
If sintering temperature is increased to improve adhesion, then bonding strength is improved, but separation of layers may occur due to excessive thermal stress
Solution Approach 1:
The patent optimizes the sintering temperature parameter to a specific range (900-1100°C) where the glass powder undergoes crystallization to form lithium ion conducting crystallines. This controlled parameter change achieves sufficient bonding strength through crystalline formation while avoiding excessive thermal stress that would cause layer separation.
Solution Approach 2:
The glass powder acts as an intermediary material that facilitates bonding between the solid electrolyte layer and electrode layers. During sintering, it transforms into lithium ion conducting crystallines that serve as both adhesive bonds and ion conduction pathways, mediating between the structural requirements for bonding and the functional requirements for ion transport.
3Strength
If glass frits are added to current collector slurry to improve adhesion, then bonding is improved, but ion conductivity is reduced due to glass having low ion conducting property
Solution Approach 1:
The patent applies parameter change to the glass material itself by inducing crystallization during sintering. The glass powder transforms from an amorphous state with low ion conductivity to a crystalline state with high lithium ion conductivity, while maintaining its adhesive bonding function. This resolves the contradiction by changing the material's fundamental properties through thermal processing.
Solution Approach 2:
The glass powder performs dual functions: it provides adhesion between layers and simultaneously serves as a source of lithium ion conduction pathways. Through self-crystallization during sintering, the glass material generates its own lithium ion conducting crystallines, eliminating the need for separate ion conducting additives and achieving both bonding and conduction functions within the same material.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method achieves strong bonds between layers and high ion conductivity, preventing separation and enhancing the performance and reliability of lithium ion secondary batteries.
Implementation Method 1
amorphous oxide glass powder in which a crystalline having a lithium ion conducting property is precipitated in the step of sintering
Implementation Method 2
sintering the laminate
Data Source
AI summary
A method of manufacturing a lithium ion secondary battery comprising the steps of: forming a laminate by laminating an electrolyte green sheet and a positive electrode green sheet; and sintering the laminate is provided. At least one of the electrolyte green sheet and the positive electrode green sheet contains an amorphous oxide glass powder in which a crystalline having a lithium ion conducting property is precipitated in the step of sintering. A solid state battery produced in accordance with the method is provided.