Solid Electrolyte Composition for All-Solid Batteries

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Solution Overview

Problem

Existing solid electrolyte compositions for all-solid state secondary batteries face a trade-off between adhesiveness, toughness, and ion conductivity, where increasing binder content to improve these characteristics reduces ion conductivity, and existing solutions like fluorine-containing rubber and specific polymer compositions do not adequately address bend resistance and scratch resistance while maintaining high ion conductivity.

Innovation Solution

A solid electrolyte composition incorporating an inorganic solid electrolyte with a binder having a hydrocarbon polymer segment with specific functional groups and bonds, such as urethane, urea, or imide bonds, and a soft segment with a high molecular weight, which provides excellent bend resistance, scratch resistance, and maintains high ion conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If binder content is increased to improve adhesiveness and toughness, then bonding property and mechanical strength are improved, but ion conductivity is reduced

Engineering Contradiction:

Improveadhesiveness and toughnessVSAvoidion conductivity

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the binder by specifying functional groups (carboxylic acid, sulfonic acid, phosphoric acid, hydroxy, amino, or cyano groups) and molecular weight ranges (1,000-100,000). This allows optimization of both mechanical properties and ion conductivity through precise parameter control rather than simply increasing binder content

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite binder system combining organic binder molecules with specific functional groups and molecular weights with inorganic solid electrolyte particles. This composite structure provides both the mechanical strength from the binder network and the ion conductivity from the inorganic electrolyte pathways

Inventive Principle:

Principle #40Composite materials

2Productivity

If sheet is wound around winding core at high curvature, then manufacturing efficiency is improved, but active material or inorganic solid electrolyte drops from the layer

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidflex resistance

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The patent applies preliminary action by pre-forming the solid electrolyte-containing sheet with optimized binder properties before the winding operation. The binder's specific molecular weight and functional group composition prepare the sheet to withstand subsequent high-curvature winding without material drop

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent optimizes the binder's molecular weight (1,000-100,000) and functional group composition to achieve appropriate viscoelastic properties that provide flex resistance during winding while maintaining adhesion to active material and inorganic solid electrolyte particles

Inventive Principle:

Principle #35Parameter changes

3Productivity

If sheet is temporarily stored after manufacturing, then production workflow is optimized, but scratches or cracks generate on the surface

Engineering Contradiction:

Improveproduction workflow optimizationVSAvoidscratch resistance

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by designing the binder with specific protective characteristics before the sheet undergoes storage and handling. The pre-configured binder properties provide scratch resistance that protects the sheet surface during temporary storage operations

Inventive Principle:

Principle #10Preliminary action

4Strength

If fluorine-containing rubber or specific polymer composition is used to improve adhesiveness, then bonding property is improved, but sufficient bend resistance and scratch resistance are not achieved

Engineering Contradiction:

ImproveadhesivenessVSAvoidbend resistance and scratch resistance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent fundamentally changes the binder specification from conventional fluorine-containing rubber to polymers with specific molecular weight ranges (1,000-100,000) and specific functional groups. This parameter change simultaneously achieves adhesiveness, bend resistance, and scratch resistance that previous solutions could not provide

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a novel composite material system where the binder is defined by specific molecular characteristics (functional groups and molecular weight) rather than conventional polymer types. This composite approach provides balanced performance across multiple requirements that single-material solutions fail to achieve

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS11631885B2Solid electrolyte composition, solid electrolyte-containing sheet and manufacturing method therefor, all-solid state secondary battery and manufacturing method therefor, and polymer and non-aqueous solvent dispersion thereof

Publication Date: 2023.04.18 FUJIFILM CORP

AI summary

Provided are a solid electrolyte composition containing an inorganic solid electrolyte having a conductivity of an ion of a metal belonging to Group I or II of the periodic table and a binder having a specific hydrocarbon polymer segment and a specific segment, a solid electrolyte-containing sheet in which the same solid electrolyte composition is used and a manufacturing method therefor, an all-solid state secondary battery and a manufacturing method therefor, a polymer having a specific hydrocarbon polymer segment and a specific segment, and a non-aqueous solvent dispersion thereof.