Solid Electrolyte Composition with Alicyclic Dispersion Medium

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Solution Overview

Problem

Existing lithium ion secondary batteries using organic electrolytic solutions face issues with liquid leakage, short circuits, and safety concerns due to overcharging or overdischarging, necessitating improved reliability and safety, which all-solid state batteries with inorganic solid electrolytes aim to address by enhancing safety and energy density.

Innovation Solution

A solid electrolyte composition comprising an inorganic solid electrolyte, a binder, and a dispersion medium with a specific alicyclic compound that improves dispersion stability and viscosity, leading to uniform layer thickness and increased battery voltage, while preventing short circuits in all-solid state secondary batteries.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an organic electrolytic solution is used in lithium ion secondary batteries, then the battery can operate with good ion conductivity, but liquid leakage and safety issues occur due to overcharging or overdischarging

Engineering Contradiction:
ImprovesafetyVSAvoidliquid leakage
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent transitions the electrolyte from liquid phase (organic electrolytic solution) to solid phase (inorganic solid electrolyte). This phase transition eliminates liquid leakage while maintaining ion conductivity, directly resolving the safety and harmful factor issues associated with organic electrolytes

Inventive Principle:
Principle #36Phase transitions

2Reliability

If an inorganic solid electrolyte is used to improve safety and reliability, then liquid leakage is prevented, but manufacturing complexity increases due to the need for precise dispersion and layer formation

Engineering Contradiction:
ImprovesafetyVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a dispersion medium as an intermediary substance to facilitate the uniform dispersion of inorganic solid electrolyte particles. This mediator enables simplified manufacturing by allowing straightforward slurry preparation and layer formation processes, reducing the complexity that would otherwise result from handling pure solid electrolyte materials

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent controls particle size parameters of the inorganic solid electrolyte (1 μm to 100 μm range) and dispersion medium properties to optimize both safety performance and manufacturing ease. By adjusting these physical parameters, the patent achieves a balance between reliability improvement and manufacturing simplicity

Inventive Principle:
Principle #35Parameter changes

3Reliability

If a solid electrolyte layer is formed with uniform thickness to improve battery performance, then ion conductivity increases, but the manufacturing precision requirements become more stringent

Engineering Contradiction:
Improveion conductivityVSAvoidlayer thickness uniformity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The dispersion medium acts as a processing aid that enables uniform layer formation through simple coating processes. By controlling the viscosity and evaporation characteristics of the dispersion medium, the patent achieves uniform layer thickness without requiring complex precision manufacturing equipment or processes

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies a slightly excessive amount of dispersion medium during layer formation, then allows controlled evaporation to achieve the desired uniform thickness. This approach simplifies manufacturing by using a forgiving process margin rather than requiring precise single-pass coating

Inventive Principle:
Principle #16Partial or excessive action

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 proposed solution results in a solid electrolyte composition that enhances ion conductivity and achieves a higher battery voltage with improved layer uniformity, effectively addressing safety and reliability concerns in all-solid state secondary batteries.

Implementation Method 1

a solid electrolyte composition comprising an inorganic solid electrolyte, a binder, and a dispersion medium, wherein the dispersion medium includes an alicyclic compound

Methodology Applied
Scientific EffectDispersion: Dispersion (of waves)

Implementation Method 2

all-solid state secondary batteries in which an inorganic solid electrolyte is used instead of the organic electrolytic solution

Methodology Applied
Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentEP3467846B1Solid electrolyte composition, solid electrolyte-containing sheet as well as method for manufacturing the same, and all-solid-state secondary battery as well as method for manufacturing the same
Publication Date: 2020.06.03 FUJIFILM CORP
  • EP3467846B1 patent drawingFigure 1~3

AI summary

Provided are a solid electrolyte composition containing an inorganic solid electrolyte having conductivity of ions of metals belonging to Group I or II of the periodic table, a binder, and a dispersion medium, in which the dispersion medium includes an alicyclic compound composed of a carbon atom, a hydrogen atom, and/or a halogen atom, and a boiling point of the alicyclic compound at 760 mmHg is 100°C or higher and 180°C or lower, a solid electrolyte-containing sheet, an all-solid state secondary battery, and methods for manufacturing a solid electrolyte-containing sheet and an all-solid state secondary battery.