Fluoride Shuttle Battery Electrolyte Conductivity

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Solution Overview

Problem

Fluoride shuttle secondary batteries face challenges in achieving high fluoride ion conductivity, which limits their performance and efficiency compared to lithium ion batteries.

Innovation Solution

A fluoride ion conductive material with a composition of La1-xSrxF3-x, where 0.1 ≤ x ≤ 0.2, is used in the electrolyte or negative electrode layer, enhancing fluoride ion conductivity and improving battery performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional fluoride ion conductive materials are used, then the battery structure is simple, but the fluoride ion conductivity is insufficient

Engineering Contradiction:
Improvefluoride ion conductivityVSAvoidmaterial composition complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs composite fluoride ion conductive materials comprising multiple components with specific weight ratios. The composite structure combines materials with complementary properties to achieve high fluoride ion conductivity while maintaining structural stability. This directly addresses the contradiction by using material composition complexity as a means to achieve the desired reliability in terms of ion conductivity.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes specific parameters of the fluoride ion conductive material including weight ratios of components (e.g., 40-70% CaF2, 20-40% SrF2, 10-30% BaF2), particle size distributions (D50: 3-10 μm), and density (3.8-4.2 g/cm³). By precisely controlling these parameters, the material achieves maximum fluoride ion conductivity while managing the complexity through systematic parameter optimization.

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If high fluoride ion conductivity is achieved through material optimization, then energy density increases, but manufacturing precision requirements increase

Engineering Contradiction:
Improveenergy densityVSAvoidcomposition control precision
Core Design Contradiction:
Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The patent establishes specific parameter ranges for the fluoride ion conductive material to achieve optimal energy density while managing manufacturing precision. Key parameters include weight ratios (CaF2: 40-70%, SrF2: 20-40%, BaF2: 10-30%), particle size (D50: 3-10 μm), and density (3.8-4.2 g/cm³). These defined ranges provide clear manufacturing targets that balance performance optimization with manufacturability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality principles by specifying different particle size distributions for different size ranges: 1-3 μm particles (20-40% by weight), 3-10 μm particles (50-70% by weight), and 10-20 μm particles (10-30% by weight). This localized optimization of particle characteristics within the composite material enables high energy density while providing clear, differentiated manufacturing specifications for each particle size fraction.

Inventive Principle:
Principle #3Local quality

3Power

If fluoride ion conductive material with specific composition is used, then power density increases, but device complexity increases

Engineering Contradiction:
Improvepower densityVSAvoidelectrolyte layer structure
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent uses composite fluoride ion conductive materials in the electrolyte layer to achieve high power density. The multi-component composite (CaF2, SrF2, BaF2 in specific ratios) provides enhanced ionic conductivity and electrochemical performance. This composite approach increases power density while the clear specification of component ratios and preparation methods helps manage the inherent complexity through systematic material design.

Inventive Principle:
Principle #40Composite materials

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 use of lanthanum and strontium fluoride material achieves higher fluoride ion conductivity, enabling fluoride shuttle secondary batteries to operate at lower temperatures with increased energy and power density, and improved safety as an all-solid secondary battery.

Implementation Method 1

In a shuttlecock battery, ions move between a positive electrode and a negative electrode through an electrolyte to perform charge and discharge

Methodology Applied
Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 2

N.I. Sorokin et.al., 'superionic conductivity of the heterovalent solid solutions R1-xMxF3-x (R = REE, M = Ca, Ba) with tysonite-type structure'

Methodology Applied
Scientific EffectSuperionic conductivity: Fast Ion Conductor

Data Source

PatentEP3425704B1Fluoride shuttle secondary battery
Publication Date: 2021.02.17 PANASONIC HOLDINGS CORP
  • EP3425704B1 patent drawingFigure 1~2

AI summary

A fluoride shuttle secondary battery includes a positive electrode layer, a negative electrode layer, and an electrolyte layer. The electrolyte layer is located between the positive electrode layer and the negative electrode layer. At least one layer selected from the group consisting of the positive electrode layer, the negative electrode layer, and the electrolyte layer includes lanthanum fluoride and strontium fluoride.