Binder-Free Thermal Battery Electrolyte Composition

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Solution Overview

Problem

Conventional thermal battery electrolytes require binders to prevent dispersion and short circuits, but these binders increase impedance, necessitating a binder-free solution that maintains electrolyte containment and conductivity.

Innovation Solution

A substantially binder-free electrolyte material comprising at least 25 wt% lithium bromide, 4 wt% lithium chloride, 42 wt% lithium fluoride, and 1-12 wt% potassium bromide, which maintains electrolyte flowability and conductivity without binders by utilizing high melting point lithium fluoride to maintain viscosity upon activation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If binder materials are added to the electrolyte, then the electrolyte is contained within the battery assembly upon melting, but the impedance of the battery increases

Engineering Contradiction:
Improveelectrolyte containmentVSAvoidimpedance
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention extracts and removes the binder component from the electrolyte formulation, achieving binder-free electrolyte compositions that eliminate the impedance-increasing effect of binders while maintaining electrolyte containment through optimized eutectic mixture properties and battery assembly design

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the compositional parameters of the electrolyte by using specific ratios of lithium chloride (3-15 wt%), potassium chloride (75-95 wt%), and lithium bromide (0.5-5 wt%), which alter the melting point and viscosity characteristics to enable binder-free operation while maintaining effective electrolyte containment

Inventive Principle:
Principle #35Parameter changes

2Reliability

If binder materials are added to the electrolyte, then the electrolyte is contained within the battery assembly upon melting, but the electrolyte material may still disperse throughout the battery causing undesired shunts or short circuits

Engineering Contradiction:
Improveelectrolyte containmentVSAvoidshort circuits
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention removes binder materials from the electrolyte composition, achieving binder-free formulations that eliminate the impedance increase associated with binders while maintaining effective electrolyte containment through optimized eutectic mixture properties

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention uses composite electrolyte formulations combining multiple salts (lithium chloride, potassium chloride, and lithium bromide) in specific ratios to create a eutectic mixture with optimized melting point and viscosity characteristics that enable binder-free operation while preventing electrolyte dispersion and short circuits

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 solution reduces cell impedance and prevents short circuits while maintaining effective ion conduction and flowability, enhancing thermal battery performance and longevity.

Implementation Method 1

maintains electrolyte flowability and conductivity without binders by utilizing high melting point lithium fluoride to maintain viscosity upon activation

Methodology Applied
Scientific EffectHigh melting point:

Implementation Method 2

Heat produced from the pyrotechnic material causes the previously solid electrolyte to melt and become conductive, which allows the battery to provide power

Methodology Applied
Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 3

The external stimulus causes the pyrotechnic material to ignite and begin to heat

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 4

which assists in containing the electrolyte within the thermal battery assembly upon melting, such as by capillary action, surface tension, or both

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 5

which assists in containing the electrolyte within the thermal battery assembly upon melting, such as by capillary action, surface tension, or both

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Data Source

PatentEP2417658B1Thermal battery electrolyte compositions, electrode-electrolyte composites, and batteries including the same
Publication Date: 2015.08.19 EAGLEPICHER TECHNOLOGIES LLC
  • EP2417658B1 patent drawingFigure 1
  • EP2417658B1 patent drawingFigure 2
  • EP2417658B1 patent drawingFigure 3

AI summary

Ternary or quaternary electrolyte material for use in thermal batteries that is substantially free of binders is disclosed. Composites of electrodes and electrolytes that contain the electrolyte material and batteries that contain the electrolyte material are also disclosed.