Polyether Solid Electrolyte for Low-Temperature Lithium Ion Cells

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current electrolyte materials for lithium ion cells face safety issues due to abnormal reactions at the electrode interface and have limited ionic conductivity, especially at low temperatures, with polyethylene glycols crystallizing and reducing conductivity.

Innovation Solution

A solid electrolyte material comprising a polymer with an oxyalkylene structure bonded via an ether bond, combined with a specific ionic compound, enhancing lithium ionic conductivity and reduction resistance, suitable for use in lithium ion cells across a wide temperature range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If liquid electrolyte is used, then ionic conductivity is improved, but safety deteriorates due to abnormal reactions at electrode interface

Engineering Contradiction:

Improveionic conductivityVSAvoidabnormal reaction at electrode interface

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the physical state parameter from liquid to solid polymer electrolyte, eliminating the safety issues associated with liquid electrolytes while maintaining ionic conductivity through the designed polyether structure with appropriate glass transition temperature and side chain configuration

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the liquid electrolyte system with a solid polymer electrolyte system, where ion transport occurs through the polymer matrix rather than through liquid flow, providing both safety and conductivity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Object-affected harmful factors

If polymer electrolyte is used to improve safety, then reduction resistance is improved, but ionic conductivity at low temperature deteriorates

Engineering Contradiction:

Improvereduction resistanceVSAvoidionic conductivity at low temperature

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent optimizes the polymer structure parameters including the glass transition temperature, side chain length (n value), and hydrocarbon group structure to prevent crystallization at low temperatures while maintaining the solid polymer structure that provides high reduction resistance and safety

Inventive Principle:

Principle #35Parameter changes

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 electrolyte material exhibits high safety and favorable ionic conductivity at room and low temperatures, effectively addressing the limitations of existing materials by maintaining conductivity even at temperatures where polyethylene glycols freeze.

Implementation Method 1

the electrolyte material exhibits high safety and favorable ionic conductivity at room and low temperatures

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 2

maintaining conductivity even at temperatures where polyethylene glycols freeze

Methodology Applied

Scientific EffectFreezing: Freezing

Data Source

PatentUS9065150B2Electrolyte material, and battery material and secondary battery using said electrolyte material

Publication Date: 2015.06.23 NIPPON SHOKUBAI CO LTD

AI summary

The present invention provides a stable electrolyte material that provides high safety, exhibits favorable ionic conductivity not only at room temperature but also in the low temperature range at or below room temperature, has excellent reduction resistance, and can be suitably used as a material of a lithium ion cell. The electrolyte material includes, as essential components, a specific polymer having an ether bond in a side chain thereof, and a specific electrolyte salt.