Cross-linked Aromatic Separator for Flow Battery

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Solution Overview

Problem

Lithium ion conductive inorganic solid electrolytes used in nonaqueous flow batteries lack flexibility, leading to cracks and poor mechanical strength, and flexible high molecular weight solid electrolytes are prone to swelling, which degrades charge/discharge characteristics.

Innovation Solution

A flow battery design featuring a separator with a high molecular weight lithium ion conductor containing cross-linked main chains with aromatic rings and sulfo groups, which maintains mechanical strength and prevents swelling, allowing for efficient lithium ion conduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If lithium ion conductive inorganic solid electrolyte is used, then mechanical strength is improved, but flexibility deteriorates causing cracks

Engineering Contradiction:

Improvemechanical strengthVSAvoidflexibility

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The patent uses a composite material consisting of inorganic solid electrolyte particles dispersed in a flexible polymer matrix. This composite structure combines the high mechanical strength and thermal stability of inorganic particles with the flexibility and crack resistance of the polymer matrix, resolving the contradiction between strength and flexibility.

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If flexible high molecular weight solid electrolyte is used, then flexibility is improved, but swelling occurs degrading charge/discharge characteristics

Engineering Contradiction:

ImproveflexibilityVSAvoidcharge/discharge characteristics

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The flexible polymer matrix is combined with inorganic solid electrolyte particles to create a composite that maintains flexibility while the inorganic particles provide dimensional stability and prevent excessive swelling, thereby preserving charge/discharge characteristics.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The composite electrolyte membrane has a porous structure that allows controlled ion transport while the inorganic particles provide structural support that prevents uncontrolled swelling of the polymer matrix, maintaining both flexibility and reliability.

Inventive Principle:

Principle #31Porous materials

3Temperature

If inorganic solid electrolyte is used, then thermal stability is improved, but cracks develop reducing reliability

Engineering Contradiction:

Improvethermal stabilityVSAvoidcrack resistance

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The inorganic solid electrolyte particles provide thermal stability while the flexible polymer matrix absorbs thermal expansion stresses and prevents crack formation, creating a composite that maintains reliability at elevated temperatures.

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 enables a flow battery with increased charge capacity, rapid charge/discharge rates, and improved mechanical strength, maintaining charge/discharge characteristics over time without electrolyte swelling.

Implementation Method 1

The lithium ion conductor contains a compound including main chains. At least one main chain of the main chains includes one or more aromatic rings and is cross-linked to at least another main chain of the main chains. At least one aromatic ring of the one or more aromatic rings includes one or more sulfo groups.

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 2

The separator contains a lithium ion conductor. The lithium ion conductor contains a compound including main chains. At least one main chain of the main chains includes one or more aromatic rings and is cross-linked to at least another main chain of the main chains.

Methodology Applied

Scientific EffectPhysical containment: Physical Containment

Data Source

PatentUS10985425B2Flow battery containing lithium ion conductor

Publication Date: 2021.04.20 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A flow battery includes: a first liquid containing a first nonaqueous solvent; a first electrode that is at least partly immersed in the first liquid; a second electrode which is a counter electrode to the first electrode; and a separator isolating the first electrode from the second electrode. The separator contains a lithium ion conductor. The lithium ion conductor contains a compound including main chains. At least one main chain of the main chains includes one or more aromatic rings and is cross-linked to at least another main chain of the main chains. At least one aromatic ring of the one or more aromatic rings includes one or more sulfo groups.