Electrolytic Solution Proton Scavenging for Battery Swelling

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Solution Overview

Problem

Lithium phosphate hexafluoride decomposition in secondary batteries leads to the elution of cobalt or manganese from the cathode, reducing battery characteristics such as charge and discharge efficiency, and causing swelling due to hydrofluoric acid generation, especially when moisture is present and the battery is stored at high temperatures.

Innovation Solution

Incorporating 4-fluoro-1,3-dioxolan-2-one and a nitrogen compound with proton scavenging capacity, such as hexaethylenetetramine, into the electrolytic solution to effectively scavenge free acids and prevent decomposition reactions, thereby improving battery characteristics and suppressing swelling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If 4-fluoro-1,3-dioxolan-2-one is used as a solvent in the electrolytic solution, then battery characteristics such as charge and discharge efficiency can be improved, but hydrofluoric acid is generated by hydrolysis when moisture is present, promoting decomposition reaction of the electrolytic solution and causing battery swelling

Engineering Contradiction:

Improvebattery characteristicsVSAvoidhydrofluoric acid generation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

A nitrogen compound with proton scavenging capacity is introduced as an intermediary substance that captures hydrofluoric acid generated by hydrolysis of 4-fluoro-1,3-dioxolan-2-one, preventing it from causing electrolytic solution decomposition and battery swelling while allowing the solvent to maintain its beneficial electrochemical properties

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The hydrofluoric acid generated by hydrolysis, which is normally a harmful byproduct causing decomposition and swelling, is converted into a beneficial situation by using the nitrogen compound to scavenge it, thereby preventing damage while maintaining the operational benefits of the fluorinated cyclic ester carbonate solvent

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Use of energy by moving object

If lithium phosphate hexafluoride is used as an electrolyte salt, then high energy density can be achieved, but decomposition occurs generating free acid that elutes cobalt or manganese from the cathode, lowering battery characteristics

Engineering Contradiction:

Improveenergy densityVSAvoidbattery characteristics

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The nitrogen compound acts as a mediator that scavenges free acids generated by decomposition of lithium phosphate hexafluoride, preventing elution of cobalt or manganese from the cathode while allowing the electrolyte salt to provide high energy density

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The free acid generated by decomposition, which normally causes harmful elution of cathode materials, is converted into a controlled situation where the nitrogen compound scavenges it, preventing damage to battery characteristics while maintaining the high energy density benefits

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 4-fluoro-1,3-dioxolan-2-one and a nitrogen compound with proton scavenging capacity in the electrolytic solution effectively prevents decomposition reactions, enhancing charge and discharge efficiency and reducing battery swelling, especially at high temperatures.

Implementation Method 1

a compound having proton scavenging capacity

Methodology Applied

Scientific EffectProton scavenging: Absorption (physical)

Implementation Method 2

when moisture is contained inside the battery, for example, in the case that 4-fluoro-1,3-dioxolan-2-one as one of such a cyclic ester carbonate is used, a hydrofluoric acid generated by hydrolysis promotes decomposition reaction of the electrolytic solution

Methodology Applied

Scientific EffectHydrolysis: Hydrolysis

Data Source

PatentUS8916291B2Electrolytic solution and battery

Publication Date: 2014.12.23 MURATA MFG CO LTD

AI summary

An electrolytic solution capable of suppressing the battery swollenness and improving the battery characteristics such as the charge and discharge efficiency and a battery using it are provided. A cathode (21) and an anode (22) are layered with an electrolyte layer (24) in between. The electrolyte layer (24) is gelatinous, containing the electrolytic solution and a polymer compound. The electrolytic solution contains a compound having proton scavenging capacity such as hexamethylenetetramine and hexaethylenetetramine. Thereby, a free acid such as hydrofluoric acid is scavenged, and decomposition reaction of the electrolytic solution or the like is prevented.