Lithium Battery Electrolyte Additives Suppress Resistance

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Solution Overview

Problem

Lithium secondary batteries face issues with output retention and gas generation during high-temperature storage due to increased resistance, which existing electrolytes fail to adequately address.

Innovation Solution

A non-aqueous electrolyte for lithium secondary batteries is developed, comprising a non-aqueous organic solvent, a lithium salt, a first additive represented by Chemical Formulae 1 to 4, and a second additive being a cyclic sulfide-based compound, with a specific weight ratio of 0.2:1 to 10:1, effectively suppressing resistance increase and gas generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electrolytes are used in lithium secondary batteries, then the battery can operate, but resistance increases rapidly during high-temperature storage, deteriorating output retention

Engineering Contradiction:

Improveoutput retentionVSAvoidresistance increase during high-temperature storage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the chemical composition parameters of the electrolyte by introducing specific additives (cyclic carboxylate compounds and cyclic sulfide compounds) with defined molecular structures and ratios. These parameter changes suppress the resistance increase mechanism during high-temperature storage while maintaining ionic conductivity, thereby improving output retention without sacrificing battery operability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite electrolyte system by combining multiple components: conventional electrolyte base, cyclic carboxylate additive (first additive), and cyclic sulfide additive (second additive). This composite formulation synergistically addresses the resistance increase issue through the combined effects of the additives, which form protective films and suppress decomposition reactions that cause resistance growth

Inventive Principle:

Principle #40Composite materials

2Reliability

If conventional electrolytes are used in lithium secondary batteries, then the battery can operate, but gas generation occurs during high-temperature storage

Engineering Contradiction:

Improvestorage performanceVSAvoidgas generation during storage

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters by adding cyclic carboxylate and cyclic sulfide compounds in specific concentrations (0.01-5 wt% each). These parameter modifications suppress gas-generating side reactions during high-temperature storage through film formation and reaction inhibition mechanisms, reducing gas generation while preserving battery storage performance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts potentially harmful side reactions that cause gas generation into beneficial protective film formation. The cyclic carboxylate and cyclic sulfide additives undergo controlled reactions to form stable surface films on electrodes that prevent further decomposition and gas evolution, thereby transforming the harmful gas generation process into a protective mechanism

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 electrolyte improves output retention and reduces gas generation during high-temperature storage, enhancing the battery's cycle-life characteristics and storage performance.

Implementation Method 1

a first additive including a cyclic carboxylate compound and a second additive including a cyclic sulfide compound, in which a mixing ratio of the first cyclic additive and the second cyclic additive is 0.2:1 to 10:1

Methodology Applied

Scientific EffectFilm formation: Deposition (physical)

Implementation Method 2

capable of improving output retention due to an improved resistance increase rate during a high temperature storage of the lithium secondary battery, and may reduce a gas generation amount

Methodology Applied

Scientific EffectChemical absorption: Absorption (physical)

Data Source

PatentUS11557791B2Non-aqueous electrolyte for lithium secondary battery and lithium secondary battery comprising same

Publication Date: 2023.01.17 SAMSUNG SDI CO LTD

AI summary

The present invention relates to a non-aqueous electrolyte for a lithium secondary battery and a lithium secondary battery comprising the same, the non-aqueous electrolyte comprising a non-aqueous organic solvent, a lithium salt, a first additive including at least one of compounds represented by chemical formulas 1 to 4, and a second additive comprising a cyclic sulfide-based compound, wherein the mixing ratio of the first additive and the second additive is a weight ratio of 0.2:1 to 10:1.