Overcharging Preventive Electrolyte Additives for Lithium-Ion Batteries

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Solution Overview

Problem

Current lithium-ion batteries face safety issues due to overcharging, over-discharging, and overheating, which can lead to burning or explosion, and existing overcharging preventive electrolytes either damage cycle performance or have limited applications due to low oxidation potential and compatibility issues with cathodic active materials.

Innovation Solution

An overcharging preventive electrolyte comprising a lithium salt, a non-aqueous organic solvent, and a combined additive A and B, where additive B forms a protective film on the positive electrode through chelation and additive A forms a complementary film through electrochemical polymerization, enhancing stability and preventing overcharging without affecting cycle performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electro-polymerization type additives (such as biphenyl and cyclohexylbenzene) are used to inhibit battery overcharging, then overcharging protection is improved, but cycle performance is damaged

Engineering Contradiction:

Improveovercharging protectionVSAvoidcycle performance

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent combines two types of additives (electro-polymerization type and REDOX type) into a single electrolyte formulation. The electro-polymerization additive provides overcharging protection by forming a protective film at high potentials, while the REDOX additive provides reversible protection at lower potentials. This combination allows the system to achieve both overcharging protection and maintained cycle performance, as the two additives work synergistically to protect the battery at different voltage ranges without the drawbacks of using either additive alone.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If REDOX type additives (such as ferrocene and anisyl benzene) are used for reversible overcharging protection, then overcharging protection mechanism is improved, but application scope is limited due to low oxidation potential

Engineering Contradiction:

Improvereversible overcharging protectionVSAvoidapplication scope

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent creates a multi-functional electrolyte additive system that can protect different types of cathode materials (including low-potential materials like graphite and metal lithium, as well as high-potential materials). The combined additive system with adjustable oxidation potentials can adapt to various battery chemistries and voltage ranges, making it universally applicable across different lithium-ion battery systems rather than being limited to specific applications.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Stability of the object's composition

If nitrile compounds (such as glutaronitrile and adiponitrile) are used as electrolyte solvents, then electrochemical window is improved, but compatibility with low-potential cathodic active materials is poor

Engineering Contradiction:

Improveelectrochemical windowVSAvoidcompatibility with cathodic active materials

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent introduces a combination of additives that act as intermediaries between the nitrile compound solvent and the cathodic active materials. These additives form protective films on the electrode surfaces, mediating the interaction between the nitrile solvent and low-potential materials like graphite and metal lithium. This prevents direct harmful reactions while maintaining the benefits of the wide electrochemical window provided by the nitrile compounds.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 combined additives provide excellent synergistic action, preventing overcharging while maintaining the cycle performance of lithium-ion batteries, with improved stability and endurance, and compatibility with low-potential cathodic active materials.

Implementation Method 1

additive B forms a protective film on the positive electrode through chelation

Methodology Applied

Scientific EffectChelation:

Implementation Method 2

additive A forms a complementary film through electrochemical polymerization

Methodology Applied

Scientific EffectElectrochemical polymerization:

Data Source

PatentUS10243236B2Overcharging preventive electrolyte and lithium-ion battery

Publication Date: 2019.03.26 CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED

AI summary

The present disclosure provides an overcharging preventive electrolyte and a lithium-ion battery. The overcharging preventive electrolyte can improve the safety performance of a lithium-ion battery without affecting the cycle performance thereof. The overcharging preventive electrolyte comprises a lithium salt, a non-aqueous organic solvent, and a combined additive including an additive A and an additive B. The additive A is at least one selected from Formula 1, Formula 2, and Formula 3; the additive B is at least one selected from Formula 4, Formula 5, and Formula 6.