Battery Electrolyte Additives for Overcharge and Heat Safety
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Solution Overview
Problem
Rechargeable lithium batteries face safety concerns due to rapid heat generation and gas production under overcharging and high temperature exposure conditions.
Innovation Solution
An electrolyte solution for rechargeable lithium batteries is developed, comprising a non-aqueous organic solvent, a lithium salt, and an additive that includes a sulfoxide-based compound and a nitrile-based compound with three or more cyano groups, which enhances the battery's stability and safety under overcharge and heat exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolyte solutions are used to achieve high ionic conductivity, then battery performance is improved, but safety deteriorates under overcharging and high temperature conditions
Solution Approach 1:
The patent modifies the chemical composition parameters of the electrolyte by introducing specific additives (sulfoxide compound and nitrile-based compound with three or more cyano groups) at controlled concentrations (0.01-5 wt% and 0.01-3 wt% respectively). These parameter changes alter the electrolyte's thermal and electrochemical properties to suppress heat generation and gas production while maintaining ionic conductivity.
Solution Approach 2:
The patent creates a composite electrolyte system by combining the base electrolyte (containing non-aqueous organic solvent and lithium salt) with two specific additive compounds. This composite approach integrates multiple functional components: the sulfoxide compound for thermal stability and the nitrile-based compound for overcharge protection, achieving synergistic safety improvement without sacrificing performance.
2Reliability
If electrolyte additives are added to improve safety, then resistance to heat and overcharge increases, but ionic conductivity may be reduced
Solution Approach 1:
The patent optimizes the concentration parameters of the additive compounds to achieve the right balance. By controlling the sulfoxide compound at 0.01-5 wt% and nitrile-based compound at 0.01-3 wt%, the electrolyte maintains sufficient ionic conductivity while gaining safety benefits. The specific concentration ranges are determined to minimize impact on ion transport.
Solution Approach 2:
The additive compounds perform localized protective functions: the sulfoxide compound primarily addresses thermal stability through its high boiling point and thermal decomposition characteristics, while the nitrile-based compound specifically targets overcharge conditions through its electrochemical stability. This localized functional distribution allows each component to protect against specific hazards without broadly impacting ionic conductivity.
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 proposed electrolyte solution effectively reduces the risk of battery explosion during overcharge and maintains safety under high temperature conditions, ensuring improved performance and reliability of rechargeable lithium batteries.
Implementation Method 1
the electrolyte solution plays a role in transferring lithium ions, and can exhibit significantly higher ionic conductivity by including organic solvents and lithium salts
Implementation Method 2
generate electrical energy through oxidation and reduction reactions when lithium ions are intercalated and deintercalated from the positive electrode and the negative electrode
Data Source
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AI summary
The electrolyte solution for a rechargeable lithium battery according to some example embodiments includes a non-aqueous organic solvent, a lithium salt, and an additive, wherein the additive includes a first compound and a second compound which is or includes a nitrile-based compound containing three or more cyano groups.