Rechargeable Lithium Battery Electrolyte for Overcharge Heat Control
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Solution Overview
Problem
Rechargeable lithium batteries face safety concerns due to rapid heat generation and gas production during overcharging and high-temperature exposure, which can lead to cell explosions.
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 another compound represented by Chemical Formula 2, which stabilizes the lithium salt and reduces gas generation at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolyte solutions are used to enable lithium ion transfer and maintain battery performance, then ionic conductivity and battery capacity are improved, but safety deteriorates under overcharging and high-temperature conditions due to rapid heat generation and gas production
Solution Approach 1:
The patent introduces a fluorinated cyclic carbonate compound as an intermediary substance in the electrolyte solution. This compound acts as a mediator between the lithium salt and the cyclic carbonate, forming a stable interfacial layer that prevents direct harmful interactions. The fluorinated compound specifically mediates the interaction at the electrode-electrolyte interface, reducing heat generation and suppressing gas production while maintaining ionic conductivity for lithium ion transfer.
Solution Approach 2:
The patent creates a composite electrolyte system by combining multiple components: lithium salt, cyclic carbonate, chain carbonate, and fluorinated cyclic carbonate compound. This composite formulation synergistically combines the high ionic conductivity of conventional electrolytes with the thermal stability and gas suppression properties of the fluorinated additive, achieving both performance and safety improvements simultaneously.
2Quantity of substance
If organic solvents and lithium salts are included to achieve high ionic conductivity, then battery capacity and energy density are improved, but thermal stability deteriorates under high-temperature exposure
Solution Approach 1:
The patent modifies the chemical parameters of the electrolyte by introducing a fluorinated cyclic carbonate compound with specific molecular structure (Formula 1). The fluorine substitution and cyclic carbonate structure create a compound with altered electrochemical window and thermal decomposition characteristics. This parameter change enables the electrolyte to maintain ionic conductivity at operating temperatures while resisting thermal decomposition at elevated temperatures, thus improving thermal stability without sacrificing 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 electrolyte solution enhances the safety and stability of rechargeable lithium batteries under overcharge and heat exposure conditions, effectively preventing thermal runaway and maintaining battery performance.
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
AI summary
An electrolyte solution for a rechargeable lithium battery includes a non-aqueous organic solvent, a lithium salt; and an additive, wherein the additive includes a first compound and a second compound.