Lithium Battery Electrolyte Additives for High-Temperature Safety
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rechargeable lithium batteries face safety issues due to high energy density, particularly at high temperatures, with existing flame retardants compromising battery performance.
Innovation Solution
An electrolyte composition for lithium batteries incorporating a non-aqueous organic solvent, lithium salt, and specific additives, including a phosphazene-based compound and a second compound that forms a solid electrolyte interface, enhances thermal stability and reduces gas generation and internal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flame retardant additives are used to improve battery safety, then thermal stability and penetration stability are improved, but battery performance deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the additive by specifying particular compounds (cyclic carboxylic acid with specific molecular weight range of 100-500, and cyclic carbonate with specific structural formulas). By controlling the molecular weight and chemical structure parameters, the patent achieves both safety improvement and performance preservation, resolving the contradiction between using flame retardants and maintaining battery performance.
Solution Approach 2:
The patent uses a composite additive system consisting of two specific components: cyclic carboxylic acid and cyclic carbonate in defined proportions (0.1-5.0 wt% and 0.1-5.0 wt% respectively). This composite approach allows the synergistic effects of both compounds to provide flame retardancy while maintaining electrochemical performance, thus resolving the contradiction between safety and performance.
2Use of energy by moving object
If high energy density is achieved to improve battery capacity, then energy density per unit weight increases, but safety problems emerge at high temperatures
Solution Approach 1:
The patent introduces cyclic carboxylic acid and cyclic carbonate as intermediary substances that mediate between the high energy density requirements and thermal stability needs. These compounds act as protective intermediaries by forming stable SEI films on electrodes and providing flame retardancy, allowing the battery to maintain high energy density while improving thermal stability through the intermediary action of these additives.
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 composition improves high-temperature safety by suppressing gas generation and internal resistance increase, maintaining battery performance and safety.
Implementation Method 1
the electrolyte uses an organic solvent in which a lithium salt is dissolved
Implementation Method 2
a positive electrode including a positive electrode active material capable of intercalating/deintercalating lithium ions and a negative electrode including a negative electrode active material capable of intercalating/deintercalating lithium ions
Implementation Method 3
a second compound represented by Chemical Formula 2... which forms a solid electrolyte interface
Data Source
AI summary
Provided are an electrolyte for a rechargeable lithium battery and a rechargeable lithium battery including same, the electrolyte including a nonaqueous organic solvent, a lithium salt, and an additive, wherein the additive is a composition comprising a first compound represented by Chemical Formula 1 and a second compound represented by Chemical Formula 2.The details of Chemical Formulas 1 and 2 are as set forth in the specification.