Fluorinated Electrolyte for Lithium Ion Battery Gas Suppression
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Solution Overview
Problem
Lithium ion secondary batteries face issues with gas generation and deteriorated cycle characteristics due to reactions between diols or monoalcohols in high permittivity or low viscosity solvents and fluorine-containing electrolytes at room temperature, which affect battery performance over time.
Innovation Solution
An electrolyte solution containing a specific fluorine-containing acyclic carbonate and fluorine-containing maleic anhydride is used, with the solvent comprising between 0.001 and 90 vol% of the acyclic carbonate and 0.001 to 20 mass% of the maleic anhydride, along with a lithium salt, to suppress gas generation and enhance high-temperature storage characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If diols or monoalcohols are contained in high permittivity solvents or low viscosity solvents, then the battery has good initial performance, but gas is generated over time which deteriorates cycle characteristics
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by introducing fluorine-containing cyclic carbonate compounds with specific molecular structures and ratios. This modifies the electrolyte's chemical stability while maintaining its electrical properties, thereby suppressing gas generation and improving cycle characteristics without sacrificing initial performance
Solution Approach 2:
The patent creates a composite electrolyte system by combining fluorine-containing cyclic carbonate compounds with specific non-aqueous solvents in defined proportions. This composite approach leverages the beneficial properties of each component - the fluorine-containing compound provides stability and gas suppression, while the non-aqueous solvents maintain conductivity and performance
2Reliability
If conventional electrolyte compositions are used, then the battery achieves adequate performance, but high-temperature storage characteristics are poor
Solution Approach 1:
The patent modifies the electrolyte's thermal stability by incorporating fluorine-containing cyclic carbonate compounds with specific structural parameters (ring size, fluorine substitution positions). These parameter changes increase the decomposition temperature and reduce thermal reactivity, thereby improving high-temperature storage characteristics while preventing electrolyte decomposition
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 effectively reduces gas generation and improves high-temperature storage characteristics of lithium ion secondary batteries, leading to more stable and efficient battery performance.
Implementation Method 1
Use of this electrolyte solution minimizes decomposition of the electrolyte solution contained in a non-aqueous electrolyte secondary battery
Implementation Method 2
diols or monoalcohols contained in a high permittivity solvent (e.g., ethylene carbonate) or a low viscosity solvent (e.g., dimethyl carbonate) gradually react with a fluorine-containing electrolyte at room temperature to generate hydrogen fluoride (HF) gas
Data Source
AI summary
Provided is an electrolyte solution for secondary batteries that are less likely to generate gas and excellent in high-temperature storage characteristics; an electrochemical device using the electrolyte solution; and a module using the electrochemical device. The electrolyte solution contains a solvent and an electrolyte salt, the solvent containing a fluorine-containing acyclic carbonate represented by the formula (1) and a fluorine-containing maleic anhydride represented by the formula (2). The electrolyte solution contains not less than 0.001 mass % but less than 90 vol % of the fluorine-containing acyclic carbonate, and the electrolyte solution contains 0.001 to 20 mass % of the fluorine-containing maleic anhydride.