Electrolyte Additives for Battery Low-Temperature Output and High-Temperature Stability
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Solution Overview
Problem
Non-aqueous electrolyte batteries face challenges in achieving satisfactory low-temperature output characteristics, high-temperature cycle characteristics, and high-temperature storage characteristics, particularly due to increased internal resistance and reduced discharge voltage at low temperatures, and insufficient performance at high temperatures when using silane compounds with Si—F or Si—O bonds.
Innovation Solution
A non-aqueous electrolyte battery electrolyte solution containing a specific silane compound and a fluorine-containing compound with a fluorophosphoryl or fluorosulfonyl structure, which together form a stable film on electrodes to enhance ionic conductivity and durability, improving low-temperature output and high-temperature cycle and storage characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If vinylene carbonate is added to improve high-temperature characteristic, then high-temperature characteristic is improved, but internal resistance is significantly increased to lower low-temperature characteristic
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte additive by using a specific silane compound (formula 1) with controlled hydrolyzable groups and unsaturated bonds, rather than conventional vinylene carbonate. This parameter change allows formation of a stable protective film that does not significantly increase internal resistance, thus improving high-temperature characteristic without sacrificing low-temperature performance.
Solution Approach 2:
The patent creates a composite protective film on electrodes through the synergistic interaction of the silane compound (formula 1) and the fluorine-containing compound (formula 2). This composite film structure combines the benefits of both compounds: the silane provides structural stability and the fluorine-containing group enhances ionic conductivity, resulting in a film that improves high-temperature characteristic while maintaining low internal resistance for good low-temperature performance.
2Duration of action of stationary object
If silane compound with Si—F or Si—O bond is used to improve cycle characteristic, then cycle characteristic is improved, but internal resistance becomes extremely high to greatly reduce output characteristic
Solution Approach 1:
The patent modifies the silane compound structure by introducing a fluorine-containing group with specific structure (formula 2) instead of using conventional Si—F or Si—O bonded silanes. This structural parameter change reduces the electronegativity and steric hindrance, allowing the compound to form a protective film with lower resistance, thus improving cycle characteristic while maintaining high output characteristic.
Solution Approach 2:
The fluorine-containing compound (formula 2) acts as an intermediary that mediates between the silane compound and the electrode surface. It facilitates the formation of a balanced protective film that provides both cycle stability and adequate ionic conductivity, preventing the extremely high internal resistance that would otherwise occur with conventional silane compounds.
3Reliability
If conventional electrolyte additives are used to suppress decomposition, then decomposition is suppressed, but low-temperature output characteristic and high-temperature cycle characteristic remain insufficient
Solution Approach 1:
The patent employs a composite additive system consisting of the silane compound (formula 1) and fluorine-containing compound (formula 2) that work synergistically. The silane component forms a stable protective framework that suppresses decomposition, while the fluorine-containing component enhances ionic conductivity and adapts to both low-temperature and high-temperature conditions, achieving comprehensive performance improvement across different temperature ranges.
Solution Approach 2:
The patent applies local quality by designing the silane compound with specific functional groups at different positions: the hydrolyzable group (a) provides decomposition suppression, the unsaturated bond (R1) contributes to film stability, and the alkyl group (R2) with fluorine atoms enhances ionic conductivity. This localized functional distribution allows the single compound to address multiple performance requirements simultaneously.
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 combination of the silane and fluorine-containing compounds in the electrolyte solution results in a battery with improved average discharge voltage at low temperatures and enhanced cycle and storage characteristics at high temperatures, effectively addressing the limitations of existing solutions.
Implementation Method 1
a non-aqueous electrolyte battery can exert an excellent low-temperature characteristic, a high-temperature cycle characteristic, and a high-temperature storage characteristic, when a non-aqueous electrolyte solution for a non-aqueous electrolyte battery containing a non-aqueous solvent and a solute contains (1) a specific silane compound and (2) at least one compound selected from the group consisting of a fluorine-containing compound having a specific structure
Data Source
AI summary
The present invention provides an electrolyte solution for a non-aqueous electrolyte battery capable of an exerting high average discharge voltage and an excellent low-temperature output characteristic at −30° C. or lower and an excellent cycle characteristic and an excellent storage characteristic at high temperatures of 50° C. or higher, as well as a non-aqueous electrolyte battery containing the same. The present electrolyte solution comprises a non-aqueous solvent, a solute, at least one silane compound represented by the following general formula (1) as a first compound, and a fluorine-containing compound represented by the following general formula (3), for example, as a second compound.Si(R1)a(R2)4-a (1)