Non-Aqueous Battery Electrolyte Composition for Wide-Temperature Cycling
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Solution Overview
Problem
Existing non-aqueous electrolyte secondary batteries face challenges in maintaining cycle characteristics at both high and low temperatures, with existing solutions improving high-temperature performance but not low-temperature performance effectively.
Innovation Solution
The battery incorporates a liquid electrolyte composition that includes a lithium salt, methyl acetate, and dimethyl sulfone, with specific content ratios of methyl acetate (10% to 40% by mass) and dimethyl sulfone (0.1% to 5% by mass), which enhances both high-temperature and low-temperature cycle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing electrolyte additives are used to improve high-temperature cycle characteristics, then high-temperature performance is improved, but low-temperature cycle characteristics are not improved
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by introducing a specific sulfone compound (dimethyl sulfone) at optimized concentrations (0.1-5% by mass). This parameter change enables the electrolyte to exhibit improved performance across both high-temperature (45°C) and low-temperature (25°C) cycling conditions, resolving the contradiction between high-temperature and low-temperature adaptability
Solution Approach 2:
The patent creates a composite electrolyte system by combining multiple components: lithium salt, cyclic carbonate, chain carbonate, and the key additive dimethyl sulfone. This composite material approach synergistically improves both high-temperature cycle characteristics and low-temperature cycle characteristics, achieving versatility across temperature ranges that single-component additives cannot accomplish
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
This configuration achieves excellent cycle characteristics at both high (e.g., 45°C) and low (e.g., 25°C) temperatures, maintaining a high capacity retention ratio and suppressing side reactions that could increase internal resistance.
Implementation Method 1
it is considered that dimethyl sulfone has an action of forming a good quality film on the surface of the negative electrode active material alone or together with other liquid electrolyte components and suppressing excessive side reactions of the liquid electrolyte component
Implementation Method 2
Since methyl acetate contained in the solvent of the liquid electrolyte has a low viscosity, it has an action of suppressing an increase in viscosity of the liquid electrolyte under a low temperature
Implementation Method 3
the liquid electrolyte includes a lithium salt, methyl acetate, and dimethyl sulfone
Data Source
AI summary
A non-aqueous electrolyte secondary battery having a positive electrode, a separator, a negative electrode opposed to the positive electrode via the separator, and a liquid electrolyte wherein the liquid electrolyte includes a lithium salt, methyl acetate, and dimethyl sulfone. The content ratio of methyl acetate in the liquid electrolyte is 10% by mass to 40% by mass, and the content ratio of dimethyl sulfone in the liquid electrolyte is 0.1% by mass to 5% by mass.