Secondary Battery Electrolyte Viscosity and Heat Resistance
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Solution Overview
Problem
Secondary batteries, particularly lithium-ion batteries, face performance degradation due to increased viscosity of electrolyte solutions at low temperatures, leading to reduced conductivity and safety concerns in varying environmental conditions.
Innovation Solution
A nonaqueous solvent comprising an ionic liquid and an organic solvent, such as a fluorinated cyclic carbonate, is used, with the ionic liquid concentration between 50% to 95% by volume, ensuring high heat resistance and low viscosity, thereby maintaining conductivity and safety across a wide temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the viscosity of electrolyte solution is reduced to improve carrier ion conductivity at low temperatures, then conductivity is improved, but heat resistance and safety are compromised
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte solution by incorporating ionic liquids with specific molecular structures and adjusting their concentration ratios. This allows the solution to exhibit low viscosity at low temperatures for good conductivity while maintaining high heat resistance through the inherent thermal stability of ionic liquids
Solution Approach 2:
The patent creates a composite electrolyte system combining ionic liquids with traditional organic carbonates. The ionic liquid component provides low-temperature fluidity and high thermal stability, while the organic carbonate component enhances conductivity. This composite approach resolves the contradiction between low-temperature performance and heat resistance
2Ease of manufacture
If conventional electrolyte solutions are used to maintain simplicity and cost-effectiveness, then manufacturing is easier, but performance degrades at extreme temperatures
Solution Approach 1:
The patent modifies the electrolyte composition by incorporating ionic liquids at optimized concentrations, changing the physical and chemical parameters to achieve wide-temperature performance while maintaining compatibility with existing battery manufacturing processes
Solution Approach 2:
The ionic liquid acts as an intermediary substance that bridges the gap between conventional electrolytes and the requirements for extreme temperature performance. It mediates between the need for low viscosity and high heat resistance, providing a solution that works within existing manufacturing frameworks
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 solution provides a secondary battery with enhanced lithium ion conductivity and heat resistance, enabling stable performance from -40°C to 150°C, improving safety and extending the operational range of batteries in electric vehicles and electronic devices.
Implementation Method 1
adding an organic solvent to an ionic liquid enables a nonaqueous solvent to have low viscosity even at low temperatures
Implementation Method 2
low viscosity can lead to increased conductivity of the nonaqueous solvent, improving carrier ion conductivity such as lithium ion conductivity
Implementation Method 3
When containing an ionic liquid at greater than or equal to 50 vol %, a nonaqueous solvent can have high heat resistance
Data Source
AI summary
An object is to provide a nonaqueous solvent, a secondary battery, or a vehicle having a wide usable temperature range and high heat resistance. The nonaqueous solvent of the present invention contains an ionic liquid at greater than or equal to 50 vol % and less than or equal to 95 vol % and a fluorinated cyclic carbonate, and the ionic liquid contains an imidazolium cation. The nonaqueous solvent of the present invention has low viscosity at low temperatures and high heat resistance, thereby having a wide usable temperature range.