Cyano-Group Electrolyte and Composite Separator for Overcharge Safety
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Solution Overview
Problem
Lithium ion batteries face safety hazards due to gas generation and heat buildup during overcharging, leading to potential thermal runaway, explosions, or fires, especially under high temperature conditions, while also requiring improved energy density and cycle performance.
Innovation Solution
The use of an electrolyte containing 2 to 3 cyano groups and a composite separator with specific inorganic particles and polymers, which together reduce electrolyte decomposition, suppress lithium ion transfer, and enhance the stability of the battery's interfacial membrane, thereby preventing thermal runaway and improving overcharging and hot box performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional electrolytes and separators are used, then battery capacity can be improved, but safety hazards occur due to gas generation and heat buildup during overcharging and high temperature conditions
Solution Approach 1:
The patent introduces a fluorinated cyclic carbonate compound as an intermediary substance in the electrolyte that mediates between the electrodes and the electrolyte system. This compound forms a protective interfacial membrane that prevents direct harmful interactions, thereby improving safety performance while maintaining battery capacity
Solution Approach 2:
The patent uses a composite electrolyte system combining fluorinated cyclic carbonate compound with other carbonate solvents and lithium salts. This composite material approach creates synergistic effects that simultaneously improve both battery capacity and safety performance, preventing thermal runaway and gas generation
2Use of energy by moving object
If battery energy density is increased, then power supply performance is improved, but thermal runaway risk increases under high temperature conditions
Solution Approach 1:
The patent converts the potential harmful effect of high energy density into a beneficial outcome by using the fluorinated cyclic carbonate compound to form a stable interfacial membrane. This membrane acts as a thermal barrier that prevents thermal runaway, thereby converting the high energy density advantage into improved safety performance under high temperature conditions
3Ease of manufacture
If conventional separators are used, then manufacturing simplicity is maintained, but overcharging and hot box performance are insufficient
Solution Approach 1:
The patent modifies the chemical composition parameters of the electrolyte by introducing fluorinated cyclic carbonate compound with specific molecular structure and fluorine content (0.1-5 wt%). This parameter change in the electrolyte composition enables improved overcharging and hot box performance while maintaining separator manufacturing simplicity
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 effectively prevents thermal runaway and enhances the battery's overcharging and hot box performance, while promoting energy density and cycle stability, as demonstrated by improved test results in overcharging, hot box, and cyclic tests.
Implementation Method 1
the electrolyte contains a compound with 2 to 3 cyano groups... which together reduce electrolyte decomposition, suppress lithium ion transfer, and enhance the stability of the battery's interfacial membrane
Data Source
AI summary
Provided are an electrochemical device comprising a separator and an electrolyte, wherein the separator comprises a first porous layer and a second porous layer; and the electrolyte comprises at least one compound containing 2 to 3 cyano groups.