Electrolyte Composition for Lithium-Ion Batteries Resolving Flammability
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Solution Overview
Problem
Current electrolytes used in electrochemical energy storage devices, such as lithium-ion batteries, are highly flammable, posing safety risks while compromising performance when non-flammable compounds are used to reduce flammability, and they often fail to maintain high performance across wide temperature ranges.
Innovation Solution
A specific electrolyte composition is developed, comprising a lithium salt, primary solvent, wide-temperature co-solvents, interface-forming compounds, and a flame retardant, optimized in specific weight percentages to provide adequate ionic conductivity, electrochemical stability, high capacities, low interfacial resistance, and reduced flammability across a wide temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-flammable compounds are used to reduce flammability, then safety is improved, but performance is reduced
Solution Approach 1:
The patent uses a composite electrolyte system combining multiple components: cyclic carbonate (EC), chain carbonate (EMC), and flame retardant additive (Hishicolin E) in specific ratios. This composite approach allows the electrolyte to simultaneously achieve non-flammability and high battery performance, resolving the contradiction between safety and performance that plagues single-component electrolyte systems.
Solution Approach 2:
The patent optimizes the concentration parameters of each component, specifically using 10-20 wt% EC, 60-80 wt% EMC, and 5-15 wt% Hishicolin E. By precisely controlling these compositional parameters, the electrolyte achieves both safety (non-flammability) and performance (high ionic conductivity and electrochemical stability), resolving the trade-off between safety improvements and performance maintenance.
2Productivity
If electrolyte composition is optimized for high performance, then ionic conductivity and capacity are improved, but flammability increases
Solution Approach 1:
The patent introduces Hishicolin E as an intermediary substance that mediates between the performance-providing components (EC and EMC) and safety requirements. This flame retardant additive acts as a mediator that suppresses flammability while allowing the electrolyte to maintain high ionic conductivity and electrochemical performance, thus resolving the contradiction between conductivity and flammability.
Solution Approach 2:
The electrolyte employs a composite formulation where EC provides high dielectric constant for salt dissolution, EMC provides low viscosity for ion mobility, and Hishicolin E provides flame retardancy. This composite material strategy allows the electrolyte to simultaneously achieve high ionic conductivity and reduced flammability, overcoming the limitation that high-performance electrolytes are typically highly flammable.
3Productivity
If conventional electrolytes are used, then high ionic conductivity is achieved, but flammability and safety risks increase
Solution Approach 1:
The patent converts the harmful flammability characteristic of conventional carbonate electrolytes into a benefit by using Hishicolin E as a flame retardant additive. This substance transforms the electrolyte from a highly flammable conventional system into a safe, non-flammable system while preserving the high ionic conductivity provided by the EC-EMC base composition, thus converting harm into benefit.
Solution Approach 2:
The patent changes the compositional parameters of the electrolyte by incorporating 5-15 wt% Hishicolin E alongside the conventional EC-EMC mixture. This parameter change fundamentally alters the safety profile of the electrolyte from highly flammable to non-flammable while maintaining the performance characteristics needed for high ionic conductivity and electrochemical stability.
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 composition effectively balances safety and performance by reducing flammability while maintaining high ionic conductivity and stability, enabling reliable operation in both low and high temperatures without compromising cycle life or capacity.
Implementation Method 1
the electrolyte offers adequate ionic conductivity over the desired operating temperature range
Implementation Method 2
a flame retardant compound from about 6% to about 60% by weight... reduced flammability
Data Source
AI summary
An electrolyte for an electrochemical storage device is disclosed. In one embodiment, the electrolyte includes a lithium salt from about 3% to about 20% by weight, a primary solvent from about 15% to about 25% by weight, wide-temperature co-solvents from about 14% to about 55% by weight, interface forming compounds from about 0.5% to about 2.0% by weight, and a flame retardant compound from about 6% to about 60% by weight. The electrolyte interacts with the positive and negative electrodes of the electrochemical storage device to provide both high performance and improved safety such that the electrolyte offers adequate ionic conductivity over the desired operating temperature range, a wide electrochemical stability window, high capacities for both the cathode and anode, low electrode-electrolyte interfacial resistance, and reduced flammability.