Carbonate-Ester Electrolyte for Fast-Charging Lithium Batteries
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lithium secondary batteries face safety risks such as fire and explosion due to their flammable nature, and challenges in fast charging, high interfacial resistance, and degradation of battery performance, particularly in medium to large batteries used in electric vehicles and energy storage systems.
Innovation Solution
A non-aqueous liquid electrolyte comprising a mixture of a linear carbonate-based solvent and a linear ester-based solvent, with specific lithium salts and additives, is used to enhance safety and fast charging capabilities, utilizing a nickel-rich NCM-based positive electrode active material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional liquid electrolyte is used, then fast charging capability is achieved, but safety risk increases due to fire and explosion hazards
Solution Approach 1:
The patent uses a composite electrolyte system combining linear carbonate solvent (DMC or DEC) with linear ester solvent (GBL or GVL) in specific ratios (70:30 to 90:10). This composite approach leverages the high ion conductivity of carbonates for fast charging while the esters provide flame retardancy and safety, resolving the contradiction between charging speed and safety.
Solution Approach 2:
The patent modifies the chemical composition parameters of the electrolyte by selecting specific linear carbonate and linear ester compounds with defined molecular structures and ratios. This parameter optimization enables the electrolyte to simultaneously achieve low viscosity for fast ion transport and high flash point for safety, preventing fire and explosion while maintaining fast charging capability.
2Object-affected harmful factors
If flame retardant additives are used to improve safety, then fire resistance increases, but battery performance degrades and cost increases
Solution Approach 1:
The patent changes the fundamental approach from adding flame retardant chemicals to selecting electrolyte solvents with inherently high flash points (GBL: 96°C, GVL: 204°C). This parameter selection in the base electrolyte composition provides fire resistance without the performance-degrading side effects of additives, maintaining capacity and cycle life while reducing cost.
3Object-affected harmful factors
If solid electrolyte is used to improve safety, then fire and explosion risk decreases, but interfacial resistance increases leading to poor charge-discharge performance
Solution Approach 1:
The patent employs a liquid electrolyte system (hydraulic approach) rather than solid electrolyte, enabling spontaneous flow and intimate contact with electrode surfaces. This liquid state ensures low interfacial resistance and high ion conductivity for excellent charge-discharge performance while the selected linear ester/carbonate composition provides inherent fire resistance, avoiding the safety-performance trade-off of solid electrolytes.
4Object-affected harmful factors
If all-solid-state battery is used to improve safety, then fire and explosion risk decreases, but manufacturing cost increases due to ultra-high voltage requirements
Solution Approach 1:
The patent adopts a liquid electrolyte system that can be easily manufactured and replaced using conventional battery production techniques, avoiding the ultra-high voltage equipment and complex processes required for all-solid-state batteries. The linear carbonate-ester electrolyte composition provides cost-effective safety improvement through simple compositional selection rather than expensive manufacturing infrastructure.
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 enables fast charging with reduced risk of fire and explosion, maintaining high battery performance, capacity retention, and extended lifetime, even under high charging speeds.
Implementation Method 1
a non-aqueous liquid electrolyte comprising a mixture of a linear carbonate-based solvent and a linear ester-based solvent
Implementation Method 2
a liquid electrolyte including: a lithium salt; a first solvent including a compound represented by Chemical Formula 1; and a second solvent including a compound represented by Chemical Formula 2
Data Source
AI summary
The present disclosure relates to an liquid electrolyte for fast charging of a lithium secondary battery, a lithium secondary battery including the same and a method for manufacturing a lithium secondary battery, and, by including an organic solvent including a linear carbonate-based solvent and a linear ester-based solvent, the liquid electrolyte is capable of improving fast charging properties and safety with no or little risk of thermal runaway, fire and explosion of a lithium secondary battery. In addition, battery properties such as capacity, a capacity retention and initial Coulombic efficiency of the lithium secondary battery, and battery lifetime are improved, fast charging of the battery is possible, and the battery lifetime may be improved even under a condition of high charging speed.