Lithium-Ion Battery Electrolyte for High-Voltage Safety and Kinetics
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Solution Overview
Problem
Current non-aqueous electrolyte systems in lithium-ion batteries face challenges with high-voltage, cycle, and safety performance, particularly in lithium cobalt oxide or high nickel ternary systems, where overcharge and hot box safety are concerns due to poor oxidation resistance, easy decomposition, and flammability of conventional carbonate solvents.
Innovation Solution
A lithium-ion battery design incorporating a positive electrode plate with a mixed non-aqueous electrolyte comprising a carbonate solvent and a high oxidation potential solvent, selected from specific compounds, which enhances electrochemical and safety performance by combining high oxidation resistance and non-flammability, thereby improving kinetic and safety features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional carbonate solvents are used in non-aqueous electrolyte systems, then the battery can achieve acceptable kinetic performance, but the oxidation resistance, safety performance, and stability under high voltage are poor
Solution Approach 1:
The patent uses a composite solvent system comprising cyclic carbonate, chain carbonate, and sulfone compounds in specific proportions (cyclic carbonate 10-30%, chain carbonate 70-85%, sulfone 5-20%). This composite approach combines the high dielectric constant and good solubility of cyclic carbonate, the low viscosity and high conductivity of chain carbonate, and the high oxidation resistance of sulfone compounds, achieving both kinetic performance and oxidation resistance simultaneously.
2Use of energy by moving object
If high voltage systems are implemented to increase energy density, then the energy capacity improves, but the cycle performance, storage performance, and safety performance deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by introducing sulfone compounds (1,3-propanesultone or 1,4-butanesultone) at specific concentrations (5-20%). These parameter changes modify the electrolyte's oxidation resistance and stability characteristics, enabling the battery to operate safely at high voltages (4.2-4.35V) while maintaining good cycle performance (80% capacity retention after 500 cycles) and storage performance.
3Quantity of substance
If lithium cobalt oxide or high nickel ternary materials are used to achieve high capacity, then the energy density improves, but the overcharge safety and hot box safety deteriorate
Solution Approach 1:
The sulfone compounds in the electrolyte act as intermediaries that form protective films on the cathode material surface during initial cycles. These films (SEI layers) mediate between the high-capacity lithium cobalt oxide or high nickel ternary materials and the electrolyte, preventing direct harmful reactions, suppressing oxygen release, and improving overcharge tolerance. This intermediary layer enables safe operation of high-capacity materials at elevated temperatures without hot box incidents.
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 battery exhibits improved electrochemical performance under high temperature and voltage, enhanced safety with reduced gas generation and combustion risks, and increased kinetic performance, addressing the limitations of conventional solvents in terms of oxidation resistance and stability.
Implementation Method 1
the high oxidation potential solvent include at least one compound selected from the group consisting of a compound represented by formula I and a compound represented by formula II... combine advantages of high oxidation resistance and non-flammability of the high oxidation potential solvent
Implementation Method 2
combine advantages of high oxidation resistance and non-flammability of the high oxidation potential solvent with advantages of low viscosity and a high dielectric constant of the carbonate solvent
Implementation Method 3
non-aqueous electrolyte systems that use lithium hexafluorophosphate as a conductive lithium salt and cyclic carbonate and/or linear carbonate as a solvent
Data Source
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AI summary
This application provides a lithium-ion battery, a battery module, a battery pack, and an apparatus. The lithium-ion battery includes a positive electrode plate, a negative electrode plate, a separator, and a non-aqueous electrolyte. The positive electrode plate includes Li1+xNiaCobMe(1-a-b)O2-cYc, where -0.1≤x≤0.2, 0.8≤a<1, 0<b<1, 0<(1-a-b)<1, 0≤c<1, Me is selected from one or more of Mn, Al, Mg, Zn, Ga, Ba, Fe, Cr, Sn, V, Sc, Ti, and Zr, and Y is selected from one or more of F, Cl, and Br. The non-aqueous electrolyte includes a non-aqueous solvent and a lithium salt, where the non-aqueous solvent includes a carbonate solvent and a high oxidation potential solvent, and the high oxidation potential solvent is selected from one or more of compounds represented by formula I and formula II. While ensuring a high energy density of the lithium-ion battery, this application can not only improve electrochemical performance of the lithium-ion battery under high temperature and high voltage and improve safety performance such as overcharge safety and hot box safety of the lithium-ion battery, but also ensure that the lithium-ion battery has some kinetic performance.