Lithium-Ion Battery Electrolyte for Lithium Plating Resistance
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Solution Overview
Problem
Lithium-ion batteries face issues with lithium precipitation during high-input operations, leading to reduced service life and safety risks such as short circuits and explosions.
Innovation Solution
A lithium-ion battery design with a negative electrode potential maintained between 0.09 V to 0.15 V (vs. Li+/Li) during 80% SOC charging, combined with a specific CB value of 1.1 to 1.8 and an electrolyte containing lithium bis(fluorosulfonyl)imide, enhances lithium precipitation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high input properties (high charging current) are used to improve charging speed and productivity, then the charging rate increases, but the negative electrode potential drops below 0 V causing lithium precipitation which reduces reliability and service life
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by incorporating lithium bis(fluorosulfonyl)imide (LiFSO2CF2CF3) and adjusting the ratio of cyclic carbonate to chain carbonate solvents. These parameter changes modify the electrolyte's electrochemical properties to widen the potential window and prevent lithium precipitation during high-rate charging
Solution Approach 2:
The patent uses a composite electrolyte system combining multiple lithium salts (lithium bis(fluorosulfonyl)imide and lithium hexafluorophosphate) with a mixed solvent system (cyclic carbonates and chain carbonates). This composite approach creates synergistic effects that enhance both the stability window and ionic conductivity, enabling high-rate charging without lithium precipitation
2Power
If high input properties are used to improve power density, then energy delivery capability increases, but service life is significantly shortened due to lithium precipitation and safety issues
Solution Approach 1:
The patent modifies the electrolyte's physical and chemical parameters including viscosity, ionic conductivity, and electrochemical stability window by selecting specific solvent ratios and lithium salt concentrations. These parameter optimizations enable the battery to sustain high power density operations over extended periods without degradation
Solution Approach 2:
The patent applies beforehand cushioning by pre-forming a stable solid electrolyte interface (SEI) layer through the specialized electrolyte composition. This protective interface forms during initial cycles and prevents subsequent lithium precipitation during high-power operations, cushioning against service life reduction
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 significantly reduces lithium precipitation risk, improves stability, and maintains high energy and power density during high-rate charging and discharging.
Implementation Method 1
an electrolyte... When the lithium-ion battery is charged at 1C to a state of charge of 80% SOC, a potential Panode of a negative electrode satisfies: 0.09 V (vs. Li+/Li)
Implementation Method 2
lithium-ion battery includes: a positive electrode plate, a negative electrode plate, a separator, and an electrolyte
Data Source
AI summary
A lithium-ion battery and an electric apparatus are disclosed. The lithium-ion battery includes: a positive electrode plate, a negative electrode plate, a separator, and an electrolyte. The separator is located between the positive electrode plate and the negative electrode plate. When the lithium-ion battery is charged at 1C to a state of charge of 80% SOC, a potential Panode of a negative electrode satisfies: 0.09 V (vs. Li+/Li)<Panode<0.15 V (vs. Li+/Li).