Lithium Ion Battery Electrolyte Additives for Low Temperature Power
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Solution Overview
Problem
Lithium ion batteries face performance issues at low temperatures due to increased electrolyte viscosity, decreased ionic conductivity, and reduced lithium ion diffusion, while conventional additives improve low temperature performance but compromise high temperature stability.
Innovation Solution
Incorporating specific additives such as lithium carbonate, silicon-containing compounds, and boron-containing materials into the electrolyte formulation to enhance the solid electrolyte interphase (SEI) layer, improving both low temperature power and high temperature stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If solvents with very low melting points and low viscosity are added to improve low temperature performance, then power capability at low temperature is improved, but high temperature stability deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by introducing specific additive salts (carbonates, perchlorates, hexafluorophosphates, oxalates, and nitrates) that modify the properties of the base electrolyte. These additive salts alter the viscosity and ionic conductivity characteristics across different temperature ranges, enabling improved low temperature power capability while maintaining high temperature stability through controlled parameter modification rather than extreme solvent selection
Solution Approach 2:
The patent creates a composite electrolyte system by combining the base electrolyte (containing lithium salt and organic solvent) with specific additive salts. This composite formulation synergistically combines the benefits of the base electrolyte with the unique properties of each additive salt class, achieving both low temperature performance improvement and high temperature stability preservation that cannot be obtained with single-component modifications
2Reliability
If conventional electrolyte formulations are used, then high temperature stability is maintained, but low temperature power capability deteriorates
Solution Approach 1:
The additive salts perform preliminary action by modifying the electrolyte properties before the battery operates at low temperatures. The presence of these additive salts pre-conditioned the electrolyte to have lower viscosity and higher ionic conductivity at low temperatures, while the SEI layer modification prepared in advance protects against high temperature degradation during subsequent operation
Solution Approach 2:
The patent modifies the electrolyte composition parameters by adding specific concentrations of additive salts (0.01-5 wt% each) to the base electrolyte. This parameter change transforms the electrolyte's temperature-dependent properties, shifting the viscosity-temperature curve and ionic conductivity-temperature curve to achieve better low temperature performance while preserving high temperature characteristics
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 additives improve low temperature performance without significantly diminishing high temperature stability, achieving wide operating temperature performance by forming a thinner, more thermally stable SEI layer.
Implementation Method 1
enhance the solid electrolyte interphase (SEI) layer, improving both low temperature power and high temperature stability
Implementation Method 2
an increase in viscosity of the electrolyte resulting in slower lithium ion diffusion
Data Source
AI summary
Electrolyte solutions including additives or combinations of additives that provide low temperature performance and high temperature stability in lithium ion battery cells.