Nonaqueous Battery Electrolyte Composition for Low-Temperature Resistance
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Solution Overview
Problem
Nonaqueous electrolyte batteries using unsaturated bond-containing silicon compounds exhibit high internal resistance at low temperatures, which hinders improved input/output characteristics and cycle stability.
Innovation Solution
An electrolyte solution comprising a nonaqueous organic solvent, an ionic salt, and a silicon compound with unsaturated bonds and aromatic rings, along with a modified silicon compound obtained by replacing an ethenyl group with an ethyl group, is used to reduce the absolute value of resistance at low temperatures without compromising cycle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If unsaturated bond-containing silicon compounds are used as additives in nonaqueous electrolyte batteries, then cycle characteristics are improved, but internal resistance increases at low temperatures
Solution Approach 1:
The patent modifies the chemical structure of silicon compound additives by replacing vinyl groups with ethyl groups, changing the molecular parameters to reduce low-temperature resistance while maintaining cycle stability benefits
Solution Approach 2:
The patent combines modified silicon compounds with specific carbonate solvents and lithium salts to create a composite electrolyte system that achieves both low resistance at low temperatures and good cycle characteristics
2Power
If conventional electrolyte solutions are used, then high voltage and capacity are achieved, but cycle characteristics and output characteristics deteriorate
Solution Approach 1:
The patent introduces modified silicon compounds as intermediary substances that form stable interface films between electrodes and electrolyte, mediating the interaction to prevent degradation while maintaining high voltage operation
Solution Approach 2:
The patent changes the chemical composition parameters of the electrolyte by incorporating specific ratios of modified silicon compounds, linear carbonate, and cyclic carbonate to achieve optimal balance between power and reliability
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 solution effectively decreases the absolute value of resistance by more than 1% at -20°C without impairing cycle characteristics, enhancing the battery's low-temperature performance.
Implementation Method 1
when a lithium cation is inserted in the negative electrode during initial charging, a reaction occurs between the negative electrode and the lithium cation or between the negative electrode and the electrolyte solvent. As a result of the reaction, a coating film containing lithium oxide, lithium carbonate or lithium alkylcarbonate as a predominant component is formed on a surface of the negative electrode.
Implementation Method 2
Electrolyte solutions for lithium nonaqueous electrolyte batteries in which fluorine-containing electrolytes such as lithium hexafluorophosphate (hereinafter referred to as LiPF6), lithium bis(fluorosulfonyl)imide (hereinafter referred to as LiFSI) and lithium tetrafluoroborate (hereinafter referred to as LiBF4) as solutes are dissolved in solvents
Data Source
AI summary
An electrolyte solution for a nonaqueous electrolyte battery according to the present invention includes the following components: (I) a nonaqueous organic solvent; (II) an ionic salt as a solute; (III) at least one additive compound represented by the general formula (1); and (IV) at least one additive compound represented by the general formula (2), wherein the concentration of the component (IV) is 0.05 to 25.0 mass % with respect to 100 mass % of the component (III)where R1 are each independently a substituent group having at least one kind selected from unsaturated bond and aromatic ring.