Battery Electrolyte Additives for Low-Resistance, Low-Gas Cells
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Solution Overview
Problem
Conventional electrolyte solutions for lithium secondary batteries face challenges in improving output characteristics, especially at low temperatures, and suffer from gas generation and thickness increase issues at high temperatures due to poor additive properties, leading to degraded cycle characteristics and storage stability.
Innovation Solution
An electrolyte solution comprising an organic solvent, a lithium salt, a first additive with a specific cation-anion pair, and a second additive with a symmetrical structure and double bonds, which reduces discharge resistance and gas generation, and enhances high-temperature storage stability by forming a stable film on the cathode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional electrolyte solution additives are used, then output characteristics may be improved, but gas generation and thickness increase occur at high temperatures, degrading cycle characteristics and storage stability
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte solution by introducing a specific additive composition: a fluorinated cyclic carbonate compound (Formula 1) at 0.01-5 wt% and a chain carbonate compound with specific molecular weight (Formula 2) at 0.01-5 wt%. This parameter change resolves the contradiction by forming a stable SEI film that prevents gas generation while maintaining low-temperature ionic conductivity for good output characteristics
Solution Approach 2:
The patent uses a composite electrolyte solution system combining multiple components: fluorinated cyclic carbonate (Formula 1), chain carbonate (Formula 2), and conventional additives like VC and FEC. This composite approach creates synergistic effects where the fluorinated compound provides high-temperature stability while the chain carbonate ensures low-temperature performance, resolving the contradiction between power output and reliability
2Power
If electrolyte solution additive amount is increased to improve low-temperature output characteristics, then SEI film formation improves, but cathode surface decomposition and electrolyte oxidation occur during high temperature reaction
Solution Approach 1:
The patent precisely controls the concentration parameters of additives to resolve this contradiction. The fluorinated cyclic carbonate (Formula 1) is limited to 0.01-5 wt% and chain carbonate (Formula 2) to 0.01-5 wt%, creating an optimal balance where sufficient SEI film forms for low-temperature performance while preventing excessive decomposition at high temperatures
Solution Approach 2:
The patent applies local quality by using the fluorinated cyclic carbonate compound specifically to form a protective SEI film layer on the electrode surface. This localized protective layer improves low-temperature ionic conductivity while the controlled amount prevents widespread cathode decomposition and electrolyte oxidation during high-temperature operation
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 improves battery output, extends lifespan, and maintains high-temperature capacity retention by reducing internal resistance and gas generation, while preventing electrode decomposition and structural collapse, thus enhancing overall battery performance and stability.
Implementation Method 1
an electrolyte solution for batteries including electrolyte solution additives capable of improving battery output characteristics and high-temperature storage characteristics
Implementation Method 2
an electrolyte solution between a cathode and an anode enables smooth movement of lithium ions, and electricity is generated or used by oxidation-reduction reaction
Data Source
AI summary
The present invention relates to an electrolyte solution and a secondary battery including the same. According to the present invention, the present invention has an effect of providing a secondary battery having improved charging efficiency and output due to low discharge resistance and having a long lifespan and excellent high-temperature capacity retention by suppressing gas generation and increase in thickness.