Electrolyte solution and secondary battery comprising the same
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Solution Overview
Problem
Conventional electrolyte solutions for lithium secondary batteries face challenges in improving output characteristics, high-temperature storage stability, and reducing thickness increase rates due to poor additive properties, leading to decomposition of the cathode surface and oxidation of the electrolyte solution, which degrades cycle characteristics and storage stability.
Innovation Solution
An electrolyte solution comprising an organic solvent, a lithium salt, a phosphorus-based cesium salt, and specific additives represented by Chemical Formulas 1 and 2, which form a stable film on the electrodes, reducing decomposition and gas generation, and improving ion mobility and molecular structure stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional electrolyte solution additives are used, then battery output characteristics may be improved, but high-temperature storage stability deteriorates due to decomposition of cathode surface and oxidation of electrolyte solution
Solution Approach 1:
The patent uses a composite additive system comprising multiple compounds (cyclic carbonate, chain carbonate, and fluorinated cyclic carbonate) in specific weight ratios (93:7:0.1 to 97:3:0.01) to achieve synergistic effects that simultaneously improve output characteristics and high-temperature storage stability, preventing both cathode decomposition and electrolyte oxidation
Solution Approach 2:
The patent optimizes the weight ratios of different additive components and controls the total additive content (0.1-5 wt%) to achieve the desired balance between power output and storage stability, particularly by adjusting the fluorinated cyclic carbonate content to form stable SEI films that resist high-temperature degradation
2Power
If electrolyte solution additive is added to improve output characteristics, then discharge resistance may be reduced, but thickness increase rate worsens due to gas generation and electrode expansion
Solution Approach 1:
The fluorinated cyclic carbonate compound acts as an intermediary that forms a stable protective film on the electrode surface, mediating between the electrolyte and electrode to prevent direct harmful reactions that cause gas generation and thickness increase, while still allowing efficient ion transport for low discharge resistance
3Reliability
If electrolyte solution additive is used to improve cycle characteristics, then storage stability may be enhanced, but manufacturing complexity increases due to precise additive ratio requirements
Solution Approach 1:
The patent assigns specific functional roles to each additive component: cyclic carbonate for SEI film formation, chain carbonate for electrolyte solvation, and fluorinated cyclic carbonate for high-temperature stability enhancement. This localized functional assignment simplifies the formulation approach by clearly defining the purpose of each component while maintaining the required performance
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 enhances battery output by reducing discharge resistance, extends high-temperature storage capacity, and maintains structural integrity, thereby increasing the battery's lifespan and stability.
Implementation Method 1
specific additives represented by Chemical Formulas 1 and 2, which form a stable film on the electrodes
Implementation Method 2
an electrolyte solution between a cathode and an anode enables smooth movement of lithium ions
Implementation Method 3
electricity is generated or used by oxidation-reduction reaction according to intercalation and desorption at the cathode and the anode
Implementation Method 4
the secondary battery can have improved output due to reduced discharge resistance
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 rate by suppressing increase in thickness.