Non-Aqueous Electrolyte Additives for Battery Capacity Consistency
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Solution Overview
Problem
The inconsistency of battery parameters, particularly capacity, impedance, and electrical characteristics, in lithium-ion battery packs affects their service life and usability, especially in large-scale applications.
Innovation Solution
A non-aqueous electrolyte solution containing a bicyclic sulfate compound and a bicyclic sulfite compound is used to improve the high-temperature storage, low-temperature discharge, and capacity consistency of secondary batteries by forming a solid electrolyte interface (SEI) film and repairing any damage to it.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If battery structure and formation process are improved to enhance consistency, then battery consistency is improved, but capacity consistency cannot be improved
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte by introducing a specific bicyclic sulfate compound with particular molecular structure (Formula 1) and controlled purity (95-99.9%). This parameter change in the electrolyte composition directly improves capacity consistency without requiring structural modifications to the battery, resolving the limitation of prior approaches that could not improve capacity consistency through structure or process alone
Solution Approach 2:
The bicyclic sulfate compound acts as an intermediary substance that mediates between the electrolyte and electrode surfaces. It forms a protective interface layer that stabilizes electrochemical reactions, thereby improving capacity consistency. This intermediary approach allows improvement of capacity consistency without changing battery structure or formation processes
2Temperature
If battery structure is modified to reduce costs and increase heat dissipation area, then heat dissipation is improved, but capacity consistency remains unaffected
Solution Approach 1:
The patent segments the solution approach by addressing heat dissipation and capacity consistency through independent means: battery structure modifications for heat dissipation, and electrolyte composition optimization for capacity consistency. This allows both requirements to be satisfied without compromise, as the electrolyte compound works independently of thermal management structure
3Manufacturing precision
If grading process is applied to electrode sheets to improve consistency, then manufacturing consistency is improved, but capacity consistency cannot be improved
Solution Approach 1:
The patent replaces mechanical/process-based consistency improvement methods (electrode sheet grading) with a chemical solution (bicyclic sulfate compound in electrolyte). This chemical approach directly addresses capacity consistency at the molecular level, overcoming the limitations of mechanical sorting and processing methods
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 proposed solution significantly enhances the capacity performance and consistency of secondary batteries, while maintaining or improving high-temperature storage and low-temperature discharge performance, thus addressing the issue of battery parameter inconsistency.
Implementation Method 1
the bicyclic sulfate compound can form a solid electrolyte interface (SEI) film on a negative electrode to protect the battery electrode
Implementation Method 2
the small amount of bicyclic sulfite compound can be oxidized into a bicyclic sulfate compound during the battery electrochemical process, which can repair the rough or damaged SEI film
Implementation Method 3
the introduced sulfur element can increase the ionic conductivity and significantly reduce the impedance of the battery
Data Source
AI summary
The present application relates to the technical field of batteries. Disclosed are a non-aqueous electrolyte solution and a secondary battery. The non-aqueous electrolyte solution includes a bicyclic sulfate compound and a bicyclic sulfite compound; and a content of the bicyclic sulfite compound in the non-aqueous electrolyte solution is 1 ppm to 500 ppm, based on a total mass of the non-aqueous electrolyte solution.