Non-Aqueous Electrolyte Composition for High-Temperature Battery Stability
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Solution Overview
Problem
Current non-aqueous electrolyte batteries face challenges in maintaining high-temperature storage characteristics and preventing capacity deterioration and gas generation due to secondary reactions between electrodes and electrolytes, despite previous attempts to improve battery performance through the use of isocyanate and cyano compounds.
Innovation Solution
Incorporating a compound with at least two isocyanate groups and a compound with at least two cyano groups in a specific ratio within the non-aqueous electrolyte solution, along with monofluorophosphate or difluorophosphate salts, to inhibit secondary reactions and enhance battery stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If isocyanate and cyano compounds are added to the electrolyte solution, then battery cycle characteristics are improved, but capacity deterioration and gas generation occur during high-temperature storage
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte by introducing fluorinated cyclic carbonate compounds with specific molecular structures and fluorine content ratios. This modifies the electrolyte's chemical properties to suppress secondary reactions at high temperatures while maintaining cycle characteristics, resolving the contradiction between reliability and harmful effects
Solution Approach 2:
The patent creates a composite electrolyte system by combining fluorinated cyclic carbonate compounds with conventional cyclic carbonate and chain carbonate solvents. This composite approach leverages the stabilizing effect of fluorinated compounds while maintaining the beneficial properties of traditional solvents, preventing both capacity deterioration and gas generation
2Ease of manufacture
If conventional electrolyte solutions are used, then manufacturing simplicity is maintained, but secondary reactions occur between electrodes and electrolyte reducing charge/discharge capacity
Solution Approach 1:
The patent modifies the electrolyte composition by incorporating fluorinated cyclic carbonate compounds with specific fluorine content (30-70% by mass) and molecular structures. This parameter change suppresses oxidative degradation at the positive electrode during high-voltage charging while maintaining ease of manufacturing through simple mixing processes
Solution Approach 2:
The fluorinated cyclic carbonate compound acts as an intermediary substance that forms protective films on the positive electrode surface. This intermediary layer prevents direct contact and harmful secondary reactions between the electrode and bulk electrolyte, thereby preserving charge/discharge capacity while maintaining manufacturing simplicity
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 effectively inhibits capacity deterioration and gas generation during high-temperature storage, providing excellent cycle characteristics and charge/discharge performance at high current densities.
Implementation Method 1
Incorporating a compound with at least two isocyanate groups and a compound with at least two cyano groups in a specific ratio within the non-aqueous electrolyte solution, along with monofluorophosphate or difluorophosphate salts, to inhibit secondary reactions
Implementation Method 2
The solution effectively inhibits capacity deterioration and gas generation during high-temperature storage
Data Source
AI summary
Disclosed herein is a non-aqueous electrolyte secondary battery containing at least a positive electrode capable of the absorbing and releasing of a lithium ion, a negative electrode capable of the absorbing and releasing of the lithium ion, and a non-aqueous electrolyte solution containing a non-aqueous solvent and an electrolyte dissolved in the non-aqueous solvent, wherethe negative electrode contains a carbonaceous material, andthe non-aqueous electrolyte solution contains, in addition to an electrolyte and a non-aqueous solvent:(A) a compound having at least two isocyanate groups per molecule,(B) a monofluorophosphate salt or a difluorophosphate salt, at from 0.001 mass % or more to 5 mass % or less in the non-aqueous electrolyte solution.