LiBETA Electrolyte and Separator Design for Heat-Treated Li-Ion Cells
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Solution Overview
Problem
Lithium-ion secondary batteries face degradation of charging and discharging characteristics and safety concerns due to heat treatment, especially when integrated with electronic device housings, requiring enhanced heat resistance and flexibility.
Innovation Solution
A power storage device comprising a positive electrode, negative electrode, separator, and electrolytic solution with lithium bis(pentafluoroethanesulfonyl)amide (LiBETA) as the solute and a solvent mixture of propylene carbonate and ethylene carbonate, along with a separator made of polyphenylene sulfide or solvent-spun regenerated cellulosic fiber, to maintain stability and prevent degradation under high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a lithium-ion secondary battery is integrated with an electronic device housing, then the device achieves compact design and structural integration, but the battery suffers from heat treatment that degrades charging and discharging characteristics
Solution Approach 1:
The patent changes the chemical parameters of the electrolytic solution by using LiBETA as solute and a specific mixture of propylene carbonate and ethylene carbonate as solvents. This composition maintains stability under heat treatment conditions (80°C or higher), preventing degradation of charging and discharging characteristics while allowing integration with housing that requires heat treatment for manufacturing
Solution Approach 2:
The patent employs a composite electrolytic solution system combining multiple components (LiBETA solute with propylene carbonate and ethylene carbonate solvents) that work synergistically. This composite composition provides both heat resistance for integration compatibility and maintained electrochemical performance for reliable charging and discharging
2Ease of manufacture
If the battery undergoes heat treatment during manufacturing, then the housing achieves proper formation and bonding, but the battery's safety is compromised
Solution Approach 1:
The electrolytic solution composition is specifically designed to remain stable at manufacturing heat treatment temperatures (80°C or higher). The LiBETA-ethylene carbonate-propylene carbonate system prevents thermal runaway and decomposition reactions that would otherwise occur during housing formation processes, ensuring safety while allowing proper manufacturing
3Ease of manufacture
If the battery uses conventional electrolytic solution composition, then the manufacturing process is simple, but the charging and discharging characteristics are degraded by heat
Solution Approach 1:
The patent specifies precise compositional parameters for the electrolytic solution: LiBETA as solute with propylene carbonate and ethylene carbonate as solvents in specific proportions. This parameter-optimized composition provides heat resistance while maintaining ease of manufacture through standard electrolytic solution preparation 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 solution provides a power storage device with improved heat resistance, safety, and flexibility, ensuring that the charging and discharging characteristics are not degraded by heat treatment, and the device remains safe and functional across a wide temperature range.
Implementation Method 1
The electrolytic solution contains a solute and two or more kinds of solvents. The solute contains lithium bis(pentafluoroethanesulfonyl)amide (LiBETA). One of the solvents is propylene carbonate.
Implementation Method 2
The separator contains polyphenylene sulfide or solvent-spun regenerated cellulosic fiber. The separator is located between the positive electrode and the negative electrode.
Data Source
AI summary
To provide a power storage device whose charge and discharge characteristics are unlikely to be degraded by heat treatment. To provide a power storage device that is highly safe against heat treatment. The power storage device includes a positive electrode, a negative electrode, a separator, an electrolytic solution, and an exterior body. The separator is located between the positive electrode and the negative electrode. The separator contains polyphenylene sulfide or solvent-spun regenerated cellulosic fiber. The electrolytic solution contains a solute and two or more kinds of solvents. The solute contains LiBETA. One of the solvents is propylene carbonate.