HF Indicator Electrolyte for Visual Battery Defect Detection
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Solution Overview
Problem
Current methods for detecting hydrofluoric acid (HF) gas in lithium secondary batteries are inadequate, as they either fail to measure HF generated after battery assembly or provide inaccurate results due to reactions with titration reagents and moisture, leading to potential battery degradation and explosion risks.
Innovation Solution
A non-aqueous electrolyte solution containing a hydrofluoric acid indicator, such as pyrocatechol violet, which changes color upon exposure to HF, allowing visual confirmation of HF gas generation, integrated into a pouch-type lithium secondary battery with a transparent observation window for easy detection without disassembling the battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If acid-base titration method or concentration analysis method is used to detect HF before battery assembly, then HF concentration in electrolyte solution can be measured, but HF gas generated after battery assembly cannot be detected
Solution Approach 1:
The HF indicator is added to the electrolyte solution before battery assembly, enabling the system to be prepared in advance with detection capability. This preliminary action allows the indicator to be present and ready to detect HF gas generation after assembly, resolving the contradiction between early measurement and post-assembly detection.
Solution Approach 2:
The HF indicator acts as an intermediary substance that bridges the gap between electrolyte solution and HF gas detection. It remains in the electrolyte solution but responds to HF gas generation, enabling indirect detection of post-assembly HF production through color change without requiring direct access to the battery interior.
2Reliability
If LiBOB component is present in electrolyte solution, then battery performance is improved, but accurate HF concentration calculation becomes difficult due to reaction with water in titration reagent
Solution Approach 1:
The invention converts the harmful interference of LiBOB-water reaction into a beneficial detection mechanism. Instead of trying to eliminate the reaction that complicates titration, the HF indicator is used to directly detect HF gas generation, turning the problematic chemical environment into an opportunity for more accurate post-assembly HF detection that is unaffected by LiBOB presence.
3Measurement precision
If conventional detection methods are used, then HF concentration can be measured in electrolyte solution, but disassembly of battery is required for accurate measurement which increases complexity
Solution Approach 1:
The battery system performs self-diagnosis through the HF indicator embedded in the electrolyte solution. The indicator automatically detects and signals HF gas generation through color change visible through the transparent case, enabling the battery to monitor its own safety without external intervention or disassembly, thus resolving the contradiction between accurate measurement and operational simplicity.
4Reliability
If HF gas concentration increases to 150 ppm or more, then battery performance degradation occurs, but early detection and prevention become difficult
Solution Approach 1:
The HF indicator utilizes color change as a visual signal to detect HF gas concentration. The indicator changes color when exposed to HF gas, providing an immediate and easily observable warning before HF concentration reaches dangerous levels. This visual detection method significantly reduces the difficulty of early HF detection and enables timely preventive action to maintain battery safety.
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
Enables accurate and visual detection of excessive HF gas generation, facilitating defect detection in the production line and minimizing product defects by ensuring safe and reliable battery performance.
Implementation Method 1
A non-aqueous electrolyte solution containing a hydrofluoric acid indicator, such as pyrocatechol violet, which changes color upon exposure to HF
Data Source
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AI summary
A non-aqueous electrolyte solution and a lithium secondary battery including the same are disclosed herein. In some embodiments, a non-aqueous electrolyte solution includes an HF indicator, and a pouch-type lithium secondary battery includes the non-aqueous electrolyte solution in which defects generated during the preparation of the secondary battery may be easily detected because whether or not hydrofluoric acid is generated may be visually identified without disassembling a cell by including the non-aqueous electrolyte solution.