Battery Cell Defect Screening via Silicon-Graphite Anode Voltage Peaks
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Solution Overview
Problem
Existing methods for detecting defects in secondary batteries require disassembly, leading to the discard of functional cells and potential safety risks due to undetected defects like lithium metal precipitation, which can cause fires.
Innovation Solution
A method and system for detecting defective cells by charging the cell within a specific state of charge range, analyzing differential voltage data of a silicon-graphite negative electrode, and determining defects based on charging parameters associated with electrolyte impregnation and silicon response peaks, allowing for non-destructive detection and potential re-formation of defective cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If disassembly methods are used to detect defects, then detection capability is improved, but cell integrity is lost and functional cells are discarded
Solution Approach 1:
The patent replaces mechanical disassembly with electrochemical measurement. By analyzing differential voltage characteristics during charging at specific SOC ranges (80-100%), the system detects lithium precipitation defects without physically opening the cell, thus maintaining cell integrity while achieving defect detection
Solution Approach 2:
The patent uses differential voltage data as an intermediary to indirectly detect defects. Instead of directly observing the negative electrode through disassembly, the system measures voltage differences during charging and uses these measurements to infer the presence of lithium precipitation, enabling non-destructive detection
2Measurement precision
If disassembly is performed to check negative electrode state, then detection accuracy is improved, but productivity decreases due to cell discard
Solution Approach 1:
The patent substitutes mechanical disassembly with electrochemical characterization. By measuring differential voltage during charging and analyzing specific voltage plateaus (0.05-0.15V range), the system achieves accurate negative electrode state detection while maintaining 100% cell utilization, thus improving productivity
Solution Approach 2:
The patent enables cells to self-diagnose their own state during the charging process. The differential voltage measurements are obtained during normal charging operations, allowing the cell to provide its own diagnostic information without requiring external disassembly or specialized testing equipment
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 reliable, non-destructive detection of defective cells, improving detection accuracy and enabling re-formation processes to stabilize anode materials, reducing the risk of fires and enhancing cell reliability.
Implementation Method 1
obtaining first charge data including differential voltage information of a negative electrode of the cell while the cell is being charged
Data Source
AI summary
The present disclosure provides a method for detecting a defective cell. The method may include: charging a cell in a manner that the state of charge (SOC) of the cell falls within a reference range, obtaining first charge data including differential voltage information of a negative electrode of the cell while the cell is being charged, where the negative electrode includes graphite and silicon, calculating a charging parameter associated with the silicon of the negative electrode based on the first charge data, and determining whether the cell is defective based on the charging parameter associated with the silicon.