Meaning
Voltage signature regions during discharge indicate the dissolution of metallic lithium that was inappropriately plated on the negative electrode during charge. This characteristic region occurs at a specific potential and can be identified on the voltage profile of a cell during diagnostic testing. The stripping plateau provides a direct electrochemical method to detect and quantify lithium plating.
Diagnostic Method
Differential voltage analysis is applied to discharge data to reveal the presence of this plateau by analyzing the peak positions. The length of this flat region correlates with the amount of reversible lithium metal deposited on the electrode surface. This technique allows non destructive monitoring of cell health during laboratory testing.
Plating Consequence
Plating of lithium occurs when the local potential of the negative electrode falls below the reference potential during fast charging. This plated metal can become isolated, forming inactive dead lithium, which reduces the overall capacity of the cell. Monitoring the plateau helps engineers adjust charge profiles to minimize this degradation.
System Safety
Uncontrolled lithium plating poses a risk of forming dendrites that can penetrate the separator and cause internal short circuits. Early detection through this voltage signature allows the battery management system to trigger protective actions before a safety hazard arises. This diagnostic tool is valuable for ensuring long term system safety.
