Electro-Thermal Degradation Modeling for Fast-Charging Large-Format Prismatic Cells
Electro-thermal degradation modeling reveals that internal thermal gradients accelerate localized lithium plating and active inventory loss during fast charging.
Cyclic Degradation
Meaning
Physical and chemical wear occurs as an electrochemical cell transitions between charged and discharged states. Cyclic degradation results from the mechanical expansion and contraction of electrode materials as ions move in and out of their structure. This process is distinct from calendar aging, which happens even when the battery is not in use.
Material Stress
Repeated volume changes during each cycle cause microscopic cracks to form in the active particles. The accumulation of cyclic degradation leads to the loss of electrical contact and the consumption of the liquid electrolyte.
Performance Retention
Testing labs measure the number of cycles a unit can complete before its capacity falls to eighty percent of the original value. Because cyclic degradation is sensitive to temperature and depth of discharge, heavy usage in hot climates accelerates the decline. Maintaining a narrow state of charge window can slow down the rate of loss.
Capacity Fade
Reduction in available energy directly impacts the range of electric vehicles and the runtime of portable devices. Systematic tracking of cyclic degradation allows operators to plan for the eventual replacement of the battery pack. It is the primary metric for determining the economic value of a cell over its lifetime.