Meaning
Performance degradation observed when a battery cell cannot maintain its voltage under high current demands indicates a shift in internal resistance or ion transport efficiency. Rate capability loss is the decrease in the available capacity of an energy storage device as the discharge rate increases from a low current to a high current.
Capacity Retention
Energy delivery is compromised when a system requires fast power but fails to provide the total stored charge. This rate capability loss usually stems from slow lithium ion diffusion within the electrodes or high charge transfer resistance at the electrolyte interface.
Thermal Impact
High power operation accelerates the aging process due to ohmic heating. When a cell experiences rate capability loss, the internal temperature increases, which further damages the binder and the active material particles.
Kinetic Limitation
Reaction speed governs the rate at which electrochemical processes can proceed during a cycle. Designers measure rate capability loss by comparing the discharge curves at 0.1C and 5C rates to determine the power density limits of the material. A high degree of loss suggests that the electrode thickness or the particle size is too large for fast charging applications, requiring a redesign of the cell chemistry or the manufacturing process for the electrode coating.
