Quantifying Localized Lithium Plating Onset via Differential Voltage Tracking
Differential voltage tracking identifies localized lithium plating onset by detecting subtle slope shifts during charge and characteristic dV/dt relaxation plateaus.
Solid State Diffusion Kinetics
Meaning
Ion transport rate behavior that governs how quickly lithium ions move through the crystal lattice of active materials during charging and discharging. In lithium-ion battery design, solid state diffusion kinetics determine the internal resistance and rate capability of both the anode and cathode materials. The kinetics are evaluated within the solid active particles and do not include the liquid electrolyte pathways.
Rate Capability
Slow diffusion of lithium within the active material grains leads to high concentration gradients and voltage losses at high current densities. When solid state diffusion kinetics are poor, the cell suffers from low capacity retention during fast-charging events. Developers overcome this by reducing the primary particle size to shorten the diffusion distances.
Temperature Impact
Diffusion rates decrease exponentially at sub-zero temperatures, which reduces the performance of the cell in cold climates. Sourcing teams analyze these thermal diffusion profiles to choose the right battery chemistry for varying climates.
Chemical Optimization
Modifying the crystal structure through doping or applying conductive coatings can improve the ion transport rates inside the solid particles. Sourcing teams use these diffusion measurements to evaluate if a supplier’s cathode material can meet the fast-charging targets of the automotive program. This kinetic assessment represents a key step in material sourcing.