Nonlinear Kinetic Overpotential Deconvolution in Multi Ampere Hour Prismatic Cell Architectures
Deconvolution isolates activation, ohmic, and diffusion overpotentials, enabling exact boundary setting for fast charging without lithium plating risks.
Lithium Plating Window
Meaning
Operating boundaries define the range of temperature, state of charge, ambient pressure, and current density where metallic lithium deposits onto graphite anodes instead of intercalating. Beyond this operational threshold, the lithium plating window establishes the electrochemical boundary where the local anode potential falls below zero volts relative to the lithium reference electrode. This condition halts safe fast-charging protocols and shifts cell behavior toward accelerated capacity loss and potential thermal safety risks.
Anode Overpotential
Potential drops at the graphite interface occur when solid-phase diffusion rates fall behind incoming lithium flux. Polarization forces the thermodynamic potential below zero volts against reference metallic lithium.
Rate Threshold
High charge rates force rapid ion transport across the electrolyte, creating concentration gradients near the particle surface. Intercalation kinetics slow dramatically when solid solution limits are approached at high states of charge, diverting incoming current into metallic lithium deposition. Fast charging algorithms adjust current steps to keep local anode potential above zero volts throughout the charge sequence.
Prolonged exposure outside safe limits yields dendritic growths that penetrate separator membranes.
Thermal Influence
Temperature reductions decrease solid-state diffusion coefficients within active materials while increasing charge-transfer resistance across the solid electrolyte interphase. Sub-zero operation narrows acceptable charging currents to fractionally low levels.