Statistics

Mathematical analysis

Physics

Nonlinear system

Voltage

Computer science

Endocrinology

Quantum mechanics

Mathematics

Electrical engineering

Equivalent circuit

Polynomial

Flexibility (engineering)

Control theory (sociology)

State (computer science)

Medicine

Thermodynamics

Algorithm

Control (management)

Battery (electricity)

Engineering

Artificial intelligence

Power (physics)

State of charge

State of health

Lithium (medication)

Open-circuit voltage

Journal of Power Sources

An open circuit voltage-based model for state-of-health estimation of lithium-ion batteries is proposed and validated in this work. It describes the open circuit voltage as a function of the state-of-charge by a polynomial of high degree, with a lumped thermal model to account for the effect of temperature. When applied for practical use, the model requires a prior learning from the initial charging or discharging data for the sake of parameter identification, using e.g. a nonlinear least squares method, but it is undemanding to implement. The study shows that the model is able to estimate the state-of-health of a LiFePO4 cell cycled under conditions where the temperature has fluctuated significantly with a relative error less than 0.45% at most. A short part of a constant current profile is enough for state-of-health estimation, and the effect of size and location of voltage window on the model's accuracy is also studied. In particular, the reason of accuracy change with different voltage windows is explaine...

An open circuit voltage-based model for state-of-health estimation of lithium-ion batteries: Model development and validation