Determining the state of-charge of batteries via selective sampling of extrapolated open circuit voltage

摘要

A method for estimating the state-of-charge of a battery. The method includes collecting a plurality of voltage measurements during operation of the system containing the battery and determining a time-constant of relaxation and an open-circuit voltage corresponding to the battery based, at least in part, on the voltage measurements. The method further includes estimating the state-of-charge of the battery based, at least in part, on the open-circuit voltage.

主权项

1. A method of determining a state-of-charge of a battery within a system powered at least in part by the battery comprising:
collecting a plurality of voltage measurements from the battery during operation of the system; deriving a time-constant of relaxation and an open-circuit voltage corresponding to the battery from the voltage measurements and a mathematical model of the battery that relates the voltage measurements to the open-circuit voltage and the time-constant of relaxation; and, estimating the state-of-charge of the battery based, at least in part, on the open-circuit voltage; wherein the mathematical model comprises a closed mathematical expression that includes the open-circuit voltage and the time-constant of relaxation; and, wherein the closed mathematical expression is of the form: V(t)=OCV−αet/τ, wherein V(t) is one of the voltage measurements at a given point in time, OCV is the open-circuit voltage, α is an overpotential, and τ is the time-constant of relaxation.