US 10,534,038 B2 · Method and system for estimating state of charge or depth of discharge of battery, and method and system for evaluating health of battery

Abstract

It is intended to recognize the state of charge or depth of discharge of the battery more accurately than conventional technologies and to recognize health of a battery appropriately. Complex impedance between positive and negative electrodes of the battery is determined at a plurality of frequencies, and the state of charge or depth of discharge of the battery is estimated by comparing frequency dependency of Warburg impedance of the determined complex impedances with frequency dependency of Warburg impedance corresponding to a known state of charge or depth of discharge of the battery. Similarly, complex impedance is determined, and the health of the battery is evaluated by using the real part of the complex impedance at a point where the imaginary part of the complex impedance is zero on a line obtained by extending a part, which indicates frequency dependency of Warburg impedance, of a complex impedance characteristic curve representing a correlation relationship between the real and imaginary parts of the determined complex impedance.

Claims20

Dependent claims

A method for estimating a state of charge or depth of discharge of a battery of which the state of charge or depth of discharge is unknown, the method comprising:

measuring a voltage applied to the battery;
measuring a current flowing through the battery;
calculating, from the measured voltage and current, complex impedance between positive and negative electrodes of the battery corresponding to a frequency;
determining, based on respective complex impedances calculated corresponding to respective ones of a plurality of frequencies, frequency dependency of the complex impedance corresponding to the unknown state of charge or depth of discharge of the battery;
and
estimating the unknown state of charge or depth of discharge of the battery by comparing the frequency dependency of the complex impedance corresponding to the unknown state of charge or depth of discharge with frequency dependency of complex impedance determined in advance corresponding to a known state of charge or depth of discharge of the battery at a frequency range equal to or lower than approximately 100 mHz.

3 more elements

An apparatus for estimating a state of charge or a depth of discharge of a battery of which the state of charge or depth of discharge is unknown, the apparatus comprising:

a voltmeter configured to measure a voltage applied to the battery;
an ammeter configured to measure a current flowing through the battery;
and
a processor and a non-transitory memory, the processor configured to
calculate, from the measured voltage and current, complex impedance between positive and negative electrodes of the battery corresponding to a frequency;
determine, based on respective complex impedances calculated corresponding to respective ones of a plurality of frequencies, frequency dependency of the complex impedance corresponding to the unknown state of charge or depth of discharge of the battery;
and
estimate the unknown state of charge or depth of discharge of the battery by comparing the frequency dependency of the complex impedance corresponding to the unknown state of charge or depth of discharge with frequency dependency of complex impedance determined in advance and stored in the non-transitory memory corresponding to a known state of charge or depth of discharge of the battery at a frequency range equal to or lower than approximately 100 mHz.

5 more elements

Dependencies are inferred from the claim text.

Method and system for estimating state of charge or depth of discharge of battery, and method and system for evaluating health of battery

Life of this patent

Method and system for estimating state of charge or depth of discharge of battery, and method and system for evaluating health of battery

Life of this patent

Abstract

Claims20