Estimation of battery equivalent circuit model parameters by decomposition of sense current and terminal voltage into subbands

A system for estimating equivalent circuit model parameters of a battery, comprising circuitry for measuring a battery voltage across terminals of the battery and a battery current drawn from the battery, wherein the circuitry comprises:

• a multi-rate filter bank comprising a plurality of decimators configured to decimate the battery voltage and battery current into a plurality of low-frequency signals, wherein the plurality of decimators are communicatively coupled to a plurality of filters configured to receive the plurality of low-frequency signals and generate a plurality of sub-bands, each sub-band of the plurality of sub-bands based on a time constant that characterizes a temporal behavior of the battery;
• a signal selector communicatively coupled to outputs of the plurality of filters and to inputs of a plurality of transform-resistor pairs, wherein the signal selector is configured to receive the plurality of sub-bands and select, for each transform-resistor pair, a sub-band based on an associated time constant, wherein the plurality of transform-resistor pairs are configured to estimate an equivalent resistance for each sub-band of the plurality of sub-bands based on a spectral content of the battery voltage and battery current for such sub-band;
• and
• an open circuit voltage tracking module configured to estimate an open circuit voltage of the battery based at least on the spectral content of the battery voltage and battery current present in one of the plurality of sub-bands and the equivalent resistances of the plurality of sub-bands.