Patent ID: 9588185
Date: 2017-03-07
CPC Classifications: G01R

Claim:
1. Apparatus for determining a physical property of an electrochemical cell or battery comprising: immittance measuring circuitry coupled to said cell or battery with a pair of current-carrying contacts and a separate pair of voltage-sensing contacts and adapted to apply time-varying electrical excitation to said cell or battery with said pair of current-carrying contacts, to sense time-varying electrical response to said excitation with said pair of voltage-sensing contacts, and to utilize said excitation and said response to measure components of complex immittance at n discrete frequencies, where n is a finite integer equal to or greater than two but less than a maximum value; computation circuitry responsive to said complex immittance components and adapted to evaluate elements of a 2n-element equivalent circuit model from said measured complex immittance components at said n discrete frequencies; whereas said immittance measuring circuitry is further adapted to utilize said excitation and said response to measure components of complex immittance at m additional discrete frequencies where m is a finite integer equal to or greater than one but less than a maximum value, wherein said computation circuitry is not adapted to evaluate elements of the 2n-element equivalent circuit model from said measured complex immittance components at said m discrete frequencies; and, whereas said computation circuitry is further adapted to calculate complex immittance components of said 2n-element equivalent circuit model at said m additional discrete frequencies, and adapted to mathematically compare said calculated immittance components with said measured immittance components at said m additional discrete frequencies to obtain comparison results, said comparison results being related to said physical property.