DIRECT CURRENT SPECTROSCOPY (DCS) TECHNIQUE FOR IN-OPERANDO CELL DIAGNOSTICS AND ANISOTROPIC RESISTANCE MONITORING

A method of interrogating an electrochemical cell includes: applying a positive direct current to the electrochemical cell for a first time period, wherein the positive direct current is characterized by a first magnitude; applying a negative direct current to the electrochemical cell for a second time period, wherein the negative direct current is characterized by a second magnitude; wherein the first and second time periods have a combined duration of less than 2 seconds; wherein the second magnitude is equal to or within 50% of the first magnitude; recording cell resistance data of the electrochemical cell during each time period; and analyzing the cell resistance data to determine at least one of: (i) state of charge of the electrochemical cell; (ii) state of health of the electrochemical cell; and (iii) the resistance anisotropy of the cell.