Method and apparatus for predicting the available energy of a battery

A method of predicting the available energy of a battery comprising the steps of:

• determining the battery internal resistance (IR);
• measuring the battery open circuit voltage (OCV) and temperature (T);
• calculating the voltage d current points (Vgas and Igas) at which the battery transitions from one of a charge to overcharge or overcharge to charge state in response to at least one of battery charge and discharge, said step of calculating comprising
• applying to the battery a ramp of current (I) in each of the positive and negative directions;
• monitoring the voltage response (V) in response to the applied current (I),
• calculating the slope of the responses as dV/dI, and
• determining the maximum points (Vup and Iup) of Vgas and Igas of the slope on the positive current ramp at the transition from charge to overcharge and the maximum point (Vdn and Idn) on the negative ramp at the transition from overcharge to charge;
• and
• predicting the available energy on the basis of the parameters OCV, T, IR, Vup, Iup, Vdn, and Idn by developing an algorithm comprising the parameters OCT, T, IR, Vup, Iup, Vdn, and Idn, developing weighting factors for each of the parameters, acquiring for the battery under test numerical values of each of the parameters, and applying the acquired numerical values of the parameters to the algorithm.