Patent ID: 8103485

Claim:
A method for determining an estimated state of charge value and an estimated cell resistance value associated with an electrochemical cell comprising: predicting a first cell resistance value indicating a present resistance of the electrochemical cell utilizing a first nonlinear cell model; predicting a first state of charge value indicating a present state of charge of the electrochemical cell utilizing a second nonlinear cell model; measuring a voltage associated with the electrochemical cell to obtain a voltage value; measuring a current associated with the electrochemical cell to obtain a current value; calculating a second state of charge value associated with the electrochemical cell, utilizing an inverse open circuit voltage function having a parameter determined from the voltage value and the current value; calculating the estimated state of charge value indicating the present state of charge of the electrochemical cell utilizing the second nonlinear cell model based on the first state of charge value, the second state of charge value, the first cell resistance value, the voltage value, and the current value; calculating the estimated cell resistance value indicating the present resistance of the electrochemical cell utilizing the first nonlinear cell model based on the first cell resistance value, the first state of charge value, the second state of charge value, the voltage value, and the current value, and storing the estimated state of charge value and the estimated cell resistance value in a storage medium.