Patent ID: 8680815

Claim:
Method for monitoring a lithium-ion battery cell, comprising: monitoring battery cell voltage and a corresponding charge capacity of the battery cell during an electric power event comprising one of an electric power charge event and an electric power discharge event; determining a measured charge-capacity-derivative by differentiating the charge capacity in relation to the corresponding battery cell voltage during the electric power event; comparing the measured charge-capacity-derivative with a preferred anode charge-capacity-derivative of an anode curve; comparing the measured charge-capacity-derivative with a preferred cathode charge-capacity-derivative of a cathode curve; determining a first state of health parameter of the battery cell corresponding to the comparison of the measured charge-capacity-derivative with the preferred anode charge-capacity-derivative of the anode curve; and determining a second state of health parameter of the battery cell corresponding to the comparison of the measured charge-capacity-derivative with the preferred cathode charge-capacity-derivative of the cathode curve.