Estimation on the pulse power capability of high-power lithium-ion battery pack

To estimate the pulse power capability of high power lithium ion battery, an electrochemical model for lithium ion battery is developed firstly based on porous electrode and concentrated solution theory. With the model, the change in battery terminal voltage can be predicted according to the charge/discharge current and operation temperature of battery, and hence the maximum pulse discharge/charge power permitted by lithium ion battery pack at present state can be estimated. Then, for verifying the effectiveness of the model, the dynamic response process of terminal voltage in a 3.6V/8A·h lithium ion battery during 10s pulse charge/discharge with various current rates, and the acceptable 10s maximum pulse discharge/charge power of 144V/8A·h lithium ion battery pack under different SOCs and temperatures are measured on Arbin test bench. The results of tests show that when the pulse charge/discharge time exceeds 1s, the relative errors of the predicted terminal voltages are less than ±1% and the relative errors of the estimated maximum discharge/charge power of battery pack are less than ±3%. Finally, the effects of negative electrode porosity on the pulse power capability of battery pack are analyzed with the electrochemical model.