Lithium ion battery is generally used as energy storage device in spacecraft and other applications. Spacecraft battery modeling and energy balance estimation is critical. Energy balance is the measure of change back of the battery after discharge, with available charge power and time as constraints.

The proposed talk covers two models for energy balance. The first one, energy balance (EB) model for spacecraft application uses cell open circuit voltage (OCV) characteristics, internal resistance characteristics and coulomb counting. The cell characteristics are obtained by off-line tests. For series-parallel or parallel-series configured battery, the model estimates energy balance.

EB model is improved as GAGE-EB model (Genetic Algorithm based Generic Estimation - Energy Balance) which estimates deliverable capacity and internal resistance by accurately matching the terminal voltage of the model with measured voltage. Estimated parameters are used to check the energy balance for new load and generation profiles. The GAGE-EB model is validated for electrical performance with various cell types and battery configurations with respect to experimental data and is within 1% and 2% accuracy for voltage and capacity