Active Battery Management System with Physics Based Life Modeling Topology

Robust Data Acquisition on flight applications enables Researchers to rapidly advance technology. Distributed Electric Propulsion (DEP) and Hybrid Electric architectures rely heavily on batteries to achieve fuel efficiency and reduced CO2 emissions. DEP Aircraft of the future have demands for Energy Storage Systems with large counts of cells put in series and parallel to achieve needed voltage and energy levels. The X57 Maxwell Battery comprises of over 6000 cells. As the pack goes through repeated charge/discharge cycles, as well as environmental cycles, each individual cell begins to lose its capacity. Advanced high energy density chemistries (>300Wh kg) are particularly vulnerable. Cell to cell capacity variation causes the entire pack to be limited by the weakest cell. Traditional Passive Balancing topologies are limited in their ability to address cell mismatch on the discharge cycle. Active balancing allows a dynamic measurement & control system to discharge cells at variable rates. With a more robust measurement & control architecture, Active topologies have the ability to integrate more advanced algorithms. These algorithms include predictive health monitoring, life based management, physics based cell modelling. Batteries can last longer, avoid thermal runaway, and avoid maintenance. EPS is proposing development of an active BMS concept, with associated algorithms to achieve a 40% life improvement on the X57.