Batteries store energy through chemical reactions. Charging and discharging involves ions moving between electrodes and undergoing electrochemical reactions to store/release energy. Supercapacitors store energy electrostatically – as an electric charge directly on the surface of the electrode material, with no chemical reaction involved.

Hybrid systems differ quite a bit across race series, in energy storage technology, how much power they add, who controls deployment, and the underlying philosophy (efficiency vs. raw overtaking boost).