Hybrid Vehicle Propulsion Energy Storage System

A propulsion energy storage system in a hybrid electric vehicle, the propulsion energy storage system comprising:

• a first ultracapacitor pack assembly including a plurality of energy storage cells electrically coupled to each other, the energy storage cells each having a case and at least one terminal, the first ultracapacitor pack assembly configured support each energy storage cell by its respective case;
• plurality of terminal heat sinks thermally coupled to each terminal of the plurality of energy storage cells, the plurality of terminal heat sinks configured to transfer heat from its respective terminal to heat transfer fluid;
• a first housing configured to enclose the first ultracapacitor pack assembly and mount the first ultracapacitor pack assembly to the hybrid electric vehicle, the housing including a propulsion energy interface to configured to supply power to the hybrid electric vehicle;
• a first closed-loop cooling system configured to circulate heat transfer fluid in the housing, convectively transferring heat from the terminal heat sinks, and further configured to reject the transferred heat away from the ultracapacitor energy storage system;
• a communication interface to the hybrid electric vehicle, and,
• a controller configured to control cooling functions of the first closed-loop cooling system and/or electrical functions of the first ultracapacitor pack assembly.