Integration of pressure-tolerant lithium ion battery modules within the Mola Mola AUV

Battery aging coupled with additional loads placed on the power system of the Mola Mola AUV required that the original battery pack be replaced with a higher capacity system. A set of requirements were assembled to ensure the new pack would be electrically compatible, safe, and of appropriate configuration for AUV use. Pressure tolerant SeaSafe lithium ion modules, produced by the Southwest Electronic Energy Group, were selected for the new power system. Two of these modules connected in series produce a nominal 59 V and capacity of 1.6 kWh to provide adequate energy for the medium-sized AUV. A pressure-balanced oil-filled housing was built for the modules, along with interface electronics and connectors. The additional electronics are used to switch power to the vehicle, to allow connection to an external charger, and to direct serial communications from the batteries to either the vehicle or charging station.