Abstract: The disclosed technology is directed to a system for positively pressurizing a battery pack when the battery pack is submerged. In some embodiments, during a submersion event, a sensor detects a pressure inside the battery pack to generate a signal indicating the pressure inside the battery pack. The sensor then transmits the first signal to a pressure controller. The pressure controller adjusts the pressure inside the battery pack within a range based on the first signal to prevent ingress of liquid into the battery pack during the submersion event.