Review of Energy Storage Technologies Applicable in Drones and Submarines

One of the main factors in designing drones and submarines is the appropriate choice of an electrical energy storage device as the energy source of their propulsion systems. This review paper addresses the energy storage technologies, whether battery or fuel cell, applicable in drone and submarine industries. Batteries are widely used in drones due to their lower weight and occupation space and can act as a primary or secondary power supply. Among various chemical compounds, lithium-ion and lithium polymer batteries are the most common battery technologies with a higher energy density. Although the energy density of fuel cells is much higher than that of batteries and increases flight endurance and altitude, they are not yet common in the drone industry due to the high price and volume. This feature of fuel cells has led to their usage as an energy source in the air-independent propulsion technology of submarines. Also, extreme temperature variations for drones can reduce the efficiency and lifetime of batteries and even fuel cells. Battery insulation is provided for temperature drop due to an increase in altitude, and heat management systems are provided for temperature increase due to high current flow.