At present, most commercially available electric unmanned vehicles use lead acid or lithium ion batteries. In spite of battery technologies are progressing rapidly, the use of hybrid systems to store electrical energy, combining two or more technologies, is considered today as an interesting option for power systems in unmanned vehicles.
Hybrid power systems, combining two or more technologies for energy storage and power generation, have become commercial in automotive, combining internal combustion engines with battery-powered electric motors. Similar concept can be applied to unmanned vehicles with electric propulsion
The joint use of fuel cells with batteries is taking an increasing role in unmanned mobile platforms.
The main potential benefits of hybrid power systems with fuel cells, if compared with pure battery power systems, are that they can achieve a higher specific energy and energy density, while provide redundancy in power supply, reduce the possibility of failure, improve energy efficiency and offer the possibility to use different fuels to feed the fuel cell (hydrogen, methanol, LPG, etc.).
Typically, fuel cells and batteries are arranged in parallel, with or without DC/DC converters.
General configuration of a hybrid power system with fuel cell
Unmanned platforms in the project
The project will evaluate the technical feasibility of hybrid power systems, based on batteries and fuel cells, in existing unmanned vehicles. The performance of these hybrid power systems will be compared with the currently obtained from pure battery power systems, in terms of availability of energy and power, duration of missions and operating range, weight and volume, reliability and lifetime, etc.
The proposed hybrid power systems are designed and developed according to the specifications of three existing unmanned platforms, an undewater vehicle (AUV) and two ground vehicles (UGVs). These power systems will be integrated and evaluated in real operating conditions.