For each robot, designers need to select an energy source.
In comparison, a good-performance Li-ion battery provides just 0.5 kWh/kg, and the specific energy of animal fat is almost twice as high (10.6 kWh/kg). Scaling up this solution could be groundbreaking for mobile robotics.
The energy density per KG is high and it probably is an all-solid-sated battery.
Scientific and industrial centers are conducting intensive research in the area of photovoltaics to power robots [25]. A small solar-powered walking robot has been presented [26]. A hybrid approach, where solar power is used to charge a rechargeable battery pack can be seen in humanoid robots such as ATLAS [25].
Interesting designs of a solar robot with wheels include Tertill [27] and Vitirover [28]. Wheeled robots are often used as Autonomous Mobile Robots (AMRs) [13]. These robots require a suitable onboard energy system that provides appropriate voltage, power, and capacity.
This depends on the technology and function required. AMRs have been equipped with advanced sensors for the perception system (digital camera, Lidar system, etc.). The AMR picker has been equipped with robotic arms with a gripper. AMRs also require a motion drive power supply.
Li-ion batteries have been used for most of these robots. Most AMRs are equipped with modern Li-ion batteries with a LiFePO4 cathode and a graphite anode. As the voltage of a single LiFePO4/graphite cell is ∼3.25 V, the batteries are used in a series-parallel [13] connection to achieve the necessary voltage and capacity. The operating voltage for AMR batteries can range from 12 to 96 V and the capacity can vary from 10 to 200 Ah. AMRs have specialized functions affecting total mass, sensory equipment, and power supply parameters. Selected examples are shown in the Table 1 for LiFePO4/graphite and Li-ion cells.
