UAVs deployed in Iraq and Afghanistan to provide air reconnaissance are sensitive military assets that contain sophisticated and proprietary technology. Due to their financial and tactical value, precautions were taken to protect these assets from the risk of an uncontrolled crash landing caused by a catastrophic engine failure.
In the event of a catastrophic power failure, the UAVs are equipped with a battery-powered emergency recovery system (ERS) that takes control of the guidance system and enables the unmanned aircraft to glide a safe landing: a ‘smart’ solution that can save taxpayer dollars and help prevent sensitive technology from falling into enemy hands.
The emergency recovery system is powered by a custom battery pack and enclosure consisting of 96 AA-size TLM Series lithium metal oxide batteries, resulting in a highly compact power supply that is capable of delivering 32V/480W of power yet weighs just 2 Kg, including the metal enclosure. This small, lightweight power supply serves to improve the aircraft’s aerodynamics while creating added space to maximize the payload of surveillance equipment. By contrast, an equivalent battery pack made with D-size primary lithium batteries would have been far larger and heavier.
Constructed with a carbon-based anode, a multi metal oxide cathode, organic electrolyte, and a shut-down separator, lithium metal oxide cells feature an extremely high energy-to-size ratio. For instance, a AA-size lithium metal oxide cell can deliver up to 2 Wh of energy with a nominal voltage of 4V and a discharge capacity of 1,100 mAh, including the ability to generate 15A pulses and 5A continuous current.
Lithium metal oxide batteries deliver long-term reliability, including up to 20-year storage life due to a very low annual self-discharge rate (less than 1% per year). These powerful little cells can also withstand extreme temperatures (-40°C to 85°C), and comply with MIL-STD 810G specs for vibration, shock, temperature, salt fog, altitude, acceleration (50,000 gn), and spinning (30,000 rpm). These military grade batteries also meet UN 60086 standards for crush, impact, nail penetration, heat, over-charge, and short circuit.
High power lithium metal oxide batteries offer significant performance advantages over reserve/thermal batteries, a legacy battery technology that has had remained virtually unchanged for decades, and which requires the use of squibs and layers of thermal insulation. Lithium metal oxide batteries offer a more flexible, off-the-shelf, COTS-priced solution for single-use military applications such as ordinance fuses, smart munitions, and missile guidance systems. Lithium metal oxide batteries are also ideal for use in GPS tracking, emergency/safety devices, automatic external defibrillators (AEDs), and surgical power tools.