What Battery Energy Density is Required for Long-Distance Electric Aircraft?

Birds inspired us to develop aircrafts capable of flight. Before the Wright brothers mastered sustained and controlled heavier-than-air powered flight in 1903, other pioneers in aviation such as Richard Pearse, William Frost, and Gustave Whitehead had attempted several tests and trials. Aircraft technology continued to grow with superior models of fighters, commercial jets, supersonic aircraft, etc., to offer the best lift to drag ratio for large payloads and high efficiency. Over time, the release of greenhouse gases from these fuel-powered jets and aircraft began accumulating in the stratosphere, shrinking the ozone layer, and depleting our fossil fuel reserves. According to the Environment Protection Agency (EPA), global aviation is expected to generate 43 metric gigatons of CO2 by 2050; this necessitates that we shift to alternate sources of energy to fly, and one such source could be batteries.

Batteries are a collection of cells that convert the chemical reactions occurring inside the cell to create a flow of electrons to power electrical devices. Lithium-Ion batteries were the best we had until the Japanese National Institute for Material Science developed lithium-air batteries, with an energy density of over 500Wh/kg, which is almost double that of Tesla batteries, i.e., 260Wh/kg, and the best among the batteries on the market. Battery energy limitations dictate that electric planes are usually designed for domestic travel and as private jets, accommodating few passengers. However, this next generation of Li-Air battery can operate at room temperatures, is lightweight, and delivers high capacity for long-haul flights. 

Big technology companies and research organizations are on a hunt to find battery technologies that are sustainable and can power anything from handheld PSPs to something as big as a commercial airplane. Aligned to this motive, a team of engineers at the University of Texas in Austin has been successful in creating sodium-sulfur dendrite-free stable batteries exhibiting a performance of 300 life cycles. Though their charge-discharge cycles are lower than the widely used Li-Ion batteries (300 to 500 charge-discharge cycles), they have the potential to be an alternative energy source as sodium and sulfur are abundantly available, cheaper, and cleaner. These batteries are currently being tested to boost the energy density for large power requirements.

To keep our planes flying and to act responsibly in times of global climate change, we must transition to new sources of energy. Until there are any further developments on the performance of sodium-sulfur batteries, lithium-air batteries seem to be the best option, with their high energy density (500Wh/kg), compactness, ability to operate at ambient temperatures, and reduced release of greenhouse gases (GHGs). With the team planning to experiment on new materials for enhanced Li-Air battery cycle life, we are eager to see if the study will use Computational Fluid Dynamics.

CFD can help extend aircraft battery range in other ways too. Read how propellers can be used as airborne wind turbines, transforming the energy created during an aircraft’s descent into electric energy and storing it in the battery— An In-flight, Eco-friendly, Battery Recharging Mechanism