A new white paper published by the Argonne National Laboratory Collaborative Center for Energy Storage Science (ACCESS) outlines a clear set of battery requirements and research and development needs to accelerate the commercialization of electric propulsion for aviation—from air taxis in the near term to 737 class aircraft in the long term.
The white paper is the result of a two-day meeting to understand the unique R&D needs for electric aviation batteries held in December 2019 at the US Department of Energy’s (DOE) Argonne National Laboratory. The meeting, convened by DOE’s Vehicle Technologies Office (VTO) and the National Aeronautics and Space Administration (NASA) Glenn Research Center, drew nearly 100 experts from aircraft companies, component makers, battery companies, materials companies, car companies and academic and national lab researchers.
The paper explores four aircraft concepts: air taxis; 20-passenger commuter aircrafts; 50-passenger regional jets; and 150-passenger, single-aisle 737-class aircraft. For each concept, the paper describes a research area where DOE and NASA could help spur innovation in electric aviation batteries.
For the air taxi and commuter aircraft market, the paper calls for evaluating next-generation lithium-ion chemistries (e.g., silicon, advanced cathode, lithium-metal) under aviation conditions and examining failure modes and safety.
For regional jets, the paper recommends augmenting R&D in solid-state batteries to explore new designs, manufacturing approaches and high temperature operation.
For 737 class aircraft, the paper suggests studying high-energy systems, including sulfur-based batteries and hydrogen carriers, that are far beyond those currently in the R&D pipeline.
It’s clear the next decade will see a worldwide race to commercialize electric flight. The convening of the battery and aviation communities helped establish a shared language to ensure that deep knowledge gained from the electrification of ground transport could accelerate the transition for aircraft.—ACCESS director Venkat Srinivasan, a lead author of the white paper
Electric aviation is poised to take off within the next five to 10 years, with innovations already being pursued for electric vehicle batteries playing a significant role in enabling electric aviation. However, differences exist between the two applications that require dedicated focus on mission specific use of the batteries and the unique requirements that it drives, while leveraging some of the advantages offered by aviation-specific missions.
Comparison of the performance of state-of-the-art, Li-ion batteries compared to targets for EVs, eVTOLs, and 737-class aircraft. The targets for aviation are still preliminary, and more analysis is needed to ascertain the targets. Source: “Assessment of the R&D Needs for Electric Aviation”
In the long term, the energy density needs for electric aviation far outstrip the goals of current DOE and industry investments, requiring strategic thinking around the best approaches to enable this future.
The white paper findings provide a framework for the development of an investment strategy by the government agencies for battery technologies specific to electric aviation beyond the current level of investment in the automotive sector.—Ajay Misra, deputy director of Research and Engineering at NASA Glenn Research Center
Significant investment is being made in the next era of aviation by aerospace companies, including Boeing, Airbus, Rolls, GE, United Technologies, Embraer, Bell and others. In addition, numerous startup efforts in the United States focused on innovations around electric aviation. This includes Uber Elevate that aims to provide affordable shared flights by 2023 with electrification as its core principle. Also, automotive companies, including Daimler, Toyota, Hyundai and Porsche, are getting involved in aviation startups. Hyundai is in partnership with Uber on a concept air mobility vehicle with a 60-mile range.
Argonne is committed to driving the electrification of aviation and, during the December meeting, encouraged industry leaders to share ideas that would help them reach shared goals. Argonne has a storied history of battery and energy storage innovations. The Laboratory has helped revolutionize the lithium-ion battery, which became a game changer for the auto industry, noted Suresh Sunderrajan, associate laboratory director for the Energy and Global Security directorate.
In the near-term, lithium-ion batteries could be adapted for short-range aircraft concepts for initial market introduction. Continued electrification and expansion of the electrified aircraft market will occur as battery performance improves and advanced chemistries are adapted for aviation-specific needs. However, electrification of large regional and 737-class aircrafts requires new types of energy storage. So, the next decade will see a global race to commercialize electric flight, according to the white paper.
DOE and NASA plan to organize a future session of this assessment. NASA intends to examine the means to enable R&D to better define the aircraft battery needs and ensure that standards for the industry are developed. DOE plans to include requirements for aircraft in future Federal Opportunity Announcements (FOA) and national lab funding calls.
Then, DOE and NASA will consider organizing a brainstorming session to identify ways for very high-energy density electrochemical energy storage/conversion that could enable electric propulsion for large aircrafts. And the two agencies also intend to organize a brainstorming meeting to standardize battery packs for aircraft and ease the supply chain of cells or packs.
The United States has the critical mass of expertise in batteries, aviation, propulsion, and system integration to invent the power source for the next 100 years of aviation.—“Assessment of the R&D Needs for Electric Aviation”